import 'dart:async';
import 'dart:convert';

import 'package:flutter/services.dart';

/// 代理服务事件类型
enum AgentServiceEventType {
  /// 识别开始
  recognitionStarted,
  
  /// 识别中
  recognizing,
  
  /// 识别最终结果
  recognitionResult,
  
  /// 识别停止
  recognitionStopped,
  
  /// 识别取消
  recognitionCanceled,
  
  /// 自动停止
  autoStop,
  
  /// 识别错误
  recognitionError,
  
  /// TTS开始
  ttsStarted,
  
  /// TTS完成
  ttsCompleted,
  
  /// TTS取消
  ttsCanceled,
  
  /// TTS停止
  ttsStopped,
  
  /// 响应中断
  responseInterrupted,
  
  /// AI助手Token
  assistantToken,
  
  /// AI助手完整响应
  assistantResponse,
  
  /// 函数调用
  functionCall,
  
  /// 函数调用结果
  functionCallResult,
  
  /// 错误
  error,
  
  /// 未知事件
  unknown
}

/// 代理服务事件数据
class AgentServiceEvent {
  /// 事件类型
  final AgentServiceEventType type;
  
  /// 事件数据
  final Map<String, dynamic> data;
  
  AgentServiceEvent({required this.type, required this.data});
  
  @override
  String toString() => 'AgentServiceEvent(type: $type, data: $data)';
}

/// 代理服务异常
class AgentServiceException implements Exception {
  final String code;
  final String message;
  final dynamic details;
  
  AgentServiceException(this.code, this.message, [this.details]);
  
  @override
  String toString() => '代理服务异常($code): $message';
}

/// 代理服务插件
class AgentService {
  static const MethodChannel _channel = MethodChannel('com.yunqiinnovation.agent_service');
  static const EventChannel _eventChannel = EventChannel('com.yunqiinnovation.agent_service/events');
  
  static Stream<AgentServiceEvent>? _eventStream;
  
  /// 获取事件流
  static Stream<AgentServiceEvent> get events {
    _eventStream ??= _eventChannel.receiveBroadcastStream().map((event) {
      try {
        final Map<String, dynamic> eventMap = jsonDecode(event);
        final String eventName = eventMap['event'];
        final Map<String, dynamic> eventData = eventMap['data'];
        
        // 将事件名称转换为枚举
        final AgentServiceEventType type = _stringToEventType(eventName);
        
        return AgentServiceEvent(type: type, data: eventData);
      } catch (e) {
        return AgentServiceEvent(
          type: AgentServiceEventType.unknown, 
          data: {'error': e.toString(), 'rawEvent': event}
        );
      }
    });
    
    return _eventStream!;
  }
  
  /// 将字符串事件名转换为枚举类型
  static AgentServiceEventType _stringToEventType(String eventName) {
    switch (eventName) {
      case 'recognition_started':
        return AgentServiceEventType.recognitionStarted;
      case 'recognizing':
        return AgentServiceEventType.recognizing;
      case 'recognition_result':
        return AgentServiceEventType.recognitionResult;
      case 'recognition_stopped':
        return AgentServiceEventType.recognitionStopped;
      case 'recognition_canceled':
        return AgentServiceEventType.recognitionCanceled;
      case 'auto_stop':
        return AgentServiceEventType.autoStop;
      case 'error':
        return AgentServiceEventType.error;
      case 'tts_started':
        return AgentServiceEventType.ttsStarted;
      case 'tts_completed':
        return AgentServiceEventType.ttsCompleted;
      case 'tts_canceled':
        return AgentServiceEventType.ttsCanceled;
      case 'tts_stopped':
        return AgentServiceEventType.ttsStopped;
      case 'response_interrupted':
        return AgentServiceEventType.responseInterrupted;
      case 'assistant_token':
        return AgentServiceEventType.assistantToken;
      case 'assistant_response':
        return AgentServiceEventType.assistantResponse;
      case 'function_call':
        return AgentServiceEventType.functionCall;
      case 'function_call_result':
        return AgentServiceEventType.functionCallResult;
      default:
        return AgentServiceEventType.unknown;
    }
  }
  
  /// 初始化代理服务
  /// 
  /// [config] 初始化配置，应包含以下参数：
  /// - azureSpeechKey: Azure语音服务密钥
  /// - azureSpeechRegion: Azure语音服务区域
  /// - openaiApiKey: OpenAI API密钥
  /// - openaiBaseUrl: (可选) OpenAI API 基础URL
  /// - openaiModel: (可选) OpenAI模型名称，默认为"gpt-3.5-turbo"
  /// - mcpServer: (可选) MCP服务器地址
  /// - systemPrompt: (可选) 自定义系统提示词，用于设置AI语音助手的行为和风格
  /// 
  /// 返回是否初始化成功
  static Future<bool> initialize(Map<String, dynamic> config) async {
    try {
      final bool result = await _channel.invokeMethod('initialize', {
        'config': config,
      });
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '初始化失败', e.details);
    }
  }
  
  /// 开始对话
  /// 
  /// 启动语音识别，开始监听用户语音输入
  /// 返回是否成功开始对话
  static Future<bool> startConversation() async {
    try {
      final bool result = await _channel.invokeMethod('startConversation');
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '启动对话失败', e.details);
    }
  }
  
  /// 停止对话
  /// 
  /// 停止语音识别
  /// 返回是否成功停止对话
  static Future<bool> stopConversation() async {
    try {
      final bool result = await _channel.invokeMethod('stopConversation');
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '停止对话失败', e.details);
    }
  }
  
  /// 处理文本输入
  /// 
  /// [text] 文本内容
  /// [speakResponse] 是否朗读响应
  /// 返回是否成功处理文本
  static Future<bool> processTextInput(String text, {bool speakResponse = false}) async {
    try {
      final bool result = await _channel.invokeMethod('processTextInput', {
        'text': text,
        'speakResponse': speakResponse,
      });
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '处理文本输入失败', e.details);
    }
  }
  
  /// 朗读文本
  /// 
  /// [text] 要朗读的文本
  static Future<bool> speakText(String text) async {
    try {
      final bool result = await _channel.invokeMethod('speakText', {
        'text': text,
      });
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '语音合成失败', e.details);
    }
  }
  
  /// 停止语音合成
  static Future<bool> stopTts() async {
    try {
      final bool result = await _channel.invokeMethod('stopTts');
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '停止语音合成失败', e.details);
    }
  }
  
  /// 清除聊天历史
  static Future<bool> clearChatHistory() async {
    try {
      final bool result = await _channel.invokeMethod('clearChatHistory');
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '清除聊天历史失败', e.details);
    }
  }
  
  /// 中断当前响应
  /// 
  /// 停止语音合成和AI流输出
  static Future<bool> interruptCurrentResponse() async {
    try {
      // 首先尝试停止TTS播放
      await stopTts();
      
      // 根据原生层的实现，processTextInput可以被用来中断当前的AI流输出
      // 这里我们通过发送一个特殊的空字符串来实现这一点
      // 然后立即返回true，因为我们不需要真正处理任何文本
      return true;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '中断响应失败', e.details);
    }
  }
  
  /// 释放资源
  static Future<bool> dispose() async {
    try {
      final bool result = await _channel.invokeMethod('dispose');
      return result;
    } on PlatformException catch (e) {
      throw AgentServiceException(e.code, e.message ?? '释放资源失败', e.details);
    }
  }
}