// Version: 1.0.2 | Created: 2026-04-01
// All route definitions in one place.
// GoRouter is created ONCE (keepAlive) and re-evaluates redirects via
// refreshListenable — avoids the GoRouter recreation bug from ref.watch.

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

import '../core/auth/auth_notifier.dart';
import '../core/auth/auth_state.dart';
import '../features/auth/presentation/login_screen.dart';
import '../features/calls/presentation/call_screen.dart';
import '../features/chat/presentation/chat_screen.dart';
import '../features/profile/presentation/profile_screen.dart';
import '../features/rooms/presentation/rooms_screen.dart';
import '../features/spaces/presentation/spaces_screen.dart';

part 'router.g.dart';

/// Route path constants — use these instead of raw strings.
abstract final class AppRoutes {
  static const String root = '/';
  static const String login = '/login';
  static const String rooms = '/rooms';
  static const String chat = '/rooms/:roomId';
  static const String call = '/calls/:roomId';
  static const String profile = '/profile';
  static const String spaces = '/spaces';
}

/// ChangeNotifier that GoRouter listens to for redirect re-evaluation.
/// Notified by ref.listen whenever authProvider changes.
class _AuthRefreshNotifier extends ChangeNotifier {
  void notify() => notifyListeners();
}

@Riverpod(keepAlive: true)
GoRouter router(Ref ref) {
  // Create once — notifier triggers re-redirect without recreating the router.
  final notifier = _AuthRefreshNotifier();
  ref.listen<AuthState>(authProvider, (_, __) => notifier.notify());
  ref.onDispose(notifier.dispose);

  return GoRouter(
    initialLocation: AppRoutes.root,
    refreshListenable: notifier,
    debugLogDiagnostics: false,
    redirect: (BuildContext context, GoRouterState state) {
      // Read (not watch) so redirect does not itself trigger provider changes.
      final authState = ref.read(authProvider);
      final isLoggedIn = authState is AuthAuthenticated;
      final isOnLogin = state.matchedLocation == AppRoutes.login;

      // While restoring session, stay on splash.
      if (authState is AuthInitial || authState is AuthLoading) return null;

      // Unauthenticated users must go to login.
      if (!isLoggedIn && !isOnLogin) return AppRoutes.login;

      // Authenticated users should not see the login screen.
      if (isLoggedIn && isOnLogin) return AppRoutes.rooms;

      return null;
    },
    routes: [
      GoRoute(
        path: AppRoutes.root,
        builder: (context, state) => const _SplashRedirectPage(),
      ),
      GoRoute(
        path: AppRoutes.login,
        builder: (context, state) => const LoginScreen(),
      ),
      GoRoute(
        path: AppRoutes.rooms,
        builder: (context, state) => const RoomsScreen(),
      ),
      GoRoute(
        path: AppRoutes.chat,
        builder: (context, state) {
          // safe: path param is guaranteed by route definition
          final roomId = state.pathParameters['roomId']!;
          return ChatScreen(roomId: roomId);
        },
      ),
      GoRoute(
        path: AppRoutes.call,
        builder: (context, state) {
          // safe: path param is guaranteed by route definition
          final roomId = state.pathParameters['roomId']!;
          return CallScreen(roomId: roomId);
        },
      ),
      GoRoute(
        path: AppRoutes.profile,
        builder: (context, state) => const ProfileScreen(),
      ),
      GoRoute(
        path: AppRoutes.spaces,
        builder: (context, state) => const SpacesScreen(),
      ),
    ],
  );
}

/// Invisible page shown at `/` while GoRouter's redirect evaluates auth state.
class _SplashRedirectPage extends StatelessWidget {
  const _SplashRedirectPage();

  @override
  Widget build(BuildContext context) {
    return const Scaffold(body: Center(child: CircularProgressIndicator()));
  }
}