From 52892a731c6a898c040889a87b47fc3f01031953 Mon Sep 17 00:00:00 2001
From: Alex <78383757+Lextical@users.noreply.github.com>
Date: Sun, 19 Apr 2026 20:18:28 -0600
Subject: [PATCH] added comments to android

---
 .../activities/ForgotPasswordActivity.java    |   7 ++
 .../activities/HomeActivity.java              |   4 +-
 .../activities/MainActivity.java              |   5 +-
 .../adapters/ActivityLogAdapter.java          |  27 +++++
 .../adapters/AdoptionAdapter.java             |  18 +++
 .../adapters/AppointmentAdapter.java          |  24 ++++
 .../adapters/BlackTextArrayAdapter.java       |   1 +
 .../petstoremobile/adapters/ChatAdapter.java  |  18 +++
 .../adapters/CouponAdapter.java               |  24 ++++
 .../adapters/CustomerAdapter.java             |  25 +++++
 .../adapters/EmployeeAdapter.java             |  24 ++++
 .../adapters/InventoryAdapter.java            |  25 ++++-
 .../adapters/MessageAdapter.java              |  66 ++++++++++-
 .../petstoremobile/adapters/PetAdapter.java   |  36 +++++-
 .../adapters/ProductAdapter.java              |  24 ++++
 .../adapters/ProductSupplierAdapter.java      |  21 ++++
 .../adapters/PurchaseOrderAdapter.java        |  15 +++
 .../petstoremobile/adapters/SaleAdapter.java  |  15 +++
 .../adapters/ServiceAdapter.java              |  22 +++-
 .../adapters/SupplierAdapter.java             |  25 ++++-
 .../adapters/WhiteTextArrayAdapter.java       |   5 +-
 .../petstoremobile/api/ActivityLogApi.java    |   2 +
 .../petstoremobile/api/AdoptionApi.java       |   7 ++
 .../petstoremobile/api/AppointmentApi.java    |   9 +-
 .../petstoremobile/api/CategoryApi.java       |   2 +
 .../example/petstoremobile/api/ChatApi.java   |   5 +-
 .../petstoremobile/api/CustomerApi.java       |   7 ++
 .../petstoremobile/api/EmployeeApi.java       |  12 +-
 .../petstoremobile/api/InventoryApi.java      |  12 +-
 .../petstoremobile/api/MessageApi.java        |   6 +-
 .../example/petstoremobile/api/PetApi.java    |   8 +-
 .../petstoremobile/api/ProductApi.java        |  13 ++-
 .../api/ProductSupplierApi.java               |  10 +-
 .../petstoremobile/api/PurchaseOrderApi.java  |   3 +
 .../example/petstoremobile/api/RefundApi.java |   6 +
 .../example/petstoremobile/api/SaleApi.java   |   4 +
 .../petstoremobile/api/ServiceApi.java        |   2 +-
 .../example/petstoremobile/api/StoreApi.java  |   4 +
 .../example/petstoremobile/api/UserApi.java   |   3 +
 .../petstoremobile/api/auth/TokenManager.java |   1 +
 .../petstoremobile/dtos/ActivityLogDTO.java   |   3 +
 .../petstoremobile/dtos/AdoptionDTO.java      |   3 +
 .../petstoremobile/dtos/AppointmentDTO.java   |   3 +
 .../example/petstoremobile/dtos/AuthDTO.java  |   4 +-
 .../dtos/AvatarUploadResponse.java            |   3 +
 .../dtos/BulkDeleteRequest.java               |   3 +
 .../petstoremobile/dtos/CategoryDTO.java      |   3 +
 .../petstoremobile/dtos/ConversationDTO.java  |   3 +
 .../petstoremobile/dtos/CouponDTO.java        |   3 +
 .../petstoremobile/dtos/CustomerDTO.java      |   3 +
 .../petstoremobile/dtos/DropdownDTO.java      |   3 +
 .../petstoremobile/dtos/EmployeeDTO.java      |   3 +
 .../petstoremobile/dtos/ErrorResponse.java    |   5 +-
 .../petstoremobile/dtos/InventoryDTO.java     |   3 +
 .../petstoremobile/dtos/MessageDTO.java       |   3 +
 .../petstoremobile/dtos/PageResponse.java     |   4 +-
 .../example/petstoremobile/dtos/PetDTO.java   |   3 +
 .../petstoremobile/dtos/ProductDTO.java       |   3 +
 .../dtos/ProductSupplierDTO.java              |   3 +
 .../petstoremobile/dtos/PurchaseOrderDTO.java |   3 +
 .../petstoremobile/dtos/RefundDTO.java        |   3 +
 .../example/petstoremobile/dtos/SaleDTO.java  |   3 +
 .../dtos/SendMessageRequest.java              |   3 +
 .../petstoremobile/dtos/ServiceDTO.java       |   3 +
 .../example/petstoremobile/dtos/StoreDTO.java |   3 +
 .../petstoremobile/dtos/SupplierDTO.java      |   3 +
 .../dtos/UpdateConversationStatusRequest.java |   3 +
 .../example/petstoremobile/dtos/UserDTO.java  |   3 +
 .../fragments/ChatFragment.java               |  81 +++++++++++++
 .../fragments/ListFragment.java               |   7 +-
 .../fragments/ProfileFragment.java            |   6 +
 .../listfragments/ActivityLogFragment.java    |  27 +++++
 .../listfragments/AdoptionFragment.java       |  63 +++++++++++
 .../listfragments/AnalyticsFragment.java      |  61 +++++++++-
 .../listfragments/AppointmentFragment.java    |  69 ++++++++++++
 .../listfragments/CouponFragment.java         |  39 +++++++
 .../listfragments/CustomerFragment.java       |  33 ++++++
 .../listfragments/InventoryFragment.java      |  51 +++++++++
 .../fragments/listfragments/PetFragment.java  |  60 ++++++++++
 .../listfragments/ProductFragment.java        |  42 +++++++
 .../ProductSupplierFragment.java              |  51 +++++++++
 .../listfragments/PurchaseOrderFragment.java  |  45 ++++++++
 .../fragments/listfragments/SaleFragment.java |  54 +++++++++
 .../listfragments/ServiceFragment.java        |  39 +++++++
 .../listfragments/StaffFragment.java          |  36 ++++++
 .../listfragments/SupplierFragment.java       |  42 +++++++
 .../AdoptionDetailFragment.java               |  49 ++++++++
 .../AppointmentDetailFragment.java            |  64 +++++++++++
 .../detailfragments/CouponDetailFragment.java |  21 ++++
 .../CustomerDetailFragment.java               |  30 +++++
 .../InventoryDetailFragment.java              |  48 ++++++++
 .../ProductDetailFragment.java                |  45 ++++++++
 .../ProductSupplierDetailFragment.java        |  39 +++++++
 .../PurchaseOrderDetailFragment.java          |  15 +++
 .../detailfragments/RefundFragment.java       |  53 ++++++++-
 .../detailfragments/SaleDetailFragment.java   |  60 ++++++++++
 .../ServiceDetailFragment.java                |  39 +++++++
 .../detailfragments/StaffDetailFragment.java  |  39 +++++++
 .../SupplierDetailFragment.java               |  39 +++++++
 .../PetProfileFragment.java                   |  27 +++++
 .../example/petstoremobile/models/Chat.java   |   3 +
 .../petstoremobile/models/Message.java        |   3 +
 .../example/petstoremobile/models/Sale.java   |   3 +
 .../repositories/ActivityLogRepository.java   |   6 +
 .../repositories/AdoptionRepository.java      |   3 +
 .../repositories/AppointmentRepository.java   |   3 +
 .../repositories/AuthRepository.java          |   3 +
 .../repositories/BaseRepository.java          |   2 +-
 .../repositories/CategoryRepository.java      |   3 +
 .../repositories/ChatRepository.java          |   2 +-
 .../repositories/CouponRepository.java        |   3 +
 .../repositories/CustomerRepository.java      |   3 +
 .../repositories/EmployeeRepository.java      |   3 +
 .../repositories/InventoryRepository.java     |   3 +
 .../repositories/PetRepository.java           |   3 +
 .../repositories/ProductRepository.java       |   3 +
 .../ProductSupplierRepository.java            |   3 +
 .../repositories/PurchaseOrderRepository.java |   3 +
 .../repositories/SaleRepository.java          |   3 +
 .../repositories/ServiceRepository.java       |   3 +
 .../repositories/StoreRepository.java         |   3 +
 .../repositories/SupplierRepository.java      |   3 +
 .../repositories/UserRepository.java          |   3 +
 .../services/ChatNotificationService.java     |   4 +-
 .../petstoremobile/utils/EventDecorator.java  |   6 +
 .../petstoremobile/utils/FileUtils.java       |  10 ++
 .../petstoremobile/utils/SelectionHelper.java |  34 +++++-
 .../petstoremobile/utils/SpinnerUtils.java    |   7 +-
 .../viewmodels/ActivityLogListViewModel.java  |  39 +++++++
 .../viewmodels/AdoptionDetailViewModel.java   |  74 +++++++++++-
 .../viewmodels/AdoptionListViewModel.java     |  24 ++++
 .../viewmodels/AnalyticsViewModel.java        |  73 ++++++++++++
 .../AppointmentDetailViewModel.java           |   4 +-
 .../viewmodels/AppointmentListViewModel.java  |  24 ++++
 .../viewmodels/AuthViewModel.java             |  15 ++-
 .../viewmodels/ChatListViewModel.java         |  54 +++++++++
 .../viewmodels/CouponDetailViewModel.java     |  18 +++
 .../viewmodels/CouponListViewModel.java       |  20 ++++
 .../viewmodels/CustomerDetailViewModel.java   |   9 ++
 .../viewmodels/CustomerListViewModel.java     |  26 +++++
 .../viewmodels/InventoryDetailViewModel.java  |  39 +++++++
 .../viewmodels/InventoryListViewModel.java    |  24 ++++
 .../viewmodels/PetListViewModel.java          |  37 ++++++
 .../viewmodels/PetProfileViewModel.java       |   9 ++
 .../viewmodels/ProductDetailViewModel.java    |  33 ++++++
 .../viewmodels/ProductListViewModel.java      |  21 ++++
 .../ProductSupplierDetailViewModel.java       |  43 +++++++
 .../ProductSupplierListViewModel.java         |  28 +++++
 .../PurchaseOrderDetailViewModel.java         |   3 +
 .../PurchaseOrderListViewModel.java           |  21 ++++
 .../viewmodels/RefundViewModel.java           |  39 +++++++
 .../viewmodels/SaleDetailViewModel.java       | 106 ++++++++++++++++++
 .../viewmodels/SaleListViewModel.java         |  34 ++++++
 .../viewmodels/ServiceDetailViewModel.java    |  24 ++++
 .../viewmodels/ServiceListViewModel.java      |  17 +++
 .../viewmodels/StaffDetailViewModel.java      |  27 +++++
 .../viewmodels/StaffListViewModel.java        |  33 ++++++
 .../viewmodels/SupplierDetailViewModel.java   |  24 ++++
 .../viewmodels/SupplierListViewModel.java     |  17 +++
 .../websocket/StompChatManager.java           |  80 ++++++++++---
 160 files changed, 3098 insertions(+), 81 deletions(-)

diff --git a/android/app/src/main/java/com/example/petstoremobile/activities/ForgotPasswordActivity.java b/android/app/src/main/java/com/example/petstoremobile/activities/ForgotPasswordActivity.java
index 82ea9934..ef08f5ee 100644
--- a/android/app/src/main/java/com/example/petstoremobile/activities/ForgotPasswordActivity.java
+++ b/android/app/src/main/java/com/example/petstoremobile/activities/ForgotPasswordActivity.java
@@ -32,6 +32,9 @@ public class ForgotPasswordActivity extends AppCompatActivity {
 
     private ActivityForgotPasswordBinding binding;
 
+    /**
+     * Set the content view for forget password page
+     */
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         EdgeToEdge.enable(this);
@@ -54,6 +57,10 @@ public class ForgotPasswordActivity extends AppCompatActivity {
         binding.btnBackToLogin.setOnClickListener(v -> finish());
     }
 
+    /**
+     * A function to send a reset link to the given email address.
+     * Calls the forgotPassword endpoint. To send the reset link
+     * */
     private void sendResetLink(String email) {
         binding.btnSubmit.setEnabled(false);
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/activities/HomeActivity.java b/android/app/src/main/java/com/example/petstoremobile/activities/HomeActivity.java
index 01b4ca24..9e5fd6d0 100644
--- a/android/app/src/main/java/com/example/petstoremobile/activities/HomeActivity.java
+++ b/android/app/src/main/java/com/example/petstoremobile/activities/HomeActivity.java
@@ -78,7 +78,7 @@ public class HomeActivity extends AppCompatActivity {
     @Override
     protected void onNewIntent(Intent intent) {
         super.onNewIntent(intent);
-        setIntent(intent); // Set the new intent so fragments can access updated extras
+        setIntent(intent);
         handleIntent(intent);
     }
 
@@ -103,7 +103,7 @@ public class HomeActivity extends AppCompatActivity {
     }
 
     /**
-     * Requests POST_NOTIFICATIONS permission from the user if running on Android 13 and above.
+     * Requests for notification permission from the user if running on Android 13 and above.
      */
     private void requestNotificationPermission() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/activities/MainActivity.java b/android/app/src/main/java/com/example/petstoremobile/activities/MainActivity.java
index 11925052..b7aa1f1b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/activities/MainActivity.java
+++ b/android/app/src/main/java/com/example/petstoremobile/activities/MainActivity.java
@@ -98,7 +98,7 @@ public class MainActivity extends AppCompatActivity {
     }
 
     /**
-     * Executes the login process using the AuthViewModel and handles the authentication response.
+     * Perform login process using the AuthViewModel and handles the authentication response.
      */
     private void performLogin(String username, String password) {
         viewModel.login(username, password).observe(this, resource -> {
@@ -112,6 +112,7 @@ public class MainActivity extends AppCompatActivity {
                 case SUCCESS:
                     if (resource.data != null) {
                         String role = resource.data.getRole();
+                        //Check if role is staff/admin or customer
                         if ("CUSTOMER".equalsIgnoreCase(role)) {
                             UIUtils.setViewsEnabled(true, binding.btnLogin);
                             binding.tvLoginStatus.setText("Customers are not allowed to log in");
@@ -132,7 +133,7 @@ public class MainActivity extends AppCompatActivity {
     }
 
     /**
-     * Retrieves the logged-in user's profile information to save their ID before navigating to the home screen.
+     * Retrieves the user's profile information to save their ID before navigating to the home screen.
      */
     private void fetchUserIdAndNavigate() {
         viewModel.getMe().observe(this, resource -> {
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/ActivityLogAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/ActivityLogAdapter.java
index eb571ca2..ecd34994 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/ActivityLogAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/ActivityLogAdapter.java
@@ -25,10 +25,16 @@ public class ActivityLogAdapter extends RecyclerView.Adapter<ActivityLogAdapter.
 
     private final List<ActivityLogDTO> items;
 
+    /**
+     * Constructor for the ActivityLogAdapter.
+     */
     public ActivityLogAdapter(List<ActivityLogDTO> items) {
         this.items = items;
     }
 
+    /**
+     * Inflates the layout for an activity log item and creates a new ViewHolder.
+     */
     @NonNull
     @Override
     public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -37,6 +43,9 @@ public class ActivityLogAdapter extends RecyclerView.Adapter<ActivityLogAdapter.
         return new ViewHolder(view);
     }
 
+    /**
+     * Binds the data from ActivityLogDTO to the items in the ViewHolder.
+     */
     @Override
     public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
         ActivityLogDTO log = items.get(position);
@@ -71,9 +80,15 @@ public class ActivityLogAdapter extends RecyclerView.Adapter<ActivityLogAdapter.
         holder.tvTimestamp.setText(formatTimestamp(log.getLogTimestamp()));
     }
 
+    /**
+     * Returns the total number of items in the list.
+     */
     @Override
     public int getItemCount() { return items.size(); }
 
+    /**
+     * Formats the timestamp string from the API to a readable date/time format.
+     */
     private String formatTimestamp(String raw) {
         if (raw == null) return "";
         try {
@@ -85,6 +100,9 @@ public class ActivityLogAdapter extends RecyclerView.Adapter<ActivityLogAdapter.
         }
     }
 
+    /**
+     * Format the Role string to be consistent
+     */
     private String formatRole(String role) {
         if (role == null) return "";
         switch (role.toUpperCase(Locale.ROOT)) {
@@ -95,6 +113,9 @@ public class ActivityLogAdapter extends RecyclerView.Adapter<ActivityLogAdapter.
         }
     }
 
+    /**
+     * Returns the first non-null and non-blank string from the provided arguments.
+     */
     private String firstNonBlank(String... values) {
         for (String v : values) {
             if (v != null && !v.isBlank()) return v;
@@ -102,9 +123,15 @@ public class ActivityLogAdapter extends RecyclerView.Adapter<ActivityLogAdapter.
         return "";
     }
 
+    /**
+     * ViewHolder class that holds references to the UI components for an activity log item.
+     */
     public static class ViewHolder extends RecyclerView.ViewHolder {
         TextView tvActivity, tvTechnical, tvUser, tvMeta, tvTimestamp;
 
+        /**
+         * Initializes the ViewHolder by finding the views within the item layout.
+         */
         public ViewHolder(@NonNull View itemView) {
             super(itemView);
             tvActivity  = itemView.findViewById(R.id.tvLogActivity);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/AdoptionAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/AdoptionAdapter.java
index cb3eeaf2..c1d588d8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/AdoptionAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/AdoptionAdapter.java
@@ -23,6 +23,9 @@ public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.Adopti
         void onSelectionChanged(int count);
     }
 
+    /**
+     * Constructor for AdoptionAdapter.
+     */
     public AdoptionAdapter(List<AdoptionDTO> adoptionList, OnAdoptionClickListener listener) {
         this.adoptionList = adoptionList;
         this.listener = listener;
@@ -39,11 +42,17 @@ public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.Adopti
         });
     }
 
+    /**
+     * Returns a list of IDs for the currently selected adoption items.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Resets the selection state, deselecting all items.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
@@ -58,6 +67,9 @@ public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.Adopti
         }
     }
 
+    /**
+     * Inflates the layout for an adoption item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public AdoptionViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -65,6 +77,9 @@ public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.Adopti
         return new AdoptionViewHolder(binding);
     }
 
+    /**
+     * Binds adoption data to the UI components and handles click/long-click logic.
+     */
     @Override
     public void onBindViewHolder(@NonNull AdoptionViewHolder holder, int position) {
         AdoptionDTO a = adoptionList.get(position);
@@ -123,6 +138,9 @@ public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.Adopti
         });
     }
 
+    /**
+     * Returns the total number of adoption items in the list.
+     */
     @Override
     public int getItemCount() { return adoptionList.size(); }
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/AppointmentAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/AppointmentAdapter.java
index cb292c1a..737933a7 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/AppointmentAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/AppointmentAdapter.java
@@ -23,6 +23,9 @@ public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.
         void onSelectionChanged(int count);
     }
 
+    /**
+     * Constructor for AppointmentAdapter.
+     */
     public AppointmentAdapter(List<AppointmentDTO> appointmentList,
                               OnAppointmentClickListener appointmentClickListener) {
         this.appointmentList = appointmentList;
@@ -40,25 +43,40 @@ public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.
         });
     }
 
+    /**
+     * Returns a list of IDs for the currently selected appointment items.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Resets the selection state, deselecting all items.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
     }
 
+    /**
+     * ViewHolder class that holds references to the UI components for an appointment item.
+     */
     public static class AppointmentViewHolder extends RecyclerView.ViewHolder {
         private final ItemAppointmentBinding binding;
 
+        /**
+         * Initializes the ViewHolder by finding the views within the item layout.
+         */
         public AppointmentViewHolder(@NonNull ItemAppointmentBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for an appointment item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public AppointmentViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -66,6 +84,9 @@ public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.
         return new AppointmentViewHolder(binding);
     }
 
+    /**
+     * Binds appointment data to the UI components and handles click/long-click logic.
+     */
     @Override
     public void onBindViewHolder(@NonNull AppointmentViewHolder holder, int position) {
         AppointmentDTO a = appointmentList.get(position);
@@ -124,6 +145,9 @@ public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.
         });
     }
 
+    /**
+     * Returns the total number of appointment items in the list.
+     */
     @Override
     public int getItemCount() {
         return appointmentList.size();
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/BlackTextArrayAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/BlackTextArrayAdapter.java
index 22af59de..83ed123f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/BlackTextArrayAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/BlackTextArrayAdapter.java
@@ -12,6 +12,7 @@ import com.example.petstoremobile.R;
 import java.util.List;
 
 // A class that overrides the arrayAdapter so the text color changes based on theme
+// Used to make spinners have black text on white background no matter the theme
 public class BlackTextArrayAdapter<T> extends ArrayAdapter<T> {
     public BlackTextArrayAdapter(@NonNull Context context, int resource, @NonNull T[] objects) {
         super(context, resource, objects);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/ChatAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/ChatAdapter.java
index 972ac56d..329adfe8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/ChatAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/ChatAdapter.java
@@ -20,11 +20,17 @@ public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ChatViewHolder
         void onChatClick(Chat chat);
     }
 
+    /**
+     * Constructor for ChatAdapter.
+     */
     public ChatAdapter(List<Chat> chatList, OnChatClickListener listener) {
         this.chatList = chatList;
         this.listener = listener;
     }
 
+    /**
+     * Inflates the layout for a chat item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public ChatViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -32,6 +38,9 @@ public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ChatViewHolder
         return new ChatViewHolder(binding);
     }
 
+    /**
+     * Binds chat data to the UI components for a specific conversation.
+     */
     @Override
     public void onBindViewHolder(@NonNull ChatViewHolder holder, int position) {
         Chat chat = chatList.get(position);
@@ -40,14 +49,23 @@ public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ChatViewHolder
         holder.itemView.setOnClickListener(v -> listener.onChatClick(chat));
     }
 
+    /**
+     * Returns the total number of chat items in the list.
+     */
     @Override
     public int getItemCount() {
         return chatList.size();
     }
 
+    /**
+     * ViewHolder class that holds references to the UI components for a chat item.
+     */
     public static class ChatViewHolder extends RecyclerView.ViewHolder {
         final ItemChatBinding binding;
 
+        /**
+         * Initializes the ViewHolder with the chat item's view binding.
+         */
         public ChatViewHolder(@NonNull ItemChatBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/CouponAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/CouponAdapter.java
index ff9bbe65..10994ddd 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/CouponAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/CouponAdapter.java
@@ -30,11 +30,17 @@ public class CouponAdapter extends RecyclerView.Adapter<CouponAdapter.ViewHolder
         void onSelectionChanged(int count);
     }
 
+    /**
+     * Constructor for CouponAdapter.
+     */
     public CouponAdapter(List<CouponDTO> coupons, OnCouponClickListener listener) {
         this.coupons = coupons;
         this.listener = listener;
     }
 
+    /**
+     * Inflates the layout for a coupon item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -42,6 +48,9 @@ public class CouponAdapter extends RecyclerView.Adapter<CouponAdapter.ViewHolder
         return new ViewHolder(view);
     }
 
+    /**
+     * Binds coupon data to the UI components and handles interaction logic.
+     */
     @Override
     public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
         CouponDTO coupon = coupons.get(position);
@@ -95,6 +104,9 @@ public class CouponAdapter extends RecyclerView.Adapter<CouponAdapter.ViewHolder
         holder.cbSelectCoupon.setOnClickListener(v -> toggleSelection(coupon.getCouponId()));
     }
 
+    /**
+     * Toggles the selection state of a specific coupon by its ID.
+     */
     private void toggleSelection(Long id) {
         if (selectedIds.contains(id)) {
             selectedIds.remove(id);
@@ -105,6 +117,9 @@ public class CouponAdapter extends RecyclerView.Adapter<CouponAdapter.ViewHolder
         listener.onSelectionChanged(selectedIds.size());
     }
 
+    /**
+     * Enables or disables bulk selection mode.
+     */
     public void setSelectionMode(boolean selectionMode) {
         this.selectionMode = selectionMode;
         if (!selectionMode) selectedIds.clear();
@@ -112,10 +127,16 @@ public class CouponAdapter extends RecyclerView.Adapter<CouponAdapter.ViewHolder
         listener.onSelectionChanged(selectedIds.size());
     }
 
+    /**
+     * Returns the set of IDs for the currently selected coupons.
+     */
     public Set<Long> getSelectedIds() {
         return selectedIds;
     }
 
+    /**
+     * Returns the total number of coupons in the list.
+     */
     @Override
     public int getItemCount() {
         return coupons.size();
@@ -125,6 +146,9 @@ public class CouponAdapter extends RecyclerView.Adapter<CouponAdapter.ViewHolder
         TextView tvCouponCode, tvCouponDiscount, tvCouponMinOrder, tvCouponExpiry, tvCouponStatus;
         CheckBox cbSelectCoupon;
 
+        /**
+         * Initializes the ViewHolder by finding the views within the item layout.
+         */
         public ViewHolder(@NonNull View itemView) {
             super(itemView);
             tvCouponCode = itemView.findViewById(R.id.tvCouponCode);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/CustomerAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/CustomerAdapter.java
index 30b08b23..3e8f665a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/CustomerAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/CustomerAdapter.java
@@ -24,23 +24,42 @@ public class CustomerAdapter extends RecyclerView.Adapter<CustomerAdapter.Custom
         void onCustomerClick(int position);
     }
 
+    /**
+     * Constructor for CustomerAdapter.
+     */
     public CustomerAdapter(List<CustomerDTO> list, OnCustomerClickListener listener) {
         this.list = list;
         this.listener = listener;
     }
 
+    /**
+     * Sets the base URL for fetching customer profile images.
+     */
     public void setBaseUrl(String baseUrl) { this.baseUrl = baseUrl; }
+
+    /**
+     * Sets the authentication token for fetching images.
+     */
     public void setToken(String token) { this.token = token; }
 
+    /**
+     * ViewHolder class for customer items.
+     */
     public static class CustomerViewHolder extends RecyclerView.ViewHolder {
         final ItemCustomerBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public CustomerViewHolder(@NonNull ItemCustomerBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for a customer item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public CustomerViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -49,6 +68,9 @@ public class CustomerAdapter extends RecyclerView.Adapter<CustomerAdapter.Custom
         return new CustomerViewHolder(binding);
     }
 
+    /**
+     * Binds customer data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull CustomerViewHolder holder, int position) {
         CustomerDTO c = list.get(position);
@@ -75,6 +97,9 @@ public class CustomerAdapter extends RecyclerView.Adapter<CustomerAdapter.Custom
         holder.itemView.setOnClickListener(v -> listener.onCustomerClick(position));
     }
 
+    /**
+     * Returns the total number of customers in the list.
+     */
     @Override
     public int getItemCount() { return list.size(); }
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/EmployeeAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/EmployeeAdapter.java
index 8213dbd0..af8f99e5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/EmployeeAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/EmployeeAdapter.java
@@ -25,28 +25,46 @@ public class EmployeeAdapter extends RecyclerView.Adapter<EmployeeAdapter.Employ
         void onEmployeeClick(int position);
     }
 
+    /**
+     * Constructor for EmployeeAdapter.
+     */
     public EmployeeAdapter(List<EmployeeDTO> list, OnEmployeeClickListener listener) {
         this.list = list;
         this.listener = listener;
     }
 
+    /**
+     * Sets the base URL for fetching employee profile images.
+     */
     public void setBaseUrl(String baseUrl) {
         this.baseUrl = baseUrl;
     }
 
+    /**
+     * Sets the authentication token for fetching images.
+     */
     public void setToken(String token) {
         this.token = token;
     }
 
+    /**
+     * ViewHolder class for employee items.
+     */
     public static class EmployeeViewHolder extends RecyclerView.ViewHolder {
         private final ItemEmployeeBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public EmployeeViewHolder(@NonNull ItemEmployeeBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for an employee item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public EmployeeViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -55,6 +73,9 @@ public class EmployeeAdapter extends RecyclerView.Adapter<EmployeeAdapter.Employ
         return new EmployeeViewHolder(binding);
     }
 
+    /**
+     * Binds employee data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull EmployeeViewHolder holder, int position) {
         EmployeeDTO e = list.get(position);
@@ -90,6 +111,9 @@ public class EmployeeAdapter extends RecyclerView.Adapter<EmployeeAdapter.Employ
         holder.itemView.setOnClickListener(v -> listener.onEmployeeClick(position));
     }
 
+    /**
+     * Returns the total number of employees in the list.
+     */
     @Override
     public int getItemCount() { return list.size(); }
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/InventoryAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/InventoryAdapter.java
index 9fbc1481..a015bb97 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/InventoryAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/InventoryAdapter.java
@@ -27,6 +27,9 @@ public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.Inve
         void onSelectionChanged(int selectedCount);
     }
 
+    /**
+     * Constructor for InventoryAdapter.
+     */
     public InventoryAdapter(List<InventoryDTO> inventoryList, OnInventoryClickListener clickListener) {
         this.inventoryList = inventoryList;
         this.clickListener = clickListener;
@@ -43,25 +46,40 @@ public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.Inve
         });
     }
 
+    /**
+     * Returns a list of IDs for the currently selected inventory items.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Resets the selection state, deselecting all items.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
     }
 
+    /**
+     * ViewHolder class that holds references to the UI components for an inventory item.
+     */
     public static class InventoryViewHolder extends RecyclerView.ViewHolder {
         final ItemInventoryBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public InventoryViewHolder(@NonNull ItemInventoryBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for an inventory item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public InventoryViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -69,6 +87,9 @@ public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.Inve
         return new InventoryViewHolder(binding);
     }
 
+    /**
+     * Binds inventory data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull InventoryViewHolder holder, int position) {
         InventoryDTO inv = inventoryList.get(position);
@@ -84,7 +105,6 @@ public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.Inve
         int qty = inv.getQuantity() != null ? inv.getQuantity() : 0;
         binding.tvQuantity.setText("Stock: " + qty);
 
-        // Low stock = red, normal = green (like desktop reorder concept)
         if (qty <= 5) {
             binding.tvQuantity.setTextColor(Color.parseColor("#F44336"));
         } else {
@@ -119,6 +139,9 @@ public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.Inve
         });
     }
 
+    /**
+     * Returns the total number of inventory items in the list.
+     */
     @Override
     public int getItemCount() {
         return inventoryList.size();
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/MessageAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/MessageAdapter.java
index 052f34cb..a4cb725f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/MessageAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/MessageAdapter.java
@@ -37,40 +37,64 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
     private String baseUrl;
     private OnAttachmentClickListener attachmentClickListener;
 
+    /**
+     * Constructor for MessageAdapter.
+     */
     public MessageAdapter(List<Message> messages, Long currentUserId) {
         this.messages = messages;
         this.currentUserId = currentUserId;
         setHasStableIds(true);
     }
 
