feat: add permissions screen after login and send token to server

frontend/lib/constants/api_constants.dart

@@ -6,4 +6,5 @@ class ApiConstants {
   
   // User endpoints
   static const String getUserEndpoint = '/getUser';
+  static const String updateUserEndpoint = '/updateUser';
 }

frontend/lib/main.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:firebase_core/firebase_core.dart';
 import 'firebase_options.dart';
 import 'screens/home_screen.dart';
+import 'screens/notification_permission_screen.dart';
 import 'services/notification_service.dart';
 import 'services/auth_service.dart';
 import 'services/user_service.dart';
@@ -115,9 +116,6 @@ class LandingPage extends StatefulWidget {
 
 class _LandingPageState extends State<LandingPage> {
   void _navigateDirectlyToLogin() {
-    // Request notification permissions on user action
-    NotificationService().requestPermissionAndSetup();
-
     Navigator.of(
       context,
     ).push(MaterialPageRoute(builder: (context) => SignInPage()));
@@ -338,7 +336,7 @@ class _SignInPageState extends State<SignInPage> {
         final userResult = await UserService.getCurrentUser(forceRefresh: true);
         
         Navigator.of(context).pushReplacement(
-          MaterialPageRoute(builder: (context) => HomeScreen()),
+          MaterialPageRoute(builder: (context) => NotificationPermissionScreen()),
         );
       } else {
         _showErrorAlert(result['message'] ?? 'Login failed');

frontend/lib/screens/notification_permission_screen.dart

@@ -0,0 +1,242 @@
+import 'package:flutter/material.dart';
+import '../services/notification_service.dart';
+import '../services/user_service.dart';
+import 'home_screen.dart';
+
+class NotificationPermissionScreen extends StatefulWidget {
+  @override
+  _NotificationPermissionScreenState createState() =>
+      _NotificationPermissionScreenState();
+}
+
+class _NotificationPermissionScreenState
+    extends State<NotificationPermissionScreen> {
+  bool _isLoading = false;
+
+  Future<void> _requestNotificationPermission() async {
+    setState(() {
+      _isLoading = true;
+    });
+
+    try {
+      final notificationService = NotificationService();
+      await notificationService.requestPermissionAndSetup();
+
+      final fcmToken = await notificationService.getToken();
+
+      if (fcmToken != null) {
+        final result = await UserService.updateFCMToken(fcmToken);
+
+        if (result['success'] == true) {
+          Navigator.of(context).pushReplacement(
+            MaterialPageRoute(builder: (context) => HomeScreen()),
+          );
+        } else {
+          _showErrorAndContinue(
+            result['message'] ?? 'Failed to update notification settings',
+          );
+        }
+      } else {
+        _showErrorAndContinue('Failed to get notification token');
+      }
+    } catch (e) {
+      _showErrorAndContinue('Error setting up notifications: $e');
+    }
+
+    setState(() {
+      _isLoading = false;
+    });
+  }
+
+  void _showErrorAndContinue(String message) {
+    showDialog(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: Text('Notification Setup'),
+        content: Text(
+          '$message\n\nYou can enable notifications later in settings.',
+        ),
+        actions: [
+          TextButton(
+            onPressed: () {
+              Navigator.of(context).pop();
+              Navigator.of(context).pushReplacement(
+                MaterialPageRoute(builder: (context) => HomeScreen()),
+              );
+            },
+            child: Text('Continue', style: TextStyle(color: Color(0xFF6A4C93))),
+          ),
+        ],
+      ),
+    );
+  }
+
+  void _skipNotifications() {
+    Navigator.of(
+      context,
+    ).pushReplacement(MaterialPageRoute(builder: (context) => HomeScreen()));
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Container(
+        decoration: BoxDecoration(
+          gradient: LinearGradient(
+            begin: Alignment.topCenter,
+            end: Alignment.bottomCenter,
+            colors: [Color(0xFF32B0A5), Color(0xFF4600B9)],
+            stops: [0.0, 0.5],
+          ),
+        ),
+        child: SafeArea(
+          child: Padding(
+            padding: EdgeInsets.all(24),
+            child: Column(
+              children: [
+                Expanded(
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    children: [
+                      Container(
+                        width: 200,
+                        height: 200,
+                        decoration: BoxDecoration(
+                          color: Colors.white.withOpacity(0.2),
+                          shape: BoxShape.circle,
+                        ),
+                        child: Icon(
+                          Icons.rocket_launch,
+                          size: 100,
+                          color: Colors.white,
+                        ),
+                      ),
+
+                      SizedBox(height: 40),
+
+                      Text(
+                        'All Set!',
+                        style: TextStyle(
+                          fontSize: 32,
+                          fontWeight: FontWeight.bold,
+                          color: Colors.white,
+                        ),
+                      ),
+
+                      SizedBox(height: 16),
+
+                      Text(
+                        'But one last thing...',
+                        style: TextStyle(
+                          fontSize: 18,
+                          color: Colors.white.withOpacity(0.9),
+                        ),
+                      ),
+
+                      SizedBox(height: 40),
+
+                      Container(
+                        padding: EdgeInsets.all(24),
+                        decoration: BoxDecoration(
+                          color: Colors.white.withOpacity(0.1),
+                          borderRadius: BorderRadius.circular(16),
+                          border: Border.all(
+                            color: Colors.white.withOpacity(0.3),
+                          ),
+                        ),
+                        child: Column(
+                          children: [
+                            Icon(
+                              Icons.notifications_active,
+                              size: 40,
+                              color: Colors.white,
+                            ),
+                            SizedBox(height: 16),
+                            Text(
+                              'Stay Connected',
+                              style: TextStyle(
+                                fontSize: 20,
+                                fontWeight: FontWeight.w600,
+                                color: Colors.white,
+                              ),
+                            ),
+                            SizedBox(height: 8),
+                            Text(
+                              'We will only send you updates on your own invitations or posts. You can always change your notification settings later.',
+                              textAlign: TextAlign.center,
+                              style: TextStyle(
+                                fontSize: 16,
+                                color: Colors.white.withOpacity(0.8),
+                                height: 1.4,
+                              ),
+                            ),
+                          ],
+                        ),
+                      ),
+                    ],
+                  ),
+                ),
+
+                Column(
+                  children: [
+                    Container(
+                      width: double.infinity,
+                      height: 56,
+                      child: ElevatedButton(
+                        onPressed: _isLoading
+                            ? null
+                            : _requestNotificationPermission,
+                        style: ElevatedButton.styleFrom(
+                          backgroundColor: Colors.white,
+                          foregroundColor: Color(0xFF6A4C93),
+                          shape: RoundedRectangleBorder(
+                            borderRadius: BorderRadius.circular(12),
+                          ),
+                          elevation: 4,
+                        ),
+                        child: _isLoading
+                            ? CircularProgressIndicator(
+                                valueColor: AlwaysStoppedAnimation<Color>(
+                                  Color(0xFF6A4C93),
+                                ),
+                              )
+                            : Row(
+                                mainAxisAlignment: MainAxisAlignment.center,
+                                children: [
+                                  Icon(Icons.notifications, size: 20),
+                                  SizedBox(width: 8),
+                                  Text(
+                                    'Enable Notifications',
+                                    style: TextStyle(
+                                      fontSize: 16,
+                                      fontWeight: FontWeight.w600,
+                                    ),
+                                  ),
+                                ],
+                              ),
+                      ),
+                    ),
+
+                    SizedBox(height: 16),
+
+                    TextButton(
+                      onPressed: _isLoading ? null : _skipNotifications,
+                      child: Text(
+                        'Skip for now',
+                        style: TextStyle(
+                          color: Colors.white.withOpacity(0.8),
+                          fontSize: 16,
+                          decoration: TextDecoration.underline,
+                        ),
+                      ),
+                    ),
+                  ],
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

