Add scaffold for localizations (l10n) in Sharezone

.gitignore

@@ -11,6 +11,7 @@ coverage/
 .vscode/*
 !.vscode/launch.json
 !.vscode/settings.json
+!.vscode/tasks.json
 
 # FVM will create a relative symlink in your project from .fvm/versions/ to
 # the cache of the selected version. We should add this to our .gitignore.

.vscode/tasks.json

@@ -0,0 +1,22 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            // This task generates the l10n files for the
+            // sharezone_localizations.
+            //
+            // FVM is required to run this task.
+            "label": "Generate l10n for sharezone_localizations",
+            "type": "shell",
+            // Additionally, we add the license header again (the "flutter
+            // gen-l10n" always removes the license header).
+            "command": "fvm flutter gen-l10n && addlicense -c \"Sharezone UG (haftungsbeschränkt)\" -f ../../header_template.txt .",
+            "options": {
+                "cwd": "${workspaceFolder}/lib/sharezone_localizations"
+            },
+            "problemMatcher": []
+        }
+    ]
+}

app/lib/activation_code/src/bloc/enter_activation_code_bloc.dart

@@ -15,6 +15,7 @@ import 'package:flutter/material.dart';
 import 'package:key_value_store/key_value_store.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:helper_functions/helper_functions.dart';
+import 'package:sharezone/l10n/feature_flag_l10n.dart';
 
 import '../models/enter_activation_code_result.dart';
 import 'enter_activation_code_activator.dart';
@@ -26,6 +27,7 @@ class EnterActivationCodeBloc extends BlocBase {
   final _enterActivationCodeSubject =
       BehaviorSubject<EnterActivationCodeResult>();
   final KeyValueStore keyValueStore;
+  final FeatureFlagl10n featureFlagl10n;
 
   String? _lastEnteredValue;
 
@@ -34,6 +36,7 @@ class EnterActivationCodeBloc extends BlocBase {
     this.crashAnalytics,
     this.appFunctions,
     this.keyValueStore,
+    this.featureFlagl10n,
   ) {
     _changeEnterActivationCodeResult(NoDataEnterActivationCodeResult());
   }
@@ -89,6 +92,11 @@ class EnterActivationCodeBloc extends BlocBase {
       return;
     }
 
+    if (_lastEnteredValue?.trim().toLowerCase() == 'l10n') {
+      _togglel10nFeatureFlag();
+      return;
+    }
+
     _changeEnterActivationCodeResult(LoadingEnterActivationCodeResult());
 
     final enterActivationCodeResult = await _runAppFunction(enteredValue);
@@ -107,6 +115,18 @@ class EnterActivationCodeBloc extends BlocBase {
     );
   }
 
+  void _togglel10nFeatureFlag() {
+    final currentValue = featureFlagl10n.isl10nEnabled;
+    featureFlagl10n.toggle();
+
+    _changeEnterActivationCodeResult(
+      SuccessfulEnterActivationCodeResult(
+        'l10n',
+        'l10n wurde ${!currentValue ? 'aktiviert' : 'deaktiviert'}. Starte die App neu, um die Änderungen zu sehen.',
+      ),
+    );
+  }
+
   Future<void> _clearCache(BuildContext context) async {
     await Future.wait([
       keyValueStore.clear(),

app/lib/activation_code/src/bloc/enter_activation_code_bloc_factory.dart

@@ -12,18 +12,21 @@ import 'package:bloc_base/bloc_base.dart';
 import 'package:crash_analytics/crash_analytics.dart';
 import 'package:key_value_store/key_value_store.dart';
 import 'package:sharezone/activation_code/src/bloc/enter_activation_code_bloc.dart';
+import 'package:sharezone/l10n/feature_flag_l10n.dart';
 
 class EnterActivationCodeBlocFactory extends BlocBase {
   final CrashAnalytics crashAnalytics;
   final Analytics analytics;
   final SharezoneAppFunctions appFunctions;
   final KeyValueStore keyValueStore;
+  final FeatureFlagl10n featureFlagl10n;
 
   EnterActivationCodeBlocFactory({
     required this.analytics,
     required this.crashAnalytics,
     required this.appFunctions,
     required this.keyValueStore,
+    required this.featureFlagl10n,
   });
 
