feat(auth): complete Google OAuth integration with Deep Link and Provider (#18)

* feat(core): add auth layout template, custom textfield and colors

* feat(auth): implement viewmodels for auth flow (MVVM)

* feat(auth): build complete auth UI screens (Login, Register, OTP, Passwords)

* chore(main): set LoginView as initial route

* refactor(auth) : delete .gitkeep

* chore: update dependencies and pubspec.lock

* refactor(auth): optimize registration logic, timezone handling, and form validation

* feat(auth): update UI for login, registration, and forgot password screens

* feat(tasks): update task management UI and statistics screen

* chore: update main entry point and fix widget tests

* chore: ignore devtools_options.yaml

* chore: ignore devtools_options.yaml

* style(login) : rewrite title for login view

* feat(auth): configure android deep link for supabase oauth

* refactor(ui): add social login callbacks to auth layout template

* feat(auth): update oauth methods with redirect url and signout

* feat(auth): implement AuthGate using StreamBuilder for session tracking

* feat(viewmodel): add oauth logic and improve provider lifecycle

* refactor(ui): migrate LoginView to Provider pattern

* chore(main): set AuthGate as initial route and setup provider

Author: hoanghaoz

src/android/app/src/main/AndroidManifest.xml

@@ -16,6 +16,14 @@
                  the Android process has started. This theme is visible to the user
                  while the Flutter UI initializes. After that, this theme continues
                  to determine the Window background behind the Flutter UI. -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data
+                    android:scheme="taskapp"
+                    android:host="login-callback" />
+            </intent-filter>
             <meta-data
               android:name="io.flutter.embedding.android.NormalTheme"
               android:resource="@style/NormalTheme"

src/lib/core/theme/auth_layout_template.dart

@@ -14,6 +14,8 @@ class AuthLayoutTemplate extends StatelessWidget {
   final bool useCard;
   final Widget? customHeaderIcon;
   final Widget? footerContent;
+  final VoidCallback? onGoogleTap; // Login with Google
+  final VoidCallback? onFacebookTap; // Login with Facebook
 
   const AuthLayoutTemplate({
     super.key,
@@ -27,6 +29,8 @@ class AuthLayoutTemplate extends StatelessWidget {
     this.useCard = true,
     this.customHeaderIcon,
     this.footerContent,
+    this.onGoogleTap,
+    this.onFacebookTap,
   });
 
   @override
@@ -200,7 +204,7 @@ class AuthLayoutTemplate extends StatelessWidget {
             children: [
               Expanded(
                 child: OutlinedButton.icon(
-                  onPressed: () {},
+                  onPressed: onGoogleTap,
                   icon: const Icon(
                     Icons.g_mobiledata,
                     color: Colors.red,
@@ -212,7 +216,7 @@ class AuthLayoutTemplate extends StatelessWidget {
               const SizedBox(width: 16),
               Expanded(
                 child: OutlinedButton.icon(
-                  onPressed: () {},
+                  onPressed: onFacebookTap,
                   icon: const Icon(Icons.facebook, color: Color(0xFF1877F2)),
                   label: const Text('Facebook'),
                 ),

src/lib/features/auth/data/auth_helper.dart

@@ -40,6 +40,30 @@ class AuthHelper {
     }
   }
 
+  Future<bool> loginWithGoogle() async {
+    try {
+      return await supabase.auth.signInWithOAuth(
+        OAuthProvider.google,
+        redirectTo: 'taskapp://login-callback', // back to app
+      );
+    } on AuthException catch (e) {
+      print('Lỗi đăng nhập Google: ${e.message}');
+      return false;
+    }
+  }
+
+  Future<bool> loginWithFacebook() async {
+    try {
+      return await supabase.auth.signInWithOAuth(
+        OAuthProvider.facebook,
+        redirectTo: 'taskapp://login-callback', // back to app
+      );
+    } on AuthException catch (e) {
+      print('Lỗi đăng nhập Facebook: ${e.message}');
+      return false;
+    }
+  }
+
   Future<UserModel?> register(String email, String password, String username) async {
     try {
       final timezoneObj = await FlutterTimezone.getLocalTimezone();
@@ -106,4 +130,14 @@ class AuthHelper {
       rethrow;
     }
   }
+}
+
+// SignOut session
+Future<void> signOut() async {
+  try {
+    await supabase.auth.signOut();
+  } catch (e) {
+    print('Lỗi đăng xuất: $e');
+    rethrow;
+  }
 }

