import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:audioplayers/audioplayers.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:pdfrx/pdfrx.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'firebase_options.dart';
import 'providers/profile_provider.dart';
import 'models/profile.dart';
import 'app.dart';
import 'providers/notifications_provider.dart';
import 'utils/app_time.dart';
import 'utils/notification_permission.dart';
import 'services/notification_service.dart';
import 'services/notification_bridge.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'dart:convert';
import 'package:shared_preferences/shared_preferences.dart';

final AudioPlayer _player = AudioPlayer();
Map<String, String> _formatNotificationFromData(Map<String, dynamic> data) {
  final actor =
      (data['actor_name'] ??
              data['mentioner_name'] ??
              data['user_name'] ??
              data['from'] ??
              'Someone')
          .toString();
  final taskId = data['task_id'] ?? data['taskId'] ?? data['task'] ?? '';
  final ticketId =
      data['ticket_id'] ?? data['ticketId'] ?? data['ticket'] ?? '';
  final type = (data['type'] ?? '').toString().toLowerCase();

  if (taskId.isNotEmpty &&
      (type.contains('assign') ||
          data['action'] == 'assign' ||
          data['assigned'] == 'true')) {
    return {
      'title': 'Task assigned',
      'body': '$actor has assigned you a Task #$taskId',
    };
  }

  if (taskId.isNotEmpty &&
      (type.contains('mention') ||
          data['action'] == 'mention' ||
          data['mentioned'] == 'true')) {
    return {
      'title': 'Mention',
      'body': '$actor has mentioned you in Task #$taskId',
    };
  }

  if (ticketId.isNotEmpty &&
      (type.contains('mention') || data['action'] == 'mention')) {
    return {
      'title': 'Mention',
      'body': '$actor has mentioned you in Ticket #$ticketId',
    };
  }

  // Fallback to supplied title/body or generic
  final title = data['title']?.toString() ?? 'New Notification';
  final body = data['body']?.toString() ?? 'You have a new update in TasQ.';
  return {'title': title, 'body': body};
}

// Initialize the plugin
final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
    FlutterLocalNotificationsPlugin();

/// Handle messages received while the app is terminated or in background.
@pragma('vm:entry-point') // Required for background execution
Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  // 1. Initialize the plugin inside the background isolate
  final FlutterLocalNotificationsPlugin localNotifPlugin =
      FlutterLocalNotificationsPlugin();

  // 2. Extract and format title/body from the DATA payload (not message.notification)
  final formatted = _formatNotificationFromData(message.data);
  final String title = formatted['title']!;
  final String body = formatted['body']!;

  // Determine a stable ID for deduplication (prefer server-provided id)
  final String stableId =
      message.data['notification_id'] ??
      message.messageId ??
      (DateTime.now().millisecondsSinceEpoch ~/ 1000).toString();

  // Dedupe: keep a short-lived cache of recent notification IDs to avoid duplicates
  try {
    final prefs = await SharedPreferences.getInstance();
    final raw = prefs.getString('recent_notifs') ?? '{}';
    final Map<String, dynamic> recent = jsonDecode(raw);
    final int now = DateTime.now().millisecondsSinceEpoch ~/ 1000;
    const int ttl = 60; // seconds
    // prune old entries
    recent.removeWhere(
      (k, v) => (v is int ? v : int.parse(v.toString())) < now - ttl,
    );
    if (recent.containsKey(stableId)) {
      // already shown recently — skip
      return;
    }
    recent[stableId] = now;
    await prefs.setString('recent_notifs', jsonEncode(recent));
  } catch (e) {
    // If prefs fail in background isolate, fall back to showing notification
  }

  // Create a unique ID for the notification display
  final int id = DateTime.now().millisecondsSinceEpoch ~/ 1000;

  // 3. Define the exact same channel specifics
  const androidDetails = AndroidNotificationDetails(
    'tasq_custom_sound_channel_3',
    'High Importance Notifications',
    importance: Importance.max,
    priority: Priority.high,
    playSound: true,
    sound: RawResourceAndroidNotificationSound('tasq_notification'),
  );

  // 4. Show the notification manually
  await localNotifPlugin.show(
    id: id,
    title: title,
    body: body,
    notificationDetails: const NotificationDetails(android: androidDetails),
    payload: message.data['type'], // Or whatever payload you need for routing
  );
}

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  // The flag optionally hides annoying WASM warnings in your Chrome dev console
  pdfrxFlutterInitialize(dismissPdfiumWasmWarnings: true);

  // initialize Firebase before anything that uses messaging
  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);

  await dotenv.load(fileName: '.env');