+    /**
+     * Returns an ID for each message.
+     */
     @Override
     public long getItemId(int position) {
         Message m = messages.get(position);
         return m.getId() != null ? m.getId() : position;
     }
 
+    /**
+     * Updates the current user's ID and refreshes the list.
+     */
     public void setCurrentUserId(Long id) {
         this.currentUserId = id;
         notifyDataSetChanged();
     }
 
+    /**
+     * Updates the staff ID to identify staff messages in the UI.
+     */
     public void setStaffId(Long id) {
         this.staffId = id;
         notifyDataSetChanged();
     }
 
+    /**
+     * Sets the authentication token.
+     */
     public void setToken(String token) {
         this.token = token;
     }
 
+    /**
+     * Sets the base API URL.
+     */
     public void setBaseUrl(String baseUrl) {
         this.baseUrl = baseUrl;
     }
 
+    /**
+     * Sets a listener for clicks on message attachments.
+     */
     public void setOnAttachmentClickListener(OnAttachmentClickListener listener) {
         this.attachmentClickListener = listener;
     }
 
+    /**
+     * Determines if a message is 'sent' or 'received' based on the sender's ID.
+     */
     @Override
     public int getItemViewType(int position) {
         Message m = messages.get(position);
@@ -80,6 +104,9 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         return TYPE_RECEIVED;
     }
 
+    /**
+     * Inflates the chat layout for a message.
+     */
     @NonNull @Override
     public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         LayoutInflater inf = LayoutInflater.from(parent.getContext());
@@ -92,6 +119,9 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         }
     }
 
+    /**
+     * Binds message data to the appropriate ViewHolder.
+     */
     @Override
     public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
         Message m = messages.get(position);
@@ -99,14 +129,26 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         if (holder instanceof ReceivedHolder) ((ReceivedHolder) holder).bind(m, token, baseUrl, attachmentClickListener, staffId);
     }
 
+    /**
+     * Returns the total number of messages.
+     */
     @Override public int getItemCount() { return messages.size(); }
 
+    /**
+     * ViewHolder for messages sent by the user.
+     */
     static class SentHolder extends RecyclerView.ViewHolder {
         final ItemMessageSentBinding binding;
+        /**
+         * Initializes the SentHolder with view binding.
+         */
         SentHolder(ItemMessageSentBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
+        /**
+         * Binds sent message data to the bubble UI.
+         */
         void bind(Message m, String token, String baseUrl, OnAttachmentClickListener listener) {
             binding.tvSenderName.setText("You");
             binding.tvTimestamp.setText(formatTimestamp(m.getTimestamp()));
@@ -128,12 +170,21 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         }
     }
 
+    /**
+     * ViewHolder for messages received from others.
+     */
     static class ReceivedHolder extends RecyclerView.ViewHolder {
         final ItemMessageReceivedBinding binding;
+        /**
+         * Initializes the ReceivedHolder with view binding.
+         */
         ReceivedHolder(ItemMessageReceivedBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
+        /**
+         * Binds received message data to the bubble UI.
+         */
         void bind(Message m, String token, String baseUrl, OnAttachmentClickListener listener, Long staffId) {
             binding.tvSenderName.setText(resolveSenderName(m, staffId));
             binding.tvTimestamp.setText(formatTimestamp(m.getTimestamp()));
@@ -155,6 +206,9 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         }
     }
 
+    /**
+     * Resolves the display name of the sender.
+     */
     private static String resolveSenderName(Message m, Long staffId) {
         if ("BOT".equalsIgnoreCase(m.getSenderRole())) {
             return (m.getSenderDisplayName() != null && !m.getSenderDisplayName().isEmpty())
@@ -166,6 +220,9 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         return "Customer";
     }
 
+    /**
+     * Formats the timestamp string into readable format.
+     */
     private static String formatTimestamp(String timestamp) {
         if (timestamp == null || timestamp.isEmpty()) return "";
         try {
@@ -178,8 +235,11 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         }
     }
 
+    /**
+     * Logic for displaying an attachment in the chat.
+     */
     private static void displayAttachment(Message m, ImageView iv, TextView tvName, String token, String baseUrl) {
-        // Check if there's an attachment by looking at name or mime type
+        // Check if there's an attachment
         if (m.getAttachmentName() != null || m.getAttachmentMimeType() != null) {
             // Construct the download URL using the message ID
             String url;
@@ -187,7 +247,7 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
                 String cleanBase = baseUrl.endsWith("/") ? baseUrl.substring(0, baseUrl.length() - 1) : baseUrl;
                 url = cleanBase + "/api/v1/chat/messages/" + m.getId() + "/attachment";
             } else {
-                url = m.getAttachmentUrl(); // Fallback
+                url = m.getAttachmentUrl();
             }
 
             if (url == null) {
@@ -208,7 +268,7 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
                             .build());
                 }
 
-                // Use a signature to prevent Glide from showing stale cached images for the same URL/ID
+                // Use a signature to prevent Glide from showing cached images instead of loading new ones
                 String signatureKey = (m.getTimestamp() != null ? m.getTimestamp() : "") + m.getId();
 
                 Glide.with(iv.getContext()).clear(iv);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/PetAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/PetAdapter.java
index 463295bc..60fd4f24 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/PetAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/PetAdapter.java
@@ -31,7 +31,9 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> i
         void onSelectionChanged(int selectedCount);
     }
 
-    //Constructor
+    /**
+     * Constructor for PetAdapter.
+     */
     public PetAdapter(List<PetDTO> petList, OnPetClickListener petClickListener) {
         this.petList  = petList;
         this.petClickListener = petClickListener;
@@ -48,35 +50,54 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> i
         });
     }
 
+    /**
+     * Sets the base URL for fetching pet images from the server.
+     */
     public void setBaseUrl(String baseUrl) {
         this.baseUrl = baseUrl;
     }
 
+    /**
+     * Sets the authentication token
+     */
     public void setToken(String token) {
         this.token = token;
     }
 
+    /**
+     * Returns a list of IDs for the currently selected pet items.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Resets the selection state, deselecting all items.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
     }
 
-    // Get the controls of each row in recycler view
+    /**
+     * ViewHolder class that holds references to the UI components for a pet item.
+     */
     public static class PetViewHolder extends RecyclerView.ViewHolder {
         private final ItemPetBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public PetViewHolder(@NonNull ItemPetBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
-    // Create a new row view
+    /**
+     * Inflates the layout for a pet item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public PetViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -84,7 +105,9 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> i
         return new PetViewHolder(binding);
     }
 
-    //populate the row with pet data
+    /**
+     * Binds pet data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull PetViewHolder holder, int position) {
         PetDTO pet = petList.get(position);
@@ -103,7 +126,7 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> i
         
         binding.tvPetStatus.setText(pet.getPetStatus());
 
-        //Set the status color depending on availability. If available, green, If Pending, yellow, otherwise red
+        //Set the status color depending on availability
         if (pet.getPetStatus() != null) {
             switch (pet.getPetStatus()) {
                 case "Available":
@@ -157,6 +180,9 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> i
         });
     }
 
+    /**
+     * Returns the total number of pet items in the list.
+     */
     @Override
     public int getItemCount() {
         return petList.size();
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/ProductAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/ProductAdapter.java
index f5f897cc..9adea207 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/ProductAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/ProductAdapter.java
@@ -22,28 +22,46 @@ public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductV
         void onProductClick(int position);
     }
 
+    /**
+     * Constructor for ProductAdapter.
+     */
     public ProductAdapter(List<ProductDTO> productList, OnProductClickListener listener) {
         this.productList = productList;
         this.listener = listener;
     }
 
+    /**
+     * Sets the base URL for fetching product images.
+     */
     public void setBaseUrl(String baseUrl) {
         this.baseUrl = baseUrl;
     }
 
+    /**
+     * Sets the authentication token
+     */
     public void setToken(String token) {
         this.token = token;
     }
 
+    /**
+     * ViewHolder class for product items.
+     */
     public static class ProductViewHolder extends RecyclerView.ViewHolder {
         final ItemProductBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public ProductViewHolder(@NonNull ItemProductBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for a product item and creates the ViewHolder.
+     */
     @NonNull
     @Override
     public ProductViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -51,6 +69,9 @@ public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductV
         return new ProductViewHolder(binding);
     }
 
+    /**
+     * Binds product data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull ProductViewHolder holder, int position) {
         ProductDTO p = productList.get(position);
@@ -72,6 +93,9 @@ public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductV
         holder.itemView.setOnClickListener(v -> listener.onProductClick(position));
     }
 
+    /**
+     * Returns the total number of product items in the list.
+     */
     @Override
     public int getItemCount() { return productList.size(); }
 }
\ No newline at end of file
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/ProductSupplierAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/ProductSupplierAdapter.java
index 231af741..c5c07e00 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/ProductSupplierAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/ProductSupplierAdapter.java
@@ -25,6 +25,9 @@ public class ProductSupplierAdapter extends RecyclerView.Adapter<ProductSupplier
         void onSelectionChanged(int count);
     }
 
+    /**
+     * Constructor for ProductSupplierAdapter.
+     */
     public ProductSupplierAdapter(List<ProductSupplierDTO> list, OnProductSupplierClickListener listener) {
         this.list = list;
         this.listener = listener;
@@ -41,25 +44,40 @@ public class ProductSupplierAdapter extends RecyclerView.Adapter<ProductSupplier
         });
     }
 
+    /**
+     * Returns the list of selected keys for bulk deletion.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Clears all selected items and exits selection mode.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
     }
 
+    /**
+     * ViewHolder for Product-Supplier relationship items.
+     */
     public static class PSViewHolder extends RecyclerView.ViewHolder {
         final ItemProductSupplierBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public PSViewHolder(@NonNull ItemProductSupplierBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for a Product-Supplier item.
+     */
     @NonNull
     @Override
     public PSViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -67,6 +85,9 @@ public class ProductSupplierAdapter extends RecyclerView.Adapter<ProductSupplier
         return new PSViewHolder(binding);
     }
 
+    /**
+     * Binds product-supplier data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull PSViewHolder holder, int position) {
         ProductSupplierDTO ps = list.get(position);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/PurchaseOrderAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/PurchaseOrderAdapter.java
index ee98f2a3..d3d2e154 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/PurchaseOrderAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/PurchaseOrderAdapter.java
@@ -17,20 +17,32 @@ public class PurchaseOrderAdapter extends RecyclerView.Adapter<PurchaseOrderAdap
         void onPurchaseOrderClick(int position);
     }
 
+    /**
+     * Constructor for PurchaseOrderAdapter.
+     */
     public PurchaseOrderAdapter(List<PurchaseOrderDTO> list, OnPurchaseOrderClickListener listener) {
         this.list = list;
         this.listener = listener;
     }
 
+    /**
+     * ViewHolder for Purchase Order items.
+     */
     public static class POViewHolder extends RecyclerView.ViewHolder {
         final ItemPurchaseOrderBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public POViewHolder(@NonNull ItemPurchaseOrderBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for a Purchase Order item.
+     */
     @NonNull
     @Override
     public POViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -38,6 +50,9 @@ public class PurchaseOrderAdapter extends RecyclerView.Adapter<PurchaseOrderAdap
         return new POViewHolder(binding);
     }
 
+    /**
+     * Binds purchase order data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull POViewHolder holder, int position) {
         PurchaseOrderDTO po = list.get(position);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/SaleAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/SaleAdapter.java
index a7b6c2bb..6bfbac65 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/SaleAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/SaleAdapter.java
@@ -20,20 +20,32 @@ public class SaleAdapter extends RecyclerView.Adapter<SaleAdapter.SaleViewHolder
         void onSaleClick(int position);
     }
 
+    /**
+     * Constructor for SaleAdapter.
+     */
     public SaleAdapter(List<SaleDTO> saleList, OnSaleClickListener listener) {
         this.saleList = saleList;
         this.listener = listener;
     }
 
+    /**
+     * ViewHolder for Sale record items.
+     */
     public static class SaleViewHolder extends RecyclerView.ViewHolder {
         final ItemSaleBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public SaleViewHolder(@NonNull ItemSaleBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
+    /**
+     * Inflates the layout for a Sale record item.
+     */
     @NonNull
     @Override
     public SaleViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -41,6 +53,9 @@ public class SaleAdapter extends RecyclerView.Adapter<SaleAdapter.SaleViewHolder
         return new SaleViewHolder(binding);
     }
 
+    /**
+     * Binds sale transaction data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull SaleViewHolder holder, int position) {
         SaleDTO s = saleList.get(position);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/ServiceAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/ServiceAdapter.java
index 30a5b8d7..490ec26b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/ServiceAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/ServiceAdapter.java
@@ -31,6 +31,9 @@ public class ServiceAdapter extends RecyclerView.Adapter<ServiceAdapter.ServiceV
         void onSelectionChanged(int count);
     }
 
+    /**
+     * Constructor for ServiceAdapter.
+     */
     public ServiceAdapter(List<ServiceDTO> serviceList, OnServiceClickListener clickListener) {
         this.serviceList = serviceList;
         this.clickListener = clickListener;
@@ -47,29 +50,40 @@ public class ServiceAdapter extends RecyclerView.Adapter<ServiceAdapter.ServiceV
         });
     }
 
+    /**
+     * Returns the list of selected keys for bulk deletion.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Clears all selected items and exits selection mode.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
     }
 
     /**
-     * ViewHolder class for service items.
+     * ViewHolder for Service items.
      */
     public static class ServiceViewHolder extends RecyclerView.ViewHolder {
         final ItemServiceBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public ServiceViewHolder(@NonNull ItemServiceBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
-    // Create a new row view
+    /**
+     * Inflates the layout for a Service item.
+     */
     @NonNull
     @Override
     public ServiceViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -77,7 +91,9 @@ public class ServiceAdapter extends RecyclerView.Adapter<ServiceAdapter.ServiceV
         return new ServiceViewHolder(binding);
     }
 
-    //populate the row with service data
+    /**
+     * Binds service data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull ServiceViewHolder holder, int position) {
         ServiceDTO service = serviceList.get(position);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/SupplierAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/SupplierAdapter.java
index 980dc071..919a9b14 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/SupplierAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/SupplierAdapter.java
@@ -26,7 +26,9 @@ public class SupplierAdapter extends RecyclerView.Adapter<SupplierAdapter.Suppli
         void onSelectionChanged(int count);
     }
 
-    //Constructor
+    /**
+     * Constructor for SupplierAdapter.
+     */
     public SupplierAdapter(List<SupplierDTO> supplierList, OnSupplierClickListener supplierClickListener) {
         this.supplierList  = supplierList;
         this.supplierClickListener = supplierClickListener;
@@ -43,27 +45,40 @@ public class SupplierAdapter extends RecyclerView.Adapter<SupplierAdapter.Suppli
         });
     }
 
+    /**
+     * Returns the list of selected keys for bulk deletion.
+     */
     @Override
     public List<String> getSelectedKeys() {
         return selectionHelper.getSelectedKeys();
     }
 
+    /**
+     * Clears all selected items and exits selection mode.
+     */
     @Override
     public void clearSelection() {
         selectionHelper.clearSelection();
     }
 
-    // Get the controls of each row in recycler view
+    /**
+     * ViewHolder for Supplier items.
+     */
     public static class SupplierViewHolder extends RecyclerView.ViewHolder {
         final ItemSupplierBinding binding;
 
+        /**
+         * Initializes the ViewHolder with view binding.
+         */
         public SupplierViewHolder(@NonNull ItemSupplierBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
         }
     }
 
-    // Create a new row view
+    /**
+     * Inflates the layout for a Supplier item.
+     */
     @NonNull
     @Override
     public SupplierViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -71,7 +86,9 @@ public class SupplierAdapter extends RecyclerView.Adapter<SupplierAdapter.Suppli
         return new SupplierViewHolder(binding);
     }
 
-    //populate the row with supplier data
+    /**
+     * Binds supplier data to the UI components.
+     */
     @Override
     public void onBindViewHolder(@NonNull SupplierViewHolder holder, int position) {
         SupplierDTO supplier = supplierList.get(position);
diff --git a/android/app/src/main/java/com/example/petstoremobile/adapters/WhiteTextArrayAdapter.java b/android/app/src/main/java/com/example/petstoremobile/adapters/WhiteTextArrayAdapter.java
index 42042207..4921dc3b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/adapters/WhiteTextArrayAdapter.java
+++ b/android/app/src/main/java/com/example/petstoremobile/adapters/WhiteTextArrayAdapter.java
@@ -12,9 +12,8 @@ import androidx.core.content.ContextCompat;
 import com.example.petstoremobile.R;
 import java.util.List;
 
-/**
- * A class that overrides the arrayAdapter so the text color is white and background is transparent.
- */
+// A class that overrides the arrayAdapter so the text color changes based on theme
+// Used to make spinners have white text on dark background no matter the theme
 public class WhiteTextArrayAdapter<T> extends ArrayAdapter<T> {
     public WhiteTextArrayAdapter(@NonNull Context context, int resource, @NonNull T[] objects) {
         super(context, resource, objects);
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/ActivityLogApi.java b/android/app/src/main/java/com/example/petstoremobile/api/ActivityLogApi.java
index 12ceb5bd..4ff8af6d 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/ActivityLogApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/ActivityLogApi.java
@@ -8,8 +8,10 @@ import retrofit2.Call;
 import retrofit2.http.GET;
 import retrofit2.http.Query;
 
+// api calls to get activity logs
 public interface ActivityLogApi {
 
+    // Get activity logs with filters
     @GET("api/v1/activity-logs")
     Call<List<ActivityLogDTO>> getActivityLogs(
             @Query("limit") int limit,
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/AdoptionApi.java b/android/app/src/main/java/com/example/petstoremobile/api/AdoptionApi.java
index 6e1de73d..fa9114b5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/AdoptionApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/AdoptionApi.java
@@ -14,8 +14,10 @@ import retrofit2.http.PUT;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for adoptions
 public interface AdoptionApi {
 
+    // Get all adoptions with filters
     @GET("api/v1/adoptions")
     Call<PageResponse<AdoptionDTO>> getAllAdoptions(
             @Query("page") int page,
@@ -27,18 +29,23 @@ public interface AdoptionApi {
             @Query("employeeId") Long employeeId,
             @Query("sort") String sort);
 
+    // Get adoption by id
     @GET("api/v1/adoptions/{id}")
     Call<AdoptionDTO> getAdoptionById(@Path("id") Long id);
 
+    // Create adoption
     @POST("api/v1/adoptions")
     Call<AdoptionDTO> createAdoption(@Body AdoptionDTO adoption);
 
+    // Update adoption
     @PUT("api/v1/adoptions/{id}")
     Call<AdoptionDTO> updateAdoption(@Path("id") Long id, @Body AdoptionDTO adoption);
 
+    // Delete adoption
     @DELETE("api/v1/adoptions/{id}")
     Call<Void> deleteAdoption(@Path("id") Long id);
 
+    // Bulk delete adoptions
     @HTTP(method = "DELETE", path = "api/v1/adoptions", hasBody = true)
     Call<Void> bulkDeleteAdoptions(@Body BulkDeleteRequest request);
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/AppointmentApi.java b/android/app/src/main/java/com/example/petstoremobile/api/AppointmentApi.java
index 5bc88643..f0752c00 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/AppointmentApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/AppointmentApi.java
@@ -14,8 +14,10 @@ import retrofit2.http.PUT;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for appointments
 public interface AppointmentApi {
 
+    // Get all appointments with filters
     @GET("api/v1/appointments")
     Call<PageResponse<AppointmentDTO>> getAllAppointments(
             @Query("page") int page,
@@ -27,18 +29,23 @@ public interface AppointmentApi {
             @Query("employeeId") Long employeeId,
             @Query("sort") String sort);
 
+    // Get appointment by id
     @GET("api/v1/appointments/{id}")
     Call<AppointmentDTO> getAppointmentById(@Path("id") Long id);
 
+    // Create appointment
     @POST("api/v1/appointments")
     Call<AppointmentDTO> createAppointment(@Body AppointmentDTO appointment);
 
+    // Update appointment
     @PUT("api/v1/appointments/{id}")
     Call<AppointmentDTO> updateAppointment(@Path("id") Long id, @Body AppointmentDTO appointment);
 
+    // Delete appointment
     @DELETE("api/v1/appointments/{id}")
     Call<Void> deleteAppointment(@Path("id") Long id);
 
+    // Bulk delete appointments
     @HTTP(method = "DELETE", path = "api/v1/appointments", hasBody = true)
     Call<Void> bulkDeleteAppointments(@Body BulkDeleteRequest request);
-}
\ No newline at end of file
+}
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/CategoryApi.java b/android/app/src/main/java/com/example/petstoremobile/api/CategoryApi.java
index d1084482..a82e0ab8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/CategoryApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/CategoryApi.java
@@ -6,8 +6,10 @@ import retrofit2.Call;
 import retrofit2.http.GET;
 import retrofit2.http.Query;
 
+// api calls for categories
 public interface CategoryApi {
 
+    // Get all categories with pagination
     @GET("api/v1/categories")
     Call<PageResponse<CategoryDTO>> getAllCategories(
             @Query("page") int page,
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/ChatApi.java b/android/app/src/main/java/com/example/petstoremobile/api/ChatApi.java
index 7a4ab393..8a818a0a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/ChatApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/ChatApi.java
@@ -12,15 +12,18 @@ import retrofit2.http.GET;
 import retrofit2.http.PUT;
 import retrofit2.http.Path;
 
-//api calls to get conversations
+// api calls for chat conversations
 public interface ChatApi {
     
+    // Get all conversations
     @GET("api/v1/chat/conversations")
     Call<List<ConversationDTO>> getAllConversations();
 
+    // Get conversation by id
     @GET("api/v1/chat/conversations/{conversationId}")
     Call<ConversationDTO> getConversationById(@Path("conversationId") Long conversationId);
 
+    // Update conversation status
     @PUT("api/v1/chat/conversations/{conversationId}")
     Call<ConversationDTO> updateConversationStatus(@Path("conversationId") Long conversationId, @Body UpdateConversationStatusRequest request);
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/CustomerApi.java b/android/app/src/main/java/com/example/petstoremobile/api/CustomerApi.java
index 55c51682..14be64e0 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/CustomerApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/CustomerApi.java
@@ -15,23 +15,30 @@ import retrofit2.http.PUT;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for customers
 public interface CustomerApi {
 
+    // Get all customers with pagination
     @GET("api/v1/customers")
     Call<PageResponse<CustomerDTO>> getAllCustomers(@Query("page") int page, @Query("size") int size);
 
+    // Get customer by id
     @GET("api/v1/customers/{customerId}")
     Call<CustomerDTO> getCustomerById(@Path("customerId") Long customerId);
 
+    // Update customer
     @PUT("api/v1/customers/{customerId}")
     Call<CustomerDTO> updateCustomer(@Path("customerId") Long customerId, @Body CustomerDTO customer);
 
+    // Delete customer
     @DELETE("api/v1/customers/{customerId}")
     Call<Void> deleteCustomer(@Path("customerId") Long customerId);
 
+    // Register customer
     @POST("api/v1/auth/register")
     Call<CustomerDTO> registerCustomer(@Body CustomerDTO customer);
 
+    // Get customer dropdowns
     @GET("api/v1/dropdowns/customers")
     Call<List<DropdownDTO>> getCustomerDropdowns();
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/EmployeeApi.java b/android/app/src/main/java/com/example/petstoremobile/api/EmployeeApi.java
index bbd873c3..33f08264 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/EmployeeApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/EmployeeApi.java
@@ -5,28 +5,28 @@ import com.example.petstoremobile.dtos.PageResponse;
 import retrofit2.Call;
 import retrofit2.http.*;
 
+// api calls for employees
 public interface EmployeeApi {
 
+    // Get all employees with pagination
     @GET("api/v1/employees")
     Call<PageResponse<EmployeeDTO>> getAllEmployees(
             @Query("page") int page,
             @Query("size") int size);
 
+    // Get employee by id
     @GET("api/v1/employees/{id}")
     Call<EmployeeDTO> getEmployeeById(@Path("id") Long id);
 
+    // Create employee
     @POST("api/v1/employees")
     Call<EmployeeDTO> createEmployee(@Body EmployeeDTO employee);
 
+    // Update employee
     @PUT("api/v1/employees/{id}")
     Call<EmployeeDTO> updateEmployee(@Path("id") Long id, @Body EmployeeDTO employee);
 
+    // Delete employee
     @DELETE("api/v1/employees/{id}")
     Call<Void> deleteEmployee(@Path("id") Long id);
 }
-
-
-
-
-
-
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/InventoryApi.java b/android/app/src/main/java/com/example/petstoremobile/api/InventoryApi.java
index fa1e17b4..e9b3bb7c 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/InventoryApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/InventoryApi.java
@@ -14,8 +14,10 @@ import retrofit2.http.PUT;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for inventory
 public interface InventoryApi {
 
+    // Get all inventory with filters
     @GET("api/v1/inventory")
     Call<PageResponse<InventoryDTO>> getAllInventory(
             @Query("page") int page,
@@ -24,23 +26,23 @@ public interface InventoryApi {
             @Query("storeId") Long storeId,
             @Query("sort") String sort);
 
-    // GET /api/v1/inventory/{id}
+    // Get inventory by id
     @GET("api/v1/inventory/{id}")
     Call<InventoryDTO> getInventoryById(@Path("id") Long id);
 
-    // POST /api/v1/inventory
+    // Create inventory
     @POST("api/v1/inventory")
     Call<InventoryDTO> createInventory(@Body InventoryDTO request);
 
-    // PUT /api/v1/inventory/{id}
+    // Update inventory
     @PUT("api/v1/inventory/{id}")
     Call<InventoryDTO> updateInventory(@Path("id") Long id, @Body InventoryDTO request);
 
-    // DELETE /api/v1/inventory/{id}
+    // Delete inventory
     @DELETE("api/v1/inventory/{id}")
     Call<Void> deleteInventory(@Path("id") Long id);
 
-    // DELETE /api/v1/inventory (bulk delete)
+    // Bulk delete inventory
     @HTTP(method = "DELETE", path = "api/v1/inventory", hasBody = true)
     Call<Void> bulkDeleteInventory(@Body BulkDeleteRequest request);
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/MessageApi.java b/android/app/src/main/java/com/example/petstoremobile/api/MessageApi.java
index e5504a03..cb921932 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/MessageApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/MessageApi.java
@@ -15,15 +15,18 @@ import retrofit2.http.Part;
 import retrofit2.http.Path;
 import retrofit2.http.Streaming;
 
-//api calls to get and send messages
+// api calls for messages
 public interface MessageApi {
 
+    // Get messages for a conversation
     @GET("api/v1/chat/conversations/{id}/messages")
     Call<List<MessageDTO>> getMessages(@Path("id") Long conversationId);
 
+    // Send a message
     @POST("api/v1/chat/conversations/{id}/messages")
     Call<MessageDTO> sendMessage(@Path("id") Long conversationId, @Body SendMessageRequest request);
 
+    // Send a message with attachment
     @Multipart
     @POST("api/v1/chat/conversations/{id}/attachments")
     Call<MessageDTO> sendMessageWithAttachment(
@@ -32,6 +35,7 @@ public interface MessageApi {
             @Part MultipartBody.Part file
     );
 
+    // Download attachment
     @GET("api/v1/chat/messages/{id}/attachment")
     @Streaming
     Call<ResponseBody> downloadAttachment(@Path("id") Long messageId);
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/PetApi.java b/android/app/src/main/java/com/example/petstoremobile/api/PetApi.java
index b554166b..06e522f0 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/PetApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/PetApi.java
@@ -20,7 +20,7 @@ import retrofit2.http.Part;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
-//api calls to CRUD pets
+// api calls to CRUD pets
 public interface PetApi {
     // endpoint for downloading the pet's image file
     String PET_IMAGE_PATH = "api/v1/pets/%d/image";
@@ -38,18 +38,23 @@ public interface PetApi {
             @Query("sort") String sort
     );
 
+    // Get pets by customer id
     @GET("api/v1/dropdowns/customers/{customerId}/pets")
     Call<List<DropdownDTO>> getCustomerPets(@Path("customerId") Long customerId);
 
+    // Get adoption pets
     @GET("api/v1/dropdowns/adoption-pets")
     Call<List<DropdownDTO>> getAdoptionPets(@Query("storeId") Long storeId);
 
+    // Get pet dropdowns
     @GET("api/v1/dropdowns/pets")
     Call<List<DropdownDTO>> getPetDropdowns();
 
+    // Get pet species dropdowns
     @GET("api/v1/dropdowns/pet-species")
     Call<List<DropdownDTO>> getPetSpeciesDropdowns();
 
+    // Get pet breeds dropdowns
     @GET("api/v1/dropdowns/pet-breeds")
     Call<List<DropdownDTO>> getPetBreedsDropdowns(@Query("species") String species);
 
@@ -81,5 +86,4 @@ public interface PetApi {
     // Delete pet image
     @DELETE("api/v1/pets/{id}/image")
     Call<Void> deletePetImage(@Path("id") Long id);
-
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/ProductApi.java b/android/app/src/main/java/com/example/petstoremobile/api/ProductApi.java
index 8aeb596e..88d7df0f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/ProductApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/ProductApi.java
@@ -9,9 +9,12 @@ import retrofit2.http.*;
 
 import java.util.List;
 
+// api calls for products
 public interface ProductApi {
+    // endpoint for downloading the product's image file
     String PRODUCT_IMAGE_PATH = "api/v1/products/%d/image";
 
+    // Get all products with filters
     @GET("api/v1/products")
     Call<PageResponse<ProductDTO>> getAllProducts(
             @Query("q") String query,
@@ -20,28 +23,36 @@ public interface ProductApi {
             @Query("size") int size,
             @Query("sort") String sort);
 
+    // Get product by id
     @GET("api/v1/products/{id}")
     Call<ProductDTO> getProductById(@Path("id") Long id);
 
+    // Create product
     @POST("api/v1/products")
     Call<ProductDTO> createProduct(@Body ProductDTO product);
 
+    // Update product
     @PUT("api/v1/products/{id}")
     Call<ProductDTO> updateProduct(@Path("id") Long id, @Body ProductDTO product);
 
+    // Delete product
     @DELETE("api/v1/products/{id}")
     Call<Void> deleteProduct(@Path("id") Long id);
 
+    // Upload product image
     @Multipart
     @POST("api/v1/products/{id}/image")
     Call<Void> uploadProductImage(@Path("id") Long id, @Part MultipartBody.Part image);
 
+    // Delete product image
     @DELETE("api/v1/products/{id}/image")
     Call<Void> deleteProductImage(@Path("id") Long id);
 
+    // Get product dropdowns
     @GET("api/v1/dropdowns/products")
     Call<List<DropdownDTO>> getProductDropdowns();
 
+    // Get category dropdowns
     @GET("api/v1/dropdowns/categories")
     Call<List<DropdownDTO>> getCategoryDropdowns();
-}
\ No newline at end of file
+}
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/ProductSupplierApi.java b/android/app/src/main/java/com/example/petstoremobile/api/ProductSupplierApi.java
index b4414be5..03f6d891 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/ProductSupplierApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/ProductSupplierApi.java
@@ -6,8 +6,10 @@ import com.example.petstoremobile.dtos.ProductSupplierDTO;
 import retrofit2.Call;
 import retrofit2.http.*;
 
