Moved appointments businiss logic to modelview andriod

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AppointmentDetailFragment.java

@@ -13,16 +13,12 @@ import androidx.navigation.fragment.NavHostFragment;
 
 import com.example.petstoremobile.databinding.FragmentAppointmentDetailBinding;
 import com.example.petstoremobile.dtos.*;
+import com.example.petstoremobile.utils.DateTimeUtils;
 import com.example.petstoremobile.utils.DialogUtils;
 import com.example.petstoremobile.utils.Resource;
 import com.example.petstoremobile.utils.SpinnerUtils;
 import com.example.petstoremobile.utils.UIUtils;
 import com.example.petstoremobile.viewmodels.AppointmentViewModel;
-import com.example.petstoremobile.viewmodels.CustomerViewModel;
-import com.example.petstoremobile.viewmodels.PetViewModel;
-import com.example.petstoremobile.viewmodels.ServiceViewModel;
-import com.example.petstoremobile.viewmodels.StoreViewModel;
-import com.example.petstoremobile.viewmodels.UserViewModel;
 
 import java.util.*;
 
@@ -36,40 +32,22 @@ public class AppointmentDetailFragment extends Fragment {
 
     private FragmentAppointmentDetailBinding binding;
 
-    private long appointmentId = -1;
-    private boolean isEditing = false;
-    private boolean isPastAppointment = false;
     private long preselectedPetId = -1;
     private long preselectedServiceId = -1;
     private long preselectedCustomerId = -1;
     private long preselectedStoreId = -1;
     private long preselectedStaffId = -1;
 
-    private List<DropdownDTO> petList = new ArrayList<>();
-    private List<ServiceDTO> serviceList = new ArrayList<>();
-    private List<DropdownDTO> customerList = new ArrayList<>();
-    private List<DropdownDTO> storeList = new ArrayList<>();
-    private List<DropdownDTO> staffList = new ArrayList<>();
-
     private final Integer[] HOURS = {9,10,11,12,13,14,15,16,17};
     private final Integer[] MINUTES = {0,15,30,45};
 
     private AppointmentViewModel appointmentViewModel;
-    private PetViewModel petViewModel;
+    private boolean isUpdatingUI = false;
-    private ServiceViewModel serviceViewModel;
-    private StoreViewModel storeViewModel;
-    private CustomerViewModel customerViewModel;
-    private UserViewModel userViewModel;
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         appointmentViewModel = new ViewModelProvider(this).get(AppointmentViewModel.class);
-        petViewModel = new ViewModelProvider(this).get(PetViewModel.class);
-        serviceViewModel = new ViewModelProvider(this).get(ServiceViewModel.class);
-        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
-        customerViewModel = new ViewModelProvider(this).get(CustomerViewModel.class);
-        userViewModel = new ViewModelProvider(this).get(UserViewModel.class);
     }
 
     @Override
@@ -83,7 +61,8 @@ public class AppointmentDetailFragment extends Fragment {
         super.onViewCreated(view, savedInstanceState);
         setupSpinners();
         setupDatePicker();
-        loadSpinnersData();
+        observeViewModel();
+        appointmentViewModel.loadInitialFormData();
         handleArguments();
 
         binding.btnApptBack.setOnClickListener(v -> navigateBack());
@@ -101,9 +80,10 @@ public class AppointmentDetailFragment extends Fragment {
      * Configures the adapters for spinners.
      */
     private void setupSpinners() {
-        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAppointmentStatus,
+        //Status Spinner is empty by default the date determines whats in here
-                new String[]{"Booked", "Completed", "Cancelled", "Missed"});
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAppointmentStatus, new String[]{});
 
+        // Set up hour and minute spinners
         String[] hours = new String[HOURS.length];
         for (int i = 0; i < HOURS.length; i++)
             hours[i] = String.format("%02d:00", HOURS[i]);
@@ -113,50 +93,41 @@ public class AppointmentDetailFragment extends Fragment {
         // Pet and Staff spinners disabled by until parent selection
         UIUtils.setViewsEnabled(false, binding.spinnerPet, binding.spinnerStaff);
 
-        // Listener to load pets based on selected customer
+        // Listener to notify ViewModel of customer selection
         binding.spinnerCustomer.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
             @Override
             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
-                if (position > 0 && position <= customerList.size()) {
+                appointmentViewModel.onCustomerSelected(position);
-                    DropdownDTO selectedCustomer = customerList.get(position - 1);
-                    loadPets(selectedCustomer.getId());
-                    if (!isEditing) {
-                        UIUtils.setViewsEnabled(true, binding.spinnerPet);
-                    }
-                } else {
-                    petList.clear();
-                    refreshPetSpinner();
-                    if (!isEditing) {
-                        binding.spinnerPet.setSelection(0);
-                        UIUtils.setViewsEnabled(false, binding.spinnerPet);
-                    }
-                }
             }
-
             @Override
             public void onNothingSelected(AdapterView<?> parent) {}
         });
 
-        // Listener to load staff based on selected store
+        // Listener to notify ViewModel of store selection
         binding.spinnerStore.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
             @Override
             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
-                if (position > 0 && position <= storeList.size()) {
+                appointmentViewModel.onStoreSelected(position);
-                    DropdownDTO selectedStore = storeList.get(position - 1);
-                    loadStaff(selectedStore.getId());
-                    if (!isPastAppointment) {
-                        UIUtils.setViewsEnabled(true, binding.spinnerStaff);
-                    }
-                } else {
-                    staffList.clear();
-                    refreshStaffSpinner();
-                    if (!isEditing) {
-                        binding.spinnerStaff.setSelection(0);
-                        UIUtils.setViewsEnabled(false, binding.spinnerStaff);
-                    }
-                }
             }
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {}
+        });
 
