import 'dart:async';
import 'dart:math' as math;
import 'package:flutter/services.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:get/get.dart';
import '../../core/utils/logger.dart';

/// 识别事件类型
enum RecognitionEventType {
  started,
  recognizing,
  finalResult,
  error,
  completed,
}

/// 识别事件
class RecognitionEvent {
  final RecognitionEventType type;
  final String text;
  final String? error;

  RecognitionEvent({
    required this.type,
    this.text = '',
    this.error,
  });
}

/// 火山语音识别服务
/// 
/// 该服务提供了通过平台通道与 Android 上的火山语音识别 SDK 交互的接口
class VolcanoVoiceRecognitionService extends GetxService {
  static const MethodChannel _channel = MethodChannel('com.example.deep_voice/speech_recognition');
  static const EventChannel _eventChannel = EventChannel('com.example.deep_voice/speech_recognition_events');
  
  bool _isInitialized = false;
  late final String _subscriptionKey;
  late final String _serviceRegion;
  
  // 连续识别相关
  bool _isContinuousRecognitionActive = false;
  StreamController<RecognitionEvent>? _eventStreamController;
  StreamSubscription? _eventSubscription;
  
  // 公开的事件流
  Stream<RecognitionEvent>? _recognitionStream;
  Stream<RecognitionEvent>? get recognitionStream => _recognitionStream;
  
  // 最新的识别结果
  final _latestRecognizedText = ''.obs;
  String get latestRecognizedText => _latestRecognizedText.value;
  
  // 识别状态
  final isListening = false.obs;
  
  // 识别结果列表
  final RxList<String> _recognitionResults = <String>[].obs;
  List<String> get recognitionResults => _recognitionResults;
  
  // 错误信息
  final RxString _errorMessage = ''.obs;
  String get errorMessage => _errorMessage.value;
  
  VolcanoVoiceRecognitionService() {
    _loadConfig();
  }
  
  /// 从环境变量加载配置
  void _loadConfig() {
    // 只使用统一的APP_ID和APP_KEY
    _subscriptionKey = dotenv.env['VOLCANO_APP_ID'] ?? '';
    _serviceRegion = dotenv.env['VOLCANO_APP_KEY'] ?? '';
    
    Logger.info('火山语音识别配置: APP_ID=${_subscriptionKey.isNotEmpty ? "已设置" : "未设置"}, APP_KEY=${_serviceRegion.isNotEmpty ? "已设置" : "未设置"}');
    
    if (_subscriptionKey.isEmpty || _serviceRegion.isEmpty) {
      throw Exception('未找到火山语音服务配置。请在 .env 文件中设置 VOLCANO_APP_ID 和 VOLCANO_APP_KEY');
    }
  }
  
  @override
  void onInit() {
    super.onInit();
    _setupMethodCallHandler();
  }
  
  /// 设置方法通道处理器
  void _setupMethodCallHandler() {
    _channel.setMethodCallHandler((call) async {
      switch (call.method) {
        case 'onRecognitionResult':
          final String result = call.arguments as String;
          _handleRecognitionResult(result);
          break;
        case 'onRecognitionError':
          final String error = call.arguments as String;
          _handleRecognitionError(error);
          break;
        case 'onRecognitionComplete':
          _handleRecognitionComplete();
          break;
      }
    });
  }
  
  /// 处理识别结果
  void _handleRecognitionResult(String result) {
    Logger.debug('Recognition result: $result');
    _recognitionResults.add(result);
    _latestRecognizedText.value = result;
    
    if (_eventStreamController != null) {
      _eventStreamController!.add(RecognitionEvent(
        type: RecognitionEventType.finalResult,
        text: result,
      ));
    }
  }
  
  /// 处理识别错误
  void _handleRecognitionError(String error) {
    Logger.error('Recognition error: $error');
    _errorMessage.value = error;
    isListening.value = false;
    
    if (_eventStreamController != null) {
      _eventStreamController!.add(RecognitionEvent(
        type: RecognitionEventType.error,
        text: '',
        error: error,
      ));
    }
  }
  
  /// 处理识别完成
  void _handleRecognitionComplete() {
    Logger.debug('Recognition complete');
    isListening.value = false;
    _isContinuousRecognitionActive = false;
    
    if (_eventStreamController != null) {
      _eventStreamController!.add(RecognitionEvent(
        type: RecognitionEventType.completed,
        text: '',
      ));
    }
  }
  
  /// 初始化语音识别引擎
  Future<bool> initialize() async {
    if (_isInitialized) return true;
    
    try {
      Logger.info('开始初始化火山语音识别服务，APP_ID: ${_subscriptionKey.substring(0, math.min(3, _subscriptionKey.length))}***，APP_KEY: ${_serviceRegion.length > 10 ? "${_serviceRegion.substring(0, 5)}..." : _serviceRegion}');
      
      final bool result = await _channel.invokeMethod('initialize', {
        'subscriptionKey': _subscriptionKey,
        'serviceRegion': _serviceRegion,
      });
      
