import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:timezone/data/latest_all.dart' as tz;
import 'package:timezone/timezone.dart' as tz;

class NotifyService {
  static final NotifyService _instance = NotifyService._internal();

  factory NotifyService() => _instance;

  NotifyService._internal();

  late FlutterLocalNotificationsPlugin _notifications;

  // 使用绝对时间（而不是相对时间），避免时区转换问题。
  final dateInterpretation = UILocalNotificationDateInterpretation.absoluteTime;

  // Android特殊模式，即使设备处于省电模式也能准时触发。
  final scheduleMode = AndroidScheduleMode.exactAllowWhileIdle;

  // 初始化通知服务
  Future<void> initialize() async {
    _notifications = FlutterLocalNotificationsPlugin();

    // 初始化时区
    tz.initializeTimeZones();
    // String timeZoneName = await FlutterNativeTimezone.getLocalTimezone();
    tz.setLocalLocation(tz.getLocation("Asia/Shanghai"));

    // 设置Android平台的初始化配置 使用应用图标作为通知图标
    const AndroidInitializationSettings androidSettings =
        AndroidInitializationSettings('@mipmap/ic_launcher');

    // 设置iOS平台的初始化配置
    const DarwinInitializationSettings iosSettings =
        DarwinInitializationSettings(
          requestAlertPermission: true,
          requestBadgePermission: true,
          requestSoundPermission: true,
        );

    // 初始化设置
    const InitializationSettings settings = InitializationSettings(
      android: androidSettings,
      iOS: iosSettings,
    );

    await _notifications.initialize(settings);
  }

  // 创建Android通知详情
  AndroidNotificationDetails _androidNotificationDetails() {
    const channelId = 'com.cxx.flisp_app';
    const channelName = '闪灵';
    const channelDescription = '闪灵通知';
    return const AndroidNotificationDetails(
      channelId,
      channelName,
      channelDescription: channelDescription,
      importance: Importance.high,
      priority: Priority.high,
      playSound: true,
      enableVibration: true,
    );
  }

  // 创建iOS通知详情
  DarwinNotificationDetails _iosNotificationDetails() {
    return const DarwinNotificationDetails(
      presentAlert: true,
      presentBadge: true,
      presentSound: true,
    );
  }

  NotificationDetails get _details {
    return NotificationDetails(
      android: _androidNotificationDetails(),
      iOS: _iosNotificationDetails(),
    );
  }

  // 立即显示通知
  Future<void> showInstantNotification({
    required String title,
    required String body,
    int id = 0,
  }) async {
    await _notifications.show(id, title, body, _details);
  }

  // 安排定时通知
  Future<void> scheduleNotification({
    required int id,
    required String title,
    required String body,
    required DateTime scheduledTime,
  }) async {
    await _notifications.zonedSchedule(
      id,
      title,
      body,
      tz.TZDateTime.from(scheduledTime, tz.local),
      _details,
      uiLocalNotificationDateInterpretation:
          UILocalNotificationDateInterpretation.absoluteTime,
      androidScheduleMode: AndroidScheduleMode.exactAllowWhileIdle,
    );
  }

  // 取消特定通知
  Future<void> cancelNotification(int id) async {
    try {
      await _notifications.cancel(id);
    } catch(e) {
      print('取消通知失败: $e');
    }
  }

  // 取消所有通知
  Future<void> cancelAllNotifications() async {
    await _notifications.cancelAll();
  }

  // 检查通知权限
  Future<bool> checkPermission() async {
    final bool? result =
        await _notifications
            .resolvePlatformSpecificImplementation<
              AndroidFlutterLocalNotificationsPlugin
            >()
            ?.areNotificationsEnabled();
    return result ?? false;
  }

  // 请求权限
  Future<void> requestPermission() async {
    await _notifications
        .resolvePlatformSpecificImplementation<
          IOSFlutterLocalNotificationsPlugin
        >()
        ?.requestPermissions(alert: true, badge: true, sound: true);
  }

  // 获取所有待处理的通知
  Future<List<PendingNotificationRequest>> getPendingNotifications() async {
    return await _notifications.pendingNotificationRequests();
  }
}