android/app/src/main/java/com/example/petstoremobile/viewmodels/PetDetailViewModel.java

@@ -20,6 +20,7 @@ import javax.inject.Inject;
 
 import dagger.hilt.android.lifecycle.HiltViewModel;
 
+// ViewModel for the pet detail/create screen
 @HiltViewModel
 public class PetDetailViewModel extends ViewModel {
     private static final String STATUS_AVAILABLE = "Available";
@@ -38,13 +39,13 @@ public class PetDetailViewModel extends ViewModel {
     private final MutableLiveData<Boolean> isLoading = new MutableLiveData<>(false);
     private final MutableLiveData<ViewState> viewState = new MutableLiveData<>(new ViewState());
 
-    private long petId = -1;
+    private long petId = -1; // -1 means creating a new pet
     private Long selectedCustomerId = null;
     private Long selectedStoreId = null;
     private String selectedSpecies = null;
     private String selectedBreed = null;
-    private boolean isOriginallyOwnedOrAdopted = false;
+    private boolean isOriginallyOwnedOrAdopted = false; // used to restrict staff edits
-    private Long originalCustomerId = null;
+    private Long originalCustomerId = null; // used to detect owner changes
 
     @Inject
     public PetDetailViewModel(PetRepository petRepository, CustomerRepository customerRepository, StoreRepository storeRepository) {
@@ -53,6 +54,7 @@ public class PetDetailViewModel extends ViewModel {
         this.storeRepository = storeRepository;
     }
 
+    // Loads customers, stores, and species dropdowns needed for the form
     public void loadInitialFormData() {
         observeOnce(customerRepository.getCustomerDropdowns(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -78,26 +80,18 @@ public class PetDetailViewModel extends ViewModel {
         initMode(id != -1);
     }
 
-    public long getPetId() {
+    public long getPetId() { return petId; }
-        return petId;
-    }
 
     public boolean isEditing() {
         ViewState current = viewState.getValue();
         return current != null && current.isEditing;
     }
 
-    public boolean isOriginallyOwnedOrAdopted() {
+    public boolean isOriginallyOwnedOrAdopted() { return isOriginallyOwnedOrAdopted; }
-        return isOriginallyOwnedOrAdopted;
-    }
 
-    public Long getOriginalCustomerId() {
+    public Long getOriginalCustomerId() { return originalCustomerId; }
-        return originalCustomerId;
-    }
 
-    public LiveData<ViewState> getViewState() {
+    public LiveData<ViewState> getViewState() { return viewState; }
-        return viewState;
-    }
 
     public void onCustomerSelected(int position) {
         List<DropdownDTO> list = customerList.getValue();
@@ -106,7 +100,6 @@ public class PetDetailViewModel extends ViewModel {
         } else {
             selectedCustomerId = null;
         }
-
         updateViewState(state -> state.selectedCustomerId = selectedCustomerId);
     }
 
@@ -114,7 +107,7 @@ public class PetDetailViewModel extends ViewModel {
         List<DropdownDTO> list = speciesList.getValue();
         if (position > 0 && list != null && position <= list.size()) {
             selectedSpecies = list.get(position - 1).getLabel();
-            loadBreeds(selectedSpecies);
+            loadBreeds(selectedSpecies); // reload breeds when species changes
         } else {
             selectedSpecies = null;
             breedList.setValue(new ArrayList<>());
@@ -150,17 +143,17 @@ public class PetDetailViewModel extends ViewModel {
         } else {
             selectedStoreId = null;
         }
-
         updateViewState(state -> state.selectedStoreId = selectedStoreId);
     }
 
     public void onStatusSelected(String status) {
         updateViewState(state -> {
             state.selectedStatus = normalizeStatus(status);
-            applyStatusRules(state, true);
+            applyStatusRules(state, true); // clear invalid selections when status changes
         });
     }
 
+    // Sets up initial ViewState based on whether we're editing or creating
     public void initMode(boolean isEditing) {
         updateViewState(state -> {
             state.isEditing = isEditing;
@@ -177,6 +170,7 @@ public class PetDetailViewModel extends ViewModel {
             }
 