  AppTime.initialize(location: 'Asia/Manila');

  final supabaseUrl = dotenv.env['SUPABASE_URL'] ?? '';
  final supabaseAnonKey = dotenv.env['SUPABASE_ANON_KEY'] ?? '';

  if (supabaseUrl.isEmpty || supabaseAnonKey.isEmpty) {
    runApp(const _MissingConfigApp());
    return;
  }

  await Supabase.initialize(url: supabaseUrl, anonKey: supabaseAnonKey);

  // ensure token saved shortly after startup if already signed in.
  // Run this after runApp so startup is not blocked by network/token ops.
  final supaClient = Supabase.instance.client;

  // listen for auth changes to register/unregister token accordingly
  supaClient.auth.onAuthStateChange.listen((data) async {
    final event = data.event;
    if (kIsWeb) {
      debugPrint(
        'auth state change $event on web: skipping FCM token handling',
      );
      return;
    }
    String? token;
    try {
      token = await FirebaseMessaging.instance.getToken();
    } catch (e) {
      debugPrint('FCM getToken failed during auth change: $e');
      token = null;
    }
    debugPrint('auth state change $event, token=$token');
    if (token == null) return;
    final ctrl = NotificationsController(supaClient);
    if (event == AuthChangeEvent.signedIn) {
      await ctrl.registerFcmToken(token);
    } else if (event == AuthChangeEvent.signedOut) {
      await ctrl.unregisterFcmToken(token);
    }
  });

  if (!kIsWeb) {
    // on Android 13+ we must request POST_NOTIFICATIONS at runtime; without it
    // notifications are automatically denied and cannot be re‑enabled from the
    // system settings. The helper uses `permission_handler`.
    final granted = await ensureNotificationPermission();
    if (!granted) {
      // we don’t block startup, but it’s worth logging so developers notice.
      // A real app might show a dialog pointing the user to settings.
      // debugPrint('notification permission not granted');
    }

    // request FCM permission (iOS/Android13+) and handle foreground messages
    await FirebaseMessaging.instance.requestPermission();
  }

  FirebaseMessaging.onMessage.listen((RemoteMessage message) async {
    // Prefer the data payload and format friendly messages, with dedupe.
    final formatted = _formatNotificationFromData(message.data);
    final String stableId =
        message.data['notification_id'] ??
        message.messageId ??
        (DateTime.now().millisecondsSinceEpoch ~/ 1000).toString();
    try {
      final prefs = await SharedPreferences.getInstance();
      final raw = prefs.getString('recent_notifs') ?? '{}';
      final Map<String, dynamic> recent = jsonDecode(raw);
      final int now = DateTime.now().millisecondsSinceEpoch ~/ 1000;
      const int ttl = 60;
      recent.removeWhere(
        (k, v) => (v is int ? v : int.parse(v.toString())) < now - ttl,
      );
      if (!recent.containsKey(stableId)) {
        recent[stableId] = now;
        await prefs.setString('recent_notifs', jsonEncode(recent));
        NotificationService.show(
          id: DateTime.now().millisecondsSinceEpoch ~/ 1000,
          title: formatted['title']!,
          body: formatted['body']!,
          payload: message.data['payload'],
        );
      }
    } catch (e) {
      // On failure, just show the notification to avoid dropping alerts
      NotificationService.show(
        id: DateTime.now().millisecondsSinceEpoch ~/ 1000,
        title: formatted['title']!,
        body: formatted['body']!,
        payload: message.data['payload'],
      );
    }
  });

  // initialize the local notifications plugin so we can post alerts later
  await NotificationService.initialize(
    onDidReceiveNotificationResponse: (response) {
      // handle user tapping a notification; the payload format is up to us
      final payload = response.payload;
      if (payload != null && payload.startsWith('ticket:')) {
        // ignore if context not mounted; we might use a navigator key in real
        // app, but keep this simple for now
        // TODO: navigate to ticket/task as appropriate
      }
    },
  );

  // 1. Define the High Importance Channel (This MUST match your manifest exactly)
  const AndroidNotificationChannel channel = AndroidNotificationChannel(
    'tasq_custom_sound_channel', // id
    'High Importance Notifications', // title visible to user in phone settings
    description: 'This channel is used for important TasQ notifications.',
    importance:
        Importance.max, // THIS is what forces the sound and heads-up banner
    playSound: true,
    // 👇 Tell Android to use your specific file in the raw folder
    sound: RawResourceAndroidNotificationSound('tasq_notification'),
  );