+        // Listeners for other selections
+        binding.spinnerService.setOnItemSelectedListener(new OnIndexSelected(p -> appointmentViewModel.onServiceSelected(p)));
+        binding.spinnerPet.setOnItemSelectedListener(new OnIndexSelected(p -> appointmentViewModel.onPetSelected(p)));
+        binding.spinnerStaff.setOnItemSelectedListener(new OnIndexSelected(p -> appointmentViewModel.onStaffSelected(p)));
+
+        // Listeners for time changes
+        binding.spinnerHour.setOnItemSelectedListener(new OnIndexSelected(p -> notifyDateTimeStatusChange()));
+        binding.spinnerMinute.setOnItemSelectedListener(new OnIndexSelected(p -> notifyDateTimeStatusChange()));
+
+        // Listener to notify ViewModel of status selection
+        binding.spinnerAppointmentStatus.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
+            @Override
+            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+                notifyDateTimeStatusChange();
+            }
             @Override
             public void onNothingSelected(AdapterView<?> parent) {}
         });
@@ -167,11 +138,13 @@ public class AppointmentDetailFragment extends Fragment {
      */
     private void setupDatePicker() {
         binding.etAppointmentDate.setOnClickListener(v -> {
-            if (isPastAppointment) return;
             Calendar c = Calendar.getInstance();
             DatePickerDialog d = new DatePickerDialog(requireContext(),
-                    (dp,y,m,d1) -> binding.etAppointmentDate.setText(
+                    (dp,y,m,d1) -> {
-                            String.format("%04d-%02d-%02d", y, m+1, d1)),
+                        String selectedDate = String.format("%04d-%02d-%02d", y, m+1, d1);
+                        binding.etAppointmentDate.setText(selectedDate);
+                        notifyDateTimeStatusChange();
+                    },
                     c.get(Calendar.YEAR), c.get(Calendar.MONTH),
                     c.get(Calendar.DAY_OF_MONTH));
             d.getDatePicker().setMinDate(System.currentTimeMillis() - 1000);
@@ -180,118 +153,79 @@ public class AppointmentDetailFragment extends Fragment {
     }
 
     /**
-     * Fetches all required data for spinners from the backend.
+     * Observes the ViewModel for UI state and list updates.
      */
-    private void loadSpinnersData() {
+    private void observeViewModel() {
-        loadServices();
+        appointmentViewModel.getViewState().observe(getViewLifecycleOwner(), this::applyViewState);
-        loadCustomers();
+        
-        loadStores();
+        // Populate spinners when data arrives
+        appointmentViewModel.getCustomers().observe(getViewLifecycleOwner(), list ->
+            SpinnerUtils.populateSpinner(requireContext(), binding.spinnerCustomer, list, DropdownDTO::getLabel, "-- Select Customer --", preselectedCustomerId, DropdownDTO::getId));
+        
+        appointmentViewModel.getStores().observe(getViewLifecycleOwner(), list ->
+            SpinnerUtils.populateSpinner(requireContext(), binding.spinnerStore, list, DropdownDTO::getLabel, "-- Select Store --", preselectedStoreId, DropdownDTO::getId));
+        
+        appointmentViewModel.getServices().observe(getViewLifecycleOwner(), list ->
+            SpinnerUtils.populateSpinner(requireContext(), binding.spinnerService, list, ServiceDTO::getServiceName, "-- Select Service --", preselectedServiceId, ServiceDTO::getServiceId));
+
+        appointmentViewModel.getCustomerPets().observe(getViewLifecycleOwner(), list ->
+            SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPet, list, DropdownDTO::getLabel, "-- Select Pet --", preselectedPetId, DropdownDTO::getId));
+
+        appointmentViewModel.getStoreEmployees().observe(getViewLifecycleOwner(), list ->
+            SpinnerUtils.populateSpinner(requireContext(), binding.spinnerStaff, list, DropdownDTO::getLabel, "-- Select Staff --", preselectedStaffId, DropdownDTO::getId));
     }
 
     /**
-     * Loads the list of pets from the ViewModel, filtered by customerId.
+     * Applies the ViewState provided by the ViewModel to the UI components.
      */
-    private void loadPets(Long customerId) {
+    private void applyViewState(AppointmentViewModel.ViewState state) {
-        petViewModel.getCustomerPets(customerId).observe(getViewLifecycleOwner(), resource -> {
+        isUpdatingUI = true;
-            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+        
-                petList = resource.data;
+        // Mode specific UI
-                refreshPetSpinner();
+        binding.tvApptMode.setText(state.isEditing ? "Edit Appointment" : "Add Appointment");
-            }
+        binding.tvAppointmentId.setText("ID: " + appointmentViewModel.getAppointmentId());
-        });
+        binding.tvAppointmentId.setVisibility(state.isEditing ? View.VISIBLE : View.GONE);
+        binding.btnDeleteAppointment.setVisibility(state.isDeleteVisible ? View.VISIBLE : View.GONE);
+        binding.btnSaveAppointment.setVisibility(state.isSaveVisible ? View.VISIBLE : View.GONE);
+        
+        // Enabling/Disabling Views
+        UIUtils.setViewsEnabled(state.isCustomerEnabled, binding.spinnerCustomer);
+        UIUtils.setViewsEnabled(state.isStoreEnabled, binding.spinnerStore);
+        UIUtils.setViewsEnabled(state.isPetEnabled, binding.spinnerPet);
+        UIUtils.setViewsEnabled(state.isServiceEnabled, binding.spinnerService);
+        UIUtils.setViewsEnabled(state.isStaffEnabled, binding.spinnerStaff);
+        UIUtils.setViewsEnabled(state.isDateEnabled, binding.etAppointmentDate);
+        UIUtils.setViewsEnabled(state.isTimeEnabled, binding.spinnerHour, binding.spinnerMinute);
+        UIUtils.setViewsEnabled(state.isStatusEnabled, binding.spinnerAppointmentStatus);
+
+        // Alpha for disabled look
+        float alpha = 1.0f;
+        float disabledAlpha = 0.5f;
+        UIUtils.setViewsAlpha(state.isCustomerEnabled ? alpha : disabledAlpha, binding.tvLabelCustomer);
+        UIUtils.setViewsAlpha(state.isStoreEnabled ? alpha : disabledAlpha, binding.tvLabelStore);
+        UIUtils.setViewsAlpha(state.isPetEnabled ? alpha : disabledAlpha, binding.tvLabelPet);
+        UIUtils.setViewsAlpha(state.isServiceEnabled ? alpha : disabledAlpha, binding.tvLabelService);
+        UIUtils.setViewsAlpha(state.isStaffEnabled ? alpha : disabledAlpha, binding.tvLabelStaff);
+        UIUtils.setViewsAlpha(state.isDateEnabled ? alpha : disabledAlpha, binding.tvLabelDate);
+        UIUtils.setViewsAlpha(state.isTimeEnabled ? alpha : disabledAlpha, binding.tvLabelTime);
+
+        // Update status options
+        Object selected = binding.spinnerAppointmentStatus.getSelectedItem();
+        String current = selected != null ? selected.toString() : "";
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAppointmentStatus, state.availableStatuses);
+        SpinnerUtils.setSelectionByValue(binding.spinnerAppointmentStatus, current);
+
+        isUpdatingUI = false;
     }
 
