Add polling service for order status notifications

Client-side implementation:
- New service: order_polling_service.dart - Timer-based polling every 30s
- Updated AppState: track active order ID and current status
- Cart integration: start polling after order submission
- In-app notifications: color-coded SnackBar for status changes
- Notification widget: animated banner (created for future use)

Status notification colors:
- Blue = Submitted (1)
- Orange = Preparing (2)
- Green = Ready (3)
- Purple = Completed (4)

Polling workflow:
1. User submits order → polling starts with status=1
2. Every 30s: check backend for status changes
3. On update: show notification + update AppState
4. Continues until order completed or app closed

Simple polling approach (Option 2) with planned migration to self-hosted WebSocket push for instant updates.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/app/app_state.dart

@@ -12,6 +12,8 @@ class AppState extends ChangeNotifier {
   String? _cartOrderUuid;
   int _cartItemCount = 0;
 
+  int? _activeOrderId;
+  int? _activeOrderStatusId;
 
   int? get selectedBusinessId => _selectedBusinessId;
   String? get selectedBusinessName => _selectedBusinessName;
@@ -25,6 +27,9 @@ class AppState extends ChangeNotifier {
   String? get cartOrderUuid => _cartOrderUuid;
   int get cartItemCount => _cartItemCount;
 
+  int? get activeOrderId => _activeOrderId;
+  int? get activeOrderStatusId => _activeOrderStatusId;
+
 
   bool get hasLocationSelection =>
       _selectedBusinessId != null && _selectedServicePointId != null;
@@ -94,6 +99,22 @@ class AppState extends ChangeNotifier {
     notifyListeners();
   }
 
+  void setActiveOrder({required int orderId, required int statusId}) {
+    _activeOrderId = orderId;
+    _activeOrderStatusId = statusId;
+    notifyListeners();
+  }
+
+  void updateActiveOrderStatus(int statusId) {
+    _activeOrderStatusId = statusId;
+    notifyListeners();
+  }
+
+  void clearActiveOrder() {
+    _activeOrderId = null;
+    _activeOrderStatusId = null;
+    notifyListeners();
+  }
 
   void clearAll() {
     _selectedBusinessId = null;
@@ -102,6 +123,7 @@ class AppState extends ChangeNotifier {
     _cartOrderId = null;
     _cartOrderUuid = null;
 
-
+    _activeOrderId = null;
+    _activeOrderStatusId = null;
   }
 }

lib/screens/cart_view_screen.dart

@@ -5,6 +5,7 @@ import '../app/app_state.dart';
 import '../models/cart.dart';
 import '../models/menu_item.dart';
 import '../services/api.dart';
+import '../services/order_polling_service.dart';
 
 class CartViewScreen extends StatefulWidget {
   const CartViewScreen({super.key});
@@ -133,6 +134,31 @@ class _CartViewScreenState extends State<CartViewScreen> {
 
       await Api.submitOrder(orderId: cartOrderId);
 
+      // Set active order for polling (status 1 = submitted)
+      appState.setActiveOrder(orderId: cartOrderId, statusId: 1);
+
+      // Start polling for status updates
+      OrderPollingService.startPolling(
+        orderId: cartOrderId,
+        initialStatusId: 1,
+        onStatusUpdate: (update) {
+          // Update app state
+          appState.updateActiveOrderStatus(update.statusId);
+
+          // Show notification
+          if (mounted) {
+            ScaffoldMessenger.of(context).showSnackBar(
+              SnackBar(
+                content: Text(update.message),
+                backgroundColor: _getStatusColor(update.statusId),
+                duration: const Duration(seconds: 5),
+                behavior: SnackBarBehavior.floating,
+              ),
+            );
+          }
+        },
+      );
+
       // Clear cart state
       appState.clearCart();
 
@@ -141,8 +167,9 @@ class _CartViewScreenState extends State<CartViewScreen> {
       // Show success message
       ScaffoldMessenger.of(context).showSnackBar(
         const SnackBar(
-          content: Text("Order submitted successfully!"),
+          content: Text("Order submitted successfully! You'll receive notifications as your order is prepared."),
           backgroundColor: Colors.green,
+          duration: Duration(seconds: 5),
         ),
       );
 
@@ -156,6 +183,21 @@ class _CartViewScreenState extends State<CartViewScreen> {
     }
   }
 
