"""
MCP 客户端管理模块

管理 Model Context Protocol 客户端的初始化和获取。
"""
from typing import Optional

from langchain_mcp_adapters.client import MultiServerMCPClient

from core.config import settings
from logger.logging import get_logger

logger = get_logger(__name__)

# 全局 MCP 客户端
_mcp_client: Optional[MultiServerMCPClient] = None


async def get_mcp_client() -> MultiServerMCPClient:
    """
    获取或创建全局 MCP 客户端
    
    Returns:
        MultiServerMCPClient: MCP 客户端实例
    """
    global _mcp_client
    
    if _mcp_client is None:
        logger.info("初始化 MCP 客户端...")
        
        # 构建 MCP 服务器配置
        mcp_servers = {}

        if settings.mcp_url:
            mcp_servers["my-mcp"] = {
                "transport": settings.mcp_transport,
                "url": settings.mcp_url,
            }
        else:
            logger.warning("未配置 MCP_URL，跳过第三方 MCP 服务")
        
        _mcp_client = MultiServerMCPClient(mcp_servers)
        logger.info("MCP 客户端初始化完成")
    
    return _mcp_client


async def close_mcp_client():
    """关闭 MCP 客户端"""
    global _mcp_client
    
    if _mcp_client is not None:
        logger.info("关闭 MCP 客户端...")
        # MCP 客户端可能没有显式的关闭方法，但我们清理引用
        _mcp_client = None
        logger.info("MCP 客户端已关闭")