import httpx

from app.config import get_settings


class WechatMiniClientError(Exception):
    pass


class WechatMiniClient:
    """微信小程序 code2session / getPhoneNumber 客户端。

    未配置 appid/secret 时视为 mock 模式，由上层跳过真实调用。
    """

    CODE2SESSION_URL = "https://api.weixin.qq.com/sns/jscode2session"
    ACCESS_TOKEN_URL = "https://api.weixin.qq.com/cgi-bin/token"
    GET_PHONE_URL = "https://api.weixin.qq.com/wxa/business/getuserphonenumber"

    def __init__(self) -> None:
        settings = get_settings()
        self.appid = settings.wx_mini_appid
        self.secret = settings.wx_mini_secret
        self.timeout = 10.0

    @property
    def configured(self) -> bool:
        return bool(self.appid and self.secret)

    def code2session(self, js_code: str) -> dict:
        params = {
            "appid": self.appid,
            "secret": self.secret,
            "js_code": js_code,
            "grant_type": "authorization_code",
        }
        with httpx.Client(timeout=self.timeout, trust_env=False) as client:
            resp = client.get(self.CODE2SESSION_URL, params=params)
        data = resp.json()
        if data.get("errcode"):
            raise WechatMiniClientError(f"code2session 失败: {data.get('errmsg')}")
        return data

    def _access_token(self) -> str:
        params = {
            "grant_type": "client_credential",
            "appid": self.appid,
            "secret": self.secret,
        }
        with httpx.Client(timeout=self.timeout, trust_env=False) as client:
            resp = client.get(self.ACCESS_TOKEN_URL, params=params)
        data = resp.json()
        token = data.get("access_token")
        if not token:
            raise WechatMiniClientError(f"获取 access_token 失败: {data.get('errmsg')}")
        return token

    def get_phone_number(self, phone_code: str) -> str:
        token = self._access_token()
        url = f"{self.GET_PHONE_URL}?access_token={token}"
        with httpx.Client(timeout=self.timeout, trust_env=False) as client:
            resp = client.post(url, json={"code": phone_code})
        data = resp.json()
        if data.get("errcode"):
            raise WechatMiniClientError(f"getPhoneNumber 失败: {data.get('errmsg')}")
        phone_info = data.get("phone_info") or {}
        phone = phone_info.get("purePhoneNumber") or phone_info.get("phoneNumber")
        if not phone:
            raise WechatMiniClientError("getPhoneNumber 未返回手机号")
        return phone