realtime controller

lib/providers/realtime_controller.dart

@@ -0,0 +1,107 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:supabase_flutter/supabase_flutter.dart';
+
+import 'supabase_provider.dart';
+
+final realtimeControllerProvider = ChangeNotifierProvider<RealtimeController>((
+  ref,
+) {
+  final client = ref.watch(supabaseClientProvider);
+  final controller = RealtimeController(client);
+  ref.onDispose(controller.dispose);
+  return controller;
+});
+
+/// A lightweight controller that attempts to recover the Supabase Realtime
+/// connection when the app returns to the foreground or when auth tokens
+/// are refreshed.
+class RealtimeController extends ChangeNotifier {
+  RealtimeController(this._client) {
+    _init();
+  }
+
+  final SupabaseClient _client;
+
+  bool isConnecting = false;
+  bool _disposed = false;
+
+  void _init() {
+    try {
+      // Listen for auth changes and try to recover the realtime connection
+      _client.auth.onAuthStateChange.listen((data) {
+        final event = data.event;
+        if (event == AuthChangeEvent.tokenRefreshed ||
+            event == AuthChangeEvent.signedIn) {
+          recoverConnection();
+        }
+      });
+    } catch (_) {}
+  }
+
+  /// Try to reconnect the realtime client using a small exponential backoff.
+  Future<void> recoverConnection() async {
+    if (_disposed) return;
+    if (isConnecting) return;
+
+    isConnecting = true;
+    notifyListeners();
+
+    try {
+      int attempt = 0;
+      int maxAttempts = 4;
+      int delaySeconds = 1;
+      while (attempt < maxAttempts && !_disposed) {
+        attempt++;
+        try {
+          // Best-effort disconnect then connect so the realtime client picks
+          // up any refreshed tokens.
+          try {
+            // Try to refresh session/token if the SDK supports it. Use dynamic
+            // to avoid depending on a specific SDK version symbol.
+            try {
+              await (_client.auth as dynamic).refreshSession?.call();
+            } catch (_) {}
+
+            // Best-effort disconnect then connect so the realtime client picks
+            // up any refreshed tokens. The realtime connect/disconnect are
+            // marked internal by the SDK; suppress the lint here since this
+            // is a deliberate best-effort recovery.
+            // ignore: invalid_use_of_internal_member
+            _client.realtime.disconnect();
+          } catch (_) {}
+          await Future.delayed(const Duration(milliseconds: 300));
+          try {
+            // ignore: invalid_use_of_internal_member
+            _client.realtime.connect();
+          } catch (_) {}
+
+          // Give the socket a moment to stabilise.
+          await Future.delayed(const Duration(seconds: 1));
+
+          // Exit early; we don't have a reliable sync API for connection
+          // state across all platforms, so treat this as a best-effort
+          // resurrection.
+          break;
+        } catch (_) {
+          await Future.delayed(Duration(seconds: delaySeconds));
+          delaySeconds = delaySeconds * 2;
+        }
+      }
+    } finally {
+      if (!_disposed) {
+        isConnecting = false;
+        notifyListeners();
+      }
+    }
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+}

lib/services/notification_bridge.dart

@@ -4,6 +4,7 @@ import 'package:firebase_messaging/firebase_messaging.dart';
 
 import '../models/notification_item.dart';
 import '../providers/notifications_provider.dart';
+import '../providers/realtime_controller.dart';
 
 /// Wraps the app and installs both a Supabase realtime listener and the
 /// FCM handlers described in the frontend design.
@@ -24,21 +25,35 @@ class NotificationBridge extends ConsumerStatefulWidget {
   ConsumerState<NotificationBridge> createState() => _NotificationBridgeState();
 }
 
-class _NotificationBridgeState extends ConsumerState<NotificationBridge> {
+class _NotificationBridgeState extends ConsumerState<NotificationBridge>
+    with WidgetsBindingObserver {
   // store previous notifications to diff
   List<NotificationItem> _prevList = [];
 
   @override
   void initState() {
     super.initState();
+    WidgetsBinding.instance.addObserver(this);
     _setupFcmHandlers();
   }
 
   @override
   void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
     super.dispose();
   }
 
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    super.didChangeAppLifecycleState(state);
+    if (state == AppLifecycleState.resumed) {
+      try {
+        // Trigger a best-effort realtime reconnection when the app resumes.
+        ref.read(realtimeControllerProvider).recoverConnection();
+      } catch (_) {}
+    }
+  }
+
   void _showBanner(String type, NotificationItem item) {
     final ctx = widget.navigatorKey.currentState?.overlay?.context;
     if (ctx == null) return;