ailine/backend/app/mcp/mcp_client.py

"""
MCP客户端
负责与MCP服务器通信
"""
import asyncio
from typing import Dict, Any, Optional, List
from dataclasses import dataclass, field
import json


@dataclass
class MCPServerConfig:
    """MCP服务器配置"""
    name: str
    server_type: str = "stdio"  # stdio 或 http
    command: Optional[str] = None  # for stdio
    args: List[str] = field(default_factory=list)  # for stdio
    url: Optional[str] = None  # for http
    headers: Dict[str, str] = field(default_factory=dict)  # for http
    env: Dict[str, str] = field(default_factory=dict)
    timeout: int = 120
    enabled: bool = True


class MCPClient:
    """
    MCP客户端
    
    支持：
    1. 多MCP服务器管理
    2. 工具发现和调用
    3. 连接管理和重试
    """
    
    def __init__(self):
        self._servers: Dict[str, MCPServerConfig] = {}
        self._connections: Dict[str, Any] = {}
        self._tools: Dict[str, Dict[str, Any]] = {}
        self._initialized = False
    
    def register_server(self, config: MCPServerConfig):
        """注册一个MCP服务器"""
        if not config.enabled:
            return
        self._servers[config.name] = config
    
    async def initialize(self):
        """初始化所有MCP服务器连接"""
        if self._initialized:
            return
        
        print(f"[MCP] 初始化 {len(self._servers)} 个MCP服务器...")
        
        for name, config in self._servers.items():
            try:
                await self._connect_server(name, config)
            except Exception as e:
                print(f"[MCP] 服务器 {name} 连接失败: {e}")
        
        self._initialized = True
        print(f"[MCP] 初始化完成，可用工具: {list(self._tools.keys())}")
    
    async def _connect_server(self, name: str, config: MCPServerConfig):
        """连接到单个MCP服务器"""
        # 这里是简化实现，实际使用可以集成真实的MCP SDK
        # 目前先模拟MCP工具发现
        print(f"[MCP] 连接服务器: {name} (type: {config.server_type})")
        
        # 模拟发现一些工具
        if name == "filesystem":
            self._tools[f"{name}_list_directory"] = {
                "server": name,
                "name": "list_directory",
                "description": "列出目录内容",
            }
            self._tools[f"{name}_read_file"] = {
                "server": name,
                "name": "read_file",
                "description": "读取文件内容",
            }
        elif name == "news":
            self._tools[f"{name}_search_news"] = {
                "server": name,
                "name": "search_news",
                "description": "搜索新闻资讯",
            }
        elif name == "dictionary":
            self._tools[f"{name}_lookup_word"] = {
                "server": name,
                "name": "lookup_word",
                "description": "查询单词释义",
            }
        elif name == "email":
            self._tools[f"{name}_list_emails"] = {
                "server": name,
                "name": "list_emails",
                "description": "列出邮件",
            }
            self._tools[f"{name}_send_email"] = {
                "server": name,
                "name": "send_email",
                "description": "发送邮件",
            }
    
    async def call_tool(
        self, 
        tool_name: str, 
        arguments: Dict[str, Any]
    ) -> Dict[str, Any]:
        """
        调用MCP工具
        
        Args:
            tool_name: 工具名称（带server前缀，如 "filesystem_read_file"）
            arguments: 工具参数
            
        Returns:
            工具执行结果
        """
        if not self._initialized:
            await self.initialize()
        
        if tool_name not in self._tools:
            return {
                "success": False,
                "error": f"工具 {tool_name} 不存在",
                "fallback": True
            }
        
        tool_info = self._tools[tool_name]
        server_name = tool_info["server"]
        
        try:
            # 目前是模拟调用，实际使用时替换为真实的MCP SDK调用
            result = await self._mock_tool_call(server_name, tool_info["name"], arguments)
            return {
                "success": True,
                "result": result,
                "source": f"mcp_{server_name}"
            }
        except Exception as e:
            return {
                "success": False,
                "error": str(e),
                "fallback": True
            }
    
    async def _mock_tool_call(
        self,
        server_name: str,
        tool_name: str,
        arguments: Dict[str, Any]
    ) -> Any:
        """模拟MCP工具调用（待替换为真实实现）"""
        from datetime import datetime
        
        if server_name == "news" and tool_name == "search_news":
            query = arguments.get("query", "")
            return [
                {
                    "title": f"最新关于 {query} 的资讯",
                    "source": "MCP News",
                    "summary": f"这是通过MCP获取的关于 {query} 的新闻摘要...",
                    "published_at": datetime.now().isoformat(),
                    "keywords": [query, "AI", "科技"]
                }
            ]
        elif server_name == "dictionary" and tool_name == "lookup_word":
            word = arguments.get("word", "")
            return {
                "word": word,
                "phonetic": "/ˈsɪmplɪ/",
                "definitions": [f"{word} 的释义1", f"{word} 的释义2"],
                "examples": [f"This is an example with {word}."]
            }
        elif server_name == "email" and tool_name == "list_emails":
            return [
                {
                    "id": "1",
                    "subject": "来自MCP的邮件",
                    "sender": "mcp@example.com",
                    "date": datetime.now().isoformat(),
                    "snippet": "这是通过MCP获取的邮件内容..."
                }
            ]
        elif server_name == "email" and tool_name == "send_email":
            return {
                "success": True,
                "message": "邮件已通过MCP发送"
            }
        else:
            return {"message": f"MCP工具 {server_name}.{tool_name} 已调用", "arguments": arguments}
    
    def get_available_tools(self) -> List[str]:
        """获取所有可用工具"""
        return list(self._tools.keys())
    
    def is_available(self) -> bool:
        """检查MCP是否可用"""
        return len(self._tools) > 0