import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import 'package:mymuseum_visitapp/Services/Glasses/engines/wake_word_engine.dart';

/// Wake word via OpenWakeWord — service Android natif (foreground service).
/// Utilise ONNX Runtime pour l'inférence on-device du modèle hey_visit.onnx.
/// Survit au background Android contrairement au STT continu.
///
/// iOS non supporté — fallback sur SpeechToTextWakeWordEngine côté iOS.
class OpenWakeWordEngine implements WakeWordEngine {
  static const _methodChannel = MethodChannel('be.unov.mymuseum/wake_word');
  static const _eventChannel = EventChannel('be.unov.mymuseum/wake_word_events');

  /// Nom du fichier .tflite dans assets/files (sans extension).
  /// Ex: "hey_visit", "hey_museum", "hey_guide"
  final String modelName;

  StreamSubscription<dynamic>? _subscription;
  void Function()? _onDetected;
  bool _running = false;

  OpenWakeWordEngine({this.modelName = 'hey_visit'});

  @override
  Future<void> start({
    required void Function() onDetected,
    void Function(String command)? onDetectedWithCommand,
  }) async {
    if (_running) return;
    if (!_isAndroid) {
      debugPrint('[OpenWakeWordEngine] Android only — no-op on this platform');
      return;
    }

    _onDetected = onDetected;
    _running = true;

    _subscription = _eventChannel.receiveBroadcastStream().listen(
      (event) {
        if (event == 'detected' && _running) {
          debugPrint('[OpenWakeWordEngine] Wake word detected');
          // OpenWakeWord ne capture pas la commande inline — l'orchestrateur
          // lance un cycle STT séparé via onDetected()
          _onDetected?.call();
        }
      },
      onError: (e) => debugPrint('[OpenWakeWordEngine] Event error: $e'),
    );

    await _methodChannel.invokeMethod('start', {'modelName': modelName});
    debugPrint('[OpenWakeWordEngine] Service started (model: $modelName)');
  }

  @override
  Future<void> stop() async {
    if (!_running) return;
    _running = false;
    await _subscription?.cancel();
    _subscription = null;
    if (_isAndroid) {
      await _methodChannel.invokeMethod('stop');
    }
    debugPrint('[OpenWakeWordEngine] Service stopped');
  }

  bool get _isAndroid => defaultTargetPlatform == TargetPlatform.android;
}