-    /**
+    private void notifyDateTimeStatusChange() {
-     * Populates the pet selection spinner.
+        if (isUpdatingUI) return;
-     */
-    private void refreshPetSpinner() {
-        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPet, petList,
-                DropdownDTO::getLabel, "-- Select Pet --",
-                preselectedPetId, DropdownDTO::getId);
-    }
 
-    /**
+        String date = binding.etAppointmentDate.getText().toString();
-     * Loads the list of services from the API.
+        String time = buildTimeString();
-     */
+        Object selected = binding.spinnerAppointmentStatus.getSelectedItem();
-    private void loadServices() {
+        String status = selected != null ? selected.toString() : "";
-        serviceViewModel.getAllServices(0, 200, null, "serviceName").observe(getViewLifecycleOwner(), resource -> {
+        appointmentViewModel.onDateOrTimeChanged(date, time, status);
-            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
-                serviceList = resource.data.getContent();
-                refreshServiceSpinner();
-            }
-        });
-    }
-
-    /**
-     * Populates the service selection spinner.
-     */
-    private void refreshServiceSpinner() {
-        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerService, serviceList,
-                ServiceDTO::getServiceName, "-- Select Service --",
-                preselectedServiceId, ServiceDTO::getServiceId);
-    }
-
-    /**
-     * Loads the list of customers from the API.
-     */
-    private void loadCustomers() {
-        customerViewModel.getCustomerDropdowns().observe(getViewLifecycleOwner(), resource -> {
-            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
-                customerList = resource.data;
-                refreshCustomerSpinner();
-            }
-        });
-    }
-
-    /**
-     * Populates the customer selection spinner.
-     */
-    private void refreshCustomerSpinner() {
-        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerCustomer, customerList,
-                DropdownDTO::getLabel,
-                "-- Select Customer --",
-                preselectedCustomerId, DropdownDTO::getId);
-    }
-
-    /**
-     * Loads the list of stores from the API.
-     */
-    private void loadStores() {
-        storeViewModel.getStoreDropdowns().observe(getViewLifecycleOwner(), resource -> {
-            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
-                storeList = resource.data;
-                refreshStoreSpinner();
-            }
-        });
-    }
-
-    /**
-     * Populates the store selection spinner.
-     */
-    private void refreshStoreSpinner() {
-        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerStore, storeList,
-                DropdownDTO::getLabel, "-- Select Store --",
-                preselectedStoreId, DropdownDTO::getId);
-    }
-
-    /**
-     * Loads the list of staff for a specific store.
-     */
-    private void loadStaff(Long storeId) {
-        storeViewModel.getStoreEmployees(storeId).observe(getViewLifecycleOwner(), resource -> {
-            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
-                staffList = resource.data;
-                refreshStaffSpinner();
-            }
-        });
-    }
-
-    /**
-     * Populates the staff selection spinner.
-     */
-    private void refreshStaffSpinner() {
-        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerStaff, staffList,
-                DropdownDTO::getLabel, "-- Select Staff --",
-                preselectedStaffId, DropdownDTO::getId);
     }
 
     /**
@@ -300,27 +234,10 @@ public class AppointmentDetailFragment extends Fragment {
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("appointmentId")) {
-            //edit mode
+            appointmentViewModel.setAppointmentId(a.getLong("appointmentId"));
-            isEditing = true;
-            appointmentId = a.getLong("appointmentId");
-            binding.tvApptMode.setText("Edit Appointment");
-            binding.tvAppointmentId.setText("ID: " + appointmentId);
-            binding.tvAppointmentId.setVisibility(View.VISIBLE);
-            binding.btnDeleteAppointment.setVisibility(View.VISIBLE);
-
-            UIUtils.setViewsEnabled(false, binding.spinnerCustomer, binding.spinnerStore, binding.spinnerPet, binding.spinnerService);
-            UIUtils.setViewsAlpha(0.5f, binding.tvLabelCustomer, binding.tvLabelStore, binding.tvLabelPet, binding.tvLabelService);
-
             loadAppointmentData();
         } else {
-            //add mode
+            appointmentViewModel.setAppointmentId(-1);
-            binding.tvApptMode.setText("Add Appointment");
-            binding.btnDeleteAppointment.setVisibility(View.GONE);
-            binding.tvAppointmentId.setVisibility(View.GONE);
-
-            UIUtils.setViewsEnabled(true, binding.spinnerCustomer, binding.spinnerStore, binding.spinnerService);
-            UIUtils.setViewsEnabled(false, binding.spinnerPet, binding.spinnerStaff, binding.spinnerAppointmentStatus);
-            UIUtils.setViewsAlpha(1.0f, binding.tvLabelCustomer, binding.tvLabelStore, binding.tvLabelPet, binding.tvLabelService, binding.tvLabelStaff);
         }
     }
 
@@ -328,229 +245,83 @@ public class AppointmentDetailFragment extends Fragment {
      * Fetches specific appointment details from the backend using the ID.
      */
     private void loadAppointmentData() {
-        appointmentViewModel.getAppointmentById(appointmentId).observe(getViewLifecycleOwner(), resource -> {
+        appointmentViewModel.loadAppointment().observe(getViewLifecycleOwner(), resource -> {
-            if (resource == null) return;
+            if (resource == null || resource.status != Resource.Status.SUCCESS || resource.data == null) return;
-            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+            AppointmentDTO a = resource.data;
-                AppointmentDTO a = resource.data;
+            preselectedPetId = a.getPetId() != null ? a.getPetId() : -1;
-                preselectedPetId = (a.getPetId() != null) ? a.getPetId() : -1;
+            preselectedServiceId = a.getServiceId() != null ? a.getServiceId() : -1;
-                preselectedServiceId = (a.getServiceId() != null) ? a.getServiceId() : -1;
+            preselectedCustomerId = a.getCustomerId() != null ? a.getCustomerId() : -1;
-                preselectedCustomerId = (a.getCustomerId() != null) ? a.getCustomerId() : -1;
+            preselectedStoreId = a.getStoreId() != null ? a.getStoreId() : -1;
-                preselectedStoreId = (a.getStoreId() != null) ? a.getStoreId() : -1;
+            preselectedStaffId = a.getEmployeeId() != null ? a.getEmployeeId() : -1;
-                preselectedStaffId = (a.getEmployeeId() != null) ? a.getEmployeeId() : -1;
 