   EnterActivationCodeBloc createBloc() {
@@ -32,6 +35,7 @@ class EnterActivationCodeBlocFactory extends BlocBase {
       crashAnalytics,
       appFunctions,
       keyValueStore,
+      featureFlagl10n,
     );
   }
 

app/lib/l10n/feature_flag_l10n.dart

@@ -0,0 +1,42 @@
+// Copyright (c) 2024 Sharezone UG (haftungsbeschränkt)
+// Licensed under the EUPL-1.2-or-later.
+//
+// You may obtain a copy of the Licence at:
+// https://joinup.ec.europa.eu/software/page/eupl
+//
+// SPDX-License-Identifier: EUPL-1.2
+
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:sharezone/util/cache/streaming_key_value_store.dart';
+
+class FeatureFlagl10n extends ChangeNotifier {
+  FeatureFlagl10n(this.keyValueStore) {
+    _subscription = keyValueStore
+        .getBool('l10n_enabled', defaultValue: false)
+        .listen((event) {
+      final newValue = event == true;
+      if (isl10nEnabled != newValue) {
+        isl10nEnabled = newValue;
+        notifyListeners();
+      }
+    });
+  }
+
+  final StreamingKeyValueStore keyValueStore;
+  late StreamSubscription<bool> _subscription;
+  bool isl10nEnabled = false;
+
+  void toggle() {
+    isl10nEnabled = !isl10nEnabled;
+    keyValueStore.setBool('l10n_enabled', isl10nEnabled);
+    notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _subscription.cancel();
+    super.dispose();
+  }
+}

app/lib/l10n/flutter_app_local_gateway.dart

@@ -0,0 +1,42 @@
+// Copyright (c) 2024 Sharezone UG (haftungsbeschränkt)
+// Licensed under the EUPL-1.2-or-later.
+//
+// You may obtain a copy of the Licence at:
+// https://joinup.ec.europa.eu/software/page/eupl
+//
+// SPDX-License-Identifier: EUPL-1.2
+
+import 'dart:convert';
+
+import 'package:sharezone/l10n/feature_flag_l10n.dart';
+import 'package:sharezone/util/cache/streaming_key_value_store.dart';
+import 'package:sharezone_localizations/sharezone_localizations.dart';
+
+class FlutterAppLocaleProviderGateway extends AppLocaleProviderGateway {
+  const FlutterAppLocaleProviderGateway({
+    required this.keyValueStore,
+    required this.featureFlagl10n,
+  });
+
+  final FeatureFlagl10n featureFlagl10n;
+  final StreamingKeyValueStore keyValueStore;
+
+  @override
+  Stream<AppLocale> getLocale() {
+    final defaultValue = jsonEncode(featureFlagl10n.isl10nEnabled
+        ? AppLocale.system.toMap()
+        : AppLocale.en.toMap());
+    return keyValueStore
+        .getString('locale', defaultValue: defaultValue)
+        .map((event) => AppLocale.fromMap(jsonDecode(event)));
+  }
+
+  @override
+  Future<void> setLocale(AppLocale locale) async {
+    final value = jsonEncode(locale.toMap());
+    keyValueStore.setString(
+      'locale',
+      value,
+    );
+  }
+}

app/lib/main/sharezone.dart

@@ -21,16 +21,20 @@ import 'package:provider/provider.dart';
 import 'package:sharezone/dynamic_links/beitrittsversuch.dart';
 import 'package:sharezone/dynamic_links/dynamic_link_bloc.dart';
 import 'package:sharezone/dynamic_links/dynamic_links.dart';
+import 'package:sharezone/l10n/feature_flag_l10n.dart';
+import 'package:sharezone/l10n/flutter_app_local_gateway.dart';
 import 'package:sharezone/main/auth_app.dart';
 import 'package:sharezone/main/bloc_dependencies.dart';
 import 'package:sharezone/main/sharezone_app.dart';
 import 'package:sharezone/main/sharezone_bloc_providers.dart';
 import 'package:sharezone/navigation/logic/navigation_bloc.dart';
 import 'package:sharezone/notifications/notifications_permission.dart';
 import 'package:sharezone/onboarding/group_onboarding/logic/signed_up_bloc.dart';
+import 'package:sharezone/util/cache/streaming_key_value_store.dart';
 import 'package:sharezone/util/flavor.dart';
 import 'package:sharezone/widgets/animation/color_fade_in.dart';
 import 'package:sharezone/widgets/development_stage_banner.dart';
+import 'package:sharezone_localizations/sharezone_localizations.dart';
 import 'package:sharezone_utils/device_information_manager.dart';
 import 'package:sharezone_widgets/sharezone_widgets.dart';
 
@@ -72,6 +76,8 @@ class Sharezone extends StatefulWidget {
 class _SharezoneState extends State<Sharezone> with WidgetsBindingObserver {
   late SignUpBloc signUpBloc;
   late StreamSubscription<AuthUser?> authSubscription;
+  late StreamingKeyValueStore streamingKeyValueStore;
+  late FeatureFlagl10n featureFlagl10n;
 