             if (!isEditing) {
+                // Reset all selections for a blank create form
                 selectedCustomerId = null;
                 selectedStoreId = null;
                 selectedSpecies = null;
@@ -202,6 +196,7 @@ public class PetDetailViewModel extends ViewModel {
                 selectedStoreId = pet.getStoreId();
                 selectedSpecies = pet.getPetSpecies();
                 selectedBreed = pet.getPetBreed();
+                // Track original status to restrict staff from editing owned/adopted pets
                 isOriginallyOwnedOrAdopted = STATUS_OWNED.equalsIgnoreCase(pet.getPetStatus())
                         || STATUS_ADOPTED.equalsIgnoreCase(pet.getPetStatus());
                 originalCustomerId = pet.getCustomerId();
@@ -217,7 +212,7 @@ public class PetDetailViewModel extends ViewModel {
                     state.selectedBreed = selectedBreed;
                     state.selectedStatus = normalizeStatus(pet.getPetStatus());
                     state.isBreedEnabled = !state.isEditing && (selectedSpecies != null);
-                    applyStatusRules(state, false);
+                    applyStatusRules(state, false); // don't clear selections when loading existing data
                 });
             }
 
@@ -231,46 +226,26 @@ public class PetDetailViewModel extends ViewModel {
             petDTO.setPetId(petId);
             return petRepository.updatePet(petId, petDTO);
         }
-
         return petRepository.createPet(petDTO);
     }
 
-    public LiveData<Resource<Void>> deletePet() {
+    public LiveData<Resource<Void>> deletePet() { return petRepository.deletePet(petId); }
-        return petRepository.deletePet(petId);
-    }
 
     public LiveData<Resource<Void>> uploadPetImage(okhttp3.MultipartBody.Part image) {
         return petRepository.uploadPetImage(petId, image);
     }
 
-    public LiveData<Resource<Void>> deletePetImage() {
+    public LiveData<Resource<Void>> deletePetImage() { return petRepository.deletePetImage(petId); }
-        return petRepository.deletePetImage(petId);
-    }
 
-    public LiveData<List<DropdownDTO>> getCustomerList() {
+    public LiveData<List<DropdownDTO>> getCustomerList() { return customerList; }
-        return customerList;
+    public LiveData<List<DropdownDTO>> getStoreList() { return storeList; }
-    }
+    public LiveData<List<DropdownDTO>> getSpeciesList() { return speciesList; }
+    public LiveData<List<DropdownDTO>> getBreedList() { return breedList; }
+    public LiveData<Boolean> getIsLoading() { return isLoading; }
 
-    public LiveData<List<DropdownDTO>> getStoreList() {
+    public void setLoading(boolean loading) { isLoading.setValue(loading); }
-        return storeList;
-    }
-
-    public LiveData<List<DropdownDTO>> getSpeciesList() {
-        return speciesList;
-    }
-
-    public LiveData<List<DropdownDTO>> getBreedList() {
-        return breedList;
-    }
-
-    public LiveData<Boolean> getIsLoading() {
-        return isLoading;
-    }
-
-    public void setLoading(boolean loading) {
-        isLoading.setValue(loading);
-    }
 
+    // Enables/disables customer and store spinners based on the selected status
     private void applyStatusRules(ViewState state, boolean clearInvalidSelections) {
         if (STATUS_AVAILABLE.equalsIgnoreCase(state.selectedStatus)) {
             state.isCustomerEnabled = false;
@@ -292,10 +267,12 @@ public class PetDetailViewModel extends ViewModel {
             return;
         }
 
+        // Adopted and Pending: both customer and store required
         state.isCustomerEnabled = true;
         state.isStoreEnabled = true;
     }
 
+    // Normalizes any status string to one of the four known constants
     private String normalizeStatus(String status) {
         if (status == null) return STATUS_AVAILABLE;
         String normalized = status.trim();
@@ -305,6 +282,7 @@ public class PetDetailViewModel extends ViewModel {
         return STATUS_AVAILABLE;
     }
 
+    // Mutates the current ViewState and re-posts it to trigger UI updates
     private void updateViewState(Action<ViewState> action) {
         ViewState current = viewState.getValue();
         if (current != null) {
@@ -317,6 +295,7 @@ public class PetDetailViewModel extends ViewModel {
         void run(T target);
     }
 
+    // Observes a LiveData exactly once, removing itself after the first non-loading result
     private <T> void observeOnce(LiveData<Resource<T>> liveData, Observer<Resource<T>> handler) {
         liveData.observeForever(new Observer<Resource<T>>() {
             @Override
@@ -329,6 +308,7 @@ public class PetDetailViewModel extends ViewModel {
         });
     }
 
+    // Holds all UI state for the pet detail screen
     public static class ViewState {
         public boolean isEditing = false;
         public boolean isDeleteVisible = false;
@@ -346,4 +326,4 @@ public class PetDetailViewModel extends ViewModel {
         public Long selectedCustomerId = null;
         public Long selectedStoreId = null;
     }
-}
+}