Add localization (l10n/i18n) support with language selection

l10n.yaml

@@ -0,0 +1,6 @@
+arb-dir: lib/l10n
+template-arb-file: app_en.arb
+output-localization-file: app_localizations.dart
+output-class: AppLocalizations
+output-dir: lib/l10n
+nullable-getter: false

lib/l10n/app_en.arb

@@ -0,0 +1,80 @@
+{
+  "@@locale": "en",
+  "appTitle": "Ell-ena",
+  "@appTitle": {
+    "description": "The application title shown in the task switcher and browser tab."
+  },
+  "login": "Sign In",
+  "@login": {
+    "description": "Primary authentication action on the login screen."
+  },
+  "signUp": "Sign Up",
+  "@signUp": {
+    "description": "Registration action on the authentication screens."
+  },
+  "logout": "Logout",
+  "@logout": {
+    "description": "Logout action label."
+  },
+  "logoutTitle": "Log out?",
+  "@logoutTitle": {
+    "description": "Title for the logout confirmation dialog."
+  },
+  "logoutMessage": "You will need to log in again to access your account.",
+  "@logoutMessage": {
+    "description": "Body text for the logout confirmation dialog."
+  },
+  "dashboard": "Dashboard",
+  "@dashboard": {
+    "description": "Dashboard navigation label."
+  },
+  "tasks": "Tasks",
+  "@tasks": {
+    "description": "Tasks section label."
+  },
+  "tickets": "Tickets",
+  "@tickets": {
+    "description": "Tickets section label."
+  },
+  "meetings": "Meetings",
+  "@meetings": {
+    "description": "Meetings section label."
+  },
+  "settings": "Settings",
+  "@settings": {
+    "description": "Settings section label."
+  },
+  "cancel": "Cancel",
+  "@cancel": {
+    "description": "Generic cancel action."
+  },
+  "save": "Save",
+  "@save": {
+    "description": "Generic save action."
+  },
+  "loading": "Loading...",
+  "@loading": {
+    "description": "Generic loading indicator label."
+  },
+  "search": "Search",
+  "@search": {
+    "description": "Generic search placeholder label."
+  },
+  "language": "Language",
+  "@language": {
+    "description": "Language preference setting label."
+  },
+  "languageName": "{localeCode, select, en{English} hi{हिन्दी} other{{localeCode}}}",
+  "@languageName": {
+    "description": "Display name for a language identified by locale code.",
+    "placeholders": {
+      "localeCode": {
+        "type": "String"
+      }
+    }
+  },
+  "selectLanguage": "Select Language",
+  "@selectLanguage": {
+    "description": "Title for the language selection sheet."
+  }
+}

lib/l10n/app_hi.arb

@@ -0,0 +1,21 @@
+{
+  "@@locale": "hi",
+  "appTitle": "Ell-ena",
+  "login": "साइन इन",
+  "signUp": "साइन अप",
+  "logout": "लॉग आउट",
+  "logoutTitle": "लॉग आउट करें?",
+  "logoutMessage": "अपने खाते तक पहुँचने के लिए आपको दोबारा लॉग इन करना होगा।",
+  "dashboard": "डैशबोर्ड",
+  "tasks": "कार्य",
+  "tickets": "टिकट",
+  "meetings": "मीटिंग",
+  "settings": "सेटिंग्स",
+  "cancel": "रद्द करें",
+  "save": "सहेजें",
+  "loading": "लोड हो रहा है...",
+  "search": "खोजें",
+  "language": "भाषा",
+  "languageName": "{localeCode, select, en{अंग्रेज़ी} hi{हिन्दी} other{{localeCode}}}",
+  "selectLanguage": "भाषा चुनें"
+}

lib/main.dart

@@ -1,13 +1,18 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart'
     hide ChangeNotifierProvider;
 import 'package:provider/provider.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'l10n/app_localizations.dart';
 import 'screens/splash_screen.dart';
 import 'screens/home/home_screen.dart';
 import 'screens/chat/chat_screen.dart';
 import 'services/navigation_service.dart';
 import 'services/supabase_service.dart';
 import 'services/ai_service.dart';
+import 'providers/locale_provider.dart';
+import 'providers/shared_preferences_provider.dart';
 import 'providers/theme_provider.dart';
 import 'theme/theme_controller.dart';
 import 'theme/app_themes.dart';
@@ -21,33 +26,44 @@ void main() async {
   } catch (e) {
     debugPrint('Error initializing services: $e');
   }
-
+
+  final prefs = await SharedPreferences.getInstance();
   final themeController = await ThemeController.create();
 
-runApp(
-  WidgetsBindingObserverWidget(
-    child: ProviderScope(
-      overrides: [
-        themeControllerProvider.overrideWith((ref) => themeController),
-      ],
-      child: ChangeNotifierProvider<ThemeController>.value(
-        value: themeController,
-        child: const MyApp(),
+  runApp(
+    WidgetsBindingObserverWidget(
+      child: ProviderScope(
+        overrides: [
+          sharedPreferencesProvider.overrideWithValue(prefs),
+          themeControllerProvider.overrideWith((ref) => themeController),
+        ],
+        child: ChangeNotifierProvider<ThemeController>.value(
+          value: themeController,
+          child: const MyApp(),
+        ),
       ),
     ),
-  ),
-);
-
+  );
 }
+
 class MyApp extends ConsumerWidget {
   const MyApp({super.key});
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final themeController = ref.watch(themeControllerProvider);
+    final locale = ref.watch(localeControllerProvider);
     return MaterialApp(
-      title: 'Ell-ena',
+      onGenerateTitle: (context) => AppLocalizations.of(context).appTitle,
       debugShowCheckedModeBanner: false,
+      locale: locale,
+      localizationsDelegates: const [
+        AppLocalizations.delegate,
+        GlobalMaterialLocalizations.delegate,
+        GlobalWidgetsLocalizations.delegate,
+        GlobalCupertinoLocalizations.delegate,
+      ],
+      supportedLocales: AppLocalizations.supportedLocales,
       navigatorKey: NavigationService().navigatorKey,
       navigatorObservers: <NavigatorObserver>[AppRouteObserver.instance],
       theme: lightTheme,

