import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'core/auth/auth_notifier.dart';
import 'features/splash/splash_screen.dart';
import 'features/auth/screens/login_screen.dart';
import 'features/auth/screens/otp_screen.dart';
import 'features/home/home_screen.dart';
import 'features/chat/screens/active_sessions_screen.dart';
import 'features/chat/screens/mitra_chat_screen.dart';
import 'features/chat/screens/chat_history_screen.dart';
import 'features/chat/screens/chat_transcript_screen.dart';

class RouterNotifier extends ChangeNotifier {
  final Ref _ref;

  RouterNotifier(this._ref) {
    _ref.listen(mitraAuthProvider, (_, __) => notifyListeners());
  }
}

final routerProvider = Provider<GoRouter>((ref) => buildRouter(ref));

GoRouter buildRouter(Ref ref) {
  final notifier = RouterNotifier(ref);

  return GoRouter(
    initialLocation: '/splash',
    refreshListenable: notifier,
    redirect: (context, state) {
      final authState = ref.read(mitraAuthProvider);
      final isSplash = state.matchedLocation == '/splash';
      final isAuthRoute = state.matchedLocation.startsWith('/login') ||
          state.matchedLocation.startsWith('/otp');

      // Show splash while loading
      if (authState is AsyncLoading) return isSplash ? null : '/splash';

      final data = authState.valueOrNull;
      if (data == null) {
        // Error state — show login
        if (!isAuthRoute && !isSplash) return '/login';
        if (isSplash) return '/login';
        return null;
      }

      if (data is MitraAuthAuthenticatedData) {
        return (isSplash || isAuthRoute) ? '/home' : null;
      }
      if (!isAuthRoute && !isSplash) return '/login';
      if (isSplash) return '/login';
      return null;
    },
    routes: [
      GoRoute(path: '/splash', builder: (_, __) => const SplashScreen()),
      GoRoute(path: '/login', builder: (_, __) => const LoginScreen()),
      GoRoute(path: '/otp', builder: (context, state) => OtpScreen(phone: state.extra as String)),
      GoRoute(path: '/home', builder: (_, __) => const HomeScreen()),
      GoRoute(path: '/sessions', builder: (_, __) => const ActiveSessionsScreen()),
      GoRoute(path: '/chat/session/:sessionId', builder: (context, state) {
        final extra = state.extra as Map<String, dynamic>?;
        return MitraChatScreen(
          sessionId: state.pathParameters['sessionId']!,
          customerName: extra?['customerName'] as String? ?? 'Customer',
        );
      }),
      GoRoute(path: '/chat/history', builder: (_, __) => const MitraChatHistoryScreen()),
      GoRoute(path: '/chat/history/:sessionId', builder: (context, state) {
        return MitraChatTranscriptScreen(sessionId: state.pathParameters['sessionId']!);
      }),
    ],
  );
}