// 功能描述：故障描述语音识别适配，应用只复用一个系统识别实例，不保存录音。
// 版本：1.0.0。
import 'package:speech_to_text/speech_to_text.dart';

/// 识别结果为本轮完整短句；调用方负责替换临时结果，不能逐次追加。
abstract interface class RepairSpeech {
  Future<bool> start({
    required void Function(String) onWords,
    required void Function(String) onError,
    required void Function() onDone,
  });
  Future<void> stop();
  Future<void> cancel();
}

/// 系统回调只初始化一次，每轮重新绑定当前界面，离页后忽略迟到结果。
class SystemRepairSpeech implements RepairSpeech {
  SystemRepairSpeech._();
  static final SystemRepairSpeech instance = SystemRepairSpeech._();
  final SpeechToText _speech = SpeechToText();
  void Function(String)? _words, _error;
  void Function()? _done;
  int _generation = 0;
  @override
  Future<bool> start({
    required void Function(String) onWords,
    required void Function(String) onError,
    required void Function() onDone,
  }) async {
    final generation = ++_generation;
    _words = onWords;
    _error = onError;
    _done = onDone;
    final available = await _speech.initialize(
      onError: (error) => _error?.call(error.errorMsg),
      onStatus: (status) {
        if (status == SpeechToText.doneStatus) _done?.call();
      },
      options: [SpeechToText.androidNoBluetooth],
    );
    if (generation != _generation || !available) return false;
    final locales = await _speech.locales();
    if (generation != _generation) return false;
    String? locale;
    for (final item in locales) {
      if (item.localeId.toLowerCase().replaceAll('_', '-') == 'zh-cn') {
        locale = item.localeId;
        break;
      }
    }
    await _speech.listen(
      onResult: (result) {
        if (generation == _generation) _words?.call(result.recognizedWords);
      },
      listenOptions: SpeechListenOptions(
        localeId: locale,
        partialResults: true,
        cancelOnError: true,
        listenMode: ListenMode.dictation,
        listenFor: const Duration(seconds: 45),
        pauseFor: const Duration(seconds: 5),
      ),
    );
    return generation == _generation;
  }

  @override
  Future<void> stop() => _speech.stop();
  @override
  Future<void> cancel() async {
    ++_generation;
    _words = null;
    _error = null;
    _done = null;
    await _speech.cancel();
  }
}