lib/providers/locale_provider.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+import '../l10n/app_localizations.dart';
+import 'shared_preferences_provider.dart';
+
+part 'locale_provider.g.dart';
+
+const String _localeStorageKey = 'app_locale';
+const Locale _defaultLocale = Locale('en');
+
+/// Manages the active app [Locale] with SharedPreferences persistence.
+@Riverpod(keepAlive: true)
+class LocaleController extends _$LocaleController {
+  @override
+  Locale build() {
+    final prefs = ref.watch(sharedPreferencesProvider);
+    final code = prefs.getString(_localeStorageKey);
+    if (code != null && code.isNotEmpty) {
+      for (final locale in AppLocalizations.supportedLocales) {
+        if (locale.languageCode == code) {
+          return locale;
+        }
+      }
+    }
+    return _defaultLocale;
+  }
+
+  /// Updates locale and persists the language code.
+  Future<void> setLocale(Locale locale) async {
+    final prefs = ref.read(sharedPreferencesProvider);
+    await prefs.setString(_localeStorageKey, locale.languageCode);
+    state = locale;
+  }
+}

lib/providers/shared_preferences_provider.dart

@@ -0,0 +1,9 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+/// SharedPreferences instance overridden at app startup.
+final sharedPreferencesProvider = Provider<SharedPreferences>((ref) {
+  throw StateError(
+    'sharedPreferencesProvider must be overridden in ProviderScope',
+  );
+});

lib/screens/auth/login_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import 'package:supabase_flutter/supabase_flutter.dart';
+import '../../l10n/app_localizations.dart';
 import '../../widgets/custom_widgets.dart';
 import '../../services/navigation_service.dart';
 import '../../services/supabase_service.dart';
@@ -159,6 +160,7 @@ class _LoginScreenState extends State<LoginScreen>
 
   @override
   Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context);
     return AuthScreenWrapper(
       title: 'Welcome Back',
       subtitle: 'Sign in to continue with Ell-ena',
@@ -221,7 +223,7 @@ class _LoginScreenState extends State<LoginScreen>
                   ),
                   const SizedBox(height: 24),
                   CustomButton(
-                    text: 'Sign In',
+                    text: l10n.login,
                     onPressed: _isLoading ? null : _handleLogin,
                     isLoading: _isLoading,
                   ),
@@ -292,7 +294,7 @@ class _LoginScreenState extends State<LoginScreen>
                           NavigationService().navigateTo(const SignupScreen());
                         },
                         child: Text(
-                          'Sign Up',
+                          l10n.signUp,
                           style: TextStyle(
                             color: Colors.green.shade400,
                             fontWeight: FontWeight.w600,

lib/screens/home/home_screen.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import '../../l10n/app_localizations.dart';
 import '../../widgets/custom_widgets.dart';
 import '../../services/navigation_service.dart';
 import '../workspace/workspace_screen.dart';
@@ -140,6 +141,7 @@ class _HomeScreenState extends State<HomeScreen>
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final l10n = AppLocalizations.of(context);
     return Scaffold(
       body: IndexedStack(index: _selectedIndex, children: _screens),
       bottomNavigationBar: BottomNavigationBar(
@@ -148,10 +150,10 @@ class _HomeScreenState extends State<HomeScreen>
         type: BottomNavigationBarType.fixed,
         selectedItemColor: theme.colorScheme.primary,
         unselectedItemColor: theme.colorScheme.onSurfaceVariant,
-        items: const [
+        items: [
           BottomNavigationBarItem(
-            icon: Icon(Icons.dashboard),
-            label: 'Dashboard',
+            icon: const Icon(Icons.dashboard),
+            label: l10n.dashboard,
           ),
           BottomNavigationBarItem(
             icon: Icon(Icons.calendar_today),

lib/screens/profile/edit_profile_screen.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import '../../l10n/app_localizations.dart';
 import '../../services/supabase_service.dart';
 
 class EditProfileScreen extends StatefulWidget {
@@ -120,6 +121,7 @@ class _EditProfileScreenState extends State<EditProfileScreen> {
 
   @override
   Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context);
     return Scaffold(
       backgroundColor: Theme.of(context).scaffoldBackgroundColor,
       appBar: AppBar(
@@ -136,9 +138,10 @@ class _EditProfileScreenState extends State<EditProfileScreen> {
                         strokeWidth: 2, color: Colors.white))
                 : Icon(Icons.save,
                     color: Theme.of(context).colorScheme.onSurface),
-            label: Text('Save',
-                style:
-                    TextStyle(color: Theme.of(context).colorScheme.onSurface)),
+            label: Text(
+              l10n.save,
+              style: TextStyle(color: Theme.of(context).colorScheme.onSurface),
+            ),
           ),
         ],
       ),