import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:flutter/foundation.dart';

class NotificationService {
  static final NotificationService _instance = NotificationService._internal();
  factory NotificationService() => _instance;
  NotificationService._internal();

  final FlutterLocalNotificationsPlugin _notifications = FlutterLocalNotificationsPlugin();
  bool _isInitialized = false;

  Future<void> initialize() async {
    if (_isInitialized) return;

    const androidSettings = AndroidInitializationSettings('@mipmap/ic_launcher');
    const iosSettings = DarwinInitializationSettings(
      requestAlertPermission: true,
      requestBadgePermission: true,
      requestSoundPermission: true,
    );
    const macSettings = DarwinInitializationSettings(
      requestAlertPermission: true,
      requestBadgePermission: true,
      requestSoundPermission: true,
    );

    const initSettings = InitializationSettings(
      android: androidSettings,
      iOS: iosSettings,
      macOS: macSettings,
    );

    try {
      await _notifications.initialize(
        initSettings,
        onDidReceiveNotificationResponse: _onNotificationTapped,
      );
      _isInitialized = true;
    } catch (e) {
      debugPrint('Error initializing notifications: $e');
    }
  }

  Future<bool> requestPermissions() async {
    if (!_isInitialized) {
      await initialize();
    }

    // Request Android 13+ notification permission
    final androidPlugin = _notifications.resolvePlatformSpecificImplementation<
        AndroidFlutterLocalNotificationsPlugin>();
    if (androidPlugin != null) {
      final granted = await androidPlugin.requestNotificationsPermission();
      return granted ?? false;
    }

    // iOS permissions are requested during initialization
    final iosPlugin = _notifications.resolvePlatformSpecificImplementation<
        IOSFlutterLocalNotificationsPlugin>();
    if (iosPlugin != null) {
      final granted = await iosPlugin.requestPermissions(
        alert: true,
        badge: true,
        sound: true,
      );
      return granted ?? false;
    }

    return true;
  }

  Future<void> showMessageNotification({
    required String contactName,
    required String message,
    String? contactId,
    int? badgeCount,
  }) async {
    if (!_isInitialized) {
      await initialize();
    }

    final androidDetails = AndroidNotificationDetails(
      'messages',
      'Messages',
      channelDescription: 'New message notifications',
      importance: Importance.high,
      priority: Priority.high,
      icon: '@mipmap/ic_launcher',
      number: badgeCount,
    );

    final iosDetails = DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
      badgeNumber: badgeCount,
    );

    final macDetails = DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
      badgeNumber: badgeCount,
    );

    final notificationDetails = NotificationDetails(
      android: androidDetails,
      iOS: iosDetails,
      macOS: macDetails,
    );

    await _notifications.show(
      contactId?.hashCode ?? 0,
      'New message from $contactName',
      message.length > 100 ? '${message.substring(0, 100)}...' : message,
      notificationDetails,
      payload: 'message:$contactId',
    );
  }

  Future<void> showAdvertNotification({
    required String contactName,
    required String contactType,
    String? contactId,
  }) async {
    if (!_isInitialized) {
      await initialize();
    }

    const androidDetails = AndroidNotificationDetails(
      'adverts',
      'Advertisements',
      channelDescription: 'New node advertisement notifications',
      importance: Importance.defaultImportance,
      priority: Priority.defaultPriority,
      icon: '@mipmap/ic_launcher',
    );

    const iosDetails = DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
    );

    const macDetails = DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
    );

    const notificationDetails = NotificationDetails(
      android: androidDetails,
      iOS: iosDetails,
      macOS: macDetails,
    );

    await _notifications.show(
      contactId?.hashCode ?? DateTime.now().millisecondsSinceEpoch,
      'New $contactType discovered',
      contactName,
      notificationDetails,
      payload: 'advert:$contactId',
    );
  }

  Future<void> showChannelMessageNotification({
    required String channelName,
    required String message,
    int? channelIndex,
    int? badgeCount,
  }) async {
    if (!_isInitialized) {
      await initialize();
    }

    final androidDetails = AndroidNotificationDetails(
      'channel_messages',
      'Channel Messages',
      channelDescription: 'New channel message notifications',
      importance: Importance.high,
      priority: Priority.high,
      icon: '@mipmap/ic_launcher',
      number: badgeCount,
    );

    final iosDetails = DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
      badgeNumber: badgeCount,
    );

    final macDetails = DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
      badgeNumber: badgeCount,
    );

    final notificationDetails = NotificationDetails(
      android: androidDetails,
      iOS: iosDetails,
      macOS: macDetails,
    );

    final preview = _truncateMessage(message, 30);
    final body = preview.isEmpty
        ? 'Received new message'
        : preview;

    await _notifications.show(
      channelIndex?.hashCode ?? DateTime.now().millisecondsSinceEpoch,
      channelName,
      body,
      notificationDetails,
      payload: 'channel:$channelIndex',
    );
  }

  String _truncateMessage(String message, int maxLength) {
    final trimmed = message.trim();
    if (trimmed.length <= maxLength) return trimmed;
    return '${trimmed.substring(0, maxLength)}...';
  }

  void _onNotificationTapped(NotificationResponse response) {
    final payload = response.payload;
    if (payload != null) {
      debugPrint('Notification tapped: $payload');
      // Handle navigation based on payload
      // This can be extended to navigate to specific screens
    }
  }

  Future<void> cancelAll() async {
    await _notifications.cancelAll();
  }

  Future<void> cancel(int id) async {
    await _notifications.cancel(id);
  }
}