frontend/lib/services/user_service.dart

@@ -4,7 +4,9 @@ import 'http_service.dart';
 import 'auth_service.dart';
 
 class UserService {
-  static Future<Map<String, dynamic>> getCurrentUser({bool forceRefresh = false}) async {
+  static Future<Map<String, dynamic>> getCurrentUser({
+    bool forceRefresh = false,
+  }) async {
     if (!forceRefresh) {
       final cachedData = await AuthService.getCachedUserData();
       if (cachedData != null) {
@@ -20,15 +22,60 @@ class UserService {
         await AuthService.saveUserData(data);
         return {'success': true, 'data': data};
       } else if (response.statusCode == 401) {
-        return {'success': false, 'message': 'Session expired. Please login again.'};
+        return {
+          'success': false,
+          'message': 'Session expired. Please login again.',
+        };
       } else if (response.statusCode == 403) {
-        return {'success': false, 'message': 'Access denied. Invalid credentials.'};
+        return {
+          'success': false,
+          'message': 'Access denied. Invalid credentials.',
+        };
       } else {
-        return {'success': false, 'message': 'Server error (${response.statusCode})'};
+        return {
+          'success': false,
+          'message': 'Server error (${response.statusCode})',
+        };
       }
     } catch (e) {
       print('Error fetching user: $e');
-      return {'success': false, 'message': 'Network error. Please check your connection.'};
+      return {
+        'success': false,
+        'message': 'Network error. Please check your connection.',
+      };
+    }
+  }
+
+  static Future<Map<String, dynamic>> updateFCMToken(String fcmToken) async {
+    try {
+      final response = await HttpService.post(ApiConstants.updateUserEndpoint, {
+        'fcmToken': fcmToken,
+      });
+
+      if (response.statusCode == 200) {
+        return {'success': true};
+      } else if (response.statusCode == 401) {
+        return {
+          'success': false,
+          'message': 'Session expired. Please login again.',
+        };
+      } else if (response.statusCode == 403) {
+        return {
+          'success': false,
+          'message': 'Access denied. Invalid credentials.',
+        };
+      } else {
+        return {
+          'success': false,
+          'message': 'Server error (${response.statusCode})',
+        };
+      }
+    } catch (e) {
+      print('Error updating FCM token: $e');
+      return {
+        'success': false,
+        'message': 'Network error. Please check your connection.',
+      };
     }
   }
 }