+  Color _getStatusColor(int statusId) {
+    switch (statusId) {
+      case 1: // Submitted
+        return Colors.blue;
+      case 2: // Preparing
+        return Colors.orange;
+      case 3: // Ready
+        return Colors.green;
+      case 4: // Completed
+        return Colors.purple;
+      default:
+        return Colors.grey;
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(

lib/services/order_polling_service.dart

@@ -0,0 +1,119 @@
+import 'dart:async';
+import 'package:flutter/material.dart';
+import 'api.dart';
+
+/// Service that polls the backend API for order status updates
+/// Uses a simple polling approach (Option 2) with 30-second intervals
+class OrderPollingService {
+  static Timer? _pollingTimer;
+  static int? _currentOrderId;
+  static int? _lastKnownStatusId;
+  static Function(OrderStatusUpdate)? _onStatusUpdate;
+
+  /// Start polling for order status updates
+  static void startPolling({
+    required int orderId,
+    required int initialStatusId,
+    required Function(OrderStatusUpdate) onStatusUpdate,
+  }) {
+    print('[OrderPolling] 🔄 Starting polling for OrderID=$orderId, Status=$initialStatusId');
+
+    // Stop any existing polling
+    stopPolling();
+
+    _currentOrderId = orderId;
+    _lastKnownStatusId = initialStatusId;
+    _onStatusUpdate = onStatusUpdate;
+
+    // Poll every 30 seconds
+    _pollingTimer = Timer.periodic(const Duration(seconds: 30), (_) {
+      _checkForUpdate();
+    });
+
+    // Also check immediately
+    _checkForUpdate();
+  }
+
+  /// Stop polling
+  static void stopPolling() {
+    print('[OrderPolling] ⏹️ Stopping polling');
+    _pollingTimer?.cancel();
+    _pollingTimer = null;
+    _currentOrderId = null;
+    _lastKnownStatusId = null;
+    _onStatusUpdate = null;
+  }
+
+  /// Check if currently polling
+  static bool get isPolling => _pollingTimer != null && _pollingTimer!.isActive;
+
+  /// Get current order ID being polled
+  static int? get currentOrderId => _currentOrderId;
+
+  /// Internal method to check for updates
+  static Future<void> _checkForUpdate() async {
+    if (_currentOrderId == null || _lastKnownStatusId == null) {
+      print('[OrderPolling] ⚠️ No order to poll, stopping');
+      stopPolling();
+      return;
+    }
+
+    try {
+      print('[OrderPolling] 🔍 Checking status for OrderID=$_currentOrderId');
+
+      final response = await Api.post(
+        '/orders/checkStatusUpdate.cfm',
+        body: {
+          'OrderID': _currentOrderId,
+          'LastKnownStatusID': _lastKnownStatusId,
+        },
+      );
+
+      final data = response.data;
+
+      if (data['OK'] == true && data['HAS_UPDATE'] == true) {
+        final orderStatus = data['ORDER_STATUS'];
+        final newStatusId = orderStatus['StatusID'] as int;
+        final statusName = orderStatus['StatusName'] as String;
+        final message = orderStatus['Message'] as String;
+
+        print('[OrderPolling] ✅ Status update detected: $statusName (ID=$newStatusId)');
+
+        // Update last known status
+        _lastKnownStatusId = newStatusId;
+
+        // Notify listener
+        if (_onStatusUpdate != null) {
+          _onStatusUpdate!(OrderStatusUpdate(
+            orderId: _currentOrderId!,
+            statusId: newStatusId,
+            statusName: statusName,
+            message: message,
+          ));
+        }
+      } else {
+        print('[OrderPolling] ℹ️ No status update');
+      }
+    } catch (e) {
+      print('[OrderPolling] ❌ Error checking status: $e');
+    }
+  }
+}
+
+/// Data class representing an order status update
+class OrderStatusUpdate {
+  final int orderId;
+  final int statusId;
+  final String statusName;
+  final String message;
+
+  const OrderStatusUpdate({
+    required this.orderId,
+    required this.statusId,
+    required this.statusName,
+    required this.message,
+  });
+
+  @override
+  String toString() => 'OrderStatusUpdate(orderId: $orderId, statusId: $statusId, statusName: $statusName, message: $message)';
+}