-                binding.etAppointmentDate.setText(a.getAppointmentDate());
+            binding.etAppointmentDate.setText(a.getAppointmentDate());
-
+            parseAndSetTimeSpinners(a.getAppointmentTime() != null ? a.getAppointmentTime() : "09:00");
-                // Pre-fill time spinners
+            
-                String time = a.getAppointmentTime() != null ? a.getAppointmentTime() : "09:00";
+            String status = a.getAppointmentStatus();
-                if (time.length() > 5) time = time.substring(0, 5);
+            if (status != null && !status.isEmpty()) {
-                String[] parts = time.split(":");
+                SpinnerUtils.setSelectionByValue(binding.spinnerAppointmentStatus, DateTimeUtils.formatStatusFromBackend(status));
-                if (parts.length == 2) {
-                    try {
-                        int hour = Integer.parseInt(parts[0]);
-                        int min = Integer.parseInt(parts[1]);
-                        for (int i = 0; i < HOURS.length; i++)
-                            if (HOURS[i] == hour) { binding.spinnerHour.setSelection(i); break; }
-                        for (int i = 0; i < MINUTES.length; i++)
-                            if (MINUTES[i] == min) { binding.spinnerMinute.setSelection(i); break; }
-                    } catch (NumberFormatException ignored) {}
-                }
-
-                // Match Title labels with backend values
-                String status = a.getAppointmentStatus();
-                if (status != null && !status.isEmpty()) {
-                    String formattedStatus = status.substring(0, 1).toUpperCase() + status.substring(1).toLowerCase();
-                    SpinnerUtils.setSelectionByValue(binding.spinnerAppointmentStatus, formattedStatus);
-                }
-
-                checkIfPastAndDisable(a.getAppointmentDate(), time);
-
-                refreshPetSpinner();
-                refreshServiceSpinner();
-                refreshCustomerSpinner();
-                refreshStoreSpinner();
-                refreshStaffSpinner();
-            } else if (resource.status == Resource.Status.ERROR) {
-                Toast.makeText(getContext(), "Failed to load appointment: " + resource.message, Toast.LENGTH_SHORT).show();
             }
+            notifyDateTimeStatusChange();
         });
     }
 
-    /**
-     * Checks if the appointment is in the past and disables fields.
-     */
-    private void checkIfPastAndDisable(String date, String time) {
-        if (date == null || time == null) return;
-        try {
-            Calendar selected = Calendar.getInstance();
-            String[] dateParts = date.split("-");
-            String[] timeParts = time.split(":");
-            selected.set(
-                    Integer.parseInt(dateParts[0]),
-                    Integer.parseInt(dateParts[1]) - 1,
-                    Integer.parseInt(dateParts[2]),
-                    Integer.parseInt(timeParts[0]),
-                    Integer.parseInt(timeParts[1]),
-                    0
-            );
-
-            Object selectedItem = binding.spinnerAppointmentStatus.getSelectedItem();
-            String currentStatus = selectedItem != null ? selectedItem.toString() : "";
-
-            // If the appointment is already Cancelled, disable all fields
-            if ("Cancelled".equalsIgnoreCase(currentStatus)) {
-                isPastAppointment = true;
-                disableAllExceptStatus();
-                UIUtils.setViewsEnabled(false, binding.spinnerAppointmentStatus);
-                binding.btnSaveAppointment.setVisibility(View.GONE);
-                return;
-            }
-
-            // If the appointment date/time is in the past
-            if (selected.before(Calendar.getInstance())) {
-                isPastAppointment = true;
-                disableAllExceptStatus();
-
-                // Make status spinner only have Completed or Missed
-                SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAppointmentStatus,
-                        new String[]{"Completed", "Missed"});
-
-                // Restore selection if it's already one of the valid options
-                if (currentStatus.equals("Completed") || currentStatus.equals("Missed")) {
-                    SpinnerUtils.setSelectionByValue(binding.spinnerAppointmentStatus, currentStatus);
-                }
-            }
-        } catch (Exception e) {
-            Log.e("APPT_DETAIL", "Error parsing date/time for past check: " + e.getMessage());
-        }
-    }
-
-    /**
-     * Disables all input fields except the status spinner
-     */
-    private void disableAllExceptStatus() {
-        UIUtils.setViewsEnabled(false, 
-                binding.spinnerCustomer, binding.spinnerStore, binding.spinnerPet, 
-                binding.spinnerService, binding.spinnerStaff, binding.etAppointmentDate, 
-                binding.spinnerHour, binding.spinnerMinute);
-        
-        UIUtils.setViewsAlpha(0.5f, 
-                binding.tvLabelCustomer, binding.tvLabelStore, binding.tvLabelPet, 
-                binding.tvLabelService, binding.tvLabelStaff, binding.tvLabelDate, 
-                binding.tvLabelTime);
-
-        // Keep status enabled
-        UIUtils.setViewsEnabled(true, binding.spinnerAppointmentStatus);
-    }
-
     /**
      * Validates input and saves the appointment to the backend.
      */
     private void saveAppointment() {
-        if (binding.spinnerCustomer.getSelectedItemPosition() == 0) {
+        if (!validateRequiredFields()) return;
-            Toast.makeText(getContext(), "Select a customer", Toast.LENGTH_SHORT).show(); return;
+
-        }
-        if (binding.spinnerStore.getSelectedItemPosition() == 0) {
-            Toast.makeText(getContext(), "Select a store", Toast.LENGTH_SHORT).show(); return;
-        }
-        if (binding.spinnerPet.getSelectedItemPosition() == 0) {
-            Toast.makeText(getContext(), "Select a pet", Toast.LENGTH_SHORT).show(); return;
-        }
-        if (binding.spinnerService.getSelectedItemPosition() == 0) {
-            Toast.makeText(getContext(), "Select a service", Toast.LENGTH_SHORT).show(); return;
-        }
         String date = binding.etAppointmentDate.getText().toString().trim();
-        if (date.isEmpty()) {
+        String time = buildTimeString();
-            Toast.makeText(getContext(), "Select a date", Toast.LENGTH_SHORT).show(); return;
-        }
-
-        DropdownDTO customer = customerList.get(binding.spinnerCustomer.getSelectedItemPosition() - 1);
-        DropdownDTO store    = storeList.get(binding.spinnerStore.getSelectedItemPosition() - 1);
-        DropdownDTO pet      = petList.get(binding.spinnerPet.getSelectedItemPosition() - 1);
-        ServiceDTO service   = serviceList.get(binding.spinnerService.getSelectedItemPosition() - 1);
-        
-        Long employeeId = null;
-        if (binding.spinnerStaff.getSelectedItemPosition() > 0) {
-            employeeId = staffList.get(binding.spinnerStaff.getSelectedItemPosition() - 1).getId();
-        }
-
-        String time = String.format("%02d:%02d",
-                HOURS[binding.spinnerHour.getSelectedItemPosition()],
-                MINUTES[binding.spinnerMinute.getSelectedItemPosition()]);
-        
-        // Get status and convert to uppercase for backend
         String status = binding.spinnerAppointmentStatus.getSelectedItem().toString().toUpperCase();
 
