import time
import asyncio
import httpx
from app.config import settings

# token 缓存
_token_cache: dict = {}
_lock = asyncio.Lock()


async def get_access_token() -> str:
    """获取 access_token，带缓存和并发刷新保护"""
    now = int(time.time())
    if _token_cache.get("access_token") and _token_cache.get("expires_at", 0) > now + 300:
        return _token_cache["access_token"]

    async with _lock:
        # 双重检查
        if _token_cache.get("access_token") and _token_cache.get("expires_at", 0) > now + 300:
            return _token_cache["access_token"]

        async with httpx.AsyncClient() as client:
            url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken"
            resp = await client.get(url, params={
                "corpid": settings.corpid,
                "corpsecret": settings.secret,
            })
            data = resp.json()
            if data.get("errcode") != 0:
                raise Exception(f"获取 access_token 失败: {data}")

            _token_cache["access_token"] = data["access_token"]
            _token_cache["expires_at"] = now + data["expires_in"]
            return _token_cache["access_token"]