+// api calls for product-supplier relationships
 public interface ProductSupplierApi {
 
+    // Get all product-suppliers with filters
     @GET("api/v1/product-suppliers")
     Call<PageResponse<ProductSupplierDTO>> getAllProductSuppliers(
             @Query("page") int page,
@@ -17,24 +19,30 @@ public interface ProductSupplierApi {
             @Query("supplierId") Long supplierId,
             @Query("sort") String sort);
 
+    // Get product-supplier by composite id
     @GET("api/v1/product-suppliers/{productId}/{supplierId}")
     Call<ProductSupplierDTO> getProductSupplierById(
             @Path("productId") Long productId,
             @Path("supplierId") Long supplierId);
 
+    // Create product-supplier
     @POST("api/v1/product-suppliers")
     Call<ProductSupplierDTO> createProductSupplier(@Body ProductSupplierDTO dto);
 
+    // Update product-supplier
     @PUT("api/v1/product-suppliers/{productId}/{supplierId}")
     Call<ProductSupplierDTO> updateProductSupplier(
             @Path("productId") Long productId,
             @Path("supplierId") Long supplierId,
             @Body ProductSupplierDTO dto);
 
+    // Delete product-supplier
     @DELETE("api/v1/product-suppliers/{productId}/{supplierId}")
     Call<Void> deleteProductSupplier(
             @Path("productId") Long productId,
             @Path("supplierId") Long supplierId);
+
+    // Bulk delete product-suppliers
     @HTTP(method = "DELETE", path = "api/v1/product-suppliers", hasBody = true)
     Call<Void> bulkDeleteProductSuppliers(@Body BulkDeleteRequest request);
-}
\ No newline at end of file
+}
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/PurchaseOrderApi.java b/android/app/src/main/java/com/example/petstoremobile/api/PurchaseOrderApi.java
index ebb99139..8746ed08 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/PurchaseOrderApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/PurchaseOrderApi.java
@@ -7,8 +7,10 @@ import retrofit2.http.GET;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for purchase orders
 public interface PurchaseOrderApi {
 
+    // Get all purchase orders with filters
     @GET("api/v1/purchase-orders")
     Call<PageResponse<PurchaseOrderDTO>> getAllPurchaseOrders(
             @Query("page") int page,
@@ -17,6 +19,7 @@ public interface PurchaseOrderApi {
             @Query("storeId") Long storeId,
             @Query("sort") String sort);
 
+    // Get purchase order by id
     @GET("api/v1/purchase-orders/{id}")
     Call<PurchaseOrderDTO> getPurchaseOrderById(@Path("id") Long id);
 }
\ No newline at end of file
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/RefundApi.java b/android/app/src/main/java/com/example/petstoremobile/api/RefundApi.java
index d7ba9575..6e3591bc 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/RefundApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/RefundApi.java
@@ -6,20 +6,26 @@ import retrofit2.http.*;
 
 import java.util.List;
 
+// api calls for refunds
 public interface RefundApi {
 
+    // Get all refunds
     @GET("api/v1/refunds")
     Call<List<RefundDTO>> getAllRefunds();
 
+    // Get refund by id
     @GET("api/v1/refunds/{id}")
     Call<RefundDTO> getRefundById(@Path("id") Long id);
 
+    // Create refund
     @POST("api/v1/refunds")
     Call<RefundDTO> createRefund(@Body RefundDTO refund);
 
+    // Update refund
     @PUT("api/v1/refunds/{id}")
     Call<RefundDTO> updateRefund(@Path("id") Long id, @Body RefundDTO refund);
 
+    // Delete refund
     @DELETE("api/v1/refunds/{id}")
     Call<Void> deleteRefund(@Path("id") Long id);
 }
\ No newline at end of file
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/SaleApi.java b/android/app/src/main/java/com/example/petstoremobile/api/SaleApi.java
index cec94044..6d333dd5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/SaleApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/SaleApi.java
@@ -10,8 +10,10 @@ import retrofit2.http.POST;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for sales
 public interface SaleApi {
 
+    // Get all sales with filters
     @GET("api/v1/sales")
     Call<PageResponse<SaleDTO>> getAllSales(
             @Query("page") int page,
@@ -23,9 +25,11 @@ public interface SaleApi {
             @Query("customerId") Long customerId,
             @Query("sort") String sort);
 
+    // Get sale by id
     @GET("api/v1/sales/{id}")
     Call<SaleDTO> getSaleById(@Path("id") Long id);
 
+    // Create sale
     @POST("api/v1/sales")
     Call<SaleDTO> createSale(@Body SaleDTO sale);
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/ServiceApi.java b/android/app/src/main/java/com/example/petstoremobile/api/ServiceApi.java
index 43014a53..9784524b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/ServiceApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/ServiceApi.java
@@ -14,7 +14,7 @@ import retrofit2.http.PUT;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
-//api calls to CRUD services
+// api calls to CRUD services
 public interface ServiceApi {
     // Get all services
     @GET("api/v1/services")
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/StoreApi.java b/android/app/src/main/java/com/example/petstoremobile/api/StoreApi.java
index f71b92b6..3370dd03 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/StoreApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/StoreApi.java
@@ -11,16 +11,20 @@ import retrofit2.http.GET;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+// api calls for stores
 public interface StoreApi {
 
+    // Get all stores with pagination
     @GET("api/v1/stores")
     Call<PageResponse<StoreDTO>> getAllStores(
             @Query("page") int page,
             @Query("size") int size);
 
+    // Get store dropdowns
     @GET("api/v1/dropdowns/stores")
     Call<List<DropdownDTO>> getStoreDropdowns();
 
+    // Get employees of a specific store
     @GET("api/v1/dropdowns/stores/{storeId}/employees")
     Call<List<DropdownDTO>> getStoreEmployees(@Path("storeId") Long storeId);
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/UserApi.java b/android/app/src/main/java/com/example/petstoremobile/api/UserApi.java
index 8346e221..dbc5640b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/UserApi.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/UserApi.java
@@ -7,9 +7,12 @@ import retrofit2.Call;
 import retrofit2.http.GET;
 import retrofit2.http.Query;
 
+// api calls for users
 public interface UserApi {
+    // endpoint for downloading the user's avatar file
     String AVATAR_PATH = "api/v1/users/%d/avatar/file";
 
+    // Get all users with filters
     @GET("api/v1/users")
     Call<PageResponse<UserDTO>> getUsers(@Query("role") String role, @Query("page") int page, @Query("size") int size);
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/api/auth/TokenManager.java b/android/app/src/main/java/com/example/petstoremobile/api/auth/TokenManager.java
index dc6096de..f28395d3 100644
--- a/android/app/src/main/java/com/example/petstoremobile/api/auth/TokenManager.java
+++ b/android/app/src/main/java/com/example/petstoremobile/api/auth/TokenManager.java
@@ -8,6 +8,7 @@ import javax.inject.Singleton;
 
 import dagger.hilt.android.qualifiers.ApplicationContext;
 
+//Used to save and retrieve login data
 @Singleton
 public class TokenManager {
     private static final String TOKEN_KEY = "token";
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/ActivityLogDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/ActivityLogDTO.java
index 2d4d0f6d..4a210a5d 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/ActivityLogDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/ActivityLogDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for activity logs.
+ */
 public class ActivityLogDTO {
     private Long logId;
     private String activity;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/AdoptionDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/AdoptionDTO.java
index d48bc942..66459bee 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/AdoptionDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/AdoptionDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.math.BigDecimal;
 
+/**
+ * Data Transfer Object for pet adoptions.
+ */
 public class AdoptionDTO {
 
     private Long adoptionId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/AppointmentDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/AppointmentDTO.java
index 37f6640f..c793a142 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/AppointmentDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/AppointmentDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for appointments.
+ */
 public class AppointmentDTO {
 
     private Long appointmentId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/AuthDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/AuthDTO.java
index 6aecdbc3..563b1b5f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/AuthDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/AuthDTO.java
@@ -1,6 +1,8 @@
 package com.example.petstoremobile.dtos;
 
-//Used to send login data to the backend
+/**
+ * Data Transfer Object for authentication credentials.
+ */
 public class AuthDTO {
     public static class LoginRequest {
         private String username;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/AvatarUploadResponse.java b/android/app/src/main/java/com/example/petstoremobile/dtos/AvatarUploadResponse.java
index 194be1f4..4495e05e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/AvatarUploadResponse.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/AvatarUploadResponse.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Response containing the URL of a newly uploaded avatar.
+ */
 public class AvatarUploadResponse {
     private String avatarUrl;
     private String message;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/BulkDeleteRequest.java b/android/app/src/main/java/com/example/petstoremobile/dtos/BulkDeleteRequest.java
index e53c8369..0fd6ae5a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/BulkDeleteRequest.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/BulkDeleteRequest.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.util.List;
 
+/**
+ * Request body for deleting multiple records at once.
+ */
 public class BulkDeleteRequest {
     private List<String> ids;
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/CategoryDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/CategoryDTO.java
index 6596845b..b8c84b7c 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/CategoryDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/CategoryDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for product categories.
+ */
 public class CategoryDTO {
     private Long categoryId;
     private String categoryName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/ConversationDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/ConversationDTO.java
index 3a7ea42e..135bd84d 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/ConversationDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/ConversationDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for chat conversations.
+ */
 public class ConversationDTO {
     private Long id;
     private Long customerId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/CouponDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/CouponDTO.java
index e2ecb2c4..647d9baf 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/CouponDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/CouponDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.math.BigDecimal;
 
+/**
+ * Data Transfer Object for coupons.
+ */
 public class CouponDTO {
     private Long couponId;
     private String couponCode;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/CustomerDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/CustomerDTO.java
index c190342e..0872252c 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/CustomerDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/CustomerDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import com.google.gson.annotations.SerializedName;
 
+/**
+ * Data Transfer Object for customers.
+ */
 public class CustomerDTO {
     @SerializedName("id")
     private Long customerId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/DropdownDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/DropdownDTO.java
index 3174dae5..3f46d119 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/DropdownDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/DropdownDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for simple dropdown selection lists.
+ */
 public class DropdownDTO {
     private Long id;
     private String label;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/EmployeeDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/EmployeeDTO.java
index f29b4beb..f7288d73 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/EmployeeDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/EmployeeDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for employees.
+ */
 public class EmployeeDTO {
 
     private Long id;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/ErrorResponse.java b/android/app/src/main/java/com/example/petstoremobile/dtos/ErrorResponse.java
index ddb23eaa..56cc726c 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/ErrorResponse.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/ErrorResponse.java
@@ -1,7 +1,8 @@
 package com.example.petstoremobile.dtos;
 
-//Used to get messages of any errors from the backend
-
+/**
+ * Used to get messages of any errors from the backend.
+ */
 public class ErrorResponse {
     private String message;
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/InventoryDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/InventoryDTO.java
index ddafd045..3fd6be57 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/InventoryDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/InventoryDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for inventory stock.
+ */
 public class InventoryDTO {
     // Response fields (from backend InventoryResponse)
     private Long inventoryId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/MessageDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/MessageDTO.java
index 8302ba86..17b54fa8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/MessageDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/MessageDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import com.google.gson.annotations.SerializedName;
 
+/**
+ * Data Transfer Object for chat messages.
+ */
 public class MessageDTO {
 
     @SerializedName("id")
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/PageResponse.java b/android/app/src/main/java/com/example/petstoremobile/dtos/PageResponse.java
index 7237105e..56558e15 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/PageResponse.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/PageResponse.java
@@ -2,7 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.util.List;
 
-//Used to get data from the API
+/**
+ * Generic response wrapper for paginated API results.
+ */
 public class PageResponse<T> {
     private List<T> content;
     private int totalPages;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/PetDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/PetDTO.java
index 0e9a0b3f..3a3314d5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/PetDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/PetDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object representing a pet.
+ */
 public class PetDTO {
     private Long petId;
     private String petName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/ProductDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/ProductDTO.java
index 2b016b28..c95f0a32 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/ProductDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/ProductDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.math.BigDecimal;
 
+/**
+ * Data Transfer Object for products.
+ */
 public class ProductDTO {
     private Long prodId;
     private String prodName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/ProductSupplierDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/ProductSupplierDTO.java
index 887d29e1..e25f82ec 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/ProductSupplierDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/ProductSupplierDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.math.BigDecimal;
 
+/**
+ * Data Transfer Object for mapping products to suppliers.
+ */
 public class ProductSupplierDTO {
     private Long productId;
     private String productName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/PurchaseOrderDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/PurchaseOrderDTO.java
index 813633c9..eb760e59 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/PurchaseOrderDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/PurchaseOrderDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for purchase orders.
+ */
 public class PurchaseOrderDTO {
     private Long purchaseOrderId;
     private Long supId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/RefundDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/RefundDTO.java
index 5f47e1ce..dc3d2d67 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/RefundDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/RefundDTO.java
@@ -2,6 +2,9 @@ package com.example.petstoremobile.dtos;
 
 import java.math.BigDecimal;
 
+/**
+ * Data Transfer Object for refund processing.
+ */
 public class RefundDTO {
     // Response fields
     private Long id;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/SaleDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/SaleDTO.java
index 9dc76029..d8501995 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/SaleDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/SaleDTO.java
@@ -3,6 +3,9 @@ package com.example.petstoremobile.dtos;
 import java.math.BigDecimal;
 import java.util.List;
 
+/**
+ * Data Transfer Object for sales transactions.
+ */
 public class SaleDTO {
     // Response fields
     private Long saleId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/SendMessageRequest.java b/android/app/src/main/java/com/example/petstoremobile/dtos/SendMessageRequest.java
index 7a521de3..aab51a90 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/SendMessageRequest.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/SendMessageRequest.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Request body for sending a new chat message.
+ */
 public class SendMessageRequest {
 
     private String content;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/ServiceDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/ServiceDTO.java
index 56e44371..cfbacb8e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/ServiceDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/ServiceDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for services.
+ */
 public class ServiceDTO {
     private Long serviceId;
     private String serviceName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/StoreDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/StoreDTO.java
index da66f046..ba4d732a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/StoreDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/StoreDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for store information.
+ */
 public class StoreDTO {
     private Long storeId;
     private String storeName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/SupplierDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/SupplierDTO.java
index e34816c1..e39d22c8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/SupplierDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/SupplierDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for suppliers.
+ */
 public class SupplierDTO {
     private Long supId;
     private String supCompany;
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/UpdateConversationStatusRequest.java b/android/app/src/main/java/com/example/petstoremobile/dtos/UpdateConversationStatusRequest.java
index 4d7987e1..e0fe3fe2 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/UpdateConversationStatusRequest.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/UpdateConversationStatusRequest.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Request body for updating chat conversation status.
+ */
 public class UpdateConversationStatusRequest {
     private String status;
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/dtos/UserDTO.java b/android/app/src/main/java/com/example/petstoremobile/dtos/UserDTO.java
index 2ab9902e..05866080 100644
--- a/android/app/src/main/java/com/example/petstoremobile/dtos/UserDTO.java
+++ b/android/app/src/main/java/com/example/petstoremobile/dtos/UserDTO.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.dtos;
 
+/**
+ * Data Transfer Object for user account details.
+ */
 public class UserDTO {
     private Long id;
     private String username;
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/ChatFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/ChatFragment.java
index 88bb0f09..83678a68 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/ChatFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/ChatFragment.java
@@ -65,6 +65,9 @@ import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
 import okhttp3.ResponseBody;
 
+/**
+ * Fragment for handling customer support chat.
+ */
 @AndroidEntryPoint
 public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickListener, StompChatManager.MessageListener,
         StompChatManager.ConversationListener, StompChatManager.ConnectionListener {
@@ -90,6 +93,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
     private StompChatManager stompChatManager;
     private ActivityResultLauncher<Intent> attachmentLauncher;
 
+    /**
+     * Initializes the view model and attachment launcher.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -105,6 +111,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         );
     }
 
+    /**
+     * Inflates the layout and sets up UI event listeners.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater,
                              ViewGroup container, Bundle savedInstanceState) {
@@ -137,6 +146,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         return binding.getRoot();
     }
 
+    /**
+     * Sets up the logic to open and close the chat drawer.
+     */
     private void setupDrawerToggles() {
         binding.headerActiveChats.setOnClickListener(v -> {
             if (binding.rvActiveChats.getVisibility() == View.VISIBLE) {
@@ -159,6 +171,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Configures the adapters and layout managers for chat lists and message history.
+     */
     private void setupRecyclerViews() {
         activeChatAdapter = new ChatAdapter(activeChatList, this);
         binding.rvActiveChats.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -187,6 +202,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         setConversationActive(false, null);
     }
 
+    /**
+     * Displays a full-screen image preview for message attachments.
+     */
     private void showFullScreenImage(Message message) {
         if (baseUrl == null || message.getId() == null) return;
 
@@ -208,6 +226,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         dialog.show();
     }
 
+    /**
+     * Initiates the download process for a message attachment.
+     */
     private void downloadFile(Message message) {
         if (message.getId() == null) return;
 
@@ -227,6 +248,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Saves the downloaded file body to the device's downloads folder.
+     */
     private void saveFileToDownloads(ResponseBody body, String fileName, String mimeType) {
         android.os.Handler mainHandler = new android.os.Handler(android.os.Looper.getMainLooper());
         new Thread(() -> {
@@ -270,6 +294,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }).start();
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update chat lists and messages.
+     */
     private void observeViewModel() {
         viewModel.getActiveChats().observe(getViewLifecycleOwner(), list -> {
             activeChatList.clear();
@@ -300,12 +327,18 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         viewModel.getIsLoading().observe(getViewLifecycleOwner(), this::setLoading);
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Updates the chat header and input state if the active conversation changes.
+     */
     private void updateTitleAndStateIfActive(List<Chat> list) {
         if (activeConversationId != null) {
             for (Chat chat : list) {
@@ -318,6 +351,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Loads initial chat data and establishes WebSocket connection.
+     */
     private void loadInitialData() {
         String token = tokenManager.getToken();
         Long currentUserId = tokenManager.getUserId();
@@ -353,6 +389,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Handles clicks on a chat from the drawer to switch the active conversation.
+     */
     @Override
     public void onChatClick(Chat chat) {
         activeConversationId = Long.parseLong(chat.getChatId());
@@ -368,6 +407,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         viewModel.loadMessageHistory(activeConversationId);
     }
 
+    /**
+     * Closes the active chat conversation.
+     */
     private void closeChat() {
         if (activeConversationId == null) return;
 
@@ -392,6 +434,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Sends a text message to the active conversation.
+     */
     private void sendMessage() {
         if (activeConversationId == null) return;
         String text = binding.etMessage.getText().toString().trim();
@@ -408,12 +453,18 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Opens a file picker to select an attachment.
+     */
     private void selectAttachment() {
         Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
         intent.setType("*/*");
         attachmentLauncher.launch(intent);
     }
 
+    /**
+     * Displays a preview of the selected attachment.
+     */
     private void showAttachmentPreview(Uri uri) {
         pendingAttachmentUri = uri;
         binding.layoutAttachmentPreview.setVisibility(View.VISIBLE);
@@ -427,11 +478,17 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Removes the currently selected attachment from the preview.
+     */
     private void removeAttachment() {
         pendingAttachmentUri = null;
         binding.layoutAttachmentPreview.setVisibility(View.GONE);
     }
 
+    /**
+     * Sends a message with a file attachment.
+     */
     private void sendWithAttachment(Uri uri) {
         if (activeConversationId == null) return;
 
@@ -468,6 +525,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Callback for when a new message is received through the WebSocket.
+     */
     @Override
     public void onMessageReceived(MessageDTO dto) {
         requireActivity().runOnUiThread(() -> {
@@ -478,6 +538,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Callback for when a conversation's status or last message is updated.
+     */
     @Override
     public void onConversationUpdated(ConversationDTO dto) {
         requireActivity().runOnUiThread(() -> {
@@ -489,6 +552,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Callback for when the WebSocket connection is successfully opened.
+     */
     @Override
     public void onSocketOpened() {
         if (!isAdded()) return;
@@ -498,12 +564,18 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Callback for when the WebSocket connection is closed.
+     */
     @Override
     public void onSocketClosed() {
         if (!isAdded()) return;
         requireActivity().runOnUiThread(viewModel::loadConversations);
     }
 
+    /**
+     * Callback for when a WebSocket error occurs.
+     */
     @Override
     public void onSocketError() {
         if (!isAdded()) return;
@@ -513,6 +585,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
+    /**
+     * Scrolls the message list to the most recent message.
+     */
     private void scrollToBottom() {
         if (!messageList.isEmpty()) {
             binding.rvMessages.post(() ->
@@ -520,6 +595,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Updates the UI state based on whether a conversation is active and its status.
+     */
     private void setConversationActive(boolean active, String status) {
         boolean isClosed = "CLOSED".equalsIgnoreCase(status);
         UIUtils.setViewsEnabled(active && !isClosed, binding.btnSend, binding.etMessage, binding.btnAttach);
@@ -541,6 +619,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Cleans up resources and disconnects the WebSocket when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/ListFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/ListFragment.java
index 6f2c643b..8c3f3c2e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/ListFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/ListFragment.java
@@ -23,7 +23,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
-//The Fragment for the displaying the list of entities to be viewed
+/**
+ * Fragment that serves as a container for various list-based screens, providing a navigation drawer.
+ */
 @AndroidEntryPoint
 public class ListFragment extends Fragment {
 
@@ -97,6 +99,9 @@ public class ListFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/ProfileFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/ProfileFragment.java
index 7f8fc039..fb1decb7 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/ProfileFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/ProfileFragment.java
@@ -173,12 +173,18 @@ public class ProfileFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ActivityLogFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ActivityLogFragment.java
index f369d383..6dab8ec3 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ActivityLogFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ActivityLogFragment.java
@@ -34,6 +34,9 @@ import java.util.List;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for viewing application activity logs with various filtering options.
+ */
 @AndroidEntryPoint
 public class ActivityLogFragment extends Fragment {
     private FragmentActivityLogBinding binding;
@@ -46,6 +49,9 @@ public class ActivityLogFragment extends Fragment {
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Inflates the layout, checks for admin access, and initializes ViewModel and UI components.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -69,12 +75,18 @@ public class ActivityLogFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Triggers initial data loading after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
         viewModel.loadInitialData();
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new ActivityLogAdapter(logList);
         binding.recyclerViewActivityLog.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -97,6 +109,9 @@ public class ActivityLogFragment extends Fragment {
         });
     }
 
+    /**
+     * Sets up filters for logs, including search, role, store, and date range.
+     */
     private void setupFilters() {
         UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter,
                 binding.etSearchLog, binding.spinnerRoleFilter, binding.spinnerStoreFilter);
@@ -123,6 +138,9 @@ public class ActivityLogFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a date picker dialog and updates the selected start or end date.
+     */
     private void showDatePicker(boolean isStart) {
         Calendar cal = Calendar.getInstance();
         new DatePickerDialog(requireContext(), (view, year, month, day) -> {
@@ -141,12 +159,18 @@ public class ActivityLogFragment extends Fragment {
         }, cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH)).show();
     }
 
+    /**
+     * Handles store selection from the filter spinner.
+     */
     private void onStoreSelected() {
         int pos = binding.spinnerStoreFilter.getSelectedItemPosition();
         Long storeId = (pos > 0 && !storeList.isEmpty()) ? storeList.get(pos - 1).getId() : null;
         viewModel.setStoreFilter(storeId);
     }
 
+    /**
+     * Observes the ViewModel for log list updates, store options, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getLogs().observe(getViewLifecycleOwner(), list -> {
             logList.clear();
@@ -164,6 +188,9 @@ public class ActivityLogFragment extends Fragment {
                 binding.swipeRefreshActivityLog.setRefreshing(loading));
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AdoptionFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AdoptionFragment.java
index a6ba396e..fd4209f1 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AdoptionFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AdoptionFragment.java
@@ -44,6 +44,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of adoptions with a calendar view and filtering.
+ */
 @AndroidEntryPoint
 public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdoptionClickListener {
 
@@ -58,12 +61,18 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(AdoptionListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components, calendar, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -88,6 +97,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for adoption list, stores, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getAdoptions().observe(getViewLifecycleOwner(), list -> {
             adoptionList.clear();
@@ -106,6 +118,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         });
     }
 
+    /**
+     * Configures the bulk delete handler for multiple adoption record deletion.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -119,6 +134,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         );
     }
 
+    /**
+     * Reloads adoption data and stores when the fragment resumes.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -126,6 +144,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         if (!isStaff()) viewModel.loadStores();
     }
 
+    /**
+     * Toggles between month and week display modes for the calendar.
+     */
     private void toggleCalendarMode() {
         isMonthMode = !isMonthMode;
         binding.calendarViewAdoption.state().edit()
@@ -133,6 +154,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
                 .commit();
     }
 
+    /**
+     * Sets up the filter visibility toggle, considering user roles.
+     */
     private void setupFilterToggle() {
         if (isStaff()) {
             UIUtils.setupFilterToggle(binding.btnToggleFilterAdoption, binding.layoutFilterAdoption,
@@ -144,10 +168,16 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         }
     }
 
+    /**
+     * Checks if the currently logged-in user has the STAFF role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Configures the calendar view for date-based filtering.
+     */
     private void setupCalendar() {
         binding.calendarViewAdoption.setOnDateChangedListener((widget, date, selected) -> {
             if (selected) {
@@ -164,6 +194,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         });
     }
 
+    /**
+     * Updates calendar decorators to highlight dates with adoptions.
+     */
     private void updateCalendarDecorators() {
         HashSet<CalendarDay> datesWithAdoptions = new HashSet<>();
         for (AdoptionDTO adoption : adoptionList) {
@@ -184,6 +217,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         binding.calendarViewAdoption.addDecorator(new EventDecorator(Color.RED, datesWithAdoptions));
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new AdoptionAdapter(adoptionList, this);
         binding.recyclerViewAdoptions.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -206,23 +242,38 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         });
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchAdoption, () -> loadAdoptions(true));
     }
 
+    /**
+     * Configures the status filter spinner.
+     */
     private void setupStatusFilter() {
         String[] statuses = {"All Statuses", "Completed", "Pending", "Missed", "Cancelled"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatusAdoption, statuses, () -> loadAdoptions(true));
     }
 
+    /**
+     * Configures the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStoreAdoption, () -> loadAdoptions(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshAdoption.setOnRefreshListener(() -> loadAdoptions(true));
     }
 
+    /**
+     * Loads adoption data based on current filters, search query, and selected date.
+     */
     private void loadAdoptions(boolean reset) {
         String query = binding.etSearchAdoption.getText().toString().trim();
         String status = binding.spinnerStatusAdoption.getSelectedItem() != null ? binding.spinnerStatusAdoption.getSelectedItem().toString() : "All Statuses";
@@ -250,6 +301,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         viewModel.loadAdoptions(reset, query, status, storeId, selectedDateString, null);
     }
 
+    /**
+     * Navigates to the adoption detail screen.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -259,9 +313,15 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         NavHostFragment.findNavController(this).navigate(R.id.nav_adoption_detail, args);
     }
 
+    /**
+     * Handles adoption item clicks by opening details.
+     */
     @Override
     public void onAdoptionClick(int position) { openDetail(position); }
 
+    /**
+     * Forwards selection changes to the bulk delete handler.
+     */
     @Override
     public void onSelectionChanged(int selectedCount) {
         if (bulkDeleteHandler != null) {
@@ -269,6 +329,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         }
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AnalyticsFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AnalyticsFragment.java
index 89aeb098..e493b0e3 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AnalyticsFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AnalyticsFragment.java
@@ -18,6 +18,9 @@ import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.util.*;
 
+/**
+ * Fragment for displaying business analytics, including revenue, transactions, and product performance.
+ */
 @AndroidEntryPoint
 public class AnalyticsFragment extends Fragment {
 
@@ -31,6 +34,9 @@ public class AnalyticsFragment extends Fragment {
     private static final String[] TOP_N_OPTIONS = {"5", "10", "15", "20"};
     private static final int[] TOP_N_VALUES    = { 5,   10,   15,   20 };
 
+    /**
+     * Inflates the layout, initializes ViewModel, and sets up UI components and filters.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -51,6 +57,9 @@ public class AnalyticsFragment extends Fragment {
     private static final int COLOR_SELECTED = 0xFF4ECDC4;
     private static final int COLOR_UNSELECTED = 0xFFCBD5E1;
 
+    /**
+     * Configures the view mode toggle buttons (My Analytics vs Store Analytics).
+     */
     private void setupViewModeToggle() {
         updateViewModeButtonStyles(viewModel.getViewMode());
 
@@ -67,6 +76,9 @@ public class AnalyticsFragment extends Fragment {
         });
     }
 
+    /**
+     * Updates the styles of the view mode buttons based on the selected mode.
+     */
     private void updateViewModeButtonStyles(String mode) {
         binding.btnMyAnalytics.setBackgroundTintList(
             android.content.res.ColorStateList.valueOf(mode.equals("mine") ? COLOR_SELECTED : COLOR_UNSELECTED));
@@ -74,6 +86,9 @@ public class AnalyticsFragment extends Fragment {
             android.content.res.ColorStateList.valueOf(mode.equals("store") ? COLOR_SELECTED : COLOR_UNSELECTED));
     }
 
+    /**
+     * Updates the visibility of the store filter based on the user's role and selected view mode.
+     */
     private void updateStoreFilterVisibility(String mode) {
         boolean isAdmin = "ADMIN".equalsIgnoreCase(tokenManager.getRole());
         int vis = (isAdmin && mode.equals("store")) ? View.VISIBLE : View.GONE;
@@ -81,8 +96,10 @@ public class AnalyticsFragment extends Fragment {
         binding.spinnerFilterStore.setVisibility(vis);
     }
 
-    // Filter Panel
 
+    /**
+     * Configures the filter panel, including date pickers, presets, and action buttons.
+     */
     private void setupFilterPanel() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerTopN, TOP_N_OPTIONS);
 
@@ -111,12 +128,18 @@ public class AnalyticsFragment extends Fragment {
         binding.btnFilterReset.setOnClickListener(v -> resetFilters());
     }
 
+    /**
+     * Toggles the visibility of the filter content section.
+     */
     private void toggleFilters() {
         filtersExpanded = !filtersExpanded;
         binding.llFilterContent.setVisibility(filtersExpanded ? View.VISIBLE : View.GONE);
         binding.tvFilterToggleIcon.setText(filtersExpanded ? "▲" : "▼");
     }
 
+    /**
+     * Applies a date range preset to the filter fields.
+     */
     private void applyPreset(int startOffset, int endOffset) {
         binding.etFilterStartDate.setText(getDateString(startOffset));
         binding.etFilterEndDate.setText(getDateString(endOffset));
@@ -124,6 +147,9 @@ public class AnalyticsFragment extends Fragment {
         applyFiltersFromUI();
     }
 
