feat: add home and profile screens

lib/app.dart

@@ -3,16 +3,43 @@ import 'package:go_router/go_router.dart';
 import 'package:phone_login/auth/auth_state.dart';
 import 'package:phone_login/auth/phone_input_screen.dart';
 import 'package:phone_login/auth/sms_verification_screen.dart';
+import 'package:phone_login/home/home_screen.dart';
+import 'package:phone_login/profile/profile_screen.dart';
 import 'package:provider/provider.dart';
 
 final _router = GoRouter(
   routes: [
-    GoRoute(path: '/', builder: (context, state) => const PhoneInputScreen()),
+    GoRoute(path: '/', builder: (context, state) => const HomeScreen()),
+    GoRoute(
+      path: '/login',
+      builder: (context, state) => const PhoneInputScreen(),
+    ),
     GoRoute(
       path: '/sms_verify',
       builder: (context, state) => const SmsVerificationScreen(),
     ),
+    GoRoute(
+      path: '/profile',
+      builder: (context, state) => const ProfileScreen(),
+    ),
   ],
+  redirect: (BuildContext context, GoRouterState state) {
+    final authState = Provider.of<AuthState>(context, listen: false);
+    final bool loggedIn = authState.isLoggedIn;
+    final bool loggingIn =
+        state.matchedLocation == '/login' ||
+        state.matchedLocation == '/sms_verify';
+
+    if (!loggedIn && !loggingIn) {
+      return '/login';
+    }
+
+    if (loggedIn && loggingIn) {
+      return '/';
+    }
+
+    return null;
+  },
 );
 
 class App extends StatelessWidget {

lib/auth/auth_state.dart

@@ -1,18 +1,11 @@
 import 'package:flutter/material.dart';
-import 'package:firebase_auth/firebase_auth.dart';
 
 class AuthState extends ChangeNotifier {
-  User? _user;
-  User? get user => _user;
+  bool _isLoggedIn = false;
+  bool get isLoggedIn => _isLoggedIn;
 
-  final FirebaseAuth _auth = FirebaseAuth.instance;
-
-  AuthState() {
-    _auth.authStateChanges().listen((user) {
-      _user = user;
+  void toggleLogin() {
+    _isLoggedIn = !_isLoggedIn;
     notifyListeners();
-    });
   }
-
-  bool get isLoggedIn => _user != null;
 }

lib/home/home_screen.dart

@@ -0,0 +1,59 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:provider/provider.dart';
+import 'package:phone_login/auth/auth_state.dart';
+
+class HomeScreen extends StatefulWidget {
+  const HomeScreen({super.key});
+
+  @override
+  State<HomeScreen> createState() => _HomeScreenState();
+}
+
+class _HomeScreenState extends State<HomeScreen> {
+  int _selectedIndex = 0;
+
+  void _onItemTapped(int index) {
+    setState(() {
+      _selectedIndex = index;
+    });
+    if (index == 1) {
+      context.go('/profile');
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final authState = Provider.of<AuthState>(context);
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Home')),
+      body: Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: [
+            if (authState.isLoggedIn)
+              const Text('Welcome back!')
+            else
+              const Text('Please log in.'),
+            const SizedBox(height: 20),
+            ElevatedButton(
+              onPressed: () {
+                authState.toggleLogin();
+              },
+              child: Text(authState.isLoggedIn ? 'Logout' : 'Login'),
+            ),
+          ],
+        ),
+      ),
+      bottomNavigationBar: BottomNavigationBar(
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(icon: Icon(Icons.home), label: 'Home'),
+          BottomNavigationBarItem(icon: Icon(Icons.person), label: 'Profile'),
+        ],
+        currentIndex: _selectedIndex,
+        onTap: _onItemTapped,
+      ),
+    );
+  }
+}

lib/profile/profile_screen.dart

@@ -0,0 +1,24 @@
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import 'package:phone_login/auth/auth_state.dart';
+
+class ProfileScreen extends StatelessWidget {
+  const ProfileScreen({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final authState = Provider.of<AuthState>(context, listen: false);
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Profile')),
+      body: Center(
+        child: ElevatedButton(
+          onPressed: () {
+            authState.toggleLogin();
+          },
+          child: const Text('Logout'),
+        ),
+      ),
+    );
+  }
+}