retail/lib/features/auth/example_usage.dart

// ignore_for_file: unused_local_variable, avoid_print

/// Example usage of the authentication system
///
/// This file demonstrates how to use the authentication feature
/// in your Flutter app. Copy the patterns shown here into your
/// actual implementation.

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'presentation/providers/auth_provider.dart';

// ============================================================================
// EXAMPLE 1: Login Flow
// ============================================================================

class LoginExample extends ConsumerWidget {
  final TextEditingController emailController;
  final TextEditingController passwordController;

  const LoginExample({
    super.key,
    required this.emailController,
    required this.passwordController,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    // Watch auth state
    final authState = ref.watch(authProvider);

    return Column(
      children: [
        // Show loading indicator
        if (authState.isLoading) const CircularProgressIndicator(),

        // Login button
        ElevatedButton(
          onPressed: authState.isLoading
              ? null
              : () async {
                  // Call login
                  final success = await ref.read(authProvider.notifier).login(
                        email: emailController.text.trim(),
                        password: passwordController.text,
                      );

                  // Handle result
                  if (success) {
                    // Login successful - navigate to home
                    if (context.mounted) {
                      Navigator.pushReplacementNamed(context, '/home');
                    }
                  } else {
                    // Login failed - show error
                    final error = ref.read(authProvider).errorMessage;
                    if (context.mounted) {
                      ScaffoldMessenger.of(context).showSnackBar(
                        SnackBar(
                          content: Text(error ?? 'Login failed'),
                          backgroundColor: Colors.red,
                        ),
                      );
                    }
                  }
                },
          child: const Text('Login'),
        ),
      ],
    );
  }
}

// ============================================================================
// EXAMPLE 2: Register Flow
// ============================================================================

class RegisterExample extends ConsumerStatefulWidget {
  const RegisterExample({super.key});

  @override
  ConsumerState<RegisterExample> createState() => _RegisterExampleState();
}

class _RegisterExampleState extends ConsumerState<RegisterExample> {
  final _nameController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();

  @override
  void dispose() {
    _nameController.dispose();
    _emailController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  Future<void> _handleRegister() async {
    final success = await ref.read(authProvider.notifier).register(
          name: _nameController.text.trim(),
          email: _emailController.text.trim(),
          password: _passwordController.text,
          roles: ['user'], // Optional, defaults to ['user']
        );

    if (!mounted) return;

    if (success) {
      // Registration successful
      Navigator.pushReplacementNamed(context, '/home');
    } else {
      // Registration failed
      final error = ref.read(authProvider).errorMessage;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(error ?? 'Registration failed'),
          backgroundColor: Colors.red,
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final authState = ref.watch(authProvider);

    return ElevatedButton(
      onPressed: authState.isLoading ? null : _handleRegister,
      child: const Text('Register'),
    );
  }
}

// ============================================================================
// EXAMPLE 3: Check Authentication Status
// ============================================================================

class AuthStatusExample extends ConsumerWidget {
  const AuthStatusExample({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    // Method 1: Watch entire auth state
    final authState = ref.watch(authProvider);

    // Method 2: Use convenience providers
    final isAuthenticated = ref.watch(isAuthenticatedProvider);
    final currentUser = ref.watch(currentUserProvider);

    return Column(
      children: [
        // Check if authenticated
        if (authState.isAuthenticated) ...[
          Text('Welcome ${authState.user?.name}!'),
          Text('Email: ${authState.user?.email}'),
          Text('Roles: ${authState.user?.roles.join(", ")}'),

          // Check user roles
          if (currentUser?.isAdmin ?? false)
            const Text('You are an admin'),
          if (currentUser?.isManager ?? false)
            const Text('You are a manager'),
          if (currentUser?.isCashier ?? false)
            const Text('You are a cashier'),
        ] else ...[
          const Text('Not authenticated'),
        ],
      ],
    );
  }
}

// ============================================================================
// EXAMPLE 4: Protected Route Guard
// ============================================================================

class AuthGuard extends ConsumerWidget {
  final Widget child;

  const AuthGuard({super.key, required this.child});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final isAuthenticated = ref.watch(isAuthenticatedProvider);
    final isLoading = ref.watch(authProvider.select((s) => s.isLoading));

    // Show loading while checking auth status
    if (isLoading) {
      return const Scaffold(
        body: Center(child: CircularProgressIndicator()),
      );
    }

    // If not authenticated, show login page
    if (!isAuthenticated) {
      return const Scaffold(
        body: Center(
          child: Text('Please login to continue'),
        ),
      );
      // In real app: return const LoginPage();
    }

    // User is authenticated, show protected content
    return child;
  }
}

// Usage in main app:
// MaterialApp(
//   home: AuthGuard(
//     child: HomePage(),
//   ),
// );

// ============================================================================
// EXAMPLE 5: Logout
// ============================================================================

class LogoutExample extends ConsumerWidget {
  const LogoutExample({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return ElevatedButton(
      onPressed: () async {
        // Show confirmation dialog
        final confirmed = await showDialog<bool>(
          context: context,
          builder: (context) => AlertDialog(
            title: const Text('Logout'),
            content: const Text('Are you sure you want to logout?'),
            actions: [
              TextButton(
                onPressed: () => Navigator.pop(context, false),
                child: const Text('Cancel'),
              ),
              TextButton(
                onPressed: () => Navigator.pop(context, true),
                child: const Text('Logout'),
              ),
            ],
          ),
        );

        if (confirmed == true) {
          // Perform logout
          await ref.read(authProvider.notifier).logout();