+    /**
+     * Reads filter values from the UI and applies them to the ViewModel.
+     */
     private void applyFiltersFromUI() {
         AnalyticsViewModel.FilterState filter = new AnalyticsViewModel.FilterState();
         filter.startDate = binding.etFilterStartDate.getText().toString().trim();
@@ -142,6 +168,9 @@ public class AnalyticsFragment extends Fragment {
         viewModel.applyFilter(filter);
     }
 
+    /**
+     * Resets all filters to their default values.
+     */
     private void resetFilters() {
         binding.etFilterStartDate.setText("");
         binding.etFilterEndDate.setText("");
@@ -152,6 +181,9 @@ public class AnalyticsFragment extends Fragment {
         viewModel.resetFilter();
     }
 
+    /**
+     * Updates the text summary of the currently selected date range.
+     */
     private void updateFilterSummary() {
         String start = binding.etFilterStartDate.getText().toString().trim();
         String end   = binding.etFilterEndDate.getText().toString().trim();
@@ -166,10 +198,16 @@ public class AnalyticsFragment extends Fragment {
         }
     }
 
+    /**
+     * Formats a date string into a shorter version for display.
+     */
     private String shortDate(String date) {
         return (date != null && date.length() >= 10) ? date.substring(5) : date;
     }
 
+    /**
+     * Returns a formatted date string for a given day.
+     */
     private String getDateString(int offsetDays) {
         Calendar c = Calendar.getInstance();
         c.add(Calendar.DAY_OF_YEAR, offsetDays);
@@ -177,8 +215,10 @@ public class AnalyticsFragment extends Fragment {
                 c.get(Calendar.YEAR), c.get(Calendar.MONTH) + 1, c.get(Calendar.DAY_OF_MONTH));
     }
 
-    // ViewModel Observation
 
+    /**
+     * Observes the ViewModel for analytics data, loading status, errors, and filter options.
+     */
     private void observeViewModel() {
         viewModel.getAnalyticsData().observe(getViewLifecycleOwner(), this::computeAndDisplay);
 
@@ -216,14 +256,19 @@ public class AnalyticsFragment extends Fragment {
         });
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
-    // Display
 
+    /**
+     * Computes and displays analytics data in summary cards and bar charts.
+     */
     private void computeAndDisplay(AnalyticsViewModel.AnalyticsData data) {
         if (data == null) return;
 
@@ -312,8 +357,10 @@ public class AnalyticsFragment extends Fragment {
         }
     }
 
-    // Chart Helpers
 
+    /**
+     * Dynamically adds a bar chart row to a given layout container.
+     */
     private void addBarRow(LinearLayout parent, String label, String value, float ratio, String color) {
         if (getContext() == null) return;
         LinearLayout row = new LinearLayout(getContext());
@@ -359,6 +406,9 @@ public class AnalyticsFragment extends Fragment {
         parent.addView(row);
     }
 
+    /**
+     * Adds an empty message row to a given layout container.
+     */
     private void addEmptyRow(LinearLayout parent, String message) {
         if (getContext() == null) return;
         TextView tv = new TextView(getContext());
@@ -368,6 +418,9 @@ public class AnalyticsFragment extends Fragment {
         parent.addView(tv);
     }
 
+    /**
+     * Displays an error message and updates UI to reflect the error state.
+     */
     private void showError(String msg) {
         if (getContext() == null || binding == null) return;
         binding.tvTotalRevenue.setText("Error");
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AppointmentFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AppointmentFragment.java
index b8196775..99530081 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AppointmentFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AppointmentFragment.java
@@ -45,6 +45,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of appointments with calendar integration and filtering.
+ */
 @AndroidEntryPoint
 public class AppointmentFragment extends Fragment implements AppointmentAdapter.OnAppointmentClickListener {
 
@@ -63,6 +66,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
     private Long currentUserId = null;
     private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());
 
+    /**
+     * Initializes ViewModels for appointment and authentication data.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -70,6 +76,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         authViewModel = new ViewModelProvider(this).get(AuthViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components, calendar, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -97,6 +106,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for appointment list, stores, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getAppointments().observe(getViewLifecycleOwner(), list -> {
             appointmentList.clear();
@@ -115,6 +127,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
+    /**
+     * Configures the bulk delete handler for multiple appointment deletion.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -128,6 +143,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         );
     }
 
+    /**
+     * Reloads appointment data and stores when the fragment resumes.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -135,6 +153,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         if (!isStaff()) viewModel.loadStores();
     }
 
+    /**
+     * Toggles between month and week display modes for the calendar.
+     */
     private void toggleCalendarMode() {
         isMonthMode = !isMonthMode;
         binding.calendarView.state().edit()
@@ -142,12 +163,18 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
                 .commit();
     }
 
+    /**
+     * Sets up the "My Appointments" filter button.
+     */
     private void setupMyAppointmentFilter() {
         binding.btnMyAppointments.setOnClickListener(v -> {
             loadAppointmentData(true);
         });
     }
 
+    /**
+     * Loads information about the currently logged-in user.
+     */
     private void loadCurrentUserInfo() {
         authViewModel.getMe().observe(getViewLifecycleOwner(), resource -> {
             if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -156,6 +183,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
+    /**
+     * Sets up the filter visibility toggle.
+     */
     private void setupFilterToggle() {
         if (isStaff()) {
             UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchAppointment, binding.spinnerStatus);
@@ -166,6 +196,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         }
     }
 
+    /**
+     * Configures the calendar view for date-based filtering.
+     */
     private void setupCalendar() {
         binding.calendarView.setOnDateChangedListener((widget, date, selected) -> {
             if (selected) {
@@ -182,6 +215,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
+    /**
+     * Updates calendar decorators to highlight dates with appointments.
+     */
     private void updateCalendarDecorators() {
         HashSet<CalendarDay> datesWithAppointments = new HashSet<>();
         for (AppointmentDTO appointment : appointmentList) {
@@ -200,23 +236,38 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         binding.calendarView.addDecorator(new EventDecorator(Color.RED, datesWithAppointments));
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchAppointment, () -> loadAppointmentData(true));
     }
 
+    /**
+     * Configures the status filter spinner.
+     */
     private void setupStatusFilter() {
         String[] statuses = {"All Statuses", "Booked", "Completed", "Cancelled", "Missed"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatus, statuses, () -> loadAppointmentData(true));
     }
 
+    /**
+     * Configures the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStore, () -> loadAppointmentData(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshAppointment.setOnRefreshListener(() -> loadAppointmentData(true));
     }
 
+    /**
+     * Navigates to the appointment detail screen.
+     */
     private void openAppointmentDetails(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -226,11 +277,17 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         NavHostFragment.findNavController(this).navigate(R.id.nav_appointment_detail, args);
     }
 
+    /**
+     * Handles appointment item clicks by opening details.
+     */
     @Override
     public void onAppointmentClick(int position) {
         openAppointmentDetails(position);
     }
 
+    /**
+     * Forwards selection changes to the bulk delete handler.
+     */
     @Override
     public void onSelectionChanged(int count) {
         if (bulkDeleteHandler != null) {
@@ -238,10 +295,16 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         }
     }
 
+    /**
+     * Checks if the currently logged-in user has the STAFF role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Loads appointment data based on current filters, search query, and selected date.
+     */
     private void loadAppointmentData(boolean reset) {
         String query = binding.etSearchAppointment.getText().toString().trim();
         String status = binding.spinnerStatus.getSelectedItem() != null ? binding.spinnerStatus.getSelectedItem().toString() : "All Statuses";
@@ -274,6 +337,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         viewModel.loadAppointments(reset, query, status, storeId, selectedDateString, employeeId);
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new AppointmentAdapter(appointmentList, this);
         binding.recyclerViewAppointments.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -296,6 +362,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CouponFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CouponFragment.java
index c0beebfe..9bc754b4 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CouponFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CouponFragment.java
@@ -27,6 +27,9 @@ import java.util.List;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of coupons.
+ */
 @AndroidEntryPoint
 public class CouponFragment extends Fragment implements CouponAdapter.OnCouponClickListener {
     private FragmentCouponBinding binding;
@@ -34,6 +37,9 @@ public class CouponFragment extends Fragment implements CouponAdapter.OnCouponCl
     private CouponAdapter adapter;
     private final List<CouponDTO> couponList = new ArrayList<>();
 
+    /**
+     * Inflates the layout, initializes ViewModel, and sets up UI components.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -59,6 +65,9 @@ public class CouponFragment extends Fragment implements CouponAdapter.OnCouponCl
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for coupon list updates and loading status.
+     */
     private void observeViewModel() {
         viewModel.getCoupons().observe(getViewLifecycleOwner(), list -> {
             couponList.clear();
@@ -71,6 +80,9 @@ public class CouponFragment extends Fragment implements CouponAdapter.OnCouponCl
         });
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new CouponAdapter(couponList, this);
         binding.recyclerViewCoupon.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -93,24 +105,39 @@ public class CouponFragment extends Fragment implements CouponAdapter.OnCouponCl
         });
     }
 
+    /**
+     * Configures the status filter spinner.
+     */
     private void setupStatusFilter() {
         String[] statuses = {"All Statuses", "Active", "Inactive"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatusCoupon, statuses, () -> applyFilters(true));
     }
 
+    /**
+     * Configures the discount type filter spinner.
+     */
     private void setupTypeFilter() {
         String[] types = {"All Types", "FIXED", "PERCENT"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerTypeCoupon, types, () -> applyFilters(true));
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchCoupon, () -> applyFilters(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshCoupon.setOnRefreshListener(() -> applyFilters(true));
     }
 
+    /**
+     * Applies filters and loads the coupon list.
+     */
     private void applyFilters(boolean reset) {
         String statusStr = binding.spinnerStatusCoupon.getSelectedItem() != null ?
                 binding.spinnerStatusCoupon.getSelectedItem().toString() : "All Statuses";
@@ -125,22 +152,34 @@ public class CouponFragment extends Fragment implements CouponAdapter.OnCouponCl
         viewModel.loadCoupons(reset, active, discountType, null);
     }
 
+    /**
+     * Navigates to the coupon detail screen.
+     */
     private void openDetail(long id) {
         Bundle args = new Bundle();
         args.putLong("couponId", id);
         Navigation.findNavController(requireView()).navigate(R.id.couponDetailFragment, args);
     }
 
+    /**
+     * Handles coupon item clicks by opening details.
+     */
     @Override
     public void onCouponClick(CouponDTO coupon) {
         openDetail(coupon.getCouponId());
     }
 
+    /**
+     * Shows or hides the bulk delete button based on selection count.
+     */
     @Override
     public void onSelectionChanged(int count) {
         binding.btnBulkDeleteCoupons.setVisibility(count > 0 ? View.VISIBLE : View.GONE);
     }
 
+    /**
+     * Displays a confirmation dialog for deleting multiple coupons.
+     */
     private void confirmBulkDelete() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("Confirm Bulk Delete")
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CustomerFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CustomerFragment.java
index 5afe4d1f..87155463 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CustomerFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/CustomerFragment.java
@@ -22,6 +22,9 @@ import java.util.*;
 import javax.inject.Inject;
 import javax.inject.Named;
 
+/**
+ * Fragment for displaying and managing a list of customers.
+ */
 @AndroidEntryPoint
 public class CustomerFragment extends Fragment implements CustomerAdapter.OnCustomerClickListener {
 
@@ -33,6 +36,9 @@ public class CustomerFragment extends Fragment implements CustomerAdapter.OnCust
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
+    /**
+     * Inflates the layout, initializes ViewModel, and sets up UI components and filters.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -56,6 +62,9 @@ public class CustomerFragment extends Fragment implements CustomerAdapter.OnCust
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for customer list updates and loading status.
+     */
     private void observeViewModel() {
         viewModel.getFilteredCustomers().observe(getViewLifecycleOwner(), list -> {
             customerList.clear();
@@ -68,6 +77,9 @@ public class CustomerFragment extends Fragment implements CustomerAdapter.OnCust
         });
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new CustomerAdapter(customerList, this);
         adapter.setBaseUrl(baseUrl);
@@ -92,15 +104,24 @@ public class CustomerFragment extends Fragment implements CustomerAdapter.OnCust
         });
     }
 
+    /**
+     * Configures the status filter spinner.
+     */
     private void setupStatusFilter() {
         String[] statuses = {"All Statuses", "Active", "Inactive"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatusCustomer, statuses, this::applyFilters);
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchCustomer, this::applyFilters);
     }
 
+    /**
+     * Applies filters and triggers data reloading or filtering in ViewModel.
+     */
     private void applyFilters() {
         String query = binding.etSearchCustomer.getText().toString().trim();
         String status = binding.spinnerStatusCustomer.getSelectedItem() != null ?
@@ -108,10 +129,16 @@ public class CustomerFragment extends Fragment implements CustomerAdapter.OnCust
         viewModel.filter(query, status);
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshCustomer.setOnRefreshListener(() -> viewModel.loadCustomers(true));
     }
 
+    /**
+     * Navigates to the customer detail screen.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -129,11 +156,17 @@ public class CustomerFragment extends Fragment implements CustomerAdapter.OnCust
         NavHostFragment.findNavController(this).navigate(R.id.nav_customer_detail, args);
     }
 
+    /**
+     * Handles customer item clicks by opening details.
+     */
     @Override
     public void onCustomerClick(int position) {
         openDetail(position);
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/InventoryFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/InventoryFragment.java
index 4e2c2337..c01fb710 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/InventoryFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/InventoryFragment.java
@@ -32,6 +32,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing inventory items.
+ */
 @AndroidEntryPoint
 public class InventoryFragment extends Fragment implements InventoryAdapter.OnInventoryClickListener {
 
@@ -43,12 +46,18 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(InventoryListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components, filters, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -71,6 +80,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for inventory list updates, store list, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getInventory().observe(getViewLifecycleOwner(), list -> {
             inventoryList.clear();
@@ -88,6 +100,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
+    /**
+     * Configures the bulk delete handler for multiple inventory item deletion.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -101,18 +116,27 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         );
     }
 
+    /**
+     * Reloads store data if necessary when the fragment resumes.
+     */
     @Override
     public void onResume() {
         super.onResume();
         if (!isStaff()) viewModel.loadStores();
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Sets up the filter visibility toggle, considering user roles.
+     */
     private void setupFilterToggle() {
         if (isStaff()) {
             UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchInventory);
@@ -122,18 +146,30 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         }
     }
 
+    /**
+     * Checks if the currently logged-in user has the STAFF role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchInventory, () -> loadInventory(true));
     }
 
+    /**
+     * Configures the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStore, () -> loadInventory(true));
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new InventoryAdapter(inventoryList, this);
         binding.recyclerViewInventory.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -156,10 +192,16 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshInventory.setOnRefreshListener(() -> loadInventory(true));
     }
 
+    /**
+     * Loads inventory data based on current search query and store filter.
+     */
     private void loadInventory(boolean reset) {
         String query = binding.etSearchInventory != null ? binding.etSearchInventory.getText().toString().trim() : "";
         if (query.isEmpty()) query = null;
@@ -178,6 +220,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         viewModel.loadInventory(reset, query, storeId);
     }
 
+    /**
+     * Navigates to the inventory detail screen.
+     */
     private void openDetail(InventoryDTO inv) {
         Bundle args = new Bundle();
         if (inv != null) {
@@ -186,6 +231,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         NavHostFragment.findNavController(this).navigate(R.id.nav_inventory_detail, args);
     }
 
+    /**
+     * Handles inventory item clicks by opening details.
+     */
     @Override
     public void onInventoryClick(int position) {
         if (position >= 0 && position < inventoryList.size()) {
@@ -193,6 +241,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         }
     }
 
+    /**
+     * Forwards selection changes to the bulk delete handler.
+     */
     @Override
     public void onSelectionChanged(int selectedCount) {
         if (bulkDeleteHandler != null) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PetFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PetFragment.java
index 96225e6a..c7139548 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PetFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PetFragment.java
@@ -33,6 +33,9 @@ import javax.inject.Named;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of pets.
+ */
 @AndroidEntryPoint
 public class PetFragment extends Fragment implements PetAdapter.OnPetClickListener {
     private FragmentPetBinding binding;
@@ -44,12 +47,18 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the view model.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(PetListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and initializes UI components and filters.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -72,6 +81,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         return binding.getRoot();
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the list and filter options.
+     */
     private void observeViewModel() {
         viewModel.getPets().observe(getViewLifecycleOwner(), list -> {
             petList.clear();
@@ -94,6 +106,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         });
     }
 
+    /**
+     * Configures the handler for bulk deletion of pets.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -107,6 +122,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         );
     }
 
+    /**
+     * Refreshes pet data and filters when the fragment is resumed.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -115,6 +133,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         if (!isStaff()) viewModel.loadStores();
     }
 
+    /**
+     * Sets up the visibility of filters based on the user's role.
+     */
     private void setupFilterToggle() {
         if (isStaff()) {
             UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchPet,
@@ -126,32 +147,53 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         }
     }
 
+    /**
+     * Checks if the current user has the 'STAFF' role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Attaches search functionality to the search input field.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchPet, () -> loadPetData(true));
     }
 
+    /**
+     * Initializes the status filter spinner.
+     */
     private void setupStatusFilter() {
         String[] statuses = {"All Statuses", "Available", "Adopted", "Owned", "Pending"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatus, statuses, () -> loadPetData(true));
     }
 
+    /**
+     * Initializes the species filter spinner.
+     */
     private void setupSpeciesFilter() {
         String[] initial = {"All Species"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerSpecies, initial, () -> loadPetData(true));
     }
 
+    /**
+     * Initializes the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStore, () -> loadPetData(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshPet.setOnRefreshListener(() -> loadPetData(true));
     }
 
+    /**
+     * Triggers loading of pet data from the backend with current filters.
+     */
     private void loadPetData(boolean reset) {
         String query = binding.etSearchPet.getText().toString().trim();
         String status = binding.spinnerStatus.getSelectedItem() != null ? binding.spinnerStatus.getSelectedItem().toString() : "All Statuses";
@@ -171,6 +213,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         viewModel.loadPets(reset, query, status, species, storeId);
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new PetAdapter(petList, this);
         adapter.setBaseUrl(baseUrl);
@@ -195,6 +240,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         });
     }
 
+    /**
+     * Navigates to the profile view of a specific pet.
+     */
     private void openPetProfile(int position) {
         Bundle args = new Bundle();
         PetDTO pet = petList.get(position);
@@ -202,15 +250,24 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         NavHostFragment.findNavController(this).navigate(R.id.nav_pet_profile, args);
     }
 
+    /**
+     * Navigates to the screen for adding a new pet.
+     */
     private void openPetDetails() {
         NavHostFragment.findNavController(this).navigate(R.id.nav_pet_detail);
     }
 
+    /**
+     * Handles clicks on individual pets in the list.
+     */
     @Override
     public void onPetClick(int position) {
         openPetProfile(position);
     }
 
+    /**
+     * Notifies the bulk delete handler when item selection changes.
+     */
     @Override
     public void onSelectionChanged(int selectedCount) {
         if (bulkDeleteHandler != null) {
@@ -218,6 +275,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         }
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductFragment.java
index 0820aca6..34d30e6a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductFragment.java
@@ -31,6 +31,9 @@ import javax.inject.Named;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of products.
+ */
 @AndroidEntryPoint
 public class ProductFragment extends Fragment implements ProductAdapter.OnProductClickListener {
 
@@ -41,12 +44,18 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
 
     @Inject @Named("baseUrl") String baseUrl;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ProductListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -66,6 +75,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for product list, categories, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getProducts().observe(getViewLifecycleOwner(), list -> {
             productList.clear();
@@ -83,6 +95,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         });
     }
 
+    /**
+     * Reloads product data and categories when the fragment resumes.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -90,23 +105,38 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         viewModel.loadCategories();
     }
 
+    /**
+     * Sets up the filter visibility toggle.
+     */
     private void setupFilterToggle() {
         UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter,
                 binding.etSearchProduct, binding.spinnerCategory);
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchProduct, () -> loadProductData(true));
     }
 
+    /**
+     * Configures the category filter spinner.
+     */
     private void setupCategoryFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerCategory, () -> loadProductData(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshProduct.setOnRefreshListener(() -> loadProductData(true));
     }
 
+    /**
+     * Loads product data based on current filters and search query.
+     */
     private void loadProductData(boolean reset) {
         String query = binding.etSearchProduct.getText().toString().trim();
         if (query.isEmpty()) query = null;
@@ -120,6 +150,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         viewModel.loadProducts(reset, query, categoryId);
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new ProductAdapter(productList, this);
         adapter.setBaseUrl(baseUrl);
@@ -143,6 +176,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         });
     }
 
+    /**
+     * Navigates to the product detail screen.
+     */
     private void openProductDetails(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -152,11 +188,17 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         NavHostFragment.findNavController(this).navigate(R.id.nav_product_detail, args);
     }
 
+    /**
+     * Handles product item clicks by opening details.
+     */
     @Override
     public void onProductClick(int position) {
         openProductDetails(position);
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductSupplierFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductSupplierFragment.java
index c4751ae3..d3b63523 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductSupplierFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductSupplierFragment.java
@@ -29,6 +29,9 @@ import java.util.List;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing the relationships between products and suppliers.
+ */
 @AndroidEntryPoint
 public class ProductSupplierFragment extends Fragment
         implements ProductSupplierAdapter.OnProductSupplierClickListener {
@@ -40,12 +43,18 @@ public class ProductSupplierFragment extends Fragment
     private ProductSupplierListViewModel viewModel;
     private BulkDeleteHandler bulkDeleteHandler;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ProductSupplierListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components, filters, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -67,6 +76,9 @@ public class ProductSupplierFragment extends Fragment
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for product-supplier list, products, suppliers, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getProductSuppliers().observe(getViewLifecycleOwner(), list -> {
             psList.clear();
@@ -89,6 +101,9 @@ public class ProductSupplierFragment extends Fragment
         });
     }
 
+    /**
+     * Configures the bulk delete handler for multiple product-supplier relationship deletion.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -102,6 +117,9 @@ public class ProductSupplierFragment extends Fragment
         );
     }
 
+    /**
+     * Reloads data and filter options when the fragment resumes.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -109,17 +127,26 @@ public class ProductSupplierFragment extends Fragment
         viewModel.loadFilterData();
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Sets up the filter visibility toggle.
+     */
     private void setupFilterToggle() {
         UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchPS,
                 binding.spinnerProduct, binding.spinnerSupplier);
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new ProductSupplierAdapter(psList, this);
         binding.recyclerViewPS.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -142,22 +169,37 @@ public class ProductSupplierFragment extends Fragment
         });
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchPS, () -> loadData(true));
     }
 
+    /**
+     * Configures the product filter spinner.
+     */
     private void setupProductFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerProduct, () -> loadData(true));
     }
 
+    /**
+     * Configures the supplier filter spinner.
+     */
     private void setupSupplierFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerSupplier, () -> loadData(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshPS.setOnRefreshListener(() -> loadData(true));
     }
 
+    /**
+     * Loads product-supplier data based on current search query and filters.
+     */
     private void loadData(boolean reset) {
         String query = binding.etSearchPS.getText().toString().trim();
         if (query.isEmpty()) query = null;
@@ -177,6 +219,9 @@ public class ProductSupplierFragment extends Fragment
         viewModel.loadProductSuppliers(reset, query, productId, supplierId);
     }
 
+    /**
+     * Navigates to the product-supplier detail screen.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -187,9 +232,15 @@ public class ProductSupplierFragment extends Fragment
         NavHostFragment.findNavController(this).navigate(R.id.nav_product_supplier_detail, args);
     }
 
+    /**
+     * Handles product-supplier item clicks by opening details.
+     */
     @Override
     public void onProductSupplierClick(int position) { openDetail(position); }
 
+    /**
+     * Forwards selection changes to the bulk delete handler.
+     */
     @Override
     public void onSelectionChanged(int count) {
         if (bulkDeleteHandler != null) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PurchaseOrderFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PurchaseOrderFragment.java
index f4e4e230..ea4a2bbd 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PurchaseOrderFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PurchaseOrderFragment.java
@@ -30,6 +30,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of purchase orders.
+ */
 @AndroidEntryPoint
 public class PurchaseOrderFragment extends Fragment
         implements PurchaseOrderAdapter.OnPurchaseOrderClickListener {
@@ -41,12 +44,18 @@ public class PurchaseOrderFragment extends Fragment
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(PurchaseOrderListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components, filters, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -64,6 +73,9 @@ public class PurchaseOrderFragment extends Fragment
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for purchase order list, stores, and loading status.
+     */
     private void observeViewModel() {
         viewModel.getPurchaseOrders().observe(getViewLifecycleOwner(), list -> {
             poList.clear();
@@ -81,6 +93,9 @@ public class PurchaseOrderFragment extends Fragment
         });
     }
 
+    /**
+     * Reloads data and stores if necessary when the fragment resumes.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -88,6 +103,9 @@ public class PurchaseOrderFragment extends Fragment
         if (!isStaff()) viewModel.loadStores();
     }
 
+    /**
+     * Sets up the filter visibility toggle
+     */
     private void setupFilterToggle() {
         if (isStaff()) {
             UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchPO);
@@ -97,18 +115,30 @@ public class PurchaseOrderFragment extends Fragment
         }
     }
 
+    /**
+     * Checks if the currently logged-in user has the STAFF role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchPO, () -> loadData(true));
     }
 
+    /**
+     * Configures the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStore, () -> loadData(true));
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new PurchaseOrderAdapter(poList, this);
         binding.recyclerViewPO.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -131,10 +161,16 @@ public class PurchaseOrderFragment extends Fragment
         });
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshPO.setOnRefreshListener(() -> loadData(true));
     }
 
+    /**
+     * Loads purchase order data based on current search query and store filter.
+     */
     private void loadData(boolean reset) {
         String query = binding.etSearchPO != null ? binding.etSearchPO.getText().toString().trim() : "";
         if (query.isEmpty()) query = null;
@@ -153,6 +189,9 @@ public class PurchaseOrderFragment extends Fragment
         viewModel.loadPurchaseOrders(reset, query, storeId);
     }
 
+    /**
+     * Navigates to the purchase order detail screen.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         PurchaseOrderDTO po = poList.get(position);
@@ -160,11 +199,17 @@ public class PurchaseOrderFragment extends Fragment
         NavHostFragment.findNavController(this).navigate(R.id.nav_purchase_order_detail, args);
     }
 
+    /**
+     * Handles purchase order item clicks by opening details.
+     */
     @Override
     public void onPurchaseOrderClick(int position) {
         openDetail(position);
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SaleFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SaleFragment.java
index f6d0c388..890f8c68 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SaleFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SaleFragment.java
@@ -31,6 +31,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of sales.
+ */
 @AndroidEntryPoint
 public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickListener {
 
@@ -41,6 +44,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Inflates the layout for this fragment.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -48,6 +54,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         return binding.getRoot();
     }
 
+    /**
+     * Initializes UI components and observers after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -79,6 +88,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
                 NavHostFragment.findNavController(this).navigate(R.id.nav_refund));
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the list and filter options.
+     */
     private void observeViewModel() {
         viewModel.getSales().observe(getViewLifecycleOwner(), list -> {
             saleList.clear();
@@ -101,6 +113,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         });
     }
 
+    /**
+     * Refreshes lookup data when the fragment is resumed.
+     */
     @Override
     public void onResume() {
         super.onResume();
@@ -108,6 +123,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         viewModel.loadCustomers();
     }
 
+    /**
+     * Sets up the visibility of filters.
+     */
     private void setupFilterToggle() {
         if (isStaff()) {
             UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchSale,
@@ -119,32 +137,53 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         }
     }
 
+    /**
+     * Checks if the current user has the 'STAFF' role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Checks if the current user has the 'ADMIN' role.
+     */
     private boolean isAdmin() {
         return "ADMIN".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Initializes the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStore, () -> loadSales(true));
     }
 
+    /**
+     * Initializes the payment method filter spinner.
+     */
     private void setupPaymentMethodFilter() {
         String[] paymentMethods = {"All Payments", "Cash", "Card"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerPaymentMethod, paymentMethods, () -> loadSales(true));
     }
 
+    /**
+     * Initializes the refund status filter spinner.
+     */
     private void setupRefundStatusFilter() {
         String[] refundStatuses = {"All Status", "Sale", "Refund"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerRefundStatus, refundStatuses, () -> loadSales(true));
     }
 
+    /**
+     * Initializes the customer filter spinner.
+     */
     private void setupCustomerFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerCustomer, () -> loadSales(true));
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new SaleAdapter(saleList, this);
         binding.recyclerViewSales.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -168,14 +207,23 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         });
     }
 
+    /**
+     * Attaches search functionality to the search input field.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchSale, () -> loadSales(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshSale.setOnRefreshListener(() -> loadSales(true));
     }
 
+    /**
+     * Triggers loading of sale data from the backend with current filters.
+     */
     private void loadSales(boolean reset) {
         String query = binding.etSearchSale != null ? binding.etSearchSale.getText().toString().trim() : "";
         if (query.isEmpty()) query = null;
@@ -210,6 +258,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         viewModel.loadSales(reset, query, paymentMethod, storeId, isRefund, customerId);
     }
 
+    /**
+     * Handles clicks on individual sales in the list.
+     */
     @Override
     public void onSaleClick(int position) {
         if (position < 0 || position >= saleList.size()) return;
@@ -225,6 +276,9 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         NavHostFragment.findNavController(this).navigate(R.id.nav_sale_detail, args);
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ServiceFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ServiceFragment.java
index 1aaf625d..d5a73312 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ServiceFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ServiceFragment.java
@@ -39,12 +39,18 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
     private ServiceListViewModel viewModel;
     private BulkDeleteHandler bulkDeleteHandler;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ServiceListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -67,6 +73,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for service list updates and loading status.
+     */
     private void observeViewModel() {
         viewModel.getServices().observe(getViewLifecycleOwner(), list -> {
             serviceList.clear();
@@ -79,6 +88,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         });
     }
 
+    /**
+     * Configures the bulk delete handler for multiple service deletion.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -92,20 +104,32 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         );
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Sets up the filter visibility toggle.
+     */
     private void setupFilterToggle() {
         UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchService);
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchService, () -> loadServices(true));
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new ServiceAdapter(serviceList, this);
         binding.recyclerViewServices.setLayoutManager(new LinearLayoutManager(getContext()));
@@ -128,16 +152,25 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         });
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshService.setOnRefreshListener(() -> loadServices(true));
     }
 
+    /**
+     * Loads service data based on current filters and search query.
+     */
     private void loadServices(boolean reset) {
         String query = binding.etSearchService.getText().toString().trim();
         if (query.isEmpty()) query = null;
         viewModel.loadServices(reset, query);
     }
 
+    /**
+     * Navigates to the service detail screen.
+     */
     private void openDetail(ServiceDTO service) {
         Bundle args = new Bundle();
         if (service != null) {
@@ -146,6 +179,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         NavHostFragment.findNavController(this).navigate(R.id.nav_service_detail, args);
     }
 