-
+        if (!appointmentViewModel.isValidFutureBooking(status, date, time)) {
-        // Validate future date+time if status is BOOKED
+            DialogUtils.showInfoDialog(requireContext(), "Invalid Time", "Booked appointments must be in the future.");
-        if ("BOOKED".equalsIgnoreCase(status)) {
+            return;
-            try {
-                String[] dateParts = date.split("-");
-                String[] timeParts = time.split(":");
-                Calendar selected = Calendar.getInstance();
-                selected.set(
-                        Integer.parseInt(dateParts[0]),
-                        Integer.parseInt(dateParts[1]) - 1,
-                        Integer.parseInt(dateParts[2]),
-                        Integer.parseInt(timeParts[0]),
-                        Integer.parseInt(timeParts[1]),
-                        0
-                );
-                if (selected.before(Calendar.getInstance())) {
-                    DialogUtils.showInfoDialog(requireContext(), "Invalid Time",
-                            "Booked appointments must be in the future. " +
-                                    "Please select a future date and time.");
-                    return;
-                }
-            } catch (Exception e) {
-                Log.e("APPT_SAVE", "Date parse error: " + e.getMessage());
-            }
         }
 
-        // Build DTO with all required IDs
+        appointmentViewModel.saveAppointment(date, time, status).observe(getViewLifecycleOwner(), resource -> {
-        AppointmentDTO dto = new AppointmentDTO(
-                customer.getId(),
-                store.getId(),
-                service.getServiceId(),
-                employeeId,
-                date,
-                time,
-                status,
-                pet.getId()
-        );
-
-        androidx.lifecycle.Observer<Resource<AppointmentDTO>> observer = resource -> {
             if (resource.status == Resource.Status.SUCCESS) {
-                Toast.makeText(getContext(), isEditing ? "Updated" : "Saved", Toast.LENGTH_SHORT).show();
+                AppointmentViewModel.ViewState state = appointmentViewModel.getViewState().getValue();
+                String message = (state != null && state.isEditing) ? "Updated" : "Saved";
+                Toast.makeText(getContext(), message, Toast.LENGTH_SHORT).show();
                 navigateBack();
             } else if (resource.status == Resource.Status.ERROR) {
                 handleSaveError(resource.message);
             }
-        };
+        });
+    }
 
-        if (isEditing) {
+    /**
-            appointmentViewModel.updateAppointment(appointmentId, dto).observe(getViewLifecycleOwner(), observer);
+     * Validates that all required fields are selected.
-        } else {
+     */
-            appointmentViewModel.createAppointment(dto).observe(getViewLifecycleOwner(), observer);
+    private boolean validateRequiredFields() {
-        }
+        if (binding.spinnerCustomer.getSelectedItemPosition() == 0) return showToast("Select a customer");
+        if (binding.spinnerStore.getSelectedItemPosition() == 0) return showToast("Select a store");
+        if (binding.spinnerPet.getSelectedItemPosition() == 0) return showToast("Select a pet");
+        if (binding.spinnerService.getSelectedItemPosition() == 0) return showToast("Select a service");
+        if (binding.etAppointmentDate.getText().toString().trim().isEmpty()) return showToast("Select a date");
+        return true;
+    }
+
+    private boolean showToast(String msg) {
+        Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
+        return false;
+    }
+
+    /**
+     * Builds a time string from the hour and minute spinners.
+     */
+    private String buildTimeString() {
+        return String.format("%02d:%02d", HOURS[binding.spinnerHour.getSelectedItemPosition()], MINUTES[binding.spinnerMinute.getSelectedItemPosition()]);
     }
 
     /**
      * Handles errors that occur during the saving process.
      */
     private void handleSaveError(String errorMessage) {
-        if (errorMessage != null) {
+        if (errorMessage != null && errorMessage.toLowerCase().contains("not available")) showNoAvailabilityDialog();
-            Log.e("APPT_SAVE", "Error: " + errorMessage);
+        else Toast.makeText(getContext(), errorMessage != null ? errorMessage : "Error saving", Toast.LENGTH_SHORT).show();
-            if (errorMessage.toLowerCase().contains("future")) {
-                DialogUtils.showInfoDialog(requireContext(), "Invalid Date/Time",
-                        "Booked appointments must be scheduled in the future.");
-            } else if (errorMessage.toLowerCase().contains("not available")) {
-                showNoAvailabilityDialog();
-            } else {
-                Toast.makeText(getContext(), errorMessage, Toast.LENGTH_SHORT).show();
-            }
-        } else {
-            Toast.makeText(getContext(), "Something went wrong", Toast.LENGTH_SHORT).show();
-        }
     }
 
