import 'package:flutter/material.dart';
import '../../core/service_locator.dart';
import '../../data/session/session_service.dart';
import '../../data/local/local_storage_service.dart';
import '../../data/nostr/nostr_service.dart';
import '../../data/sync/sync_engine.dart';
import '../../data/firebase/firebase_service.dart';
import '../home/home_screen.dart';
import '../recipes/recipes_screen.dart';
import '../add_recipe/add_recipe_screen.dart';
import '../favourites/favourites_screen.dart';
import '../relay_management/relay_management_screen.dart';
import '../relay_management/relay_management_controller.dart';
import '../session/session_screen.dart';

/// Route names for the app navigation.
class AppRoutes {
  static const String home = '/';
  static const String recipes = '/recipes';
  static const String addRecipe = '/add-recipe';
  static const String favourites = '/favourites';
  static const String relayManagement = '/relay-management';
  static const String session = '/session';
  static const String login = '/login';
}

/// Route guard that requires authentication.
class AuthGuard {
  final SessionService? sessionService;

  AuthGuard(this.sessionService);

  /// Checks if user is authenticated.
  bool get isAuthenticated => sessionService?.isLoggedIn ?? false;

  /// Redirects to login if not authenticated.
  String? checkAuth(String route) {
    if (_requiresAuth(route) && !isAuthenticated) {
      return AppRoutes.login;
    }
    return null;
  }

  /// Checks if a route requires authentication.
  bool _requiresAuth(String route) {
    // Routes that require authentication
    const protectedRoutes = [
      AppRoutes.session,
    ];
    return protectedRoutes.contains(route);
  }
}

/// App router for managing navigation and route guards.
class AppRouter {
  final SessionService? sessionService;
  final LocalStorageService? localStorageService;
  final NostrService? nostrService;
  final SyncEngine? syncEngine;
  final FirebaseService? firebaseService;

  late final AuthGuard _authGuard;

  AppRouter({
    this.sessionService,
    this.localStorageService,
    this.nostrService,
    this.syncEngine,
    this.firebaseService,
  }) {
    _authGuard = AuthGuard(sessionService);
  }

  /// Generates routes for the app.
  Route<dynamic>? generateRoute(RouteSettings settings) {
    // Check route guard
    final redirect = _authGuard.checkAuth(settings.name ?? '');
    if (redirect != null) {
      return MaterialPageRoute(
        builder: (_) => _buildLoginScreen(),
        settings: settings,
      );
    }

    switch (settings.name) {
      case AppRoutes.home:
        return MaterialPageRoute(
          builder: (_) => const HomeScreen(),
          settings: settings,
        );

      case AppRoutes.recipes:
        return MaterialPageRoute(
          builder: (_) => const RecipesScreen(),
          settings: settings,
        );

      case AppRoutes.addRecipe:
        return MaterialPageRoute(
          builder: (_) => const AddRecipeScreen(),
          settings: settings,
        );

      case AppRoutes.favourites:
        return MaterialPageRoute(
          builder: (_) => const FavouritesScreen(),
          settings: settings,
        );

      case AppRoutes.relayManagement:
        final nostrService = ServiceLocator.instance.nostrService;
        final syncEngine = ServiceLocator.instance.syncEngine;
        if (nostrService == null || syncEngine == null) {
          return MaterialPageRoute(
            builder: (_) => _buildErrorScreen('Nostr service not available'),
            settings: settings,
          );
        }
        return MaterialPageRoute(
          builder: (_) => RelayManagementScreen(
            controller: RelayManagementController(
              nostrService: nostrService,
              syncEngine: syncEngine,
            ),
          ),
          settings: settings,
        );

      case AppRoutes.session:
        return MaterialPageRoute(
          builder: (_) => const SessionScreen(),
          settings: settings,
        );

      case AppRoutes.login:
        return MaterialPageRoute(
          builder: (_) => _buildLoginScreen(),
          settings: settings,
        );

      default:
        return MaterialPageRoute(
          builder: (_) => _buildErrorScreen('Route not found: ${settings.name}'),
          settings: settings,
        );
    }
  }

  Widget _buildLoginScreen() {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Login Required'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(
              Icons.lock_outline,
              size: 64,
              color: Colors.grey,
            ),
            const SizedBox(height: 16),
            const Text(
              'Please login to access this feature',
              style: TextStyle(fontSize: 16),
            ),
            const SizedBox(height: 24),
            ElevatedButton(
              onPressed: () {
                // Navigation will be handled by the navigation scaffold
              },
              child: const Text('Go to Login'),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildErrorScreen(String message) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Error'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(
              Icons.error_outline,
              size: 64,
              color: Colors.red,
            ),
            const SizedBox(height: 16),
            Text(
              message,
              style: const TextStyle(fontSize: 16),
              textAlign: TextAlign.center,
            ),
          ],
        ),
      ),
    );
  }
}