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

import 'package:flutter/services.dart';

/// OpenAI和MCP集成插件
class OpenAI {
  /// 插件通道
  static const MethodChannel _channel =
      MethodChannel('com.yunqiinnovation.open_ai');

  /// 流式输出事件回调
  static final Map<String, StreamCallback> _streamCallbacks = {};

  /// 构造函数
  OpenAI() {
    _channel.setMethodCallHandler(_handleMethodCall);
  }

  /// 处理来自原生端的方法调用
  Future<dynamic> _handleMethodCall(MethodCall call) async {
    if (call.method == 'onStreamEvent') {
      final Map<String, dynamic> args = Map<String, dynamic>.from(call.arguments);
      final String streamId = args['streamId'];
      final String type = args['type'];

      final callback = _streamCallbacks[streamId];
      if (callback != null) {
        switch (type) {
          case 'token':
            callback.onToken(args['data']);
            break;
          case 'complete':
            callback.onComplete();
            _streamCallbacks.remove(streamId);
            break;
          case 'error':
            callback.onError(Exception(args['error']));
            _streamCallbacks.remove(streamId);
            break;
          case 'functionCall':
            final functionCall = jsonDecode(args['data']);
            callback.onFunctionCall(functionCall);
            break;
          case 'functionCallResult':
            final functionCall = jsonDecode(args['functionCall']);
            final functionCallResult = jsonDecode(args['result']);
            callback.onFunctionCallResult(functionCall, functionCallResult);
            break;
        }
      }
    }
    return null;
  }

  /// 初始化OpenAI服务
  /// 
  /// [apiKey] OpenAI API密钥
  /// [baseUrl] API基础URL，可选
  /// [model] 模型名称，可选
  /// [mcpServer] MCP服务器URL，可选
  Future<bool> initialize({
    required String apiKey,
    String baseUrl = '',
    String model = '',
    String mcpServer = '',
  }) async {
    final result = await _channel.invokeMethod<bool>('initialize', {
      'apiKey': apiKey,
      'baseUrl': baseUrl,
      'model': model,
      'mcpServer': mcpServer,
    });
    return result ?? false;
  }

  /// 创建用户消息
  Future<Map<String, dynamic>> createUserMessage(String content) async {
    final result = await _channel.invokeMethod<String>('createUserMessage', {
      'content': content,
    });
    return jsonDecode(result ?? '{}');
  }

  /// 创建系统消息
  Future<Map<String, dynamic>> createSystemMessage(String content) async {
    final result = await _channel.invokeMethod<String>('createSystemMessage', {
      'content': content,
    });
    return jsonDecode(result ?? '{}');
  }

  /// 创建助手消息
  Future<Map<String, dynamic>> createAssistantMessage(String content) async {
    final result = await _channel.invokeMethod<String>('createAssistantMessage', {
      'content': content,
    });
    return jsonDecode(result ?? '{}');
  }

  /// 创建带图片的用户消息
  Future<Map<String, dynamic>> createUserMessageWithImage(
    String text,
    String imageBase64,
  ) async {
    final result = await _channel.invokeMethod<String>(
      'createUserMessageWithImage',
      {
        'text': text,
        'imageBase64': imageBase64,
      },
    );
    return jsonDecode(result ?? '{}');
  }

  /// 发送消息（非流式输出）
  Future<String> sendMessage(List<Map<String, dynamic>> messages) async {
    final messagesJson = jsonEncode(messages);
    return await _channel.invokeMethod('sendMessage', {
      'messages': messagesJson,
    });
  }

  /// 发送消息（流式输出）
  Future<String> sendMessageStream(
    List<Map<String, dynamic>> messages,
    StreamCallback callback,
  ) async {
    final messagesJson = jsonEncode(messages);
    final streamId = DateTime.now().millisecondsSinceEpoch.toString();
    
    // 注册回调
    _streamCallbacks[streamId] = callback;
    
    final result = await _channel.invokeMethod<String>('sendMessageStream', {
      'messages': messagesJson,
      'streamId': streamId,
    });
    
    return result ?? streamId;
  }

  /// 取消当前流式请求
  Future<bool> cancelCurrentStream() async {
    final result = await _channel.invokeMethod<bool>('cancelCurrentStream');
    return result ?? false;
  }

  /// 释放资源
  Future<void> dispose() async {
    await _channel.invokeMethod('dispose');
    _streamCallbacks.clear();
  }
}

/// 流式输出回调接口
class StreamCallback {
  /// 收到令牌
  final void Function(String token) onToken;
  
  /// 完成回调
  final void Function() onComplete;
  
  /// 错误回调
  final void Function(Exception e) onError;
  
  /// 函数调用回调
  final void Function(Map<String, dynamic> functionCall) onFunctionCall;
  
  /// 函数调用结果回调
  final void Function(
    Map<String, dynamic> functionCall,
    Map<String, dynamic> functionCallResult,
  ) onFunctionCallResult;

  /// 构造函数
  StreamCallback({
    required this.onToken,
    required this.onComplete,
    required this.onError,
    required this.onFunctionCall,
    required this.onFunctionCallResult,
  });
}