Caching

mobile/lib/abstract/connectivity_service.dart

@@ -0,0 +1,3 @@
+abstract class ConnectivityBaseService {
+  Future<bool> hasInternet();
+}

mobile/lib/abstract/local_cache_service.dart

@@ -0,0 +1,5 @@
+abstract class LocalCacheBaseService {
+  Future<void> cacheData(String boxName, dynamic data);
+  Future<dynamic> getCachedData(String boxName);
+  Future<void> clearCache(String boxName);
+}

mobile/lib/abstract/offline_sync_service.dart

@@ -0,0 +1,9 @@
+import 'package:yaspo_mobile/model/offline_sync/offline_sync_request.dart';
+
+abstract class OfflineSyncService {
+  Stream<void> get onSyncComplete;
+
+  Future<void> enqueueRequest(OfflineSyncRequest request);
+
+  void onInternetConnected();
+}

mobile/lib/core/authenticated_dio.dart

@@ -1,9 +1,11 @@
 import 'dart:async';
-
+import 'dart:io';
 import 'package:dio/dio.dart';
 import 'package:get_it/get_it.dart';
 import 'package:yaspo_mobile/core/api_url.dart';
 import 'package:yaspo_mobile/abstract/token_storage_service.dart';
+import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:yaspo_mobile/abstract/offline_sync_service.dart';
 
 final authenticatedDio = Dio(
   BaseOptions(baseUrl: baseUrl, headers: {'Content-Type': 'application/json'}),
@@ -12,6 +14,26 @@ final authenticatedDio = Dio(
 bool _isRefreshing = false;
 final List<Completer<String>> _failedQueue = [];
 
+class _OfflineRequest {
+  final Completer<Response> completer;
+  final RequestOptions requestOptions;
+  _OfflineRequest(this.completer, this.requestOptions);
+}
+
+final List<_OfflineRequest> _offlineQueue = [];
+bool _isConnectivityListening = false;
+
+bool _isOfflineError(DioException err) {
+  var method = err.requestOptions.method.toUpperCase();
+  if (method == 'GET') return false;
+
+  return err.type == DioExceptionType.connectionError ||
+      err.type == DioExceptionType.connectionTimeout ||
+      err.type == DioExceptionType.receiveTimeout ||
+      err.type == DioExceptionType.sendTimeout ||
+      err.error is SocketException;
+}
+
 Future<String> _waitForTokenRefresh() {
   var completer = Completer<String>();
   _failedQueue.add(completer);
@@ -29,7 +51,53 @@ void _processQueue(Object? error, String? token) {
   _failedQueue.clear();
 }
 
+Future<Response> _waitForInternetAndRetry(RequestOptions requestOptions) {
+  var completer = Completer<Response>();
+  _offlineQueue.add(_OfflineRequest(completer, requestOptions));
+  return completer.future;
+}
+
+void _processOfflineQueue() async {
+  if (_offlineQueue.isEmpty) return;
+
+  var queueCopy = List.of(_offlineQueue);
+  _offlineQueue.clear();
+
+  for (int i = 0; i < queueCopy.length; i++) {
+    var req = queueCopy[i];
+    try {
+      var response = await authenticatedDio.fetch(req.requestOptions);
+      req.completer.complete(response);
+    } catch (e) {
+      if (e is DioException && _isOfflineError(e)) {
+        _offlineQueue.addAll(queueCopy.sublist(i));
+        break;
+      } else {
+        req.completer.completeError(e);
+      }
+    }
+  }
+}
+
+void _initConnectivityListener() {
+  if (_isConnectivityListening) return;
+  _isConnectivityListening = true;
+  Connectivity().onConnectivityChanged.listen((event) {
+    bool hasConnection = false;
+    hasConnection = event.any((result) => result != ConnectivityResult.none);
+
+    if (hasConnection) {
+      GetIt.I<OfflineSyncService>().onInternetConnected();
+      if (_offlineQueue.isNotEmpty) {
+        _processOfflineQueue();
+      }
+    }
+  });
+}
+
 void setupAuthenticatedDio() {
+  _initConnectivityListener();
+
   authenticatedDio.interceptors.add(
     InterceptorsWrapper(
       onRequest: (options, handler) async {
@@ -42,6 +110,17 @@ void setupAuthenticatedDio() {
       onError: (err, handler) async {
         var originalRequest = err.requestOptions;
 
+        if (_isOfflineError(err) &&
+            originalRequest.extra['offline_retry'] != true) {
+          originalRequest.extra['offline_retry'] = true;
+          try {
+            var response = await _waitForInternetAndRetry(originalRequest);
+            return handler.resolve(response);
+          } catch (e) {
+            return handler.reject(e as DioException);
+          }
+        }
+
         if (err.response?.statusCode == 401 &&
             originalRequest.extra['retry'] != true) {
           originalRequest.extra['retry'] = true;
@@ -68,18 +147,34 @@ void setupAuthenticatedDio() {
               var newAccessToken = response.data['access_token'];
               var newRefreshToken = response.data['refresh_token'];
 
