FCM push Notifications

lib/providers/notifications_provider.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:supabase_flutter/supabase_flutter.dart';
+import '../utils/device_id.dart';
 
 import '../models/notification_item.dart';
 import 'profile_provider.dart';
@@ -165,10 +166,16 @@ class NotificationsController {
   Future<void> registerFcmToken(String token) async {
     final userId = _client.auth.currentUser?.id;
     if (userId == null) return;
-    final res = await _client.from('fcm_tokens').insert({
+    final deviceId = await DeviceId.getId();
+    // upsert using a unique constraint on (user_id, device_id) so a single
+    // device keeps its token updated without overwriting other devices.
+    final payload = {
       'user_id': userId,
+      'device_id': deviceId,
       'token': token,
-    });
+      'created_at': DateTime.now().toUtc().toIso8601String(),
+    };
+    final res = await _client.from('fcm_tokens').upsert(payload);
     if (res == null) {
       debugPrint(
         'registerFcmToken: null response for user=$userId token=$token',
@@ -189,11 +196,14 @@ class NotificationsController {
   Future<void> unregisterFcmToken(String token) async {
     final userId = _client.auth.currentUser?.id;
     if (userId == null) return;
+    final deviceId = await DeviceId.getId();
+    // Prefer to delete by device_id to avoid removing other devices' tokens.
     final res = await _client
         .from('fcm_tokens')
         .delete()
         .eq('user_id', userId)
-        .eq('token', token);
+        .eq('device_id', deviceId)
+        .or('token.eq.$token');
     if (res == null) {
       debugPrint(
         'unregisterFcmToken: null response for user=$userId token=$token',