  // 2. Create the channel on the device
  await flutterLocalNotificationsPlugin
      .resolvePlatformSpecificImplementation<
        AndroidFlutterLocalNotificationsPlugin
      >()
      ?.createNotificationChannel(channel);

  // global navigator key used for snackbars/navigation from notification
  final navigatorKey = GlobalKey<NavigatorState>();

  runApp(
    ProviderScope(
      observers: [NotificationSoundObserver()],
      child: NotificationBridge(
        navigatorKey: navigatorKey,
        child: const TasqApp(),
      ),
    ),
  );

  // Post-startup: register current FCM token without blocking UI.
  if (!kIsWeb) {
    Future.microtask(() async {
      try {
        final token = await FirebaseMessaging.instance.getToken().timeout(
          const Duration(seconds: 10),
        );
        if (token != null && supaClient.auth.currentUser != null) {
          debugPrint('post-startup registering FCM token: $token');
          final ctrl = NotificationsController(supaClient);
          await ctrl.registerFcmToken(token);
        }
      } catch (e) {
        debugPrint('post-startup FCM token registration failed: $e');
      }
    });
  }
}

class NotificationSoundObserver extends ProviderObserver {
  StreamSubscription<String?>? _tokenSub;

  @override
  void didUpdateProvider(
    ProviderBase provider,
    Object? previousValue,
    Object? newValue,
    ProviderContainer container,
  ) {
    // play sound + show OS notification on unread-count increase
    if (provider == unreadNotificationsCountProvider) {
      final prev = previousValue as int?;
      final next = newValue as int?;
      if (prev != null && next != null && next > prev) {
        _maybeShowUnreadNotification(next);
      }
    }

    // when profile changes, register or unregister tokens
    if (provider == currentProfileProvider) {
      final profile = newValue as Profile?;
      final controller = container.read(notificationsControllerProvider);

      if (profile != null) {
        // signed in: save current token and keep listening for refreshes
        if (!kIsWeb) {
          FirebaseMessaging.instance
              .getToken()
              .then((token) {
                if (token != null) {
                  debugPrint('profile observer registering token: $token');
                  controller.registerFcmToken(token);
                }
              })
              .catchError((e) {
                debugPrint('getToken error: $e');
                return null;
              });
          _tokenSub = FirebaseMessaging.instance.onTokenRefresh.listen((token) {
            debugPrint('token refreshed: $token');
            controller.registerFcmToken(token);
          });
        }
      } else {
        // signed out: unregister whatever token we currently have
        _tokenSub?.cancel();
        if (!kIsWeb) {
          FirebaseMessaging.instance
              .getToken()
              .then((token) {
                if (token != null) {
                  debugPrint('profile observer unregistering token: $token');
                  controller.unregisterFcmToken(token);
                }
              })
              .catchError((e) {
                debugPrint('getToken error: $e');
                return null;
              });
        }
      }
    }
  }
}

void _maybeShowUnreadNotification(int next) async {
  try {
    final prefs = await SharedPreferences.getInstance();
    final raw = prefs.getString('recent_notifs') ?? '{}';
    final Map<String, dynamic> recent = jsonDecode(raw);
    final int now = DateTime.now().millisecondsSinceEpoch ~/ 1000;
    const int ttl = 60; // seconds
    // prune old entries
    recent.removeWhere(
      (k, v) => (v is int ? v : int.parse(v.toString())) < now - ttl,
    );
    // if there is any recent notification (from server or other), skip duplicating
    if (recent.isNotEmpty) return;

    // mark a synthetic unread-notif to prevent immediate duplicates
    recent['unread_summary'] = now;
    await prefs.setString('recent_notifs', jsonEncode(recent));

    _player.play(AssetSource('tasq_notification.wav'));
    NotificationService.show(
      id: DateTime.now().millisecondsSinceEpoch ~/ 1000,
      title: 'New notifications',
      body: 'You have $next unread notifications.',
    );
  } catch (e) {
    // fallback: show notification
    _player.play(AssetSource('tasq_notification.wav'));
    NotificationService.show(
      id: DateTime.now().millisecondsSinceEpoch ~/ 1000,
      title: 'New notifications',
      body: 'You have $next unread notifications.',
    );
  }
}

class _MissingConfigApp extends StatelessWidget {
  const _MissingConfigApp();

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Scaffold(
        body: Center(
          child: Padding(
            padding: EdgeInsets.all(24),
            child: Text(
              'Missing SUPABASE_URL or SUPABASE_ANON_KEY. '
              'Provide them in the .env file.',
              textAlign: TextAlign.center,
            ),
          ),
        ),
      ),
    );
  }
}