"""物料字段 MCP 客户端：把字段查询工具交给模型使用

服务只监听本机，由应用启动时拉起；不可用时直接报错，不退回其他查询方式
"""

import asyncio
import os
import socket
import subprocess
import sys
from pathlib import Path
from urllib.parse import urlsplit

from langchain_core.tools import BaseTool
from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain_mcp_adapters.interceptors import MCPToolCallRequest
from loguru import logger
from mcp.types import CallToolResult

from app.config import settings
from app.resources.component import get_catalog_cache

SERVER_NAME = "materials"
PROJECT_ROOT = Path(__file__).resolve().parents[2]


class MaterialFieldServiceError(RuntimeError):
    """物料字段服务不可用，或与主进程的物料目录版本不一致"""


async def _check_version(request: MCPToolCallRequest, handler):
    """限制单次查询耗时；返回的目录版本须与主进程一致，否则模型查到的字段和校验依据不同"""
    try:
        result = await asyncio.wait_for(
            handler(request), timeout=settings.mcp_tool_timeout
        )
    except TimeoutError as error:
        raise MaterialFieldServiceError(f"物料字段查询超时: {request.name}") from error
    if isinstance(result, CallToolResult) and result.structuredContent:
        served = result.structuredContent.get("catalog_version")
        catalog = get_catalog_cache()
        expected = catalog.version if catalog is not None else None
        if served != expected:
            raise MaterialFieldServiceError(
                f"物料字段服务的目录版本 {served} 与主服务 {expected} 不一致，请重启服务"
            )
    return result


_client = MultiServerMCPClient(
    {
        SERVER_NAME: {
            "transport": "streamable_http",
            "url": settings.mcp_material_url,
        }
    },
    tool_interceptors=[_check_version],
    # 未知组件类型、分组等查询错误返回给模型自行修正；连接失败等仍直接抛出
    handle_tool_errors=True,
)
_tools: list[BaseTool] | None = None


async def get_material_tools() -> list[BaseTool]:
    """字段查询工具；首次使用或此前连接失败时向服务拉取工具清单"""
    global _tools
    if _tools is None:
        try:
            _tools = await asyncio.wait_for(
                _client.get_tools(server_name=SERVER_NAME),
                timeout=settings.mcp_tool_timeout,
            )
        except Exception as error:
            raise MaterialFieldServiceError(
                f"物料字段服务不可用: {settings.mcp_material_url}"
            ) from error
    return _tools


def _port_open(port: int) -> bool:
    with socket.socket() as probe:
        probe.settimeout(0.2)
        return probe.connect_ex(("127.0.0.1", port)) == 0


async def start_material_server() -> subprocess.Popen | None:
    """本机地址且尚未运行时拉起服务，返回进程供退出时关闭；已运行则直接复用"""
    target = urlsplit(settings.mcp_material_url)
    if target.hostname not in {"localhost", "127.0.0.1"}:
        raise MaterialFieldServiceError("物料字段服务只能部署在本机，不对外暴露")
    port = target.port or 80
    if _port_open(port):
        return None
    process = subprocess.Popen(
        [sys.executable, "-X", "utf8", "-m", "mcp_servers.material_server"],
        cwd=PROJECT_ROOT,
        env={**os.environ, "PORT": str(port)},
    )
    for _ in range(100):
        if process.poll() is not None:
            raise MaterialFieldServiceError("物料字段服务启动失败，请查看终端日志")
        if _port_open(port):
            logger.info("物料字段服务已启动: {}", settings.mcp_material_url)
            return process
        await asyncio.sleep(0.1)
    await stop_material_server(process)
    raise MaterialFieldServiceError("物料字段服务启动超时")


async def stop_material_server(process: subprocess.Popen | None) -> None:
    if process is None or process.poll() is not None:
        return
    process.terminate()
    try:
        await asyncio.to_thread(process.wait, timeout=5)
    except subprocess.TimeoutExpired:
        process.kill()
        await asyncio.to_thread(process.wait)