   @override
   void initState() {
@@ -93,6 +99,11 @@ class _SharezoneState extends State<Sharezone> with WidgetsBindingObserver {
     authSubscription = listenToAuthStateChanged().listen((user) {
       authUserSubject.sink.add(user);
     });
+
+    streamingKeyValueStore = FlutterStreamingKeyValueStore(
+      widget.blocDependencies.streamingSharedPreferences,
+    );
+    featureFlagl10n = FeatureFlagl10n(streamingKeyValueStore);
   }
 
   void logAppOpen() {
@@ -129,6 +140,15 @@ class _SharezoneState extends State<Sharezone> with WidgetsBindingObserver {
                                 MobileDeviceInformationRetriever(),
                           ),
                         ),
+                        ChangeNotifierProvider.value(value: featureFlagl10n),
+                        ChangeNotifierProvider(
+                          create: (context) => AppLocaleProvider(
+                            gateway: FlutterAppLocaleProviderGateway(
+                              keyValueStore: streamingKeyValueStore,
+                              featureFlagl10n: featureFlagl10n,
+                            ),
+                          ),
+                        ),
                       ],
                       child: MultiBlocProvider(
                         blocProviders: [

app/lib/main/sharezone_app.dart

@@ -46,6 +46,7 @@ import 'package:sharezone/settings/settings_page.dart';
 import 'package:sharezone/settings/src/subpages/about/about_page.dart';
 import 'package:sharezone/settings/src/subpages/changelog_page.dart';
 import 'package:sharezone/settings/src/subpages/imprint/page/imprint_page.dart';
+import 'package:sharezone/settings/src/subpages/language/language_page.dart';
 import 'package:sharezone/settings/src/subpages/my_profile/change_email.dart';
 import 'package:sharezone/settings/src/subpages/my_profile/change_password.dart';
 import 'package:sharezone/settings/src/subpages/my_profile/change_state.dart';
@@ -204,6 +205,7 @@ class _SharezoneAppState extends State<SharezoneApp>
                 ICalLinksDialog.tag: (context) => const ICalLinksDialog(),
                 CreateTermPage.tag: (context) => const CreateTermPage(),
                 GradesDialog.tag: (context) => const GradesDialog(),
+                LanguagePage.tag: (context) => const LanguagePage(),
               },
               navigatorKey: navigationService.navigatorKey,
             ),

app/lib/main/sharezone_bloc_providers.dart

@@ -84,6 +84,7 @@ import 'package:sharezone/ical_links/dialog/ical_links_dialog_controller_factory
 import 'package:sharezone/ical_links/list/ical_links_page_controller.dart';
 import 'package:sharezone/ical_links/shared/ical_link_analytics.dart';
 import 'package:sharezone/ical_links/shared/ical_links_gateway.dart';
+import 'package:sharezone/l10n/feature_flag_l10n.dart';
 import 'package:sharezone/main/application_bloc.dart';
 import 'package:sharezone/main/bloc_dependencies.dart';
 import 'package:sharezone/main/onboarding/onboarding_navigator.dart';
@@ -497,7 +498,7 @@ class _SharezoneBlocProvidersState extends State<SharezoneBlocProviders> {
         ),
         lazy: false,
       ),
-      Provider<KeyValueStore>.value(value: keyValueStore)
+      Provider<KeyValueStore>.value(value: keyValueStore),
     ];
 
     mainBlocProviders = <BlocProvider>[
@@ -593,6 +594,7 @@ class _SharezoneBlocProvidersState extends State<SharezoneBlocProviders> {
           analytics: analytics,
           appFunctions: api.references.functions,
           keyValueStore: widget.blocDependencies.keyValueStore,
+          featureFlagl10n: context.read<FeatureFlagl10n>(),
         ),
       ),
       BlocProvider<NotificationsBlocFactory>(

app/lib/main/sharezone_material_app.dart

@@ -9,10 +9,10 @@
 import 'package:analytics/analytics.dart';
 import 'package:analytics/observer.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:platform_check/platform_check.dart';
 import 'package:provider/provider.dart';
 import 'package:sharezone/main/bloc_dependencies.dart';
+import 'package:sharezone_localizations/sharezone_localizations.dart';
 import 'package:sharezone_widgets/sharezone_widgets.dart';
 
 class SharezoneMaterialApp extends StatelessWidget {
@@ -35,7 +35,7 @@ class SharezoneMaterialApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final themeSettings = context.watch<ThemeSettings>();
-
+    final localProvider = context.watch<AppLocaleProvider>();
     return MaterialApp(
       debugShowCheckedModeBanner: false,
       title: PlatformCheck.isWeb ? "Sharezone Web-App" : "Sharezone",
@@ -45,15 +45,9 @@ class SharezoneMaterialApp extends StatelessWidget {
       theme: getLightTheme().copyWith(
           visualDensity: themeSettings.visualDensitySetting.visualDensity),
       themeMode: _getThemeMode(themeSettings.themeBrightness),
-      localizationsDelegates: const [
-        GlobalMaterialLocalizations.delegate,
-        GlobalWidgetsLocalizations.delegate,
-        GlobalCupertinoLocalizations.delegate,
-      ],
-      supportedLocales: const [
-        Locale('en', 'US'),
-        Locale('de', 'DE'),
-      ],
+      localizationsDelegates: SharezoneLocalizations.localizationsDelegates,
+      supportedLocales: SharezoneLocalizations.supportedLocales,
+      locale: localProvider.locale.toLocale(),
       navigatorObservers: <NavigatorObserver>[
         AnalyticsNavigationObserver(analytics: analytics)
       ],