     /**
@@ -559,11 +330,9 @@ public class AppointmentDetailFragment extends Fragment {
     private void showNoAvailabilityDialog() {
         new androidx.appcompat.app.AlertDialog.Builder(requireContext())
                 .setTitle("No Availability")
-                .setMessage("This time slot is already booked. Please choose a different time or date.")
+                .setMessage("This time slot is already booked.")
                 .setPositiveButton("Change Time", (d, w) -> d.dismiss())
-                .setNegativeButton("Cancel Booking", (d, w) -> navigateBack())
+                .setNegativeButton("Cancel Booking", (d, w) -> navigateBack()).show();
-                .setCancelable(false)
-                .show();
     }
 
     /**
@@ -571,13 +340,8 @@ public class AppointmentDetailFragment extends Fragment {
      */
     private void confirmDelete() {
         DialogUtils.showDeleteConfirmDialog(requireContext(), "Appointment", () ->
-                appointmentViewModel.deleteAppointment(appointmentId).observe(getViewLifecycleOwner(), resource -> {
+                appointmentViewModel.deleteAppointment().observe(getViewLifecycleOwner(), resource -> {
-                    if (resource.status == Resource.Status.SUCCESS) {
+                    if (resource.status == Resource.Status.SUCCESS) navigateBack();
-                        Toast.makeText(getContext(), "Deleted", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else if (resource.status == Resource.Status.ERROR) {
-                        Toast.makeText(getContext(), "Delete failed", Toast.LENGTH_SHORT).show();
-                    }
                 }));
     }
 
@@ -587,4 +351,24 @@ public class AppointmentDetailFragment extends Fragment {
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
+
+    /**
+     * Parses a time string and sets the hour and minute spinners.
+     */
+    private void parseAndSetTimeSpinners(String time) {
+        int[] parsedTime = DateTimeUtils.parseTimeString(time);
+        if (parsedTime == null) return;
+        for (int i = 0; i < HOURS.length; i++) if (HOURS[i] == parsedTime[0]) binding.spinnerHour.setSelection(i);
+        for (int i = 0; i < MINUTES.length; i++) if (MINUTES[i] == parsedTime[1]) binding.spinnerMinute.setSelection(i);
+    }
+
+    /**
+     * Helper listener for simple index reporting.
+     */
+    private static class OnIndexSelected implements AdapterView.OnItemSelectedListener {
+        private final java.util.function.Consumer<Integer> callback;
+        public OnIndexSelected(java.util.function.Consumer<Integer> callback) { this.callback = callback; }
+        @Override public void onItemSelected(AdapterView<?> p, View v, int pos, long id) { callback.accept(pos); }
+        @Override public void onNothingSelected(AdapterView<?> p) {}
+    }
 }

android/app/src/main/java/com/example/petstoremobile/utils/DateTimeUtils.java

@@ -0,0 +1,98 @@
+package com.example.petstoremobile.utils;
+
+import android.util.Log;
+
+import java.util.Calendar;
+
+/**
+ * Utility class for date and time operations.
+ */
+public class DateTimeUtils {
+
+    private static final String TAG = "DateTimeUtils";
+
+    /**
+     * Formats status from backend format to UI format
+     * (backend is using all caps so we lower case them with this function)
+     */
+    public static String formatStatusFromBackend(String status) {
+        if (status == null || status.isEmpty()) return status;
+        return status.substring(0, 1).toUpperCase() + status.substring(1).toLowerCase();
+    }
+
+    /**
+     * Converts a date and time string to a Calendar object.
+     * format: date = "YYYY-MM-DD", time = "HH:MM"
+     */
+    public static Calendar parseDateTimeToCalendar(String date, String time) throws Exception {
+        Calendar calendar = Calendar.getInstance();
+        String[] dateParts = date.split("-");
+        String[] timeParts = time.split(":");
+
+        calendar.set(
+                Integer.parseInt(dateParts[0]),
+                Integer.parseInt(dateParts[1]) - 1,
+                Integer.parseInt(dateParts[2]),
+                Integer.parseInt(timeParts[0]),
+                Integer.parseInt(timeParts[1]),
+                0
+        );
+        return calendar;
+    }
+
+    /**
+     * Checks if a given date is in the past.
+     * format: date = "YYYY-MM-DD"
+     */
+    public static boolean isDateInPast(String date) {
+        if (date == null || date.isEmpty()) return false;
+        try {
+            Calendar selected = Calendar.getInstance();
+            String[] dateParts = date.split("-");
+            selected.set(
+                    Integer.parseInt(dateParts[0]),
+                    Integer.parseInt(dateParts[1]) - 1,
+                    Integer.parseInt(dateParts[2]),
+                    0, 0, 0
+            );
+            return selected.before(Calendar.getInstance());
+        } catch (Exception e) {
+            Log.e(TAG, "Error parsing date: " + e.getMessage());
+            return false;
+        }
+    }
+
+    /**
+     * Checks if a given date and time are in the past.
+     * format: date = "YYYY-MM-DD", time = "HH:MM"
+     */
+    public static boolean isDateTimeInPast(String date, String time) {
+        if (date == null || date.isEmpty() || time == null || time.isEmpty()) return false;
+        try {
+            Calendar selected = parseDateTimeToCalendar(date, time);
+            return selected.before(Calendar.getInstance());
+        } catch (Exception e) {
+            Log.e(TAG, "Error parsing date/time: " + e.getMessage());
+            return false;
+        }
+    }
+
+    /**
+     * Parses a time string and returns hour and minute indices for the spinners.
+     */
+    public static int[] parseTimeString(String time) {
+        if (time == null || time.isEmpty()) return null;
+        if (time.length() > 5) time = time.substring(0, 5);
+
+        String[] parts = time.split(":");
+        if (parts.length != 2) return null;
+
+        try {
+            int hour = Integer.parseInt(parts[0]);
+            int min = Integer.parseInt(parts[1]);
+            return new int[]{hour, min};
+        } catch (NumberFormatException e) {
+            return null;
+        }
+    }
+}

