flutter_clock/lib/utils/notification_manager.dart

import 'package:vibration/vibration.dart';

/// A service to handle notifications and vibration
class NotificationManager {
  static final NotificationManager _instance = NotificationManager._internal();
  
  factory NotificationManager() {
    return _instance;
  }
  
  NotificationManager._internal();
  
  /// Vibrate the device to notify user of timer completion
  Future<void> notifyTimerCompletion() async {
    await triggerVibration();
  }
  
  /// Trigger vibration pattern
  Future<void> triggerVibration() async {
    if (await Vibration.hasVibrator() ?? false) {
      // Pattern for stronger notification - will repeat 3 times with pauses
      // Vibrate for 500ms, pause for 200ms, repeat
      Vibration.vibrate(
        pattern: [0, 500, 200, 500, 200, 500],
        intensities: [0, 255, 0, 255, 0, 255],
      );
    }
  }
  
  /// Stop vibration
  Future<void> stopVibration() async {
    if (await Vibration.hasVibrator() ?? false) {
      Vibration.cancel();
    }
  }
}