import 'dart:async';
import 'package:flutter_application_1/features/auth/presentation/screens/register_screen.dart';

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

import '../../features/auth/presentation/bloc/auth_bloc.dart';
import '../../features/auth/presentation/bloc/auth_state.dart';
import '../../features/auth/presentation/screens/login_screen.dart';
import '../../features/auth/presentation/screens/home_screen_placeholder.dart';

/// Rutas nombradas de la aplicación.
abstract final class AppRoutes {
  static const String splash = '/';
  static const String login = '/login';
  static const String home = '/home';
}

/// Configuración central de navegación con go_router.
///
/// La redirección basada en estado de autenticación garantiza que
/// rutas protegidas sean inaccesibles sin sesión válida.
GoRouter createRouter(AuthBloc authBloc) {
  return GoRouter(
    initialLocation: AppRoutes.splash,
    refreshListenable: GoRouterAuthNotifier(authBloc),
    redirect: (BuildContext context, GoRouterState state) {
      final authState = authBloc.state;
      final isAuthenticated = authState is AuthAuthenticated;
      final isCheckingSession =
          authState is AuthCheckingSession || authState is AuthInitial;
      final currentLocation = state.uri.path;

      // Mientras se verifica la sesión, mostrar splash.
      if (isCheckingSession) {
        return currentLocation == AppRoutes.splash ? null : AppRoutes.splash;
      }

      // Si no está autenticado, ir a login.
      if (!isAuthenticated) {
        return currentLocation == AppRoutes.login ? null : AppRoutes.login;
      }

      // Si está autenticado y en splash o login, ir a home.
      if (isAuthenticated &&
          (currentLocation == AppRoutes.login ||
              currentLocation == AppRoutes.splash)) {
        return AppRoutes.home;
      }

      return null; // Sin redirección.
    },
    routes: [
      GoRoute(
        path: AppRoutes.splash,
        builder: (context, state) => const _SplashScreen(),
      ),
      GoRoute(
        path: AppRoutes.login,
        builder: (context, state) => const LoginScreen(),
      ),
      GoRoute(
        path: AppRoutes.home,
        builder: (context, state) => const HomeScreenPlaceholder(),
      ),
      // 📍 Agrega el import arriba si te lo pide:
// import 'package:flutter_application_1/features/auth/presentation/screens/register_screen.dart';

      GoRoute(
        path: AppRoutes.home,
        builder: (context, state) => const HomeScreenPlaceholder(),
      ),
      // 📍 CORRECCIÓN: Usamos la constante oficial del proyecto en lugar del texto a mano
       GoRoute(
        path: '/register', // 📍 CORRECCIÓN: Texto plano limpio entre comillas
        builder: (context, state) => const RegisterScreen(),
      ), // GoRoute
    ],
  );
}

/// Pantalla de splash mínima mientras se verifica la sesión.
class _SplashScreen extends StatelessWidget {
  const _SplashScreen();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFF2E7D32),
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const Icon(
              Icons.recycling_rounded,
              size: 72,
              color: Colors.white,
            ),
            const SizedBox(height: 24),
            Text(
              'WasteNotify',
              style: Theme.of(context).textTheme.headlineMedium?.copyWith(
                    color: Colors.white,
                    fontWeight: FontWeight.bold,
                    letterSpacing: 1.2,
                  ),
            ),
            const SizedBox(height: 48),
            const CircularProgressIndicator(
              valueColor: AlwaysStoppedAnimation<Color>(Colors.white70),
            ),
          ],
        ),
      ),
    );
  }
}

/// Notificador que conecta el estado del BLoC con go_router.
/// Permite que el router reaccione automáticamente a cambios de sesión.
class GoRouterAuthNotifier extends ChangeNotifier {
  final AuthBloc _authBloc;
  late final StreamSubscription<AuthState> _subscription;

  GoRouterAuthNotifier(this._authBloc) {
    _subscription = _authBloc.stream.listen((_) => notifyListeners());
  }

  @override
  void dispose() {
    _subscription.cancel();
    super.dispose();
  }
}