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

@@ -1,14 +1,23 @@
 package com.example.petstoremobile.viewmodels;
 
 import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModel;
 
 import com.example.petstoremobile.dtos.AppointmentDTO;
 import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.DropdownDTO;
 import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.ServiceDTO;
 import com.example.petstoremobile.repositories.AppointmentRepository;
+import com.example.petstoremobile.repositories.CustomerRepository;
+import com.example.petstoremobile.repositories.PetRepository;
+import com.example.petstoremobile.repositories.ServiceRepository;
+import com.example.petstoremobile.repositories.StoreRepository;
+import com.example.petstoremobile.utils.DateTimeUtils;
 import com.example.petstoremobile.utils.Resource;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import javax.inject.Inject;
@@ -18,12 +27,42 @@ import dagger.hilt.android.lifecycle.HiltViewModel;
 @HiltViewModel
 public class AppointmentViewModel extends ViewModel {
     private final AppointmentRepository repository;
+    private final CustomerRepository customerRepository;
+    private final StoreRepository storeRepository;
+    private final PetRepository petRepository;
+    private final ServiceRepository serviceRepository;
+
+    private final MutableLiveData<List<DropdownDTO>> customers = new MutableLiveData<>();
+    private final MutableLiveData<List<DropdownDTO>> stores = new MutableLiveData<>();
+    private final MutableLiveData<List<ServiceDTO>> services = new MutableLiveData<>();
+    private final MutableLiveData<List<DropdownDTO>> customerPets = new MutableLiveData<>();
+    private final MutableLiveData<List<DropdownDTO>> storeEmployees = new MutableLiveData<>();
+    
+    private final MutableLiveData<ViewState> viewState = new MutableLiveData<>(new ViewState());
+    
+    private long appointmentId = -1;
+    private Long currentCustomerId;
+    private Long currentStoreId;
+    private Long currentPetId;
+    private Long currentServiceId;
+    private Long currentStaffId;
 
     @Inject
-    public AppointmentViewModel(AppointmentRepository repository) {
+    public AppointmentViewModel(
+            AppointmentRepository repository,
+            CustomerRepository customerRepository,
+            StoreRepository storeRepository,
+            PetRepository petRepository,
+            ServiceRepository serviceRepository) {
         this.repository = repository;
+        this.customerRepository = customerRepository;
+        this.storeRepository = storeRepository;
+        this.petRepository = petRepository;
+        this.serviceRepository = serviceRepository;
     }
 
