import httpx

from app.config import settings


async def code_to_session(code: str) -> dict:
    """用小程序 code 换取 openid 和 session_key"""
    url = "https://api.weixin.qq.com/sns/jscode2session"
    params = {
        "appid": settings.wechat_app_id,
        "secret": settings.wechat_app_secret,
        "js_code": code,
        "grant_type": "authorization_code",
    }
    async with httpx.AsyncClient() as client:
        resp = await client.get(url, params=params)
        data = resp.json()

    if "errcode" in data and data["errcode"] != 0:
        raise Exception(f"微信登录失败: {data.get('errmsg', '未知错误')}")

    return {
        "openid": data["openid"],
        "session_key": data["session_key"],
        "unionid": data.get("unionid"),
    }