src/lib/features/auth/presentation/view/auth_gate.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:supabase_flutter/supabase_flutter.dart';
+import 'login_view.dart';
+import '../../../main/view/screens/main_screen.dart';
+
+class AuthGate extends StatelessWidget {
+  const AuthGate({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    // StreamBuilder continously checks the auth state
+    return StreamBuilder<AuthState>(
+      stream: Supabase.instance.client.auth.onAuthStateChange,
+      builder: (context, snapshot) {
+        // Wait response from Supabase
+        if (snapshot.connectionState == ConnectionState.waiting) {
+          return const Scaffold(
+            body: Center(child: CircularProgressIndicator()),
+          );
+        }
+
+        // Check if there is an active session ( user logged in )
+        final session = snapshot.data?.session;
+
+        // if session exists -> Navigate to MainScreen
+        if (session != null) {
+          return const MainScreen();
+        }
+
+        // if session not exists -> Navigate to LoginView
+        return const LoginView();
+      },
+    );
+  }
+}

src/lib/features/auth/presentation/view/login_view.dart

@@ -25,6 +25,18 @@ class _LoginViewState extends State<LoginView> {
         submitText: 'Đăng nhập',
         isLoading: _vm.isLoading,
         showSocial: true,
+        onGoogleTap: () async {
+          final error = await _vm.loginWithGoogle();
+          if (error != null && context.mounted) {
+            ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(error), backgroundColor: AppColors.error));
+          }
+        },
+        onFacebookTap: () async {
+          final error = await _vm.loginWithFacebook();
+          if (error != null && context.mounted) {
+            ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(error), backgroundColor: AppColors.error));
+          }
+        },
         onSubmit: () async {
           FocusScope.of(context).unfocus();
           final errorMessage = await _vm.login();

src/lib/features/auth/presentation/viewmodels/auth_viewmodels.dart

@@ -95,8 +95,37 @@ class LoginViewModel extends BaseViewModel {
       setLoading(false);
     }
   }
+  // 1.1 LOGIN WITH GOOGLE
+  Future<String?> loginWithGoogle() async {
+    setLoading(true);
+    try {
+      final success = await _authHelper.loginWithGoogle();
+      if (success) return null; // Thành công (thường Supabase sẽ tự văng ra web browser)
+      return 'Lỗi khi mở cổng đăng nhập Google!';
+    } catch (e) {
+      return handleError(e);
+    } finally {
+      setLoading(false);
+    }
+  }
+
+// 1.2 LOGIN WITH FACEBOOK
+
+  Future<String?> loginWithFacebook() async {
+    setLoading(true);
+    try {
+      final success = await _authHelper.loginWithFacebook();
+      if (success) return null;
+      return 'Lỗi khi mở cổng đăng nhập Facebook!';
+    } catch (e) {
+      return handleError(e);
+    } finally {
+      setLoading(false);
+    }
+  }
 }
 
+
 // ==========================================
 // 2. REGISTER VIEWMODEL
 // ==========================================

src/lib/main.dart

@@ -2,9 +2,11 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'core/theme/app_colors.dart';
 import 'features/auth/presentation/view/login_view.dart';
+import 'features/auth/presentation/view/auth_gate.dart';
 import 'package:flutter_dotenv/flutter_dotenv.dart';
 import 'package:supabase_flutter/supabase_flutter.dart';
 
+
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
   await dotenv.load(fileName: ".env");
@@ -42,7 +44,7 @@ class TaskApp extends StatelessWidget {
           labelLarge: TextStyle(fontSize: 16, color: AppColors.primaryBlue),
         ),
       ),
-      home: const LoginView(),
+      home: const AuthGate(),
       debugShowCheckedModeBanner: false,
     );
   }