+    /**
+     * Handles service item clicks by opening details.
+     */
     @Override
     public void onServiceClick(int position) {
         if (position >= 0 && position < serviceList.size()) {
@@ -153,6 +189,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         }
     }
 
+    /**
+     * Forwards selection changes to the bulk delete handler.
+     */
     @Override
     public void onSelectionChanged(int count) {
         if (bulkDeleteHandler != null) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/StaffFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/StaffFragment.java
index e1e92ca7..81efdd4a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/StaffFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/StaffFragment.java
@@ -24,6 +24,9 @@ import java.util.*;
 import javax.inject.Inject;
 import javax.inject.Named;
 
+/**
+ * Fragment for displaying and managing a list of staff members.
+ */
 @AndroidEntryPoint
 public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmployeeClickListener {
 
@@ -35,6 +38,9 @@ public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmploye
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
+    /**
+     * Inflates the layout and initializes UI components, filters, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -60,6 +66,9 @@ public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmploye
         return binding.getRoot();
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the list and filter options.
+     */
     private void observeViewModel() {
         viewModel.getFilteredEmployees().observe(getViewLifecycleOwner(), list -> {
             staffList.clear();
@@ -77,6 +86,9 @@ public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmploye
         });
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new EmployeeAdapter(staffList, this);
         adapter.setBaseUrl(baseUrl);
@@ -101,19 +113,31 @@ public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmploye
         });
     }
 
+    /**
+     * Initializes the status filter spinner.
+     */
     private void setupStatusFilter() {
         String[] statuses = {"All Statuses", "Active", "Inactive"};
         SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatusStaff, statuses, this::applyFilters);
     }
 
+    /**
+     * Initializes the store filter spinner.
+     */
     private void setupStoreFilter() {
         SpinnerUtils.setupFilterSpinner(binding.spinnerStoreStaff, this::applyFilters);
     }
 
+    /**
+     * Attaches search functionality to the search input field.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchStaff, this::applyFilters);
     }
 
+    /**
+     * Applies the selected filters and triggers a data reload from the view model.
+     */
     private void applyFilters() {
         String query = binding.etSearchStaff.getText().toString().trim();
         String status = binding.spinnerStatusStaff.getSelectedItem() != null ?
@@ -128,10 +152,16 @@ public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmploye
         viewModel.filter(query, storeId, status);
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshStaff.setOnRefreshListener(() -> viewModel.loadStaff(true));
     }
 
+    /**
+     * Navigates to the staff detail screen for adding or editing an employee.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -149,11 +179,17 @@ public class StaffFragment extends Fragment implements EmployeeAdapter.OnEmploye
         NavHostFragment.findNavController(this).navigate(R.id.nav_staff_detail, args);
     }
 
+    /**
+     * Handles clicks on individual staff members in the list.
+     */
     @Override
     public void onEmployeeClick(int position) {
         openDetail(position);
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SupplierFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SupplierFragment.java
index 163ac217..ca10c7d0 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SupplierFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SupplierFragment.java
@@ -27,6 +27,9 @@ import java.util.List;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and managing a list of suppliers.
+ */
 @AndroidEntryPoint
 public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupplierClickListener {
 
@@ -36,12 +39,18 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
     private SupplierListViewModel viewModel;
     private BulkDeleteHandler bulkDeleteHandler;
 
+    /**
+     * Initializes the ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(SupplierListViewModel.class);
     }
 
+    /**
+     * Inflates the layout and sets up UI components, bulk delete, and observers.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -63,6 +72,9 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         return binding.getRoot();
     }
 
+    /**
+     * Observes the ViewModel for supplier list updates and loading status.
+     */
     private void observeViewModel() {
         viewModel.getSuppliers().observe(getViewLifecycleOwner(), list -> {
             supplierList.clear();
@@ -75,6 +87,9 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         });
     }
 
+    /**
+     * Configures the bulk delete handler for multiple supplier deletion.
+     */
     private void setupBulkDelete() {
         bulkDeleteHandler = new BulkDeleteHandler(
                 this,
@@ -88,24 +103,39 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         );
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Sets up the filter visibility toggle.
+     */
     private void setupFilterToggle() {
         UIUtils.setupFilterToggle(binding.btnToggleFilter, binding.layoutFilter, binding.etSearchSupplier);
     }
 
+    /**
+     * Sets up the search input listener.
+     */
     private void setupSearch() {
         UIUtils.attachSearch(binding.etSearchSupplier, () -> loadSupplierData(true));
     }
 
+    /**
+     * Configures the swipe-to-refresh layout.
+     */
     private void setupSwipeRefresh() {
         binding.swipeRefreshSupplier.setOnRefreshListener(() -> loadSupplierData(true));
     }
 
+    /**
+     * Navigates to the supplier detail screen.
+     */
     private void openSupplierDetails(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -115,11 +145,17 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         NavHostFragment.findNavController(this).navigate(R.id.nav_supplier_detail, args);
     }
 
+    /**
+     * Handles supplier item clicks by opening details.
+     */
     @Override
     public void onSupplierClick(int position) {
         openSupplierDetails(position);
     }
 
+    /**
+     * Forwards selection changes to the bulk delete handler.
+     */
     @Override
     public void onSelectionChanged(int count) {
         if (bulkDeleteHandler != null) {
@@ -127,12 +163,18 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         }
     }
 
+    /**
+     * Loads supplier data based on current search query.
+     */
     private void loadSupplierData(boolean reset) {
         String query = binding.etSearchSupplier != null ? binding.etSearchSupplier.getText().toString().trim() : "";
         if (query.isEmpty()) query = null;
         viewModel.loadSuppliers(reset, query);
     }
 
+    /**
+     * Configures the RecyclerView and its scroll listener for pagination.
+     */
     private void setupRecyclerView() {
         adapter = new SupplierAdapter(supplierList, this);
         binding.recyclerViewSuppliers.setLayoutManager(new LinearLayoutManager(getContext()));
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AdoptionDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AdoptionDetailFragment.java
index 1cd47561..64ec51d8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AdoptionDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AdoptionDetailFragment.java
@@ -39,12 +39,18 @@ public class AdoptionDetailFragment extends Fragment {
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the fragment and its ViewModel.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(AdoptionDetailViewModel.class);
     }
 
+    /**
+     * Inflates the layout for the fragment
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -52,6 +58,9 @@ public class AdoptionDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Sets up UI components, observers, and loads initial data after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -68,6 +77,9 @@ public class AdoptionDetailFragment extends Fragment {
         binding.btnDeleteAdoption.setOnClickListener(v -> confirmDelete());
     }
 
+    /**
+     * Sets up observers for ViewModel to update the UI dynamically.
+     */
     private void observeViewModel() {
         viewModel.getViewState().observe(getViewLifecycleOwner(), this::applyViewState);
 
@@ -113,18 +125,27 @@ public class AdoptionDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Initializes the spinners with data and selection listeners.
+     */
     private void setupSpinners() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAdoptionStatus, new String[]{});
 
@@ -141,11 +162,17 @@ public class AdoptionDetailFragment extends Fragment {
         SpinnerUtils.setOnIndexSelectedListener(binding.spinnerAdoptionStatus, p -> notifyDateStatusChange());
     }
 
+    /**
+     * Configures the date picker for the adoption date field.
+     */
     private void setupDatePicker() {
         binding.etAdoptionDate.setOnClickListener(v ->
                 UIUtils.showDatePicker(requireContext(), binding.etAdoptionDate, this::notifyDateStatusChange));
     }
 
+    /**
+     * Notifies the ViewModel when the date or status changes to update available options.
+     */
     private void notifyDateStatusChange() {
         if (isUpdatingUI) return;
         String date = binding.etAdoptionDate.getText().toString();
@@ -154,6 +181,9 @@ public class AdoptionDetailFragment extends Fragment {
         viewModel.onDateChanged(date, status);
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("adoptionId")) {
@@ -164,6 +194,9 @@ public class AdoptionDetailFragment extends Fragment {
         viewModel.setAdoptionId(-1);
     }
 
+    /**
+     * Load the adoption data from the backend.
+     */
     private void loadAdoptionData() {
         viewModel.loadAdoption().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -174,6 +207,10 @@ public class AdoptionDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Applies the current ViewState to the UI elements.
+     * This handles enabling/disabling views and setting text/selections based on state.
+     */
     private void applyViewState(AdoptionDetailViewModel.ViewState state) {
         isUpdatingUI = true;
 
@@ -224,10 +261,16 @@ public class AdoptionDetailFragment extends Fragment {
         isUpdatingUI = false;
     }
 
+    /**
+     * Checks if the currently logged-in user has the STAFF role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Validates input and saves the adoption record.
+     */
     private void saveAdoption() {
         if (!InputValidator.isSpinnerSelected(binding.spinnerAdoptionCustomer, "Customer")) return;
         if (!InputValidator.isSpinnerSelected(binding.spinnerAdoptionPet, "Pet")) return;
@@ -275,6 +318,9 @@ public class AdoptionDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the adoption record.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Adoption Record", () ->
                 viewModel.deleteAdoption().observe(getViewLifecycleOwner(), resource -> {
@@ -289,6 +335,9 @@ public class AdoptionDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AppointmentDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AppointmentDetailFragment.java
index baec0c28..a426cf8e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AppointmentDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AppointmentDetailFragment.java
@@ -47,18 +47,27 @@ public class AppointmentDetailFragment extends Fragment {
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the fragment and its ViewModel.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(AppointmentDetailViewModel.class);
     }
 
+    /**
+     * Inflates the layout for the fragment
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         binding = FragmentAppointmentDetailBinding.inflate(inflater, container, false);
         return binding.getRoot();
     }
 
+    /**
+     * Sets up UI components, observers, and loads initial data after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -73,12 +82,18 @@ public class AppointmentDetailFragment extends Fragment {
         binding.btnDeleteAppointment.setOnClickListener(v -> confirmDelete());
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Initializes the spinners with data and selection listeners.
+     */
     private void setupSpinners() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAppointmentStatus, new String[]{});
 
@@ -108,11 +123,17 @@ public class AppointmentDetailFragment extends Fragment {
         SpinnerUtils.setOnIndexSelectedListener(binding.spinnerAppointmentStatus, p -> notifyDateTimeStatusChange());
     }
 
+    /**
+     * Configures the date picker for the appointment date field.
+     */
     private void setupDatePicker() {
         binding.etAppointmentDate.setOnClickListener(v ->
                 UIUtils.showDatePicker(requireContext(), binding.etAppointmentDate, this::notifyDateTimeStatusChange));
     }
 
+    /**
+     * Sets up observers for ViewModel to update the UI dynamically.
+     */
     private void observeViewModel() {
         viewModel.getViewState().observe(getViewLifecycleOwner(), this::applyViewState);
 
@@ -147,12 +168,19 @@ public class AppointmentDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Applies the current ViewState to the UI elements.
+     * This handles enabling/disabling views and setting text/selections based on state.
+     */
     private void applyViewState(AppointmentDetailViewModel.ViewState state) {
         isUpdatingUI = true;
 
@@ -201,10 +229,16 @@ public class AppointmentDetailFragment extends Fragment {
         isUpdatingUI = false;
     }
 
+    /**
+     * Checks if the currently logged-in user has the STAFF role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Notifies the ViewModel when the date, time, or status changes to update available options.
+     */
     private void notifyDateTimeStatusChange() {
         if (isUpdatingUI) return;
 
@@ -215,6 +249,9 @@ public class AppointmentDetailFragment extends Fragment {
         viewModel.onDateOrTimeChanged(date, time, status);
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("appointmentId")) {
@@ -225,6 +262,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Load the appointment data from the backend.
+     */
     private void loadAppointmentData() {
         viewModel.loadAppointment().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -244,6 +284,9 @@ public class AppointmentDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Validates input and saves the appointment record.
+     */
     private void saveAppointment() {
         if (!validateRequiredFields()) return;
 
@@ -275,6 +318,9 @@ public class AppointmentDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Validates that all required fields are selected or filled.
+     */
     private boolean validateRequiredFields() {
         if (!InputValidator.isSpinnerSelected(binding.spinnerCustomer, "Customer")) return false;
         if (!InputValidator.isSpinnerSelected(binding.spinnerStore, "Store")) return false;
@@ -284,15 +330,24 @@ public class AppointmentDetailFragment extends Fragment {
         return true;
     }
 
+    /**
+     * Formats the selected hour and minute from spinners into a time string.
+     */
     private String buildTimeString() {
         return DateTimeUtils.formatTime(HOURS[binding.spinnerHour.getSelectedItemPosition()], MINUTES[binding.spinnerMinute.getSelectedItemPosition()]);
     }
 
+    /**
+     * Handles errors that occur during the save process.
+     */
     private void handleSaveError(String errorMessage) {
         if (errorMessage != null && errorMessage.toLowerCase().contains("not available")) showNoAvailabilityDialog();
         else Toast.makeText(getContext(), errorMessage != null ? errorMessage : "Error saving", Toast.LENGTH_SHORT).show();
     }
 
+    /**
+     * Displays a dialog when the selected time slot is not available.
+     */
     private void showNoAvailabilityDialog() {
         new androidx.appcompat.app.AlertDialog.Builder(requireContext())
                 .setTitle("No Availability")
@@ -301,6 +356,9 @@ public class AppointmentDetailFragment extends Fragment {
                 .setNegativeButton("Cancel Booking", (d, w) -> navigateBack()).show();
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the appointment record.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Appointment", () ->
                 viewModel.deleteAppointment().observe(getViewLifecycleOwner(), resource -> {
@@ -310,10 +368,16 @@ public class AppointmentDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Parses a time string and sets the hour and minute spinners accordingly.
+     */
     private void parseAndSetTimeSpinners(String time) {
         int[] parsedTime = DateTimeUtils.parseTimeString(time);
         if (parsedTime == null) return;
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CouponDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CouponDetailFragment.java
index 0d243a69..47145bcf 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CouponDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CouponDetailFragment.java
@@ -29,12 +29,18 @@ import java.util.Locale;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and editing coupon details.
+ */
 @AndroidEntryPoint
 public class CouponDetailFragment extends Fragment {
     private FragmentCouponDetailBinding binding;
     private CouponDetailViewModel viewModel;
     private long couponId = -1;
 
+    /**
+     * Inflates the layout, initializes ViewModel, and sets up UI components.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -74,10 +80,16 @@ public class CouponDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Initializes the discount type spinner with options.
+     */
     private void setupDiscountTypeSpinner() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerDiscountTypeDetail, new String[]{"FIXED", "PERCENT"});
     }
 
+    /**
+     * Configures a date picker for an EditText field.
+     */
     private void setupDatePicker(android.widget.EditText editText, android.widget.EditText dependOn, Runnable onDateSet) {
         editText.setFocusable(false);
         editText.setClickable(true);
@@ -91,6 +103,9 @@ public class CouponDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Loads coupon details from the backend and populates the UI.
+     */
     private void loadCouponDetails() {
         binding.tvCouponId.setText(DateTimeUtils.formatId(couponId));
         binding.tvCouponId.setVisibility(View.VISIBLE);
@@ -111,6 +126,9 @@ public class CouponDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Validates input and saves the coupon record.
+     */
     private void saveCoupon() {
         if (!InputValidator.isNotEmpty(binding.etCouponCodeDetail, "Coupon Code")) return;
         if (!InputValidator.isGreaterThanZero(binding.etDiscountValueDetail, "Discount Value")) return;
@@ -156,6 +174,9 @@ public class CouponDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the coupon.
+     */
     private void confirmDelete() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("Delete Coupon")
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CustomerDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CustomerDetailFragment.java
index 455450cc..017c80e2 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CustomerDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/CustomerDetailFragment.java
@@ -21,6 +21,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and editing customer details.
+ */
 @AndroidEntryPoint
 public class CustomerDetailFragment extends Fragment {
 
@@ -31,6 +34,9 @@ public class CustomerDetailFragment extends Fragment {
 
     private final String[] STATUSES = {"Active", "Inactive"};
 
+    /**
+     * Inflates the layout, initializes ViewModel, and sets up UI components.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -49,10 +55,16 @@ public class CustomerDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Initializes the spinners with data.
+     */
     private void setupSpinners() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerCustomerStatus, STATUSES);
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.getBoolean("isEditing", false)) {
@@ -86,6 +98,9 @@ public class CustomerDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads customer data from the backend.
+     */
     private void loadCustomerData(long id) {
         viewModel.loadCustomer(id).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null) {
@@ -105,12 +120,18 @@ public class CustomerDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Validates input and saves the customer record.
+     */
     private void save() {
         if (!InputValidator.isNotEmpty(binding.etCustomerUsername, "Username")) return;
 
@@ -160,6 +181,9 @@ public class CustomerDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the customer.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Customer", () ->
                 viewModel.deleteCustomer().observe(getViewLifecycleOwner(), resource -> {
@@ -175,10 +199,16 @@ public class CustomerDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/InventoryDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/InventoryDetailFragment.java
index 75f1a6b3..f0e37927 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/InventoryDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/InventoryDetailFragment.java
@@ -37,12 +37,18 @@ public class InventoryDetailFragment extends Fragment {
     private long preselectedStoreId = -1;
     private long preselectedProductId = -1;
 
+    /**
+     * Initializes the fragment and its ViewModel.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(InventoryDetailViewModel.class);
     }
 
+    /**
+     * Inflates the layout for the fragment.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -50,6 +56,9 @@ public class InventoryDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Sets up UI components, observers, and loads initial data after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -63,23 +72,35 @@ public class InventoryDetailFragment extends Fragment {
         binding.btnDeleteInventory.setOnClickListener(v -> confirmDelete());
     }
 
+    /**
+     * Sets up observers for ViewModel to update the UI dynamically.
+     */
     private void observeViewModel() {
         viewModel.getStoreList().observe(getViewLifecycleOwner(), list -> refreshStoreSpinner());
         viewModel.getProductList().observe(getViewLifecycleOwner(), list -> refreshProductSpinner());
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Loads initial data for the store and product spinners.
+     */
     private void loadSpinnersData() {
         viewModel.loadStores().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -97,18 +118,27 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Refreshes the store spinner with the current data.
+     */
     private void refreshStoreSpinner() {
         SpinnerUtils.populateSpinner(requireContext(), binding.spinnerInventoryStore, viewModel.getStoreList().getValue(),
                 DropdownDTO::getLabel, "-- Select Store --",
                 preselectedStoreId, DropdownDTO::getId);
     }
 
+    /**
+     * Refreshes the product spinner with the current data.
+     */
     private void refreshProductSpinner() {
         SpinnerUtils.populateSpinner(requireContext(), binding.spinnerInventoryProduct, viewModel.getProductList().getValue(),
                 DropdownDTO::getLabel, "-- Select Product --",
                 preselectedProductId, DropdownDTO::getId);
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         Bundle args = getArguments();
         if (args != null && args.containsKey("inventoryId")) {
@@ -131,6 +161,9 @@ public class InventoryDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the inventory data from the backend.
+     */
     private void loadInventoryData() {
         viewModel.loadInventory().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -149,6 +182,9 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Validates input and saves the inventory record.
+     */
     private void saveInventory() {
         if (!InputValidator.isSpinnerSelected(binding.spinnerInventoryStore, "Store")) return;
         if (!InputValidator.isSpinnerSelected(binding.spinnerInventoryProduct, "Product")) return;
@@ -176,10 +212,16 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the inventory record.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Inventory Item", this::deleteInventory);
     }
 
+    /**
+     * Calls the ViewModel to delete the inventory record.
+     */
     private void deleteInventory() {
         setButtonsEnabled(false);
         viewModel.deleteInventory().observe(getViewLifecycleOwner(), resource -> {
@@ -197,10 +239,16 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Enables or disables the action buttons.
+     */
     private void setButtonsEnabled(boolean enabled) {
         UIUtils.setViewsEnabled(enabled, binding.btnSaveInventory, binding.btnDeleteInventory, binding.btnInventoryBack);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductDetailFragment.java
index 5d89e305..7119a447 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductDetailFragment.java
@@ -58,6 +58,9 @@ public class ProductDetailFragment extends Fragment {
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the fragment, its ViewModel, and the ImagePickerHelper.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -88,6 +91,9 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Inflates the layout for the fragment.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -95,6 +101,9 @@ public class ProductDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Sets up UI components, observers, and handles arguments after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -108,6 +117,9 @@ public class ProductDetailFragment extends Fragment {
         binding.ivProductImage.setOnClickListener(v -> imagePickerHelper.showImagePickerDialog("Select Product Image", hasImage));
     }
 
+    /**
+     * Sets up observers for the ViewModel and loads product categories.
+     */
     private void observeViewModel() {
         viewModel.getCategoryList().observe(getViewLifecycleOwner(), list -> updateCategorySpinner());
 
@@ -120,24 +132,36 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Populates the category spinner with available categories.
+     */
     private void updateCategorySpinner() {
         SpinnerUtils.populateSpinner(requireContext(), binding.spinnerProductCategory, viewModel.getCategoryList().getValue(),
                 DropdownDTO::getLabel, "-- Select Category --",
                 preselectedCategoryId, DropdownDTO::getId);
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("prodId")) {
@@ -158,6 +182,9 @@ public class ProductDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the product details from the backend.
+     */
     private void loadProductData() {
         viewModel.loadProduct().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -175,6 +202,9 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Loads the product image from the server.
+     */
     private void loadProductImage() {
         String imageUrl = baseUrl + String.format(Locale.US, ProductApi.PRODUCT_IMAGE_PATH, viewModel.getProdId());
         String token = tokenManager.getToken();
@@ -192,6 +222,9 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Performs image-related actions (removal or upload) after a successful product save.
+     */
     private void performPendingImageActions(String successMsg) {
         if (isImageRemoved) {
             viewModel.deleteProductImage().observe(getViewLifecycleOwner(), resource -> {
@@ -214,6 +247,9 @@ public class ProductDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Uploads the selected product image to the server.
+     */
     private void uploadProductImageAndNavigate(Uri uri, String successMsg) {
         File file = FileUtils.getFileFromUri(requireContext(), uri);
         if (file == null) {
@@ -239,6 +275,9 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Validates input and saves the product record.
+     */
     private void saveProduct() {
         if (!InputValidator.isNotEmpty(binding.etProductName, "Product Name")) return;
         if (!InputValidator.isSpinnerSelected(binding.spinnerProductCategory, "Category")) return;
@@ -267,6 +306,9 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the product.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Product", () ->
                 viewModel.deleteProduct().observe(getViewLifecycleOwner(), resource -> {
@@ -280,6 +322,9 @@ public class ProductDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductSupplierDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductSupplierDetailFragment.java
index 6abb918c..e0ba9409 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductSupplierDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductSupplierDetailFragment.java
@@ -35,12 +35,18 @@ public class ProductSupplierDetailFragment extends Fragment {
     private long preselectedProductId = -1;
     private long preselectedSupplierId = -1;
 
+    /**
+     * Initializes the view model.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ProductSupplierDetailViewModel.class);
     }
 
+    /**
+     * Inflates the layout for this fragment.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -48,6 +54,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Initializes the UI components and observers after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -60,23 +69,35 @@ public class ProductSupplierDetailFragment extends Fragment {
         binding.btnDeletePS.setOnClickListener(v -> confirmDelete());
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the UI.
+     */
     private void observeViewModel() {
         viewModel.getProductList().observe(getViewLifecycleOwner(), list -> refreshProductSpinner());
         viewModel.getSupplierList().observe(getViewLifecycleOwner(), list -> refreshSupplierSpinner());
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Loads lookup data for products and suppliers.
+     */
     private void loadSpinnersData() {
         viewModel.loadProducts().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -94,18 +115,27 @@ public class ProductSupplierDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Refreshes the product spinner with data from the view model.
+     */
     private void refreshProductSpinner() {
         SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPSProduct, viewModel.getProductList().getValue(),
                 ProductDTO::getProdName, "-- Select Product --",
                 preselectedProductId, ProductDTO::getProdId);
     }
 
+    /**
+     * Refreshes the supplier spinner with data from the view model.
+     */
     private void refreshSupplierSpinner() {
         SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPSSupplier, viewModel.getSupplierList().getValue(),
                 SupplierDTO::getSupCompany, "-- Select Supplier --",
                 preselectedSupplierId, SupplierDTO::getSupId);
     }
 
+    /**
+     * Handles fragment arguments to determine mode (new vs edit).
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("productId") && a.containsKey("supplierId")) {
@@ -132,6 +162,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Validates and saves the product-supplier relationship.
+     */
     private void save() {
         if (!InputValidator.isSpinnerSelected(binding.spinnerPSProduct, "Product")) return;
         if (!InputValidator.isSpinnerSelected(binding.spinnerPSSupplier, "Supplier")) return;
@@ -155,6 +188,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows a confirmation dialog before deleting the relationship.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Product Supplier Relationship", () ->
                 viewModel.deleteProductSupplier().observe(getViewLifecycleOwner(), resource -> {
@@ -169,6 +205,9 @@ public class ProductSupplierDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/PurchaseOrderDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/PurchaseOrderDetailFragment.java
index d1bbd31c..aca42375 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/PurchaseOrderDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/PurchaseOrderDetailFragment.java
@@ -27,6 +27,9 @@ public class PurchaseOrderDetailFragment extends Fragment {
     private PurchaseOrderDetailViewModel viewModel;
     private long purchaseOrderId;
 
+    /**
+     * Initializes the view model.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -57,6 +60,9 @@ public class PurchaseOrderDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Handles fragment arguments to retrieve the purchase order ID.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("purchaseOrderId")) {
@@ -65,12 +71,18 @@ public class PurchaseOrderDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Loads the details of the specified purchase order.
+     */
     private void loadPurchaseOrderData() {
         viewModel.loadPurchaseOrder(purchaseOrderId).observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -87,6 +99,9 @@ public class PurchaseOrderDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/RefundFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/RefundFragment.java
index 0dbd985f..6165be7b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/RefundFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/RefundFragment.java
@@ -21,6 +21,9 @@ import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.util.*;
 
+/**
+ * Fragment for processing refunds for existing sales.
+ */
 @AndroidEntryPoint
 public class RefundFragment extends Fragment {
 
@@ -29,6 +32,9 @@ public class RefundFragment extends Fragment {
 
     private final String[] PAYMENT_METHODS = {"Cash", "Card"};
 
+    /**
+     * Initializes the fragment's UI and view model.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -51,25 +57,37 @@ public class RefundFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Sets up the payment method spinner.
+     */
     private void setupSpinner() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerRefundPayment, PAYMENT_METHODS);
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the UI.
+     */
     private void observeViewModel() {
         viewModel.getAvailableItems().observe(getViewLifecycleOwner(), items -> renderOriginalItems());
         viewModel.getRefundCart().observe(getViewLifecycleOwner(), cart -> {
             renderRefundCart();
             updateRefundTotal();
-            renderOriginalItems(); // Re-render to reflect quantities in cart
+            renderOriginalItems();
         });
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Loads the list of all sales to allow looking up the sale to refund.
+     */
     private void loadAllSales() {
         viewModel.loadAllSales().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -84,6 +102,9 @@ public class RefundFragment extends Fragment {
         });
     }
 
+    /**
+     * Loads the details of a specific sale for refund processing.
+     */
     private void loadSale() {
         String idStr = binding.etRefundSaleId.getText().toString().trim();
         if (idStr.isEmpty()) {
@@ -145,6 +166,9 @@ public class RefundFragment extends Fragment {
         binding.btnProcessRefund.setVisibility(View.VISIBLE);
     }
 
+    /**
+     * Renders the items from the original sale that are available for refund.
+     */
     private void renderOriginalItems() {
         binding.llOriginalItems.removeAllViews();
         List<RefundViewModel.RefundItem> available = viewModel.getAvailableItems().getValue();
@@ -173,6 +197,9 @@ public class RefundFragment extends Fragment {
         }
     }
 
+    /**
+     * Renders the items selected for the refund.
+     */
     private void renderRefundCart() {
         binding.llRefundItems.removeAllViews();
         List<RefundViewModel.RefundItem> cart = viewModel.getRefundCart().getValue();
@@ -200,6 +227,9 @@ public class RefundFragment extends Fragment {
         }
     }
 
+    /**
+     * Adds a header row to the layout representing a table.
+     */
     private void addTableHeader(LinearLayout parent) {
         if (getContext() == null) return;
         LinearLayout header = new LinearLayout(getContext());
@@ -220,6 +250,9 @@ public class RefundFragment extends Fragment {
         parent.addView(header);
     }
 
+    /**
+     * Builds a UI row for an item in the original list or refund cart.
+     */
     private LinearLayout buildItemRow(String name, int qty, BigDecimal unitPrice,
                                       boolean isAdd, Runnable action) {
         if (getContext() == null) return new LinearLayout(getContext());
@@ -267,6 +300,9 @@ public class RefundFragment extends Fragment {
         return row;
     }
 
+    /**
+     * Shows a dialog to select the quantity of an item to refund.
+     */
     private void showQuantityDialog(RefundViewModel.RefundItem item, int available) {
         EditText input = new EditText(getContext());
         input.setInputType(android.text.InputType.TYPE_CLASS_NUMBER);
@@ -301,11 +337,17 @@ public class RefundFragment extends Fragment {
                 .show();
     }
 
+    /**
+     * Updates the total refund amount display.
+     */
     private void updateRefundTotal() {
         BigDecimal total = viewModel.calculateRefundTotal();
         binding.tvRefundTotal.setText("Refund Total: $" + total.setScale(2, RoundingMode.HALF_UP));
     }
 
+    /**
+     * Validates and prepares the refund for processing.
+     */
     private void processRefund() {
         if (viewModel.getCurrentSale() == null) {
             Toast.makeText(getContext(), "Load a sale first", Toast.LENGTH_SHORT).show();
@@ -325,6 +367,9 @@ public class RefundFragment extends Fragment {
                 () -> submitRefund(payment));
     }
 
+    /**
+     * Submits the refund request to the backend.
+     */
     private void submitRefund(String payment) {
         viewModel.submitRefund(payment).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null) {
@@ -339,10 +384,16 @@ public class RefundFragment extends Fragment {
         });
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SaleDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SaleDetailFragment.java
index 4963b272..b1ecb2b9 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SaleDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SaleDetailFragment.java
@@ -26,6 +26,9 @@ import dagger.hilt.android.AndroidEntryPoint;
 import java.math.BigDecimal;
 import java.util.*;
 
+/**
+ * Fragment for viewing or creating sale details.
+ */
 @AndroidEntryPoint
 public class SaleDetailFragment extends Fragment {
 
@@ -36,6 +39,9 @@ public class SaleDetailFragment extends Fragment {
 
     private final String[] PAYMENT_METHODS = { "Cash", "Card"};
 