+    // API CRUD
+
     /**
      * Fetches a paginated list of all appointments with optional filters.
      */
@@ -65,4 +104,273 @@ public class AppointmentViewModel extends ViewModel {
     public LiveData<Resource<Void>> bulkDeleteAppointments(List<String> ids) {
         return repository.bulkDeleteAppointments(new BulkDeleteRequest(ids));
     }
-}
+
+    // Initial Data Loading
+
+    /**
+     * Loads initial dropdown data for customers, stores, and services.
+     */
+    public void loadInitialFormData() {
+        customerRepository.getCustomerDropdowns().observeForever(r -> {
+            if (r.status == Resource.Status.SUCCESS) customers.setValue(r.data);
+        });
+        storeRepository.getStoreDropdowns().observeForever(r -> {
+            if (r.status == Resource.Status.SUCCESS) stores.setValue(r.data);
+        });
+        serviceRepository.getAllServices(0, 200, null, "serviceName").observeForever(r -> {
+            if (r.status == Resource.Status.SUCCESS && r.data != null) services.setValue(r.data.getContent());
+        });
+    }
+
+    // LiveData Getters
+
+    public LiveData<List<DropdownDTO>> getCustomers() { return customers; }
+    public LiveData<List<DropdownDTO>> getStores() { return stores; }
+    public LiveData<List<ServiceDTO>> getServices() { return services; }
+    public LiveData<List<DropdownDTO>> getCustomerPets() { return customerPets; }
+    public LiveData<List<DropdownDTO>> getStoreEmployees() { return storeEmployees; }
+    public LiveData<ViewState> getViewState() { return viewState; }
+
+    //State Getters
+
+    public long getAppointmentId() { return appointmentId; }
+
+    /**
+     * Sets the current appointment ID and updates the mode.
+     */
+    public void setAppointmentId(long id) {
+        this.appointmentId = id;
+        initMode(id != -1);
+    }
+
+    // Selection Handlers for spinners
+
+    public void onCustomerSelected(int position) {
+        List<DropdownDTO> list = customers.getValue();
+        if (position > 0 && list != null && position <= list.size()) {
+            currentCustomerId = list.get(position - 1).getId();
+            loadPetsForCustomer(currentCustomerId);
+            updateViewState(s -> {
+                s.selectedCustomerId = currentCustomerId;
+                s.isPetEnabled = !s.isEditing;
+            });
+        } else {
+            currentCustomerId = null;
+            customerPets.setValue(new ArrayList<>());
+            updateViewState(s -> {
+                s.selectedCustomerId = null;
+                s.isPetEnabled = false;
+            });
+        }
+    }
+
+    public void onStoreSelected(int position) {
+        List<DropdownDTO> list = stores.getValue();
+        if (position > 0 && list != null && position <= list.size()) {
+            currentStoreId = list.get(position - 1).getId();
+            loadEmployeesForStore(currentStoreId);
+            updateViewState(s -> {
+                s.selectedStoreId = currentStoreId;
+                s.isStaffEnabled = !s.isPast;
+            });
+        } else {
+            currentStoreId = null;
+            storeEmployees.setValue(new ArrayList<>());
+            updateViewState(s -> {
+                s.selectedStoreId = null;
+                s.isStaffEnabled = false;
+            });
+        }
+    }
+
+    public void onServiceSelected(int position) {
+        List<ServiceDTO> list = services.getValue();
+        currentServiceId = (position > 0 && list != null && position <= list.size()) ? list.get(position - 1).getServiceId() : null;
+        updateViewState(s -> s.selectedServiceId = currentServiceId);
+    }
+
+    public void onPetSelected(int position) {
+        List<DropdownDTO> list = customerPets.getValue();
+        currentPetId = (position > 0 && list != null && position <= list.size()) ? list.get(position - 1).getId() : null;
+        updateViewState(s -> s.selectedPetId = currentPetId);
+    }
+
+    public void onStaffSelected(int position) {
+        List<DropdownDTO> list = storeEmployees.getValue();
+        currentStaffId = (position > 0 && list != null && position <= list.size()) ? list.get(position - 1).getId() : null;
+        updateViewState(s -> s.selectedStaffId = currentStaffId);
+    }
+
+    private void loadPetsForCustomer(Long customerId) {
+        petRepository.getCustomerPets(customerId).observeForever(r -> {
+            if (r.status == Resource.Status.SUCCESS) customerPets.setValue(r.data);
+        });
+    }
+
+    private void loadEmployeesForStore(Long storeId) {
+        storeRepository.getStoreEmployees(storeId).observeForever(r -> {
+            if (r.status == Resource.Status.SUCCESS) storeEmployees.setValue(r.data);
+        });
+    }
+
+    // Appointment Detail CRUD
+
+    /**
+     * Fetches appointment details and populates internal state.
+     */
+    public LiveData<Resource<AppointmentDTO>> loadAppointment() {
+        MutableLiveData<Resource<AppointmentDTO>> result = new MutableLiveData<>();
+        repository.getAppointmentById(appointmentId).observeForever(resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                AppointmentDTO a = resource.data;
+                currentCustomerId = a.getCustomerId();
+                currentStoreId = a.getStoreId();
+                currentPetId = a.getPetId();
+                currentServiceId = a.getServiceId();
+                currentStaffId = a.getEmployeeId();
+                
+                updateViewState(s -> {
+                    s.selectedCustomerId = currentCustomerId;
+                    s.selectedStoreId = currentStoreId;
+                    s.selectedPetId = currentPetId;
+                    s.selectedServiceId = currentServiceId;
+                    s.selectedStaffId = currentStaffId;
+                });
+
+                if (currentCustomerId != null) loadPetsForCustomer(currentCustomerId);
+                if (currentStoreId != null) loadEmployeesForStore(currentStoreId);
+            }
+            result.setValue(resource);
+        });
+        return result;
+    }
+
+    /**
+     * Saves the appointment by building the DTO from tracked state.
+     */
+    public LiveData<Resource<AppointmentDTO>> saveAppointment(String date, String time, String status) {
+        AppointmentDTO dto = new AppointmentDTO(currentCustomerId, currentStoreId, currentServiceId, currentStaffId, date, time, status, currentPetId);
+        if (appointmentId != -1) {
+            return repository.updateAppointment(appointmentId, dto);
+        } else {
+            return repository.createAppointment(dto);
+        }
+    }
+
+    /**
+     * Deletes the current appointment.
+     */
+    public LiveData<Resource<Void>> deleteAppointment() {
+        return repository.deleteAppointment(appointmentId);
+    }
+
+    // --- UI Logic ---
+
+    public void onDateOrTimeChanged(String date, String time, String currentStatus) {
+        updateViewState(s -> {
+            s.availableStatuses = calculateAvailableStatuses(s.isEditing, date, time, currentStatus);
+            boolean isPast = DateTimeUtils.isDateTimeInPast(date, time);
+            boolean isCancelled = "Cancelled".equalsIgnoreCase(currentStatus);
+
+            if (isCancelled) {
+                s.isPast = true;
+                setAllFieldsEnabled(s, false);
+                s.isStatusEnabled = false;
+                s.isSaveVisible = false;
+            } else if (isPast) {
+                s.isPast = true;
+                setAllFieldsEnabled(s, false);
+                s.isStatusEnabled = true;
+            } else {
+                s.isPast = false;
+                if (!s.isEditing) {
+                    s.isCustomerEnabled = true;
+                    s.isStoreEnabled = true;
+                    s.isServiceEnabled = true;
+                    s.isPetEnabled = currentCustomerId != null;
+                }
+                s.isDateEnabled = true;
+                s.isTimeEnabled = true;
+                s.isStatusEnabled = true;
+            }
+        });
+    }
+
+    private String[] calculateAvailableStatuses(boolean isEditing, String date, String currentTime, String currentStatus) {
+        if (!isEditing) return new String[]{"Booked"};
+        if (date == null || date.isEmpty()) return new String[]{};
+        if ("Cancelled".equalsIgnoreCase(currentStatus)) return new String[]{"Cancelled"};
+        if (DateTimeUtils.isDateTimeInPast(date, currentTime)) return new String[]{"Completed", "Missed"};
+        return new String[]{"Booked", "Cancelled"};
+    }
+
+    private void setAllFieldsEnabled(ViewState s, boolean enabled) {
+        s.isCustomerEnabled = enabled;
+        s.isStoreEnabled = enabled;
+        s.isPetEnabled = enabled;
+        s.isServiceEnabled = enabled;
+        s.isStaffEnabled = enabled;
+        s.isDateEnabled = enabled;
+        s.isTimeEnabled = enabled;
+    }
+
+    public void initMode(boolean isEditing) {
+        updateViewState(s -> {
+            s.isEditing = isEditing;
+            s.isDeleteVisible = isEditing;
+            if (isEditing) {
+                s.isCustomerEnabled = false;
+                s.isStoreEnabled = false;
+                s.isPetEnabled = false;
+                s.isServiceEnabled = false;
+            } else {
+                s.isCustomerEnabled = true;
+                s.isStoreEnabled = true;
+                s.isServiceEnabled = true;
+                s.isPetEnabled = false; // until customer selected
+                s.isStaffEnabled = false; // until store selected
+                s.availableStatuses = new String[]{"Booked"};
+            }
+        });
+    }
+
+    public boolean isValidFutureBooking(String status, String date, String time) {
+        return !"BOOKED".equalsIgnoreCase(status) || !DateTimeUtils.isDateTimeInPast(date, time);
+    }
+
+    private void updateViewState(Action<ViewState> action) {
+        ViewState current = viewState.getValue();
+        if (current != null) {
+            action.run(current);
+            viewState.setValue(current);
+        }
+    }
+
+    private interface Action<T> { void run(T t); }
+
+    /**
+     * A Class to show the states of Appointment Detail Fragment.
+     */
+    public static class ViewState {
+        public boolean isPast = false;
+        public boolean isEditing = false;
+        public boolean isSaveVisible = true;
+        public boolean isDeleteVisible = false;
+        public boolean isCustomerEnabled = true;
+        public boolean isStoreEnabled = true;
+        public boolean isPetEnabled = false;
+        public boolean isServiceEnabled = true;
+        public boolean isStaffEnabled = false;
+        public boolean isDateEnabled = true;
+        public boolean isTimeEnabled = true;
+        public boolean isStatusEnabled = true;
+        public String[] availableStatuses = new String[]{};
+
+        // Selected IDs
+        public Long selectedCustomerId = null;
+        public Long selectedStoreId = null;
+        public Long selectedPetId = null;
+        public Long selectedServiceId = null;
+        public Long selectedStaffId = null;
+    }
+}