-              await GetIt.I<TokenStorageService>().setTokens(
-                newAccessToken,
-                newRefreshToken,
-              );
-              authenticatedDio.options.headers['Authorization'] =
-                  'Bearer $newAccessToken';
-              _processQueue(null, newAccessToken);
+              if (newAccessToken != null &&
+                  newAccessToken.toString().isNotEmpty) {
+                String finalRefreshToken =
+                    (newRefreshToken != null &&
+                        newRefreshToken.toString().isNotEmpty)
+                    ? newRefreshToken
+                    : refreshToken!;
 
-              originalRequest.headers['Authorization'] =
-                  'Bearer $newAccessToken';
-              var retryResponse = await authenticatedDio.fetch(originalRequest);
-              return handler.resolve(retryResponse);
+                await GetIt.I<TokenStorageService>().setTokens(
+                  newAccessToken,
+                  finalRefreshToken,
+                );
+                authenticatedDio.options.headers['Authorization'] =
+                    'Bearer $newAccessToken';
+                _processQueue(null, newAccessToken);
+
+                originalRequest.headers['Authorization'] =
+                    'Bearer $newAccessToken';
+                var retryResponse = await authenticatedDio.fetch(
+                  originalRequest,
+                );
+                return handler.resolve(retryResponse);
+              } else {
+                throw DioException(
+                  requestOptions: originalRequest,
+                  error: 'Refresh returned empty access token',
+                );
+              }
             } catch (e) {
               _processQueue(e, null);
               return handler.reject(e as DioException);

mobile/lib/cubit/quiz/quiz_session_cubit.dart

@@ -37,17 +37,13 @@ class QuizSessionCubit extends Cubit<QuizSessionState> {
 
   void nextQuestion() {
     if (state.currentQuestionIndex < state.quiz.questions!.length - 1) {
-      emit(
-        state.copyWith(currentQuestionIndex: state.currentQuestionIndex + 1),
-      );
+      emit(state.copyWith(currentQuestionIndex: state.currentQuestionIndex + 1));
     }
   }
 
   void previousQuestion() {
     if (state.currentQuestionIndex > 0) {
-      emit(
-        state.copyWith(currentQuestionIndex: state.currentQuestionIndex - 1),
-      );
+      emit(state.copyWith(currentQuestionIndex: state.currentQuestionIndex - 1));
     }
   }
 

mobile/lib/exceptions/network_exception.dart

@@ -0,0 +1,7 @@
+class OfflineException implements Exception {
+  final String message;
+  OfflineException([this.message = 'No internet connection. Please check your network and try again.']);
+
+  @override
+  String toString() => message;
+}

mobile/lib/main.dart

@@ -10,7 +10,9 @@ import 'package:yaspo_mobile/abstract/assignment_service.dart';
 import 'package:yaspo_mobile/abstract/auth_service.dart';
 import 'package:yaspo_mobile/abstract/credential_manager_service.dart';
 import 'package:yaspo_mobile/abstract/download_csv_service.dart';
+import 'package:yaspo_mobile/abstract/connectivity_service.dart';
 import 'package:yaspo_mobile/abstract/grade_sheet_service.dart';
+import 'package:yaspo_mobile/abstract/local_cache_service.dart';
 import 'package:yaspo_mobile/abstract/notification_service.dart';
 import 'package:yaspo_mobile/abstract/quiz_service.dart';
 import 'package:yaspo_mobile/abstract/staff_service.dart';
@@ -19,16 +21,18 @@ import 'package:yaspo_mobile/abstract/tenant_service.dart';
 import 'package:yaspo_mobile/abstract/token_storage_service.dart';
 import 'package:yaspo_mobile/abstract/user_service.dart';
 import 'package:yaspo_mobile/abstract/class_service.dart';
+import 'package:yaspo_mobile/abstract/offline_sync_service.dart';
 import 'package:yaspo_mobile/core/authenticated_dio.dart';
 import 'package:yaspo_mobile/cubit/grade_sheet/grade_sheet_cubit.dart';
 import 'package:yaspo_mobile/cubit/grade_sheet/grade_sheet_record_cubit.dart';
 import 'package:yaspo_mobile/cubit/student/student_cubit.dart';
 import 'package:yaspo_mobile/cubit/user/user_cubit.dart';
 import 'package:yaspo_mobile/enums/user_type.dart';
-import 'package:yaspo_mobile/exceptions/auth_exception.dart';
 import 'package:yaspo_mobile/firebase_options.dart';
 import 'package:yaspo_mobile/model/user/user.dart';
+import 'package:yaspo_mobile/services/remote_connectivity_service.dart';
 import 'package:yaspo_mobile/services/hive_token_storage_service.dart';
+import 'package:yaspo_mobile/services/local_cache_service.dart';
 import 'package:yaspo_mobile/services/remote_analytics_service.dart';
 import 'package:yaspo_mobile/services/remote_announcement_service.dart';
 import 'package:yaspo_mobile/services/remote_assignment_service.dart';
@@ -41,8 +45,9 @@ import 'package:yaspo_mobile/services/remote_staff_service.dart';
 import 'package:yaspo_mobile/services/remote_student_service.dart';
 import 'package:yaspo_mobile/services/remote_tenant_service.dart';
 import 'package:yaspo_mobile/services/remote_class_service.dart';
-import 'package:yaspo_mobile/services/local_credential_manager_service.dart';
 import 'package:yaspo_mobile/services/remote_user_service.dart';
+import 'package:yaspo_mobile/services/remote_offline_sync_service.dart';
+import 'package:yaspo_mobile/services/local_credential_manager_service.dart';
 import 'package:yaspo_mobile/theme/color_scheme.dart';
 import 'package:yaspo_mobile/ui/app/organization/student/student_organization_host.dart';
 import 'package:yaspo_mobile/ui/app/single-class/staff/staff_app_host.dart';
@@ -64,6 +69,8 @@ void main() async {
   var userCubit = UserCubit();
 