+    /**
+     * Initializes the fragment's UI and view model.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -65,14 +71,23 @@ public class SaleDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Checks if the current user has the 'STAFF' role.
+     */
     private boolean isStaff() {
         return "STAFF".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Checks if the current user has the 'ADMIN' role.
+     */
     private boolean isAdmin() {
         return "ADMIN".equalsIgnoreCase(tokenManager.getRole());
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the UI.
+     */
     private void observeViewModel() {
         viewModel.getStoreList().observe(getViewLifecycleOwner(), list -> {
             Long primaryStoreId = tokenManager.getPrimaryStoreId();
@@ -115,6 +130,9 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Handles fragment arguments to determine mode (new sale vs view existing).
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("saleId")) {
@@ -159,12 +177,18 @@ public class SaleDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Loads lookup data for stores, customers, and products.
+     */
     private void loadData() {
         viewModel.loadStores().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -183,6 +207,9 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Loads the details of an existing sale.
+     */
     private void loadSaleDetails() {
         viewModel.loadSaleDetails().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -241,6 +268,9 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Sets up the coupon application logic.
+     */
     private void setupCoupon() {
         binding.btnApplyCoupon.setOnClickListener(v -> {
             String code = binding.etCouponCode.getText().toString().trim();
@@ -284,6 +314,9 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Updates the UI to reflect an applied coupon.
+     */
     private void applyAppliedCouponUI(CouponDTO coupon) {
         String info;
         if ("PERCENTAGE".equalsIgnoreCase(coupon.getDiscountType())) {
@@ -299,12 +332,18 @@ public class SaleDetailFragment extends Fragment {
         binding.etCouponCode.setEnabled(false);
     }
 
+    /**
+     * Displays an error message related to coupon validation.
+     */
     private void showCouponError(String message) {
         binding.tvCouponInfo.setText(message);
         binding.tvCouponInfo.setTextColor(0xFFE53935);
         binding.tvCouponInfo.setVisibility(View.VISIBLE);
     }
 
+    /**
+     * Sets up the logic for adding items to the sale cart.
+     */
     private void setupAddItem() {
         binding.btnAddItem.setOnClickListener(v -> {
             if (!InputValidator.isSpinnerSelected(binding.spinnerSaleProduct, "Product")) return;
@@ -338,6 +377,9 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Renders the list of items currently in the cart.
+     */
     private void renderCartItems() {
         binding.llSaleItems.removeAllViews();
         List<SaleDTO.SaleItemDTO> items = viewModel.getCartItems().getValue();
@@ -358,6 +400,9 @@ public class SaleDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Adds a row representing a sale item to the layout.
+     */
     private void addItemRow(String name, int qty, BigDecimal price, Long prodId) {
         if (getContext() == null) return;
         LinearLayout row = new LinearLayout(getContext());
@@ -397,6 +442,9 @@ public class SaleDetailFragment extends Fragment {
         binding.llSaleItems.addView(row);
     }
 
+    /**
+     * Updates the subtotal, discounts, and total amount display.
+     */
     private void updateTotal() {
         BigDecimal subtotal = viewModel.calculateSubtotal();
         BigDecimal couponDiscount = viewModel.calculateCouponDiscount();
@@ -432,6 +480,9 @@ public class SaleDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Validates and saves the new sale.
+     */
     private void saveSale() {
         if (!InputValidator.isSpinnerSelected(binding.spinnerSaleStore, "Store")) return;
 
@@ -468,6 +519,9 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows a confirmation dialog before proceeding to the refund screen.
+     */
     private void showRefundDialog() {
         DialogUtils.showConfirmDialog(requireContext(), "Process Refund", 
             "Are you sure you want to process a refund for this sale?", () -> {
@@ -477,10 +531,16 @@ public class SaleDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ServiceDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ServiceDetailFragment.java
index d7ee6e4c..0a0612c5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ServiceDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ServiceDetailFragment.java
@@ -35,12 +35,18 @@ public class ServiceDetailFragment extends Fragment {
     private FragmentServiceDetailBinding binding;
     private ServiceDetailViewModel viewModel;
 
+    /**
+     * Initializes the fragment and its ViewModel.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ServiceDetailViewModel.class);
     }
 
+    /**
+     * Inflates the layout for the fragment.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -48,6 +54,9 @@ public class ServiceDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Sets up UI components, observers, and handles arguments after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -60,22 +69,34 @@ public class ServiceDetailFragment extends Fragment {
         binding.btnDeleteService.setOnClickListener(v -> deleteService());
     }
 
+    /**
+     * Sets up observers for ViewModel to update the UI dynamically.
+     */
     private void observeViewModel() {
         viewModel.getViewState().observe(getViewLifecycleOwner(), this::applyViewState);
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Validates input and saves the service record.
+     */
     private void saveService() {
         if (!InputValidator.isNotEmpty(binding.etServiceName, "Service Name")) return;
         if (!InputValidator.isNotEmpty(binding.etServiceDesc, "Description")) return;
@@ -111,6 +132,9 @@ public class ServiceDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the service record.
+     */
     private void deleteService() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Service", () -> 
                 viewModel.deleteService().observe(getViewLifecycleOwner(), resource -> {
@@ -126,10 +150,16 @@ public class ServiceDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         if (getArguments() != null && getArguments().containsKey("serviceId")) {
             viewModel.setServiceId(getArguments().getLong("serviceId"));
@@ -140,6 +170,9 @@ public class ServiceDetailFragment extends Fragment {
         viewModel.setServiceId(-1);
     }
 
+    /**
+     * Loads the service details from the backend.
+     */
     private void loadServiceData() {
         viewModel.loadService().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -150,6 +183,9 @@ public class ServiceDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Applies the current ViewState to the UI elements.
+     */
     private void applyViewState(ServiceDetailViewModel.ViewState state) {
         binding.tvMode.setText(state.modeTitle);
         binding.tvServiceId.setText(DateTimeUtils.formatId(viewModel.getServiceId()));
@@ -169,6 +205,9 @@ public class ServiceDetailFragment extends Fragment {
         updateIfDifferent(binding.etServicePrice, state.servicePrice);
     }
 
+    /**
+     * Updates an EditText field only if the new value is different from the current one.
+     */
     private void updateIfDifferent(EditText field, String value) {
         String current = field.getText() != null ? field.getText().toString() : "";
         String next = value != null ? value : "";
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/StaffDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/StaffDetailFragment.java
index 9bb3435d..0f69f7b5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/StaffDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/StaffDetailFragment.java
@@ -22,6 +22,9 @@ import java.util.List;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and editing staff details.
+ */
 @AndroidEntryPoint
 public class StaffDetailFragment extends Fragment {
 
@@ -32,6 +35,9 @@ public class StaffDetailFragment extends Fragment {
 
     private long preselectedStoreId = -1;
 
+    /**
+     * Inflates the layout, initializes ViewModel, and sets up UI components.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -52,14 +58,23 @@ public class StaffDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Sets up observers for the ViewModel to refresh the store spinner.
+     */
     private void observeViewModel() {
         viewModel.getStoreList().observe(getViewLifecycleOwner(), list -> refreshStoreSpinner());
     }
 
+    /**
+     * Initializes the status spinner with options.
+     */
     private void setupSpinners() {
         SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerStaffStatus, STATUSES);
     }
 
+    /**
+     * Loads the list of stores from the backend.
+     */
     private void loadStores() {
         viewModel.loadStores().observe(getViewLifecycleOwner(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -68,6 +83,9 @@ public class StaffDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Populates the store spinner with available stores.
+     */
     private void refreshStoreSpinner() {
         List<DropdownDTO> list = viewModel.getStoreList().getValue();
         if (list == null) return;
@@ -76,6 +94,9 @@ public class StaffDetailFragment extends Fragment {
                 preselectedStoreId, DropdownDTO::getId);
     }
 
+    /**
+     * Uses fragment arguments to determine if we are editing an existing record.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.getBoolean("isEditing", false)) {
@@ -96,6 +117,9 @@ public class StaffDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads staff member details from the backend.
+     */
     private void loadEmployeeData(long id) {
         viewModel.loadEmployee(id).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null) {
@@ -117,12 +141,18 @@ public class StaffDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Shows or hides the loading bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Validates input and saves the staff record.
+     */
     private void save() {
         if (!InputValidator.isNotEmpty(binding.etStaffUsername, "Username")) return;
 
@@ -198,6 +228,9 @@ public class StaffDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Displays a confirmation dialog before deleting the staff account.
+     */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Staff Account", () ->
                 viewModel.deleteEmployee().observe(getViewLifecycleOwner(), resource -> {
@@ -213,10 +246,16 @@ public class StaffDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SupplierDetailFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SupplierDetailFragment.java
index 5eb1f43b..513e627c 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SupplierDetailFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SupplierDetailFragment.java
@@ -35,12 +35,18 @@ public class SupplierDetailFragment extends Fragment {
     private FragmentSupplierDetailBinding binding;
     private SupplierDetailViewModel viewModel;
 
+    /**
+     * Initializes the view model.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(SupplierDetailViewModel.class);
     }
 
+    /**
+     * Inflates the layout for this fragment.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -48,6 +54,9 @@ public class SupplierDetailFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Initializes the UI components and observers after the view is created.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -61,22 +70,34 @@ public class SupplierDetailFragment extends Fragment {
         binding.btnDeleteSupplier.setOnClickListener(v -> deleteSupplier());
     }
 
+    /**
+     * Observes LiveData from the ViewModel to update the UI.
+     */
     private void observeViewModel() {
         viewModel.getViewState().observe(getViewLifecycleOwner(), this::applyViewState);
     }
 
+    /**
+     * Toggles the visibility of the progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding when the view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Validates and saves the supplier information.
+     */
     private void saveSupplier() {
         if (!InputValidator.isNotEmpty(binding.etSupCompany, "Company Name")) return;
         if (!InputValidator.isNotEmpty(binding.etSupContactFirstName, "First Name")) return;
@@ -115,6 +136,9 @@ public class SupplierDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Deletes the current supplier after confirmation.
+     */
     private void deleteSupplier() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Supplier", () ->
                 viewModel.deleteSupplier().observe(getViewLifecycleOwner(), resource -> {
@@ -130,10 +154,16 @@ public class SupplierDetailFragment extends Fragment {
                 }));
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Handles fragment arguments to determine mode (new vs edit).
+     */
     private void handleArguments() {
         if (getArguments() != null && getArguments().containsKey("supId")) {
             viewModel.setSupId(getArguments().getLong("supId"));
@@ -144,6 +174,9 @@ public class SupplierDetailFragment extends Fragment {
         viewModel.setSupId(-1);
     }
 
+    /**
+     * Loads the details of the specified supplier.
+     */
     private void loadSupplierData() {
         viewModel.loadSupplier().observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -154,6 +187,9 @@ public class SupplierDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Applies the current view state to the UI components.
+     */
     private void applyViewState(SupplierDetailViewModel.ViewState state) {
         binding.tvMode.setText(state.modeTitle);
         binding.tvSupId.setText(DateTimeUtils.formatId(viewModel.getSupId()));
@@ -175,6 +211,9 @@ public class SupplierDetailFragment extends Fragment {
         updateIfDifferent(binding.etSupPhone, state.supPhone);
     }
 
+    /**
+     * Updates an EditText field only if the new value is different from the current one.
+     */
     private void updateIfDifferent(EditText field, String value) {
         String current = field.getText() != null ? field.getText().toString() : "";
         String next = value != null ? value : "";
diff --git a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/listprofilefragments/PetProfileFragment.java b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/listprofilefragments/PetProfileFragment.java
index 496304a3..7cfa0910 100644
--- a/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/listprofilefragments/PetProfileFragment.java
+++ b/android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/listprofilefragments/PetProfileFragment.java
@@ -36,6 +36,9 @@ import okhttp3.MediaType;
 import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
 
+/**
+ * Fragment for displaying and managing a pet's profile.
+ */
 @AndroidEntryPoint
 public class PetProfileFragment extends Fragment {
 
@@ -49,6 +52,9 @@ public class PetProfileFragment extends Fragment {
     private PetProfileViewModel viewModel;
     private ImagePickerHelper imagePickerHelper;
 
+    /**
+     * Initializes the ViewModel and image picker helper.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -67,6 +73,9 @@ public class PetProfileFragment extends Fragment {
         });
     }
 
+    /**
+     * Inflates the layout, handles arguments, and sets up click listeners.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -95,18 +104,27 @@ public class PetProfileFragment extends Fragment {
         return binding.getRoot();
     }
 
+    /**
+     * Shows or hides the loading progress bar.
+     */
     private void setLoading(boolean loading) {
         if (binding != null && binding.progressBar != null) {
             binding.progressBar.setVisibility(loading ? View.VISIBLE : View.GONE);
         }
     }
 
+    /**
+     * Cleans up the binding reference.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
         binding = null;
     }
 
+    /**
+     * Loads pet data from the ViewModel and updates the UI.
+     */
     private void loadPetData() {
         viewModel.getPetById(petId).observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
@@ -153,6 +171,9 @@ public class PetProfileFragment extends Fragment {
         });
     }
 
+    /**
+     * Loads the pet's image using Glide with authentication.
+     */
     private void loadPetImage(int petId) {
         String imageUrl = baseUrl + String.format(Locale.US, PetApi.PET_IMAGE_PATH, petId);
         String token = tokenManager.getToken();
@@ -170,6 +191,9 @@ public class PetProfileFragment extends Fragment {
         });
     }
 
+    /**
+     * Uploads a new image for the pet.
+     */
     private void uploadPetImage(Uri uri) {
         try {
             File file = FileUtils.getFileFromUri(requireContext(), uri);
@@ -193,6 +217,9 @@ public class PetProfileFragment extends Fragment {
         }
     }
 
+    /**
+     * Deletes the pet's current image.
+     */
     private void deletePetImage() {
         viewModel.deletePetImage(petId).observe(getViewLifecycleOwner(), resource -> {
             if (resource == null) return;
diff --git a/android/app/src/main/java/com/example/petstoremobile/models/Chat.java b/android/app/src/main/java/com/example/petstoremobile/models/Chat.java
index a519093c..9d782b05 100644
--- a/android/app/src/main/java/com/example/petstoremobile/models/Chat.java
+++ b/android/app/src/main/java/com/example/petstoremobile/models/Chat.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.models;
 
+/**
+ * Model class representing a chat conversation.
+ */
 public class Chat {
     private String chatId;
     private String customerName;
diff --git a/android/app/src/main/java/com/example/petstoremobile/models/Message.java b/android/app/src/main/java/com/example/petstoremobile/models/Message.java
index e6547d23..2e0ff23e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/models/Message.java
+++ b/android/app/src/main/java/com/example/petstoremobile/models/Message.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.models;
 
+/**
+ * Model class representing a chat message.
+ */
 public class Message {
     private Long id;
     private Long conversationId;
diff --git a/android/app/src/main/java/com/example/petstoremobile/models/Sale.java b/android/app/src/main/java/com/example/petstoremobile/models/Sale.java
index ce305d58..c67126e1 100644
--- a/android/app/src/main/java/com/example/petstoremobile/models/Sale.java
+++ b/android/app/src/main/java/com/example/petstoremobile/models/Sale.java
@@ -1,5 +1,8 @@
 package com.example.petstoremobile.models;
 
+/**
+ * Model class representing a sale transaction.
+ */
 public class Sale {
     private int saleId;
     private String saleDate;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/ActivityLogRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/ActivityLogRepository.java
index 6c8acddf..ac890c9a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/ActivityLogRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/ActivityLogRepository.java
@@ -11,6 +11,9 @@ import java.util.List;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for retrieving activity logs from the ActivityLogApi.
+ */
 @Singleton
 public class ActivityLogRepository extends BaseRepository {
     private final ActivityLogApi activityLogApi;
@@ -21,6 +24,9 @@ public class ActivityLogRepository extends BaseRepository {
         this.activityLogApi = activityLogApi;
     }
 
+    /**
+     * Retrieves a list of activity logs with optional filtering.
+     */
     public LiveData<Resource<List<ActivityLogDTO>>> getActivityLogs(int limit, Long storeId, String role, String search, String startDate, String endDate) {
         return executeCall(activityLogApi.getActivityLogs(limit, storeId, role, search, startDate, endDate));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/AdoptionRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/AdoptionRepository.java
index 8758357a..fd9e5e3c 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/AdoptionRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/AdoptionRepository.java
@@ -11,6 +11,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing adoption data through the AdoptionApi.
+ */
 @Singleton
 public class AdoptionRepository extends BaseRepository {
     private final AdoptionApi adoptionApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/AppointmentRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/AppointmentRepository.java
index 6c2c4cf8..3f20ff3e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/AppointmentRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/AppointmentRepository.java
@@ -11,6 +11,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing service appointments.
+ */
 @Singleton
 public class AppointmentRepository extends BaseRepository {
     private final AppointmentApi appointmentApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/AuthRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/AuthRepository.java
index 6011bac8..3e8fa71a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/AuthRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/AuthRepository.java
@@ -22,6 +22,9 @@ import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
+/**
+ * Repository class for handling authentication-related operations.
+ */
 @Singleton
 public class AuthRepository extends BaseRepository {
     private final AuthApi authApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/BaseRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/BaseRepository.java
index cf98dfe8..f56067f4 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/BaseRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/BaseRepository.java
@@ -9,7 +9,7 @@ import com.example.petstoremobile.utils.RetrofitUtils;
 import retrofit2.Call;
 
 /**
- * Base class for all repositories to provide common functionality for API calls.
+ * Base repository class providing common functionality for executing API calls and handling responses.
  */
 public abstract class BaseRepository {
     protected final String TAG;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/CategoryRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/CategoryRepository.java
index 8d11511b..f518615b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/CategoryRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/CategoryRepository.java
@@ -10,6 +10,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing product and service categories.
+ */
 @Singleton
 public class CategoryRepository extends BaseRepository {
     private final CategoryApi categoryApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/ChatRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/ChatRepository.java
index ec8e32b6..4e5f3ada 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/ChatRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/ChatRepository.java
@@ -23,7 +23,7 @@ import okhttp3.RequestBody;
 import okhttp3.ResponseBody;
 
 /**
- * Repository for handling chat-related data operations.
+ * Repository class for managing chat messages and conversations.
  */
 @Singleton
 public class ChatRepository extends BaseRepository {
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/CouponRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/CouponRepository.java
index f97d1ca0..83f2289f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/CouponRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/CouponRepository.java
@@ -12,6 +12,9 @@ import java.util.List;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing coupon data.
+ */
 @Singleton
 public class CouponRepository extends BaseRepository {
     private final CouponApi couponApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/CustomerRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/CustomerRepository.java
index 65c9a79d..6067b625 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/CustomerRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/CustomerRepository.java
@@ -13,6 +13,9 @@ import java.util.List;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing customer information.
+ */
 @Singleton
 public class CustomerRepository extends BaseRepository {
     private final CustomerApi customerApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/EmployeeRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/EmployeeRepository.java
index b6ddcc9c..745936e6 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/EmployeeRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/EmployeeRepository.java
@@ -10,6 +10,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing employee data and roles.
+ */
 @Singleton
 public class EmployeeRepository extends BaseRepository {
     private final EmployeeApi employeeApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/InventoryRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/InventoryRepository.java
index 94526d25..83e8b9c1 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/InventoryRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/InventoryRepository.java
@@ -11,6 +11,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing inventory and stock levels.
+ */
 @Singleton
 public class InventoryRepository extends BaseRepository {
     private final InventoryApi inventoryApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/PetRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/PetRepository.java
index 11bb9ff1..f035fa92 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/PetRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/PetRepository.java
@@ -16,6 +16,9 @@ import javax.inject.Singleton;
 
 import okhttp3.MultipartBody;
 
+/**
+ * Repository class for managing pet data through the PetApi.
+ */
 @Singleton
 public class PetRepository extends BaseRepository {
     private final PetApi petApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/ProductRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/ProductRepository.java
index 636e1430..1fca4df1 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/ProductRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/ProductRepository.java
@@ -15,6 +15,9 @@ import javax.inject.Singleton;
 
 import okhttp3.MultipartBody;
 
+/**
+ * Repository class for managing product information and inventory levels.
+ */
 @Singleton
 public class ProductRepository extends BaseRepository {
     private final ProductApi productApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/ProductSupplierRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/ProductSupplierRepository.java
index 9b2f8df3..41d0393f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/ProductSupplierRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/ProductSupplierRepository.java
@@ -11,6 +11,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing relationships between products and their suppliers.
+ */
 @Singleton
 public class ProductSupplierRepository extends BaseRepository {
     private final ProductSupplierApi api;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/PurchaseOrderRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/PurchaseOrderRepository.java
index dd9bd637..70537ade 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/PurchaseOrderRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/PurchaseOrderRepository.java
@@ -10,6 +10,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing purchase orders with suppliers.
+ */
 @Singleton
 public class PurchaseOrderRepository extends BaseRepository {
     private final PurchaseOrderApi purchaseOrderApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/SaleRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/SaleRepository.java
index 182a7f0e..4fb697a0 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/SaleRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/SaleRepository.java
@@ -10,6 +10,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing sale transactions and refund data.
+ */
 @Singleton
 public class SaleRepository extends BaseRepository {
     private final SaleApi saleApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/ServiceRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/ServiceRepository.java
index bd5f3ebc..98e8b457 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/ServiceRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/ServiceRepository.java
@@ -11,6 +11,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing pet service offerings.
+ */
 @Singleton
 public class ServiceRepository extends BaseRepository {
     private final ServiceApi serviceApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/StoreRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/StoreRepository.java
index 0df93ab1..dca03260 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/StoreRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/StoreRepository.java
@@ -13,6 +13,9 @@ import java.util.List;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for retrieving store-related information.
+ */
 @Singleton
 public class StoreRepository extends BaseRepository {
     private final StoreApi storeApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/SupplierRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/SupplierRepository.java
index 7aef86a2..bfdf9e39 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/SupplierRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/SupplierRepository.java
@@ -11,6 +11,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing supplier data.
+ */
 @Singleton
 public class SupplierRepository extends BaseRepository {
     private final SupplierApi supplierApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/repositories/UserRepository.java b/android/app/src/main/java/com/example/petstoremobile/repositories/UserRepository.java
index 0ed9ced9..bfa9cc23 100644
--- a/android/app/src/main/java/com/example/petstoremobile/repositories/UserRepository.java
+++ b/android/app/src/main/java/com/example/petstoremobile/repositories/UserRepository.java
@@ -10,6 +10,9 @@ import com.example.petstoremobile.utils.Resource;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+/**
+ * Repository class for managing user profile and account data.
+ */
 @Singleton
 public class UserRepository extends BaseRepository {
     private final UserApi userApi;
diff --git a/android/app/src/main/java/com/example/petstoremobile/services/ChatNotificationService.java b/android/app/src/main/java/com/example/petstoremobile/services/ChatNotificationService.java
index 90113cac..46fc5f4d 100644
--- a/android/app/src/main/java/com/example/petstoremobile/services/ChatNotificationService.java
+++ b/android/app/src/main/java/com/example/petstoremobile/services/ChatNotificationService.java
@@ -30,7 +30,9 @@ import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
-// Service to receive notifications when a new conversation is created
+/**
+ * Service to receive and display notifications when a new chat conversation or message is created.
+ */
 @AndroidEntryPoint
 public class ChatNotificationService extends Service {
     private static final String TAG = "ChatNotificationService";
diff --git a/android/app/src/main/java/com/example/petstoremobile/utils/EventDecorator.java b/android/app/src/main/java/com/example/petstoremobile/utils/EventDecorator.java
index b58f38d4..4f3e62ad 100644
--- a/android/app/src/main/java/com/example/petstoremobile/utils/EventDecorator.java
+++ b/android/app/src/main/java/com/example/petstoremobile/utils/EventDecorator.java
@@ -8,11 +8,17 @@ import com.prolificinteractive.materialcalendarview.spans.DotSpan;
 import java.util.Collection;
 import java.util.HashSet;
 
+/**
+ * Decorator for MaterialCalendarView to highlight specific dates with a colored dot.
+ */
 public class EventDecorator implements DayViewDecorator {
 
     private final int color;
     private final HashSet<CalendarDay> dates;
 
+    /**
+     * Initializes the decorator with a color and a collection of dates to highlight.
+     */
     public EventDecorator(int color, Collection<CalendarDay> dates) {
         this.color = color;
         this.dates = new HashSet<>(dates);
diff --git a/android/app/src/main/java/com/example/petstoremobile/utils/FileUtils.java b/android/app/src/main/java/com/example/petstoremobile/utils/FileUtils.java
index bf45f4f8..174b23f5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/utils/FileUtils.java
+++ b/android/app/src/main/java/com/example/petstoremobile/utils/FileUtils.java
@@ -8,7 +8,14 @@ import java.io.File;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 
+/**
+ * Utility class for file operations, particularly handling Uris from the Android content system.
+ */
 public class FileUtils {
+    /**
+     * Creates a temporary file in the cache directory from a given Uri.
+     * This allows the app to work with a local file path instead of a content stream.
+     */
     public static File getFileFromUri(Context context, Uri uri) {
         try {
             if ("content".equals(uri.getScheme())) {
@@ -48,6 +55,9 @@ public class FileUtils {
         }
     }
 
+    /**
+     * Retrieves the display name of a file from its Uri.
+     */
     public static String getFileName(Context context, Uri uri) {
         String result = null;
         if (uri.getScheme().equals("content")) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/utils/SelectionHelper.java b/android/app/src/main/java/com/example/petstoremobile/utils/SelectionHelper.java
index 197cb557..f651c25a 100644
--- a/android/app/src/main/java/com/example/petstoremobile/utils/SelectionHelper.java
+++ b/android/app/src/main/java/com/example/petstoremobile/utils/SelectionHelper.java
@@ -5,7 +5,7 @@ import java.util.List;
 
 /**
  * Helper class to manage selection state in Adapters for bulk operations.
- * Uses String keys to support both simple Long IDs and composite keys (e.g., "id1-id2").
+ * Uses String keys to support both Long IDs and composite keys.
  */
 public class SelectionHelper {
 
@@ -13,15 +13,32 @@ public class SelectionHelper {
     private boolean selectionMode = false;
     private final SelectionListener listener;
 
+    /**
+     * Listener interface to observe selection state changes.
+     */
     public interface SelectionListener {
+        /**
+         * Called when the number of selected items changes.
+         */
         void onSelectionChanged(int count);
+
+        /**
+         * Called when selection mode is enabled or disabled.
+         */
         void onSelectionModeToggle(boolean selectionMode);
     }
 
+    /**
+     * Initializes the helper with a listener.
+     */
     public SelectionHelper(SelectionListener listener) {
         this.listener = listener;
     }
 
+    /**
+     * Toggles the selection state of a specific key.
+     * Automatically exits selection mode if the last item is deselected.
+     */
     public void toggleSelection(String key) {
         if (key == null) return;
 
@@ -39,6 +56,9 @@ public class SelectionHelper {
         }
     }
 
+    /**
+     * Enters selection mode and selects the specified key.
+     */
     public void startSelection(String key) {
         if (key == null) return;
         selectionMode = true;
@@ -47,18 +67,30 @@ public class SelectionHelper {
         listener.onSelectionModeToggle(true);
     }
 
+    /**
+     * Checks if a specific key is currently selected.
+     */
     public boolean isSelected(String key) {
         return selectedKeys.contains(key);
     }
 
+    /**
+     * Checks if the helper is currently in selection mode.
+     */
     public boolean isInSelectionMode() {
         return selectionMode;
     }
 
+    /**
+     * Returns a copy of the list of currently selected keys.
+     */
     public List<String> getSelectedKeys() {
         return new ArrayList<>(selectedKeys);
     }
 
+    /**
+     * Clears all selections and exits selection mode.
+     */
     public void clearSelection() {
         selectedKeys.clear();
         selectionMode = false;
diff --git a/android/app/src/main/java/com/example/petstoremobile/utils/SpinnerUtils.java b/android/app/src/main/java/com/example/petstoremobile/utils/SpinnerUtils.java
index de1e6304..2273b227 100644
--- a/android/app/src/main/java/com/example/petstoremobile/utils/SpinnerUtils.java
+++ b/android/app/src/main/java/com/example/petstoremobile/utils/SpinnerUtils.java
@@ -22,7 +22,7 @@ import java.util.function.Function;
 public class SpinnerUtils {
 
     /**
-     * Populates a spinner with a list of items and handles pre-selection.
+     * Populates a spinner with generic data and handles pre-selection based on an ID.
      */
     public static <T> void populateSpinner(Context context, Spinner spinner, List<T> data,
                                            Function<T, String> nameExtractor, String defaultText,
@@ -31,7 +31,7 @@ public class SpinnerUtils {
     }
 
     /**
-     * Populates a spinner with white text (for dark backgrounds).
+     * Populates a spinner with white text, suitable for dark backgrounds or overlays.
      */
     public static <T> void populateWhiteSpinner(Context context, Spinner spinner, List<T> data,
                                            Function<T, String> nameExtractor, String defaultText,
@@ -39,6 +39,9 @@ public class SpinnerUtils {
         populateSpinnerWithAdapter(context, spinner, data, nameExtractor, defaultText, preselectedId, idExtractor, true);
     }
 
+    /**
+     * Internal helper to populate a spinner with the appropriate adapter and handle pre-selection.
+     */
     private static <T> void populateSpinnerWithAdapter(Context context, Spinner spinner, List<T> data,
                                            Function<T, String> nameExtractor, String defaultText,
                                            Long preselectedId, Function<T, Long> idExtractor,
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ActivityLogListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ActivityLogListViewModel.java
index d944de83..453ddd3b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ActivityLogListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ActivityLogListViewModel.java
@@ -44,16 +44,37 @@ public class ActivityLogListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of activity logs.
+     */
     public LiveData<List<ActivityLogDTO>> getLogs() { return logs; }
+
+    /**
+     * Returns the LiveData for the store dropdown options.
+     */
     public LiveData<List<DropdownDTO>> getStoreOptions() { return storeOptions; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of logs has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads initial data for stores and logs.
+     */
     public void loadInitialData() {
         loadStores();
         loadLogs(true);
     }
 
+    /**
+     * Loads store options for filtering.
+     */
     private void loadStores() {
         observeOnce(storeRepository.getStoreDropdowns(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -62,6 +83,9 @@ public class ActivityLogListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads activity logs from the repository with current filters.
+     */
     public void loadLogs(boolean reset) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -88,21 +112,33 @@ public class ActivityLogListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Sets the role filter and reloads logs.
+     */
     public void setRoleFilter(String role) {
         currentRole = "All Roles".equals(role) ? null : role;
         loadLogs(true);
     }
 
+    /**
+     * Sets the store filter and reloads logs.
+     */
     public void setStoreFilter(Long storeId) {
         currentStoreId = storeId;
         loadLogs(true);
     }
 
+    /**
+     * Sets the search query and reloads logs.
+     */
     public void setSearchQuery(String query) {
         currentSearch = (query == null || query.trim().isEmpty()) ? null : query.trim();
         loadLogs(true);
     }
 
+    /**
+     * Sets the date range filter and reloads logs.
+     */
     public void setDateRange(String startDate, String endDate) {
         currentStartDate = startDate;
         currentEndDate = endDate;
@@ -110,6 +146,9 @@ public class ActivityLogListViewModel extends ViewModel {
     }
 
