import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter_tts/flutter_tts.dart';
import 'package:mymuseum_visitapp/Services/Glasses/engines/tts_engine.dart';

/// TTS on-device via Google (Android) / AVSpeechSynthesizer (iOS).
/// Gratuit, pas de latence réseau, supporte FR/NL/EN/DE.
class FlutterTtsEngine implements TtsEngine {
  final FlutterTts _tts = FlutterTts();
  bool _speaking = false;
  String? _lastText;
  String? _lastLang;
  Completer<void>? _completer;

  FlutterTtsEngine() {
    _tts.setStartHandler(() {
      _speaking = true;
    });
    _tts.setCompletionHandler(() {
      _speaking = false;
      _completer?.complete();
      _completer = null;
    });
    _tts.setCancelHandler(() {
      _speaking = false;
      _completer?.complete();
      _completer = null;
    });
    _tts.setErrorHandler((msg) {
      _speaking = false;
      _completer?.completeError(msg);
      _completer = null;
    });
  }

  @override
  bool get isSpeaking => _speaking;

  @override
  Future<void> speak(String text, {String languageCode = 'fr-FR'}) async {
    if (text.isEmpty) return;
    _lastText = text;
    _lastLang = languageCode;

    try {
      await _tts.stop();
      await _tts.setLanguage(languageCode);
      await _tts.setSpeechRate(0.45);
      await _tts.setVolume(1.0);
      await _tts.setPitch(1.0);

      _completer = Completer<void>();
      await _tts.speak(text);

      // Attend la vraie fin de la synthèse
      await _completer!.future.timeout(
        const Duration(seconds: 30),
        onTimeout: () {},
      );
    } catch (e) {
      debugPrint('[FlutterTtsEngine] speak error: $e');
    } finally {
      _speaking = false;
    }
  }

  @override
  Future<void> stop() async {
    await _tts.stop();
    _speaking = false;
    _completer?.complete();
    _completer = null;
  }

  @override
  Future<void> replay() async {
    if (_lastText != null) {
      await speak(_lastText!, languageCode: _lastLang ?? 'fr-FR');
    }
  }
}