          // Navigate to login
          if (context.mounted) {
            Navigator.pushReplacementNamed(context, '/login');
          }
        }
      },
      child: const Text('Logout'),
    );
  }
}

// ============================================================================
// EXAMPLE 6: Get Profile (Refresh User Data)
// ============================================================================

class ProfileExample extends ConsumerWidget {
  const ProfileExample({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final currentUser = ref.watch(currentUserProvider);

    return Column(
      children: [
        if (currentUser != null) ...[
          Text('Name: ${currentUser.name}'),
          Text('Email: ${currentUser.email}'),
          Text('Roles: ${currentUser.roles.join(", ")}'),
        ],

        // Refresh profile button
        ElevatedButton(
          onPressed: () async {
            await ref.read(authProvider.notifier).getProfile();

            if (context.mounted) {
              ScaffoldMessenger.of(context).showSnackBar(
                const SnackBar(content: Text('Profile refreshed')),
              );
            }
          },
          child: const Text('Refresh Profile'),
        ),
      ],
    );
  }
}

// ============================================================================
// EXAMPLE 7: Refresh Token
// ============================================================================

class RefreshTokenExample extends ConsumerWidget {
  const RefreshTokenExample({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return ElevatedButton(
      onPressed: () async {
        final success = await ref.read(authProvider.notifier).refreshToken();

        if (!context.mounted) return;

        if (success) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text('Token refreshed successfully')),
          );
        } else {
          // Token refresh failed - user was logged out
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text('Session expired. Please login again.'),
              backgroundColor: Colors.red,
            ),
          );
          Navigator.pushReplacementNamed(context, '/login');
        }
      },
      child: const Text('Refresh Token'),
    );
  }
}

// ============================================================================
// EXAMPLE 8: Role-Based UI
// ============================================================================

class RoleBasedUIExample extends ConsumerWidget {
  const RoleBasedUIExample({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final currentUser = ref.watch(currentUserProvider);

    return Column(
      children: [
        // Show to all authenticated users
        const Text('Dashboard'),

        // Show only to admins
        if (currentUser?.isAdmin ?? false) ...[
          const Text('Admin Panel'),
          ElevatedButton(
            onPressed: () {
              // Navigate to admin panel
            },
            child: const Text('Manage Users'),
          ),
        ],

        // Show only to managers
        if (currentUser?.isManager ?? false) ...[
          const Text('Manager Tools'),
          ElevatedButton(
            onPressed: () {
              // Navigate to manager tools
            },
            child: const Text('View Reports'),
          ),
        ],

        // Show only to cashiers
        if (currentUser?.isCashier ?? false) ...[
          const Text('POS Terminal'),
          ElevatedButton(
            onPressed: () {
              // Navigate to POS
            },
            child: const Text('Start Transaction'),
          ),
        ],
      ],
    );
  }
}

// ============================================================================
// EXAMPLE 9: Error Handling
// ============================================================================

class ErrorHandlingExample extends ConsumerWidget {
  const ErrorHandlingExample({super.key});

  Future<void> _handleLogin(BuildContext context, WidgetRef ref) async {
    final success = await ref.read(authProvider.notifier).login(
          email: 'test@example.com',
          password: 'password',
        );

    if (!context.mounted) return;

    if (!success) {
      final error = ref.read(authProvider).errorMessage;

      // Different error messages result in different UI feedback
      String userMessage;
      Color backgroundColor;

      if (error?.contains('Invalid email or password') ?? false) {
        userMessage = 'Incorrect email or password. Please try again.';
        backgroundColor = Colors.red;
      } else if (error?.contains('Network') ?? false) {
        userMessage = 'No internet connection. Please check your network.';
        backgroundColor = Colors.orange;
      } else if (error?.contains('Server') ?? false) {
        userMessage = 'Server error. Please try again later.';
        backgroundColor = Colors.red[700]!;
      } else {
        userMessage = error ?? 'Login failed. Please try again.';
        backgroundColor = Colors.red;
      }

      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(userMessage),
          backgroundColor: backgroundColor,
          action: SnackBarAction(
            label: 'Retry',
            textColor: Colors.white,
            onPressed: () => _handleLogin(context, ref),
          ),
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return ElevatedButton(
      onPressed: () => _handleLogin(context, ref),
      child: const Text('Login with Error Handling'),
    );
  }
}

// ============================================================================
// EXAMPLE 10: Using Auth in Non-Widget Code
// ============================================================================

void nonWidgetExample() {
  // If you need to access auth outside widgets (e.g., in services),
  // use the service locator directly:

  // import 'package:retail/core/di/injection_container.dart';
  // import 'package:retail/features/auth/domain/repositories/auth_repository.dart';

  // final authRepository = sl<AuthRepository>();
  //
  // // Check if authenticated
  // final isAuthenticated = await authRepository.isAuthenticated();
  //
  // // Get token
  // final token = await authRepository.getAccessToken();
  //
  // print('Token: $token');
}

// ============================================================================
// EXAMPLE 11: Automatic Token Injection Test
// ============================================================================

void tokenInjectionExample() {
  // Once logged in, all API requests automatically include the JWT token:
  //
  // The DioClient interceptor adds this header to all requests:
  // Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
  //
  // You don't need to manually add the token - it's automatic!

  // Example of making an API call after login:
  // final response = await sl<DioClient>().get('/api/products');
  //
  // The above request will automatically include:
  // Headers: {
  //   "Authorization": "Bearer <your-jwt-token>",
  //   "Content-Type": "application/json",
  //   "Accept": "application/json"
  // }
}