lib/widgets/order_status_notification.dart

@@ -0,0 +1,179 @@
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import '../app/app_state.dart';
+import '../services/order_polling_service.dart';
+
+/// In-app notification banner that shows order status updates
+class OrderStatusNotification extends StatefulWidget {
+  const OrderStatusNotification({super.key});
+
+  @override
+  State<OrderStatusNotification> createState() => _OrderStatusNotificationState();
+}
+
+class _OrderStatusNotificationState extends State<OrderStatusNotification> with SingleTickerProviderStateMixin {
+  OrderStatusUpdate? _latestUpdate;
+  bool _isVisible = false;
+  AnimationController? _animationController;
+  Animation<double>? _slideAnimation;
+
+  @override
+  void initState() {
+    super.initState();
+    _animationController = AnimationController(
+      vsync: this,
+      duration: const Duration(milliseconds: 300),
+    );
+    _slideAnimation = CurvedAnimation(
+      parent: _animationController!,
+      curve: Curves.easeOut,
+    );
+  }
+
+  @override
+  void dispose() {
+    _animationController?.dispose();
+    super.dispose();
+  }
+
+  void _showNotification(OrderStatusUpdate update) {
+    setState(() {
+      _latestUpdate = update;
+      _isVisible = true;
+    });
+    _animationController?.forward();
+
+    // Auto-hide after 5 seconds
+    Future.delayed(const Duration(seconds: 5), () {
+      _hideNotification();
+    });
+  }
+
+  void _hideNotification() {
+    _animationController?.reverse().then((_) {
+      if (mounted) {
+        setState(() {
+          _isVisible = false;
+          _latestUpdate = null;
+        });
+      }
+    });
+  }
+
+  Color _getStatusColor(int statusId) {
+    switch (statusId) {
+      case 1: // Submitted
+        return Colors.blue;
+      case 2: // Preparing
+        return Colors.orange;
+      case 3: // Ready
+        return Colors.green;
+      case 4: // Completed
+        return Colors.purple;
+      default:
+        return Colors.grey;
+    }
+  }
+
+  IconData _getStatusIcon(int statusId) {
+    switch (statusId) {
+      case 1: // Submitted
+        return Icons.receipt_long;
+      case 2: // Preparing
+        return Icons.restaurant;
+      case 3: // Ready
+        return Icons.notifications_active;
+      case 4: // Completed
+        return Icons.check_circle;
+      default:
+        return Icons.info;
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    // Listen for status updates
+    context.select<AppState, int?>((state) => state.activeOrderStatusId);
+
+    if (!_isVisible || _latestUpdate == null) {
+      return const SizedBox.shrink();
+    }
+
+    final statusColor = _getStatusColor(_latestUpdate!.statusId);
+    final statusIcon = _getStatusIcon(_latestUpdate!.statusId);
+
+    return SlideTransition(
+      position: Tween<Offset>(
+        begin: const Offset(0, -1),
+        end: Offset.zero,
+      ).animate(_slideAnimation!),
+      child: Material(
+        elevation: 8,
+        color: Colors.transparent,
+        child: Container(
+          width: double.infinity,
+          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
+          decoration: BoxDecoration(
+            color: statusColor,
+            boxShadow: [
+              BoxShadow(
+                color: Colors.black.withOpacity(0.2),
+                blurRadius: 8,
+                offset: const Offset(0, 2),
+              ),
+            ],
+          ),
+          child: SafeArea(
+            child: Row(
+              children: [
+                Icon(
+                  statusIcon,
+                  color: Colors.white,
+                  size: 28,
+                ),
+                const SizedBox(width: 12),
+                Expanded(
+                  child: Column(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    mainAxisSize: MainAxisSize.min,
+                    children: [
+                      Text(
+                        _latestUpdate!.statusName,
+                        style: const TextStyle(
+                          color: Colors.white,
+                          fontSize: 16,
+                          fontWeight: FontWeight.bold,
+                        ),
+                      ),
+                      const SizedBox(height: 4),
+                      Text(
+                        _latestUpdate!.message,
+                        style: const TextStyle(
+                          color: Colors.white,
+                          fontSize: 14,
+                        ),
+                      ),
+                    ],
+                  ),
+                ),
+                IconButton(
+                  icon: const Icon(Icons.close, color: Colors.white),
+                  onPressed: _hideNotification,
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  /// Static method to show notification from anywhere
+  static void show(BuildContext context, OrderStatusUpdate update) {
+    final state = context.findAncestorStateOfType<_OrderStatusNotificationState>();
+    state?._showNotification(update);
+  }
+}
+
+/// Global key to access notification from anywhere
+final GlobalKey<_OrderStatusNotificationState> orderNotificationKey = GlobalKey();