xianyan/lib/core/services/input/speech_provider.dart

/// ============================================================
/// 闲言APP — 语音输入Provider
/// 创建时间: 2026-05-25
/// 更新时间: 2026-05-30
/// 作用: 语音服务状态管理 + 识别结果Provider
/// 上次更新: 修复隐私问题 — build()不再自动初始化语音服务，改为用户主动触发时才初始化
/// ============================================================

import 'dart:async';

import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../services/input/speech_service.dart';
import '../../utils/logger.dart';

/// 语音服务状态
class SpeechState {
  const SpeechState({
    this.isAvailable = false,
    this.isListening = false,
    this.currentText = '',
    this.lastResult = '',
    this.locale = 'zh_CN',
    this.errorMessage,
    this.isInitialized = false,
  });

  final bool isAvailable;
  final bool isListening;
  final String currentText;
  final String lastResult;
  final String locale;
  final String? errorMessage;

  /// 是否已初始化（仅用户主动触发后才为true）
  final bool isInitialized;

  SpeechState copyWith({
    bool? isAvailable,
    bool? isListening,
    String? currentText,
    String? lastResult,
    String? locale,
    String? errorMessage,
    bool? isInitialized,
  }) {
    return SpeechState(
      isAvailable: isAvailable ?? this.isAvailable,
      isListening: isListening ?? this.isListening,
      currentText: currentText ?? this.currentText,
      lastResult: lastResult ?? this.lastResult,
      locale: locale ?? this.locale,
      errorMessage: errorMessage,
      isInitialized: isInitialized ?? this.isInitialized,
    );
  }
}

/// 语音服务Notifier
///
/// 安全设计：build()不自动初始化语音服务，避免在页面加载时
/// 触发麦克风权限申请。仅在用户主动点击语音按钮时调用init()。
class SpeechNotifier extends Notifier<SpeechState> {
  StreamSubscription<SpeechServiceState>? _stateSub;
  StreamSubscription<SpeechResult>? _resultSub;
  StreamSubscription<String>? _errorSub;

  @override
  SpeechState build() {
    ref.onDispose(_onDispose);
    return const SpeechState();
  }

  /// 用户主动触发初始化 — 仅此时才请求麦克风权限
  Future<bool> init() async {
    if (state.isInitialized) return state.isAvailable;

    final service = SpeechService.instance;
    final available = await service.init();
    state = state.copyWith(isAvailable: available, isInitialized: true);

    _stateSub = service.onStateChanged.listen((s) {
      state = state.copyWith(
        isListening: s == SpeechServiceState.listening,
        isAvailable: s != SpeechServiceState.unavailable,
      );
    });

    _resultSub = service.onResult.listen((result) {
      if (result.isFinal) {
        state = state.copyWith(
          lastResult: result.text,
          currentText: result.text,
        );
      } else {
        state = state.copyWith(currentText: result.text);
      }
    });

    _errorSub = service.onError.listen((error) {
      state = state.copyWith(errorMessage: error);
      Log.w('SpeechProvider: 错误 $error');
    });

    return available;
  }

  /// 开始语音识别
  Future<void> startListening({String? localeId}) async {
    state = state.copyWith();
    await SpeechService.instance.startListening(
      localeId: localeId ?? state.locale,
    );
  }

  /// 停止语音识别
  Future<void> stopListening() async {
    await SpeechService.instance.stopListening();
  }

  /// 取消语音识别
  Future<void> cancelListening() async {
    await SpeechService.instance.cancelListening();
  }

  /// 切换语言
  void setLocale(String localeId) {
    SpeechService.instance.setLocale(localeId);
    state = state.copyWith(locale: localeId);
  }

  /// 清除识别结果
  void clearResult() {
    state = state.copyWith(currentText: '', lastResult: '');
  }

  void _onDispose() {
    _stateSub?.cancel();
    _resultSub?.cancel();
    _errorSub?.cancel();
  }
}

/// 语音服务状态Provider
final speechProvider = NotifierProvider<SpeechNotifier, SpeechState>(
  SpeechNotifier.new,
);

/// 语音识别结果Provider — 仅暴露最终结果
final speechResultProvider = Provider<String>((ref) {
  return ref.watch(speechProvider).lastResult;
});

/// 语音是否可用Provider
final speechAvailableProvider = Provider<bool>((ref) {
  return ref.watch(speechProvider).isAvailable;
});