 
+    /**
+     * Observes a LiveData once, removing the observer after the first response.
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionDetailViewModel.java
index 7416c0fc..c25ce797 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionDetailViewModel.java
@@ -48,24 +48,39 @@ public class AdoptionDetailViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Sets the adoption ID and initializes the view mode.
+     */
     public void setAdoptionId(long id) {
         this.adoptionId = id;
         initMode(id != -1);
     }
 
+    /**
+     * Returns the current adoption ID.
+     */
     public long getAdoptionId() {
         return adoptionId;
     }
 
+    /**
+     * Checks if the fragment is currently in editing mode.
+     */
     public boolean isEditing() {
         ViewState current = viewState.getValue();
         return current != null && current.isEditing;
     }
 
+    /**
+     * Returns the LiveData for the current view state.
+     */
     public LiveData<ViewState> getViewState() {
         return viewState;
     }
 
+    /**
+     * Initializes the view state based on whether the mode is editing or adding.
+     */
     public void initMode(boolean isEditing) {
         updateViewState(state -> {
             state.isEditing = isEditing;
@@ -94,6 +109,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads initial data for the form spinners.
+     */
     public void loadInitialFormData(boolean isEditing) {
         // Pets are loaded dynamically based on store selection; no pre-load needed.
         observeOnce(customerRepository.getCustomerDropdowns(), r -> {
@@ -108,6 +126,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Handles customer selection and updates the view state.
+     */
     public void onCustomerSelected(int position) {
         List<DropdownDTO> list = customerList.getValue();
         Long customerId = (position > 0 && list != null && position <= list.size())
@@ -115,6 +136,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         updateViewState(state -> state.selectedCustomerId = customerId);
     }
 
+    /**
+     * Handles store selection, updates the view state, and loads related employees and pets.
+     */
     public void onStoreSelected(int position) {
         List<DropdownDTO> list = storeList.getValue();
         if (position > 0 && list != null && position <= list.size()) {
@@ -141,6 +165,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Handles pet selection, updates the view state, and loads the pet's price.
+     */
     public void onPetSelected(int position) {
         List<DropdownDTO> list = petList.getValue();
         if (position > 0 && list != null && position <= list.size()) {
@@ -155,6 +182,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Loads available pets for the selected store.
+     */
     private void loadAvailablePetsByStore(Long storeId) {
         observeOnce(petRepository.getAdoptionPets(storeId), r -> {
             if (r != null && r.status == Resource.Status.SUCCESS && r.data != null) {
@@ -163,6 +193,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the price for a specific pet.
+     */
     private void loadPetPrice(Long petId) {
         observeOnce(petRepository.getPetById(petId), r -> {
             if (r != null && r.status == Resource.Status.SUCCESS && r.data != null) {
@@ -181,6 +214,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads employees assigned to a specific store.
+     */
     private void loadEmployeesForStore(Long storeId) {
         observeOnce(storeRepository.getStoreEmployees(storeId), r -> {
             if (r != null && r.status == Resource.Status.SUCCESS && r.data != null) {
@@ -190,7 +226,7 @@ public class AdoptionDetailViewModel extends ViewModel {
     }
 
     /**
-     * Called when the date or status changes in the UI. Applies date-based field enabling.
+     * Called when the date or status changes in the UI.
      */
     public void onDateChanged(String date, String currentStatus) {
         updateViewState(s -> {
@@ -203,7 +239,7 @@ public class AdoptionDetailViewModel extends ViewModel {
                 s.selectedStatus = s.availableStatuses[0];
             }
 
-            if (!s.isEditing) return; // add mode: field enabling handled separately
+            if (!s.isEditing) return;
 
             boolean isPast = DateTimeUtils.isDateBeforeToday(date);
             if (isPast) {
@@ -222,6 +258,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Calculates available statuses based on the date and mode.
+     */
     private String[] calculateAvailableStatuses(boolean isEditing, String date) {
         if (!isEditing) return new String[]{"Pending"};
         if (date == null || date.isEmpty()) return new String[]{};
@@ -236,9 +275,11 @@ public class AdoptionDetailViewModel extends ViewModel {
         s.isPetEnabled = enabled;
         s.isEmployeeEnabled = enabled;
         s.isDateEnabled = enabled;
-        // fee never editable
     }
 
+    /**
+     * Fetches adoption details from the repository.
+     */
     public LiveData<Resource<AdoptionDTO>> loadAdoption() {
         MutableLiveData<Resource<AdoptionDTO>> result = new MutableLiveData<>();
         observeOnce(adoptionRepository.getAdoptionById(adoptionId), resource -> {
@@ -292,6 +333,9 @@ public class AdoptionDetailViewModel extends ViewModel {
         return result;
     }
 
+    /**
+     * Saves or updates the adoption record.
+     */
     public LiveData<Resource<AdoptionDTO>> saveAdoption(AdoptionDTO dto) {
         if (isEditing()) {
             return adoptionRepository.updateAdoption(adoptionId, dto);
@@ -299,17 +343,41 @@ public class AdoptionDetailViewModel extends ViewModel {
         return adoptionRepository.createAdoption(dto);
     }
 
+    /**
+     * Deletes the current adoption record.
+     */
     public LiveData<Resource<Void>> deleteAdoption() {
         return adoptionRepository.deleteAdoption(adoptionId);
     }
 
+    /**
+     * Returns the LiveData for the pet dropdown list.
+     */
     public LiveData<List<DropdownDTO>> getPetList() { return petList; }
+
+    /**
+     * Returns the LiveData for the customer dropdown list.
+     */
     public LiveData<List<DropdownDTO>> getCustomerList() { return customerList; }
+
+    /**
+     * Returns the LiveData for the store dropdown list.
+     */
     public LiveData<List<DropdownDTO>> getStoreList() { return storeList; }
+
+    /**
+     * Returns the LiveData for the employee dropdown list.
+     */
     public LiveData<List<DropdownDTO>> getEmployeeList() { return employeeList; }
 
+    /**
+     * Updates the employee list.
+     */
     public void setEmployeeList(List<DropdownDTO> list) { employeeList.setValue(list); }
 
+    /**
+     * Helper to update the view state atomically.
+     */
     private void updateViewState(Action<ViewState> action) {
         ViewState current = viewState.getValue();
         if (current != null) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionListViewModel.java
index 005198d1..dbfc262b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AdoptionListViewModel.java
@@ -39,11 +39,29 @@ public class AdoptionListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of adoptions.
+     */
     public LiveData<List<AdoptionDTO>> getAdoptions() { return adoptions; }
+
+    /**
+     * Returns the LiveData for the list of stores for filtering.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of adoptions has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads adoptions from the repository with the specified filters.
+     */
     public void loadAdoptions(boolean reset, String query, String status, Long storeId, String date, Long employeeId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -73,6 +91,9 @@ public class AdoptionListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of stores for filtering options.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -93,6 +114,9 @@ public class AdoptionListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple adoptions by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeleteAdoptions(List<String> ids) {
         return adoptionRepository.bulkDeleteAdoptions(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AnalyticsViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AnalyticsViewModel.java
index 4a9b94d9..95c8979f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AnalyticsViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AnalyticsViewModel.java
@@ -28,6 +28,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for retrieving and providing data for the analytics dashboard.
+ */
 @HiltViewModel
 public class AnalyticsViewModel extends ViewModel {
     private final SaleRepository saleRepository;
@@ -50,12 +53,34 @@ public class AnalyticsViewModel extends ViewModel {
         this.tokenManager = tokenManager;
     }
 
+    /**
+     * Returns the LiveData for the analytics data.
+     */
     public LiveData<AnalyticsData> getAnalyticsData() { return analyticsData; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Returns the LiveData for error messages.
+     */
     public LiveData<String> getErrorMessage() { return errorMessage; }
+
+    /**
+     * Returns the LiveData for available payment method filters.
+     */
     public LiveData<List<String>> getAvailablePaymentMethods() { return availablePaymentMethods; }
+
+    /**
+     * Returns the LiveData for available store filters.
+     */
     public LiveData<List<String>> getAvailableStores() { return availableStores; }
 
+    /**
+     * Triggers loading of analytics data with current filters.
+     */
     public void loadAnalytics() {
         isLoading.setValue(true);
         errorMessage.setValue(null);
@@ -75,35 +100,56 @@ public class AnalyticsViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Applies a new filter state and re-computes analytics.
+     */
     public void applyFilter(FilterState filter) {
         currentFilter = filter;
         applyCurrentFilter();
     }
 
+    /**
+     * Resets filters to default values and reset analytics.
+     */
     public void resetFilter() {
         currentFilter = new FilterState();
         storeFilter = "All Stores";
         applyCurrentFilter();
     }
 
+    /**
+     * Sets the view mode
+     */
     public void setViewMode(String mode) {
         viewMode = mode;
         applyCurrentFilter();
     }
 
+    /**
+     * Returns the current view mode.
+     */
     public String getViewMode() {
         return viewMode;
     }
 
+    /**
+     * Sets the store filter
+     */
     public void setStoreFilter(String store) {
         storeFilter = (store != null && !store.isEmpty()) ? store : "All Stores";
         applyCurrentFilter();
     }
 
+    /**
+     * Returns the current store filter.
+     */
     public String getStoreFilter() {
         return storeFilter;
     }
 
+    /**
+     * Applies the current filters
+     */
     private void applyCurrentFilter() {
         List<SaleDTO> salesForMode;
         if (viewMode.equals("mine")) {
@@ -124,6 +170,9 @@ public class AnalyticsViewModel extends ViewModel {
         computeAnalytics(filtered, currentFilter);
     }
 
+    /**
+     * Extracts unique store names from the cached sales data for filtering.
+     */
     private void deriveStores() {
         java.util.Set<String> stores = new java.util.TreeSet<>();
         for (SaleDTO s : cachedSales) {
@@ -137,6 +186,9 @@ public class AnalyticsViewModel extends ViewModel {
         availableStores.setValue(result);
     }
 
+    /**
+     * Extracts unique payment methods from the cached sales data for filtering.
+     */
     private void derivePaymentMethods() {
         java.util.Set<String> methods = new java.util.TreeSet<>();
         for (SaleDTO s : cachedSales) {
@@ -150,6 +202,9 @@ public class AnalyticsViewModel extends ViewModel {
         availablePaymentMethods.setValue(result);
     }
 
+    /**
+     * Filters a list of sales based on date range and payment method.
+     */
     private List<SaleDTO> filterSales(List<SaleDTO> sales, FilterState filter) {
         List<SaleDTO> result = new ArrayList<>();
         for (SaleDTO s : sales) {
@@ -165,6 +220,9 @@ public class AnalyticsViewModel extends ViewModel {
         return result;
     }
 
+    /**
+     * Computesanalytics data from a filtered list of sales.
+     */
     private void computeAnalytics(List<SaleDTO> sales, FilterState filter) {
         List<SaleDTO> regularSales = new ArrayList<>();
         for (SaleDTO s : sales) {
@@ -258,6 +316,9 @@ public class AnalyticsViewModel extends ViewModel {
         analyticsData.setValue(data);
     }
 
+    /**
+     * Returns a date string for the specified offset from today.
+     */
     private String todayString(int offsetDays) {
         Calendar c = Calendar.getInstance();
         c.add(Calendar.DAY_OF_YEAR, offsetDays);
@@ -265,6 +326,9 @@ public class AnalyticsViewModel extends ViewModel {
                 c.get(Calendar.YEAR), c.get(Calendar.MONTH) + 1, c.get(Calendar.DAY_OF_MONTH));
     }
 
+    /**
+     * Shifts a date string by a specified number of days.
+     */
     private String shiftDate(String date, int offsetDays) {
         try {
             String[] p = date.split("-");
@@ -278,6 +342,9 @@ public class AnalyticsViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Generates a list of date strings between the start and end dates.
+     */
     private List<String> buildDateRange(String start, String end, int maxDays) {
         List<String> dates = new ArrayList<>();
         try {
@@ -298,6 +365,9 @@ public class AnalyticsViewModel extends ViewModel {
         return dates;
     }
 
+    /**
+     * Builds a title for the daily revenue chart based on the date range.
+     */
     private String buildDailyTitle(FilterState filter, String rangeStart, String rangeEnd) {
         if (filter.startDate.isEmpty() && filter.endDate.isEmpty()) return "Daily Revenue (Last 7 Days)";
         String s = rangeStart.length() >= 10 ? rangeStart.substring(5) : rangeStart;
@@ -305,6 +375,9 @@ public class AnalyticsViewModel extends ViewModel {
         return "Daily Revenue (" + s + " – " + e + ")";
     }
 
+    /**
+     * Observes a LiveData once, removing the observer after the first non-loading response.
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentDetailViewModel.java
index b229c3a0..c96e21de 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentDetailViewModel.java
@@ -387,7 +387,9 @@ public class AppointmentDetailViewModel extends ViewModel {
         void run(T t);
     }
 
-    /** Observes a LiveData once, removing the observer after the first non-loading response. */
+    /**
+     * Observes a LiveData once, removing the observer after the first non-loading response.
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentListViewModel.java
index 19924349..30aa2511 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AppointmentListViewModel.java
@@ -39,11 +39,29 @@ public class AppointmentListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of appointments.
+     */
     public LiveData<List<AppointmentDTO>> getAppointments() { return appointments; }
+
+    /**
+     * Returns the LiveData for the list of stores for filtering.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of appointments has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads appointments from the repository with the specified filters.
+     */
     public void loadAppointments(boolean reset, String query, String status, Long storeId, String date, Long employeeId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -71,6 +89,9 @@ public class AppointmentListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of stores for filtering options.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -91,6 +112,9 @@ public class AppointmentListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple appointments by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeleteAppointments(List<String> ids) {
         return appointmentRepository.bulkDeleteAppointments(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AuthViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AuthViewModel.java
index 36e437bb..cc05eb3e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/AuthViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/AuthViewModel.java
@@ -16,6 +16,9 @@ import javax.inject.Inject;
 import dagger.hilt.android.lifecycle.HiltViewModel;
 import okhttp3.MultipartBody;
 
+/**
+ * ViewModel for managing user authentication and profile data.
+ */
 @HiltViewModel
 public class AuthViewModel extends ViewModel {
     private final AuthRepository repository;
@@ -26,42 +29,42 @@ public class AuthViewModel extends ViewModel {
     }
 
     /**
-     * Authenticates a user with username and password.
+     * Attempts to log in the user with the provided credentials.
      */
     public LiveData<Resource<AuthDTO.LoginResponse>> login(String username, String password) {
         return repository.login(new AuthDTO.LoginRequest(username, password));
     }
 
     /**
-     * Retrieves the profile information of the currently authenticated user.
+     * Retrieves the current user's profile information.
      */
     public LiveData<Resource<UserDTO>> getMe() {
         return repository.getMe();
     }
 
     /**
-     * Updates the profile information of the current user.
+     * Updates the current user's profile information.
      */
     public LiveData<Resource<UserDTO>> updateMe(Map<String, String> updates) {
         return repository.updateMe(updates);
     }
 
     /**
-     * Uploads a new avatar image for the current user.
+     * Uploads a new avatar for the current user.
      */
     public LiveData<Resource<AvatarUploadResponse>> uploadAvatar(MultipartBody.Part avatar) {
         return repository.uploadAvatar(avatar);
     }
 
     /**
-     * Deletes the avatar image of the current user.
+     * Deletes the current user's avatar.
      */
     public LiveData<Resource<Void>> deleteAvatar() {
         return repository.deleteAvatar();
     }
 
     /**
-     * Logs out the current user by clearing stored credentials.
+     * Logs out the user by clearing the session.
      */
     public void logout() {
         repository.logout();
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ChatListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ChatListViewModel.java
index 4d14a3b4..0010d227 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ChatListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ChatListViewModel.java
@@ -29,6 +29,9 @@ import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
 import okhttp3.ResponseBody;
 
+/**
+ * ViewModel for managing the list of chat conversations and real-time message updates.
+ */
 @HiltViewModel
 public class ChatListViewModel extends ViewModel {
     private final ChatRepository chatRepository;
@@ -48,19 +51,43 @@ public class ChatListViewModel extends ViewModel {
         this.customerRepository = customerRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of active chats.
+     */
     public LiveData<List<Chat>> getActiveChats() { return activeChats; }
+
+    /**
+     * Returns the LiveData for the list of closed chats.
+     */
     public LiveData<List<Chat>> getClosedChats() { return closedChats; }
+
+    /**
+     * Returns the LiveData for the list of messages in the current conversation.
+     */
     public LiveData<List<Message>> getMessageList() { return messageList; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
 
+    /**
+     * Returns the ID of the last active conversation.
+     */
     public Long getLastActiveConversationId() {
         return lastActiveConversationId;
     }
 
+    /**
+     * Sets the ID of the last active conversation.
+     */
     public void setLastActiveConversationId(Long conversationId) {
         this.lastActiveConversationId = conversationId;
     }
 
+    /**
+     * Loads the list of customers for name mapping.
+     */
     public void loadCustomers() {
         isLoading.setValue(true);
         customerRepository.getAllCustomers(0, 100).observeForever(resource -> {
@@ -75,6 +102,9 @@ public class ChatListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads all chat conversations from the repository.
+     */
     public void loadConversations() {
         isLoading.setValue(true);
         chatRepository.getAllConversations().observeForever(resource -> {
@@ -99,6 +129,9 @@ public class ChatListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads message history for a specific conversation.
+     */
     public void loadMessageHistory(Long conversationId) {
         isLoading.setValue(true);
         chatRepository.getMessages(conversationId).observeForever(resource -> {
@@ -115,22 +148,37 @@ public class ChatListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Sends a text message in a specific conversation.
+     */
     public LiveData<Resource<MessageDTO>> sendMessage(Long conversationId, String text) {
         return chatRepository.sendMessage(conversationId, new SendMessageRequest(text));
     }
 
+    /**
+     * Sends a message with an attachment in a specific conversation.
+     */
     public LiveData<Resource<MessageDTO>> sendMessageWithAttachment(Long conversationId, MultipartBody.Part content, MultipartBody.Part attachment) {
         return chatRepository.sendMessageWithAttachment(conversationId, content, attachment);
     }
 
+    /**
+     * Downloads an attachment for a specific message.
+     */
     public LiveData<Resource<ResponseBody>> downloadAttachment(Long messageId) {
         return chatRepository.downloadAttachment(messageId);
     }
 
+    /**
+     * Closes an active chat conversation.
+     */
     public LiveData<Resource<ConversationDTO>> closeConversation(Long conversationId) {
         return chatRepository.updateConversationStatus(conversationId, new UpdateConversationStatusRequest("CLOSED"));
     }
 
+    /**
+     * Adds a message to the local list (used for real-time updates).
+     */
     public void addMessageLocally(MessageDTO dto) {
         List<Message> current = new ArrayList<>(messageList.getValue());
         if (dto.getId() != null) {
@@ -142,6 +190,9 @@ public class ChatListViewModel extends ViewModel {
         messageList.setValue(current);
     }
 
+    /**
+     * Updates a conversation's status locally.
+     */
     public void updateConversationLocally(ConversationDTO dto) {
         updateList(activeChats, dto);
         updateList(closedChats, dto);
@@ -180,6 +231,9 @@ public class ChatListViewModel extends ViewModel {
         return m;
     }
 
+    /**
+     * Retrieves a customer's name by their ID.
+     */
     public String getCustomerName(Long customerId) {
         return customerNames.getOrDefault(customerId, "Customer #" + customerId);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponDetailViewModel.java
index 49f52ef5..93541676 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponDetailViewModel.java
@@ -23,23 +23,38 @@ public class CouponDetailViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Loads the coupon details from the repository.
+     */
     public LiveData<Resource<CouponDTO>> loadCoupon(long id) {
         return repository.getCouponById(id);
     }
 
+    /**
+     * Sets the current coupon ID and editing mode.
+     */
     public void setCouponId(long id, boolean isEditing) {
         this.couponId = id;
         this.isEditing = isEditing;
     }
 
+    /**
+     * Returns the current coupon ID.
+     */
     public long getCouponId() {
         return couponId;
     }
 
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() {
         return isEditing;
     }
 
+    /**
+     * Saves or updates the coupon record.
+     */
     public LiveData<Resource<CouponDTO>> saveCoupon(CouponDTO dto) {
         if (isEditing && couponId > 0) {
             return repository.updateCoupon(couponId, dto);
@@ -48,6 +63,9 @@ public class CouponDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Deletes the current coupon record.
+     */
     public LiveData<Resource<Void>> deleteCoupon() {
         return repository.deleteCoupon(couponId);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponListViewModel.java
index d825b935..eeb47f16 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CouponListViewModel.java
@@ -17,6 +17,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for managing the list of coupons.
+ */
 @HiltViewModel
 public class CouponListViewModel extends ViewModel {
     private final CouponRepository repository;
@@ -32,10 +35,24 @@ public class CouponListViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Returns the LiveData for the list of coupons.
+     */
     public LiveData<List<CouponDTO>> getCoupons() { return coupons; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of coupons has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads coupons from the repository with the specified filters.
+     */
     public void loadCoupons(boolean reset, Boolean active, String discountType, String sort) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -75,6 +92,9 @@ public class CouponListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple coupons by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeleteCoupons(List<Long> ids) {
         return repository.bulkDeleteCoupons(ids);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerDetailViewModel.java
index 0d0ebfaf..1604c9e8 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerDetailViewModel.java
@@ -23,6 +23,9 @@ public class CustomerDetailViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Sets the current customer ID and editing mode.
+     */
     public void setCustomerId(long id, boolean isEditing) {
         this.customerId = id;
         this.isEditing = isEditing;
@@ -48,6 +51,9 @@ public class CustomerDetailViewModel extends ViewModel {
         return repository.getCustomerById(id);
     }
 
+    /**
+     * Saves or updates the customer record.
+     */
     public LiveData<Resource<CustomerDTO>> saveCustomer(CustomerDTO dto) {
         if (isEditing && customerId > 0) {
             return repository.updateCustomer(customerId, dto);
@@ -56,6 +62,9 @@ public class CustomerDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Deletes the current customer record.
+     */
     public LiveData<Resource<Void>> deleteCustomer() {
         return repository.deleteCustomer(customerId);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerListViewModel.java
index a216c47a..2fd7393b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/CustomerListViewModel.java
@@ -17,6 +17,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for managing the list of customers, including local filtering and pagination.
+ */
 @HiltViewModel
 public class CustomerListViewModel extends ViewModel {
     private final CustomerRepository repository;
@@ -37,10 +40,24 @@ public class CustomerListViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Returns the LiveData for the list of filtered customers.
+     */
     public LiveData<List<CustomerDTO>> getFilteredCustomers() { return filteredCustomers; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of customers has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads the full list of customers from the repository.
+     */
     public void loadCustomers(boolean reset) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -69,6 +86,9 @@ public class CustomerListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Observes a LiveData once, removing the observer after the first non-loading response.
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
@@ -81,12 +101,18 @@ public class CustomerListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Filters the customer list locally based on query and status.
+     */
     public void filter(String query, String status) {
         this.lastQuery = query;
         this.lastStatus = status;
         applyFilter(customers.getValue());
     }
 
+    /**
+     * Applies the filters to the full list and updates the filtered LiveData.
+     */
     private void applyFilter(List<CustomerDTO> all) {
         if (all == null) return;
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryDetailViewModel.java
index c872ea49..3bf33373 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryDetailViewModel.java
@@ -39,26 +39,48 @@ public class InventoryDetailViewModel extends ViewModel {
         this.productRepository = productRepository;
     }
 
+    /**
+     * Sets the inventory ID and initializes the editing mode.
+     */
     public void setInventoryId(long id) {
         this.inventoryId = id;
         this.isEditing = id != -1;
     }
 
+    /**
+     * Returns the current inventory ID.
+     */
     public long getInventoryId() { return inventoryId; }
+
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() { return isEditing; }
 
+    /**
+     * Loads the inventory record from the repository.
+     */
     public LiveData<Resource<InventoryDTO>> loadInventory() {
         return inventoryRepository.getInventoryById(inventoryId);
     }
 
+    /**
+     * Loads store dropdown options.
+     */
     public LiveData<Resource<List<DropdownDTO>>> loadStores() {
         return storeRepository.getStoreDropdowns();
     }
 
+    /**
+     * Loads product dropdown options.
+     */
     public LiveData<Resource<List<DropdownDTO>>> loadProducts() {
         return productRepository.getProductDropdowns();
     }
 
+    /**
+     * Saves or updates the inventory record.
+     */
     public LiveData<Resource<InventoryDTO>> saveInventory(InventoryDTO dto) {
         if (isEditing) {
             return inventoryRepository.updateInventory(inventoryId, dto);
@@ -67,13 +89,30 @@ public class InventoryDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Deletes the current inventory record.
+     */
     public LiveData<Resource<Void>> deleteInventory() {
         return inventoryRepository.deleteInventory(inventoryId);
     }
 
+    /**
+     * Updates the store list.
+     */
     public void setStoreList(List<DropdownDTO> list) { storeList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the store list.
+     */
     public LiveData<List<DropdownDTO>> getStoreList() { return storeList; }
 
+    /**
+     * Updates the product list.
+     */
     public void setProductList(List<DropdownDTO> list) { productList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the product list.
+     */
     public LiveData<List<DropdownDTO>> getProductList() { return productList; }
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryListViewModel.java
index 66387983..8e482390 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/InventoryListViewModel.java
@@ -39,11 +39,29 @@ public class InventoryListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the inventory list.
+     */
     public LiveData<List<InventoryDTO>> getInventory() { return inventory; }
+
+    /**
+     * Returns the LiveData for the store list for filtering.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of inventory has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads inventory items from the repository with the specified filters.
+     */
     public void loadInventory(boolean reset, String query, Long storeId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -69,6 +87,9 @@ public class InventoryListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of stores for filtering options.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -89,6 +110,9 @@ public class InventoryListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple inventory items by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeleteInventory(List<String> ids) {
         return inventoryRepository.bulkDeleteInventory(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetListViewModel.java
index 89f56d51..5c04e468 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetListViewModel.java
@@ -21,6 +21,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for managing the list of pets, including filtering and bulk deletion.
+ */
 @HiltViewModel
 public class PetListViewModel extends ViewModel {
     private final PetRepository petRepository;
@@ -41,12 +44,34 @@ public class PetListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of pets.
+     */
     public LiveData<List<PetDTO>> getPets() { return pets; }
+
+    /**
+     * Returns the LiveData for the list of stores for filtering.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for available species filters.
+     */
     public LiveData<List<String>> getSpeciesOptions() { return speciesOptions; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of pets has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads pets from the repository with the specified filters.
+     */
     public void loadPets(boolean reset, String query, String status, String species, Long storeId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -79,6 +104,9 @@ public class PetListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of available species for filtering.
+     */
     public void loadSpecies() {
         observeOnce(petRepository.getPetSpeciesDropdowns(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -92,6 +120,9 @@ public class PetListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of stores for filtering options.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -100,6 +131,9 @@ public class PetListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Observes a LiveData once, removing the observer after the first non-loading response.
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
@@ -112,6 +146,9 @@ public class PetListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple pets by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeletePets(List<String> ids) {
         return petRepository.bulkDeletePets(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetProfileViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetProfileViewModel.java
index 1fb75f1c..8366bf63 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetProfileViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PetProfileViewModel.java
@@ -21,14 +21,23 @@ public class PetProfileViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Retrieves a pet's details by its ID.
+     */
     public LiveData<Resource<PetDTO>> getPetById(Long id) {
         return repository.getPetById(id);
     }
 
+    /**
+     * Uploads an image for a specific pet.
+     */
     public LiveData<Resource<Void>> uploadPetImage(Long id, MultipartBody.Part image) {
         return repository.uploadPetImage(id, image);
     }
 
+    /**
+     * Deletes the image for a specific pet.
+     */
     public LiveData<Resource<Void>> deletePetImage(Long id) {
         return repository.deletePetImage(id);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductDetailViewModel.java
index c1ac5fdd..3c157dde 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductDetailViewModel.java
@@ -35,27 +35,45 @@ public class ProductDetailViewModel extends ViewModel {
         this.categoryRepository = categoryRepository;
     }
 
+    /**
+     * Sets the product ID and initializes the editing mode.
+     */
     public void setProdId(long id) {
         this.prodId = id;
         this.isEditing = id != -1;
     }
 
+    /**
+     * Returns the current product ID.
+     */
     public long getProdId() {
         return prodId;
     }
 
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() {
         return isEditing;
     }
 
+    /**
+     * Loads product category dropdown options.
+     */
     public LiveData<Resource<List<DropdownDTO>>> loadCategories() {
         return productRepository.getCategoryDropdowns();
     }
 
+    /**
+     * Loads the product details from the repository.
+     */
     public LiveData<Resource<ProductDTO>> loadProduct() {
         return productRepository.getProductById(prodId);
     }
 
+    /**
+     * Saves or updates the product record.
+     */
     public LiveData<Resource<ProductDTO>> saveProduct(ProductDTO dto) {
         if (isEditing) {
             return productRepository.updateProduct(prodId, dto);
@@ -64,22 +82,37 @@ public class ProductDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Deletes the current product record.
+     */
     public LiveData<Resource<Void>> deleteProduct() {
         return productRepository.deleteProduct(prodId);
     }
 
+    /**
+     * Uploads an image for the current product.
+     */
     public LiveData<Resource<Void>> uploadProductImage(MultipartBody.Part image) {
         return productRepository.uploadProductImage(prodId, image);
     }
 
+    /**
+     * Deletes the current product's image.
+     */
     public LiveData<Resource<Void>> deleteProductImage() {
         return productRepository.deleteProductImage(prodId);
     }
 
+    /**
+     * Updates the category list.
+     */
     public void setCategoryList(List<DropdownDTO> list) {
         categoryList.setValue(list);
     }
 
+    /**
+     * Returns the LiveData for the category list.
+     */
     public LiveData<List<DropdownDTO>> getCategoryList() {
         return categoryList;
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductListViewModel.java
index b22dee6c..e242768f 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductListViewModel.java
@@ -38,11 +38,29 @@ public class ProductListViewModel extends ViewModel {
         this.categoryRepository = categoryRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of products.
+     */
     public LiveData<List<ProductDTO>> getProducts() { return products; }
+
+    /**
+     * Returns the LiveData for the list of categories for filtering.
+     */
     public LiveData<List<DropdownDTO>> getCategories() { return categories; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of products has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads products from the repository with the specified filters.
+     */
     public void loadProducts(boolean reset, String query, Long categoryId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -70,6 +88,9 @@ public class ProductListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of categories for filtering options.
+     */
     public void loadCategories() {
         observeOnce(productRepository.getCategoryDropdowns(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierDetailViewModel.java
index 2cbf5036..66d0201e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierDetailViewModel.java
@@ -40,28 +40,54 @@ public class ProductSupplierDetailViewModel extends ViewModel {
         this.supplierRepository = supplierRepository;
     }
 