   GetIt.I.registerSingleton<TokenStorageService>(HiveTokenStorageService());
+  GetIt.I.registerSingleton<ConnectivityBaseService>(RemoteConnectivityService());
+  GetIt.I.registerSingleton<LocalCacheBaseService>(LocalCacheService());
   GetIt.I.registerSingleton<StudentService>(RemoteStudentService());
   GetIt.I.registerSingleton<AuthService>(RemoteAuthService());
   GetIt.I.registerSingleton<TenantService>(RemoteTenantService());
@@ -76,10 +83,9 @@ void main() async {
   GetIt.I.registerSingleton<UserService>(RemoteUserService());
   GetIt.I.registerSingleton<QuizService>(RemoteQuizService());
   GetIt.I.registerSingleton<AnalyticsService>(RemoteAnalyticsService());
-  GetIt.I.registerSingleton<CredentialManagerService>(
-    LocalCredentialManagerService(),
-  );
+  GetIt.I.registerSingleton<CredentialManagerService>(LocalCredentialManagerService());
   GetIt.I.registerSingleton<ClassService>(RemoteClassService());
+  GetIt.I.registerSingleton<OfflineSyncService>(RemoteOfflineSyncService());
 
   await GetIt.I<CredentialManagerService>().init();
 
@@ -122,37 +128,39 @@ class _MyAppState extends State<MyApp> {
   }
 
   Future<void> refreshUserToken() async {
-    var refreshToken = await GetIt.I<TokenStorageService>().getRefreshToken();
-    if (refreshToken == null) {
-      setState(() {
-        isLoading = false;
-      });
+    var tokenStorage = GetIt.I<TokenStorageService>();
+    var authService = GetIt.I<AuthService>();
 
+    var refreshToken = await tokenStorage.getRefreshToken();
+    if (refreshToken == null || refreshToken.isEmpty) {
+      if (mounted) {
+        setState(() {
+          isLoading = false;
+        });
+      }
       return;
     }
 
     try {
-      var response = await GetIt.I<AuthService>().refresh(refreshToken);
+      var response = await authService.refresh(refreshToken);
 
-      await GetIt.I<TokenStorageService>().setTokens(
-        response.accessToken,
-        response.refreshToken,
-      );
+      if (response.accessToken.isNotEmpty) {
+        String newRefreshToken = response.refreshToken.isNotEmpty ? response.refreshToken : refreshToken;
 
-      if (mounted) {
-        context.read<UserCubit>().setUserModel(
-          TokenUtil.decodeToken(response.accessToken),
-        );
-      }
-    } on InvalidCredentialException {
-      await GetIt.I<TokenStorageService>().clearTokens();
+        await tokenStorage.setTokens(response.accessToken, newRefreshToken);
 
-      if (mounted) context.read<UserCubit>().setUserModel(null);
-    } catch (_) {
+        var newUser = TokenUtil.decodeToken(response.accessToken);
+        if (mounted) {
+          context.read<UserCubit>().setUserModel(newUser);
+        }
+      }
+    }  catch (_) {
     } finally {
-      setState(() {
-        isLoading = false;
-      });
+      if (mounted) {
+        setState(() {
+          isLoading = false;
+        });
+      }
     }
   }
 

mobile/lib/model/announcement/announcement.dart

@@ -3,12 +3,14 @@ class Announcement {
   final String content;
   final String authorName;
   final String createdAt;
+  final bool isPending;
 
   Announcement({
     required this.id,
     required this.content,
     required this.authorName,
     required this.createdAt,
+    this.isPending = false,
   });
 
   factory Announcement.fromJson(Map<String, dynamic> json) {
@@ -17,6 +19,17 @@ class Announcement {
       content: json['content'] ?? '',
       authorName: json['author'] ?? 'Unknown Author',
       createdAt: json['created_at'] ?? '',
+      isPending: json['isPending'] ?? false,
     );
   }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'content': content,
+      'author': authorName,
+      'created_at': createdAt,
+      'isPending': isPending,
+    };
+  }
 }