      _isInitialized = result;
      Logger.info('火山语音识别服务初始化${result ? '成功' : '失败'}');
      return result;
    } on PlatformException catch (e) {
      // 检查是否是资源授权错误
      if (e.code == 'INITIALIZATION_ERROR' && 
          (e.message?.contains('资源授权错误') == true || 
           e.message?.contains('requested resource not granted') == true ||
           e.message?.contains('requested grant not found') == true)) {
        Logger.error('火山语音识别初始化失败: 资源授权错误', e, StackTrace.current);
        Logger.info('请检查以下几点:');
        Logger.info('1. 确保您的火山引擎账户已开通语音识别服务');
        Logger.info('2. 确保您的应用ID和密钥正确且有效');
        Logger.info('3. 确保您的应用已被授权使用语音识别服务');
        _isInitialized = false;
        throw PlatformException(
          code: 'RESOURCE_AUTHORIZATION_ERROR',
          message: '语音识别服务授权失败: 请确保应用已开通语音识别服务并且密钥有效',
          details: e.message
        );
      } else {
        Logger.error('火山语音识别初始化失败: ${e.message}', e, StackTrace.current);
        _isInitialized = false;
        throw e;
      }
    } catch (e) {
      Logger.error('火山语音识别初始化发生未知错误', e, StackTrace.current);
      _isInitialized = false;
      throw Exception('初始化火山语音识别服务失败: $e');
    }
  }
  
  /// 开始一次性识别
  Future<bool> startOneTimeRecognition() async {
    if (isListening.value) {
      Logger.warning('已经在进行语音识别，请先停止当前识别');
      return false;
    }
    
    if (!_isInitialized) {
      try {
        final bool initialized = await initialize();
        if (!initialized) {
          Logger.error('语音识别服务未初始化，无法开始识别');
          _errorMessage.value = '语音识别服务未初始化，无法开始识别';
          return false;
        }
      } catch (e) {
        Logger.error('初始化语音识别服务失败: $e');
        _errorMessage.value = '初始化语音识别服务失败: $e';
        return false;
      }
    }
    
    try {
      _errorMessage.value = '';
      _recognitionResults.clear();
      
      final bool result = await _channel.invokeMethod('startOneTimeRecognition');
      isListening.value = result;
      
      if (result) {
        _eventStreamController?.add(RecognitionEvent(
          type: RecognitionEventType.started,
          text: '',
        ));
      }
      
      return result;
    } catch (e) {
      Logger.error('开始一次性识别失败: $e');
      _errorMessage.value = e.toString();
      return false;
    }
  }
  
  /// 开始连续识别
  Future<bool> startContinuousRecognition() async {
    if (isListening.value) {
      Logger.warning('已经在进行语音识别，请先停止当前识别');
      return false;
    }
    
    if (!_isInitialized) {
      try {
        final bool initialized = await initialize();
        if (!initialized) {
          Logger.error('语音识别服务未初始化，无法开始识别');
          _errorMessage.value = '语音识别服务未初始化，无法开始识别';
          return false;
        }
      } catch (e) {
        Logger.error('初始化语音识别服务失败: $e');
        _errorMessage.value = '初始化语音识别服务失败: $e';
        return false;
      }
    }
    
    try {
      _errorMessage.value = '';
      _recognitionResults.clear();
      
      // 创建事件流控制器
      _eventStreamController = StreamController<RecognitionEvent>.broadcast();
      _recognitionStream = _eventStreamController?.stream;
      
      // 设置事件监听
      _eventSubscription = _eventChannel
          .receiveBroadcastStream()
          .listen(_handleNativeEvent, onError: (error) {
            _handleRecognitionError(error.toString());
          });
      
      final bool result = await _channel.invokeMethod('startContinuousRecognition');
      isListening.value = result;
      _isContinuousRecognitionActive = result;
      
      if (result) {
        _eventStreamController?.add(RecognitionEvent(
          type: RecognitionEventType.started,
          text: '',
        ));
      }
      
      return result;
    } catch (e) {
      Logger.error('开始连续识别失败: $e');
      _errorMessage.value = e.toString();
      _cleanupEventStream();
      return false;
    }
  }
  
  /// 处理来自原生端的事件
  void _handleNativeEvent(dynamic event) {
    if (event is! Map) return;
    
    final Map<dynamic, dynamic> eventMap = event;
    final String eventType = eventMap['eventType'] as String? ?? '';
    
    switch (eventType) {
      case 'recognizing':
        final String text = eventMap['text'] as String? ?? '';
        _eventStreamController?.add(RecognitionEvent(
          type: RecognitionEventType.recognizing,
          text: text,
        ));
        break;
      case 'finalResult':
        final String text = eventMap['text'] as String? ?? '';
        _latestRecognizedText.value = text;
        _recognitionResults.add(text);
        _eventStreamController?.add(RecognitionEvent(
          type: RecognitionEventType.finalResult,
          text: text,
        ));
        break;
      case 'error':
        final String error = eventMap['error'] as String? ?? '未知错误';
        _handleRecognitionError(error);
        break;
    }
  }
  
  /// 清理事件流
  void _cleanupEventStream() {
    _eventSubscription?.cancel();
    _eventSubscription = null;
    _eventStreamController?.close();
    _eventStreamController = null;
    _recognitionStream = null;
  }
  
  /// 停止识别
  Future<bool> stopRecognition() async {
    if (!isListening.value) {
      Logger.warning('当前没有进行语音识别');
      return false;
    }
    
    try {
      final bool result = await _channel.invokeMethod('stopRecognition');
      isListening.value = !result;
      _isContinuousRecognitionActive = !result;
      
      if (result) {
        _cleanupEventStream();
      }
      
      return result;
    } catch (e) {
      Logger.error('停止识别失败: $e');
      _errorMessage.value = e.toString();
      return false;
    }
  }
  
  /// 检查连续识别是否活跃
  bool isContinuousRecognitionActive() {
    return _isContinuousRecognitionActive;
  }
  
  /// 清理资源
  Future<void> dispose() async {
    try {
      if (isListening.value) {
        await stopRecognition();
      }
      _cleanupEventStream();
    } catch (e) {
      Logger.error('清理语音识别资源失败: $e');
    }
  }
  
  @override
  void onClose() {
    dispose();
    super.onClose();
  }
}