import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:timezone/timezone.dart' as tz;
import 'package:timezone/data/latest.dart' as tz_data;
import '../database/database_helper.dart';

class NotificationService {
  static final NotificationService instance = NotificationService._init();
  final FlutterLocalNotificationsPlugin _plugin = FlutterLocalNotificationsPlugin();
  bool _initialized = false;

  NotificationService._init();

  Future<void> init() async {
    if (_initialized) return;
    tz_data.initializeTimeZones();
    const androidSettings = AndroidInitializationSettings('@mipmap/ic_launcher');
    const settings = InitializationSettings(android: androidSettings);
    await _plugin.initialize(settings);
    _initialized = true;
  }

  Future<void> scheduleRecordatorios() async {
    await _plugin.cancelAll();
    final db = DatabaseHelper.instance;
    final facturas = await db.getFacturas(estado: 'Pendiente');
    final config = await db.getConfiguracion();
    final diasStr = config?.diasRecordatorio ?? '7,3,1,0';
    final dias = diasStr.split(',').map((e) => int.tryParse(e.trim()) ?? 0).toList();

    for (final factura in facturas) {
      final vencimiento = DateTime.tryParse(factura.fechaVencimiento);
      if (vencimiento == null) continue;
      for (final dia in dias) {
        final notifDate = vencimiento.subtract(Duration(days: dia));
        final now = DateTime.now();
        if (notifDate.isAfter(now) || notifDate.day == now.day) {
          await _scheduleNotification(
            id: factura.id! * 10 + dia,
            title: dia == 0 ? 'Factura vence hoy' : 'Recordatorio de factura',
            body: 'La factura vence en $dia día(s)',
            scheduledDate: notifDate,
          );
        }
      }
    }
  }

  Future<void> _scheduleNotification({
    required int id,
    required String title,
    required String body,
    required DateTime scheduledDate,
  }) async {
    const androidDetails = AndroidNotificationDetails(
      'hogarcontrol_recordatorios',
      'Recordatorios de facturas',
      channelDescription: 'Notificaciones de recordatorio de pago',
      importance: Importance.high,
      priority: Priority.high,
    );
    const details = NotificationDetails(android: androidDetails);
    final tzDate = tz.TZDateTime.from(scheduledDate, tz.local);
    await _plugin.zonedSchedule(
      id,
      title,
      body,
      tzDate,
      details,
      androidScheduleMode: AndroidScheduleMode.inexactAllowWhileIdle,
      matchDateTimeComponents: DateTimeComponents.dayOfMonthAndTime,
      uiLocalNotificationDateInterpretation: UILocalNotificationDateInterpretation.absoluteTime,
    );
  }
}