+    /**
+     * Sets the composite key for the product-supplier relationship and enables editing mode.
+     */
     public void setEditMode(long productId, long supplierId) {
         this.isEditing = true;
         this.editProductId = productId;
         this.editSupplierId = supplierId;
     }
 
+    /**
+     * Loads the product-supplier details from the repository.
+     */
     public LiveData<Resource<ProductSupplierDTO>> loadProductSupplier() {
         return psRepository.getProductSupplierById(editProductId, editSupplierId);
     }
 
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() { return isEditing; }
+
+    /**
+     * Returns the product ID for the relationship being edited.
+     */
     public long getEditProductId() { return editProductId; }
+
+    /**
+     * Returns the supplier ID for the relationship being edited.
+     */
     public long getEditSupplierId() { return editSupplierId; }
 
+    /**
+     * Loads products for the dropdown selection.
+     */
     public LiveData<Resource<PageResponse<ProductDTO>>> loadProducts() {
         return productRepository.getAllProducts(null, null, 0, 200, "prodName");
     }
 
+    /**
+     * Loads suppliers for the dropdown selection.
+     */
     public LiveData<Resource<PageResponse<SupplierDTO>>> loadSuppliers() {
         return supplierRepository.getAllSuppliers(0, 200, null, "supCompany");
     }
 
+    /**
+     * Saves or updates the product-supplier relationship.
+     */
     public LiveData<Resource<ProductSupplierDTO>> saveProductSupplier(ProductSupplierDTO dto) {
         if (isEditing) {
             return psRepository.updateProductSupplier(editProductId, editSupplierId, dto);
@@ -70,13 +96,30 @@ public class ProductSupplierDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Deletes the current product-supplier relationship.
+     */
     public LiveData<Resource<Void>> deleteProductSupplier() {
         return psRepository.deleteProductSupplier(editProductId, editSupplierId);
     }
 
+    /**
+     * Updates the product list.
+     */
     public void setProductList(List<ProductDTO> list) { productList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the product list.
+     */
     public LiveData<List<ProductDTO>> getProductList() { return productList; }
 
+    /**
+     * Updates the supplier list.
+     */
     public void setSupplierList(List<SupplierDTO> list) { supplierList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the supplier list.
+     */
     public LiveData<List<SupplierDTO>> getSupplierList() { return supplierList; }
 }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierListViewModel.java
index 930770a4..0a568e51 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ProductSupplierListViewModel.java
@@ -44,12 +44,34 @@ public class ProductSupplierListViewModel extends ViewModel {
         this.supplierRepository = supplierRepository;
     }
 
+    /**
+     * Returns the LiveData for the product-supplier relationship list.
+     */
     public LiveData<List<ProductSupplierDTO>> getProductSuppliers() { return productSuppliers; }
+
+    /**
+     * Returns the LiveData for the list of products for filtering.
+     */
     public LiveData<List<ProductDTO>> getProducts() { return products; }
+
+    /**
+     * Returns the LiveData for the list of suppliers for filtering.
+     */
     public LiveData<List<SupplierDTO>> getSuppliers() { return suppliers; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of product-supplier relationships has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads product-supplier relationships from the repository with the specified filters.
+     */
     public void loadProductSuppliers(boolean reset, String query, Long productId, Long supplierId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -77,6 +99,9 @@ public class ProductSupplierListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads products and suppliers for filtering options.
+     */
     public void loadFilterData() {
         observeOnce(productRepository.getAllProducts(null, null, 0, 100, "prodName"), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -103,6 +128,9 @@ public class ProductSupplierListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple product-supplier relationships by their composite keys.
+     */
     public LiveData<Resource<Void>> bulkDeleteProductSuppliers(List<String> ids) {
         return psRepository.bulkDeleteProductSuppliers(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderDetailViewModel.java
index 436cfa4c..c68e1d89 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderDetailViewModel.java
@@ -20,6 +20,9 @@ public class PurchaseOrderDetailViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Loads the purchase order details from the repository.
+     */
     public LiveData<Resource<PurchaseOrderDTO>> loadPurchaseOrder(long id) {
         return repository.getPurchaseOrderById(id);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderListViewModel.java
index 923d336e..3febfe0e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/PurchaseOrderListViewModel.java
@@ -38,11 +38,29 @@ public class PurchaseOrderListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of purchase orders.
+     */
     public LiveData<List<PurchaseOrderDTO>> getPurchaseOrders() { return purchaseOrders; }
+
+    /**
+     * Returns the LiveData for the list of stores for filtering.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of purchase orders has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads purchase orders from the repository with the specified filters.
+     */
     public void loadPurchaseOrders(boolean reset, String query, Long storeId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -70,6 +88,9 @@ public class PurchaseOrderListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of stores for filtering options.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/RefundViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/RefundViewModel.java
index ff3d069e..bf96e89b 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/RefundViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/RefundViewModel.java
@@ -20,6 +20,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for processing and managing refund requests.
+ */
 @HiltViewModel
 public class RefundViewModel extends ViewModel {
     private final SaleRepository saleRepository;
@@ -34,35 +37,59 @@ public class RefundViewModel extends ViewModel {
         this.saleRepository = saleRepository;
     }
 
+    /**
+     * Loads all sales from the repository for refund selection.
+     */
     public LiveData<Resource<PageResponse<SaleDTO>>> loadAllSales() {
         return saleRepository.getAllSales(0, 1000, null, null, null, null, null, "saleDate,desc");
     }
 
+    /**
+     * Sets the list of all available sales.
+     */
     public void setAllSales(List<SaleDTO> sales) {
         allSales.setValue(sales);
     }
 
+    /**
+     * Returns the list of all available sales.
+     */
     public List<SaleDTO> getAllSalesList() {
         return allSales.getValue();
     }
 
+    /**
+     * Sets the current sale being processed for a refund and computes refundable items.
+     */
     public void setCurrentSale(SaleDTO sale) {
         currentSale.setValue(sale);
         buildRefundableItems();
     }
 
+    /**
+     * Returns the current sale being processed.
+     */
     public SaleDTO getCurrentSale() {
         return currentSale.getValue();
     }
 
+    /**
+     * Returns the LiveData for the list of items available for refund in the current sale.
+     */
     public LiveData<List<RefundItem>> getAvailableItems() {
         return availableItems;
     }
 
+    /**
+     * Returns the LiveData for the items added to the refund cart.
+     */
     public LiveData<List<RefundItem>> getRefundCart() {
         return refundCart;
     }
 
+    /**
+     * Builds the list of items available for refund, accounting for previous refunds.
+     */
     private void buildRefundableItems() {
         SaleDTO sale = currentSale.getValue();
         List<SaleDTO> sales = allSales.getValue();
@@ -103,6 +130,9 @@ public class RefundViewModel extends ViewModel {
         refundCart.setValue(new ArrayList<>());
     }
 
+    /**
+     * Adds an item to the refund cart.
+     */
     public void addToCart(RefundItem item, int qty) {
         List<RefundItem> cart = new ArrayList<>(refundCart.getValue());
         boolean merged = false;
@@ -120,12 +150,18 @@ public class RefundViewModel extends ViewModel {
         refundCart.setValue(cart);
     }
 
+    /**
+     * Removes an item from the refund cart.
+     */
     public void removeFromCart(RefundItem item) {
         List<RefundItem> cart = new ArrayList<>(refundCart.getValue());
         cart.remove(item);
         refundCart.setValue(cart);
     }
 
+    /**
+     * Calculates the total refund amount, proportional to the original total.
+     */
     public BigDecimal calculateRefundTotal() {
         SaleDTO sale = currentSale.getValue();
         List<RefundItem> cart = refundCart.getValue();
@@ -153,6 +189,9 @@ public class RefundViewModel extends ViewModel {
         return originalTotal.abs().multiply(ratio).setScale(2, RoundingMode.HALF_UP);
     }
 
+    /**
+     * Submits the refund transaction to the repository.
+     */
     public LiveData<Resource<SaleDTO>> submitRefund(String paymentMethod) {
         SaleDTO sale = currentSale.getValue();
         List<RefundItem> cart = refundCart.getValue();
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleDetailViewModel.java
index 68369cce..4160659e 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleDetailViewModel.java
@@ -24,6 +24,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for managing sale details, including creating new sales and viewing existing ones.
+ */
 @HiltViewModel
 public class SaleDetailViewModel extends ViewModel {
     private final SaleRepository saleRepository;
@@ -55,77 +58,150 @@ public class SaleDetailViewModel extends ViewModel {
         this.couponRepository = couponRepository;
     }
 
+    /**
+     * Sets the sale ID and whether the view is read-only.
+     */
     public void setSaleId(long id, boolean viewOnly) {
         this.saleId = id;
         this.viewOnly = viewOnly;
     }
 
+    /**
+     * Returns the current sale ID.
+     */
     public long getSaleId() { return saleId; }
+
+    /**
+     * Returns true if the view is in read-only mode.
+     */
     public boolean isViewOnly() { return viewOnly; }
 
+    /**
+     * Loads the details of a specific sale by its ID.
+     */
     public LiveData<Resource<SaleDTO>> loadSaleDetails() {
         return saleRepository.getSaleById(saleId);
     }
 
+    /**
+     * Loads the list of stores for selection.
+     */
     public LiveData<Resource<List<DropdownDTO>>> loadStores() {
         return storeRepository.getStoreDropdowns();
     }
 
+    /**
+     * Loads the list of customers for selection.
+     */
     public LiveData<Resource<List<DropdownDTO>>> loadCustomers() {
         return customerRepository.getCustomerDropdowns();
     }
 
+    /**
+     * Loads the list of products for sale selection.
+     */
     public LiveData<Resource<com.example.petstoremobile.dtos.PageResponse<ProductDTO>>> loadProducts() {
         return productRepository.getAllProducts(null, null, 0, 200, null);
     }
 
+    /**
+     * Submits a new sale to the repository.
+     */
     public LiveData<Resource<SaleDTO>> createSale(SaleDTO sale) {
         return saleRepository.createSale(sale);
     }
 
+    /**
+     * Sets the local list of stores.
+     */
     public void setStoreList(List<DropdownDTO> list) { storeList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the local list of stores.
+     */
     public LiveData<List<DropdownDTO>> getStoreList() { return storeList; }
 
+    /**
+     * Sets the local list of customers.
+     */
     public void setCustomerList(List<DropdownDTO> list) { customerList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the local list of customers.
+     */
     public LiveData<List<DropdownDTO>> getCustomerList() { return customerList; }
 
+    /**
+     * Sets the local list of products.
+     */
     public void setProductList(List<ProductDTO> list) { productList.setValue(list); }
+
+    /**
+     * Returns the LiveData for the local list of products.
+     */
     public LiveData<List<ProductDTO>> getProductList() { return productList; }
 
+    /**
+     * Adds an item to the sale cart.
+     */
     public void addToCart(SaleDTO.SaleItemDTO item) {
         List<SaleDTO.SaleItemDTO> currentCart = new ArrayList<>(cartItems.getValue());
         currentCart.add(item);
         cartItems.setValue(currentCart);
     }
 
+    /**
+     * Removes an item from the sale cart by product ID.
+     */
     public void removeFromCart(Long prodId) {
         List<SaleDTO.SaleItemDTO> currentCart = new ArrayList<>(cartItems.getValue());
         currentCart.removeIf(item -> item.getProdId().equals(prodId));
         cartItems.setValue(currentCart);
     }
 
+    /**
+     * Returns the LiveData for the list of items in the cart.
+     */
     public LiveData<List<SaleDTO.SaleItemDTO>> getCartItems() { return cartItems; }
 
+    /**
+     * Looks up a coupon by its code.
+     */
     public LiveData<Resource<CouponDTO>> lookupCoupon(String code) {
         return couponRepository.getCouponByCode(code);
     }
 
+    /**
+     * Sets the currently applied coupon.
+     */
     public void setAppliedCoupon(CouponDTO coupon) {
         appliedCoupon.setValue(coupon);
     }
 
+    /**
+     * Sets whether to use loyalty points for the current sale.
+     */
     public void setUseLoyaltyPoints(boolean use) {
         useLoyaltyPoints.setValue(use);
     }
 
+    /**
+     * Returns the LiveData for whether loyalty points are being used.
+     */
     public LiveData<Boolean> getUseLoyaltyPoints() {
         return useLoyaltyPoints;
     }
 
+    /**
+     * Returns the LiveData for the selected customer's full data.
+     */
     public LiveData<CustomerDTO> getSelectedCustomerData() {
         return selectedCustomerData;
     }
 
+    /**
+     * Selects a customer and loads their full data.
+     */
     public void selectCustomer(Long customerId) {
         if (customerId == null) {
             selectedCustomerData.setValue(null);
@@ -142,23 +218,38 @@ public class SaleDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Clears the currently applied coupon.
+     */
     public void clearCoupon() {
         appliedCoupon.setValue(null);
     }
 
+    /**
+     * Returns the LiveData for the applied coupon.
+     */
     public LiveData<CouponDTO> getAppliedCoupon() {
         return appliedCoupon;
     }
 
+    /**
+     * Returns the ID of the applied coupon.
+     */
     public Long getAppliedCouponId() {
         CouponDTO coupon = appliedCoupon.getValue();
         return coupon != null ? coupon.getCouponId() : null;
     }
 
+    /**
+     * Calculates the total discount (coupon + loyalty).
+     */
     public BigDecimal calculateDiscount() {
         return calculateCouponDiscount().add(calculateLoyaltyDiscount());
     }
 
+    /**
+     * Calculates the discount from the applied coupon.
+     */
     public BigDecimal calculateCouponDiscount() {
         CouponDTO coupon = appliedCoupon.getValue();
         if (coupon == null || coupon.getDiscountValue() == null) return BigDecimal.ZERO;
@@ -170,6 +261,9 @@ public class SaleDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Calculates the discount from using loyalty points.
+     */
     public BigDecimal calculateLoyaltyDiscount() {
         if (Boolean.FALSE.equals(useLoyaltyPoints.getValue())) return BigDecimal.ZERO;
         CustomerDTO customer = selectedCustomerData.getValue();
@@ -184,11 +278,17 @@ public class SaleDetailViewModel extends ViewModel {
         return BigDecimal.valueOf(pointsToUse).multiply(BigDecimal.valueOf(0.05)).setScale(2, java.math.RoundingMode.HALF_UP);
     }
 
+    /**
+     * Calculates the number of loyalty points to be used.
+     */
     public int calculatePointsToUse() {
         BigDecimal loyaltyDiscount = calculateLoyaltyDiscount();
         return loyaltyDiscount.divide(BigDecimal.valueOf(0.05), 0, java.math.RoundingMode.HALF_UP).intValue();
     }
 
+    /**
+     * Calculates the subtotal of all items in the cart.
+     */
     public BigDecimal calculateSubtotal() {
         BigDecimal total = BigDecimal.ZERO;
         List<SaleDTO.SaleItemDTO> items = cartItems.getValue();
@@ -206,10 +306,16 @@ public class SaleDetailViewModel extends ViewModel {
         return total;
     }
 
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() {
         return isLoading;
     }
 
+    /**
+     * Sets the loading state.
+     */
     public void setLoading(boolean loading) {
         isLoading.setValue(loading);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleListViewModel.java
index aee0f948..e3f4f7ee 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SaleListViewModel.java
@@ -22,6 +22,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for managing the list of sales transactions and applying filters.
+ */
 @HiltViewModel
 public class SaleListViewModel extends ViewModel {
     private final SaleRepository saleRepository;
@@ -44,12 +47,34 @@ public class SaleListViewModel extends ViewModel {
         this.customerRepository = customerRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of sales.
+     */
     public LiveData<List<SaleDTO>> getSales() { return sales; }
+
+    /**
+     * Returns the LiveData for the list of available stores.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for the list of available customers.
+     */
     public LiveData<List<CustomerDTO>> getCustomers() { return customers; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Returns true if the current page is the last page of results.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads a page of sales based on search and filter criteria.
+     */
     public void loadSales(boolean reset, String query, String paymentMethod, Long storeId, Boolean isRefund, Long customerId) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -75,6 +100,9 @@ public class SaleListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads available stores for filtering.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -83,6 +111,9 @@ public class SaleListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads available customers for filtering.
+     */
     public void loadCustomers() {
         observeOnce(customerRepository.getAllCustomers(0, 500), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -91,6 +122,9 @@ public class SaleListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Observes a LiveData once, removing the observer after the first non-loading response.
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceDetailViewModel.java
index 625abb92..352a08b7 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceDetailViewModel.java
@@ -26,24 +26,39 @@ public class ServiceDetailViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Sets the service ID and initializes the editing mode.
+     */
     public void setServiceId(long id) {
         this.serviceId = id;
         initMode(id != -1);
     }
 
+    /**
+     * Returns the current service ID.
+     */
     public long getServiceId() {
         return serviceId;
     }
 
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() {
         ViewState current = viewState.getValue();
         return current != null && current.isEditing;
     }
 
+    /**
+     * Returns the LiveData for the view state.
+     */
     public LiveData<ViewState> getViewState() {
         return viewState;
     }
 
+    /**
+     * Initializes the UI mode (Create vs Edit).
+     */
     public void initMode(boolean isEditing) {
         updateViewState(state -> {
             state.isEditing = isEditing;
@@ -55,6 +70,9 @@ public class ServiceDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Fetches service details from the repository.
+     */
     public LiveData<Resource<ServiceDTO>> loadService() {
         MutableLiveData<Resource<ServiceDTO>> result = new MutableLiveData<>();
         observeOnce(repository.getServiceById(serviceId), resource -> {
@@ -72,6 +90,9 @@ public class ServiceDetailViewModel extends ViewModel {
         return result;
     }
 
+    /**
+     * Saves or updates the service record.
+     */
     public LiveData<Resource<ServiceDTO>> saveService(ServiceDTO dto) {
         updateViewState(state -> {
             state.serviceName = safeText(dto.getServiceName());
@@ -88,6 +109,9 @@ public class ServiceDetailViewModel extends ViewModel {
         return repository.createService(dto);
     }
 
+    /**
+     * Deletes the current service record.
+     */
     public LiveData<Resource<Void>> deleteService() {
         return repository.deleteService(serviceId);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceListViewModel.java
index bbdbe270..7e3e9092 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/ServiceListViewModel.java
@@ -35,10 +35,24 @@ public class ServiceListViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Returns the LiveData for the list of services.
+     */
     public LiveData<List<ServiceDTO>> getServices() { return services; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of services has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads services from the repository with the specified filters.
+     */
     public void loadServices(boolean reset, String query) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -76,6 +90,9 @@ public class ServiceListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple services by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeleteServices(List<String> ids) {
         return repository.bulkDeleteServices(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffDetailViewModel.java
index 7927465e..8dd538a9 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffDetailViewModel.java
@@ -31,31 +31,52 @@ public class StaffDetailViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Loads store dropdown options.
+     */
     public LiveData<Resource<List<DropdownDTO>>> loadStores() {
         return storeRepository.getStoreDropdowns();
     }
 
+    /**
+     * Returns the LiveData for the store list.
+     */
     public LiveData<List<DropdownDTO>> getStoreList() {
         return storeList;
     }
 
+    /**
+     * Updates the store list.
+     */
     public void setStoreList(List<DropdownDTO> list) {
         storeList.setValue(list);
     }
 
+    /**
+     * Loads the employee details from the repository.
+     */
     public LiveData<Resource<EmployeeDTO>> loadEmployee(long id) {
         return repository.getEmployeeById(id);
     }
 
+    /**
+     * Sets the current employee ID and editing mode.
+     */
     public void setEmployeeId(long id, boolean isEditing) {
         this.employeeId = id;
         this.isEditing = isEditing;
     }
 
+    /**
+     * Returns the current employee ID.
+     */
     public long getEmployeeId() {
         return employeeId;
     }
 
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() {
         return isEditing;
     }
@@ -68,6 +89,9 @@ public class StaffDetailViewModel extends ViewModel {
         return dto;
     }
 
+    /**
+     * Saves or updates the employee record.
+     */
     public LiveData<Resource<EmployeeDTO>> saveEmployee(EmployeeDTO dto) {
         if (isEditing && employeeId > 0) {
             return repository.updateEmployee(employeeId, dto);
@@ -76,6 +100,9 @@ public class StaffDetailViewModel extends ViewModel {
         }
     }
 
+    /**
+     * Deletes the current employee record.
+     */
     public LiveData<Resource<Void>> deleteEmployee() {
         return repository.deleteEmployee(employeeId);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffListViewModel.java
index 3dc40816..ed22e3e5 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/StaffListViewModel.java
@@ -19,6 +19,9 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+/**
+ * ViewModel for managing the list of employees, including filtering and pagination.
+ */
 @HiltViewModel
 public class StaffListViewModel extends ViewModel {
     private final EmployeeRepository repository;
@@ -43,11 +46,29 @@ public class StaffListViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    /**
+     * Returns the LiveData for the list of filtered employees.
+     */
     public LiveData<List<EmployeeDTO>> getFilteredEmployees() { return filteredEmployees; }
+
+    /**
+     * Returns the LiveData for the list of stores for filtering.
+     */
     public LiveData<List<StoreDTO>> getStores() { return stores; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of employees has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads the full list of staff from the repository.
+     */
     public void loadStaff(boolean reset) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -76,6 +97,9 @@ public class StaffListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Loads the list of stores for filtering options.
+     */
     public void loadStores() {
         observeOnce(storeRepository.getAllStores(0, 100), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -84,6 +108,9 @@ public class StaffListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Observes a LiveData once
+     */
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
@@ -96,6 +123,9 @@ public class StaffListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Filters the employee list locally based on query, store, and status.
+     */
     public void filter(String query, Long storeId, String status) {
         this.lastQuery = query;
         this.lastStoreId = storeId;
@@ -103,6 +133,9 @@ public class StaffListViewModel extends ViewModel {
         applyFilter(employees.getValue());
     }
 
+    /**
+     * Applies the filters to the full list and updates the filtered LiveData.
+     */
     private void applyFilter(List<EmployeeDTO> all) {
         if (all == null) return;
 
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierDetailViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierDetailViewModel.java
index 54f83ef9..63e03b7d 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierDetailViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierDetailViewModel.java
@@ -26,24 +26,39 @@ public class SupplierDetailViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Sets the supplier ID and initializes the editing mode.
+     */
     public void setSupId(long id) {
         this.supId = id;
         initMode(id != -1);
     }
 
+    /**
+     * Returns the current supplier ID.
+     */
     public long getSupId() {
         return supId;
     }
 
+    /**
+     * Checks if the fragment is in editing mode.
+     */
     public boolean isEditing() {
         ViewState current = viewState.getValue();
         return current != null && current.isEditing;
     }
 
+    /**
+     * Returns the LiveData for the view state.
+     */
     public LiveData<ViewState> getViewState() {
         return viewState;
     }
 
+    /**
+     * Initializes the UI mode (Create vs Edit).
+     */
     public void initMode(boolean isEditing) {
         updateViewState(state -> {
             state.isEditing = isEditing;
@@ -55,6 +70,9 @@ public class SupplierDetailViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Fetches supplier details from the repository.
+     */
     public LiveData<Resource<SupplierDTO>> loadSupplier() {
         MutableLiveData<Resource<SupplierDTO>> result = new MutableLiveData<>();
         observeOnce(repository.getSupplierById(supId), resource -> {
@@ -73,6 +91,9 @@ public class SupplierDetailViewModel extends ViewModel {
         return result;
     }
 
+    /**
+     * Saves or updates the supplier record.
+     */
     public LiveData<Resource<SupplierDTO>> saveSupplier(SupplierDTO dto) {
         if (isEditing()) {
             dto.setSupId(supId);
@@ -81,6 +102,9 @@ public class SupplierDetailViewModel extends ViewModel {
         return repository.createSupplier(dto);
     }
 
+    /**
+     * Deletes the current supplier record.
+     */
     public LiveData<Resource<Void>> deleteSupplier() {
         return repository.deleteSupplier(supId);
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierListViewModel.java b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierListViewModel.java
index 33373e90..700977cf 100644
--- a/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierListViewModel.java
+++ b/android/app/src/main/java/com/example/petstoremobile/viewmodels/SupplierListViewModel.java
@@ -34,10 +34,24 @@ public class SupplierListViewModel extends ViewModel {
         this.repository = repository;
     }
 
+    /**
+     * Returns the LiveData for the list of suppliers.
+     */
     public LiveData<List<SupplierDTO>> getSuppliers() { return suppliers; }
+
+    /**
+     * Returns the LiveData for the loading state.
+     */
     public LiveData<Boolean> getIsLoading() { return isLoading; }
+
+    /**
+     * Checks if the last page of suppliers has been reached.
+     */
     public boolean isLastPage() { return isLastPage; }
 
+    /**
+     * Loads suppliers from the repository with the specified filters.
+     */
     public void loadSuppliers(boolean reset, String query) {
         if (isLoading.getValue() != null && isLoading.getValue() && !reset) return;
 
@@ -77,6 +91,9 @@ public class SupplierListViewModel extends ViewModel {
         });
     }
 
+    /**
+     * Deletes multiple suppliers by their IDs.
+     */
     public LiveData<Resource<Void>> bulkDeleteSuppliers(List<String> ids) {
         return repository.bulkDeleteSuppliers(new BulkDeleteRequest(ids));
     }
diff --git a/android/app/src/main/java/com/example/petstoremobile/websocket/StompChatManager.java b/android/app/src/main/java/com/example/petstoremobile/websocket/StompChatManager.java
index 3aad4b8d..8d77daef 100644
--- a/android/app/src/main/java/com/example/petstoremobile/websocket/StompChatManager.java
+++ b/android/app/src/main/java/com/example/petstoremobile/websocket/StompChatManager.java
@@ -18,25 +18,50 @@ import ua.naiksoftware.stomp.Stomp;
 import ua.naiksoftware.stomp.StompClient;
 import ua.naiksoftware.stomp.dto.StompHeader;
 
-//Used to handle the websocket connection for the chat
+/**
+ * Manages WebSocket connections and STOMP protocol messaging for the chat system.
+ */
 public class StompChatManager {
 
     private static final String TAG = "StompChatManager";
 
-    //Interface for when a message is received
+    /**
+     * Interface for receiving new chat messages.
+     */
     public interface MessageListener {
+        /**
+         * Called when a new message is received for the current conversation.
+         */
         void onMessageReceived(MessageDTO message);
     }
 
-    //Interface for when a conversation is created or updated
+    /**
+     * Interface for receiving updates to the list of conversations.
+     */
     public interface ConversationListener {
+        /**
+         * Called when a conversation is created or its details are updated.
+         */
         void onConversationUpdated(ConversationDTO conversation);
     }
 
-    //Interface for when the websocket connection is opened, closed, or has an error
+    /**
+     * Interface for monitoring the status of the WebSocket connection.
+     */
     public interface ConnectionListener {
+        /**
+         * Called when the connection is successfully established.
+         */
         void onSocketOpened();
+
+        /**
+         * Called when the connection is closed.
+         */
         void onSocketClosed();
+
+        /**
+         * Called when a connection error occurs.
+         */
         void onSocketError();
     }
 
@@ -59,16 +84,25 @@ public class StompChatManager {
     private boolean manualDisconnect;
     private Long pendingConversationId;
 
+    /**
+     * Initializes the manager with authentication and server details.
+     */
     public StompChatManager(String authToken, String role, String baseUrl) {
         this.authToken = authToken;
         this.role = role == null ? "" : role.trim().toUpperCase(Locale.ROOT);
         this.baseUrl = baseUrl;
     }
 
+    /**
+     * Sets the listener for incoming messages.
+     */
     public void setMessageListener(MessageListener listener) {
         this.messageListener = listener;
     }
 
+    /**
+     * Sets the listener for conversation list updates.
+     */
     public void setConversationListener(ConversationListener listener) {
         this.conversationListener = listener;
     }
@@ -77,7 +111,10 @@ public class StompChatManager {
         this.connectionListener = listener;
     }
 
-    // Set up a stomp connection
+    /**
+     * Establishes a connection to the WebSocket server using STOMP.
+     * Reconnects automatically unless manually disconnected.
+     */
     public void connect() {
         if (authToken == null || authToken.isBlank()) {
             Log.e(TAG, "Cannot connect websocket without token");
@@ -143,7 +180,10 @@ public class StompChatManager {
         ));
     }
 
-    // Subscribes to updates for a specific conversation
+    /**
+     * Subscribes to updates for a specific conversation.
+     * If not connected, the subscription is queued until the connection is established.
+     */
     public void subscribeToConversation(Long conversationId) {
         pendingConversationId = conversationId;
         if (!isConnected || stompClient == null) {
@@ -154,7 +194,9 @@ public class StompChatManager {
         subscribeToTopic(conversationId);
     }
 
-    // Clears the current conversation subscription
+    /**
+     * Stops listening for messages in the current conversation.
+     */
     public void clearConversationSubscription() {
         pendingConversationId = null;
         if (topicDisposable != null && !topicDisposable.isDisposed()) {
@@ -163,7 +205,9 @@ public class StompChatManager {
         }
     }
 
-    //helper function to subscribe to a specific conversation topic
+    /**
+     * Subscribes to the specific STOMP topic for a conversation's messages.
+     */
     private void subscribeToTopic(Long conversationId) {
         if (topicDisposable != null && !topicDisposable.isDisposed()) {
             topicDisposable.dispose();
@@ -189,7 +233,9 @@ public class StompChatManager {
         compositeDisposable.add(topicDisposable);
     }
 
-    // Listens for conversation updates and refresh the chat list
+    /**
+     * Listens for conversation updates and refresh the chat list
+     */
     private void subscribeToConversationFeeds() {
         if (conversationsDisposable != null && !conversationsDisposable.isDisposed()) {
             conversationsDisposable.dispose();
@@ -254,7 +300,9 @@ public class StompChatManager {
         compositeDisposable.add(errorQueueDisposable);
     }
 
-    // Disconnects the stomp connection
+    /**
+     * Disconnects the stomp connection
+     */
     public void disconnect() {
         manualDisconnect = true;
         isConnected = false;
@@ -267,7 +315,9 @@ public class StompChatManager {
         }
     }
 
-    // Make the URL for the websocket connection
+    /**
+     * Make the URL for the websocket connection
+    */
     private String buildWebSocketUrl() {
         String cleanBaseUrl = baseUrl.endsWith("/")
                 ? baseUrl.substring(0, baseUrl.length() - 1)
@@ -281,12 +331,16 @@ public class StompChatManager {
         return cleanBaseUrl + "/ws/chat";
     }
 
-    // Helper to check if the current user is a customer
+    /**
+     * Helper to check if the current user is a customer
+     */
     private boolean isCustomer() {
         return "CUSTOMER".equals(role);
     }
 
-    // if connection drops, try to reconnect after 1 second
+    /**
+     * if connection drops, try to reconnect after 1 second
+     */
     private void scheduleReconnect() {
         if (manualDisconnect) {
             return;