"""
微信小程序服务模块

提供微信小程序登录功能。
"""
import httpx
from typing import Optional

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

logger = get_logger(__name__)


class WechatService:
    """微信小程序服务类"""
    
    @staticmethod
    async def code2session(code: str) -> Optional[dict]:
        """
        通过微信登录凭证获取 session 信息
        
        Args:
            code: 微信登录凭证
            
        Returns:
            dict: {"openid": str, "session_key": str, "unionid": str (可选)}
        """
        if not settings.wechat_app_id or not settings.wechat_app_secret:
            logger.error("微信小程序配置缺失")
            return None
        
        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"
        }
        
        try:
            async with httpx.AsyncClient() as client:
                response = await client.get(url, params=params)
                data = response.json()
                
                if "errcode" in data and data["errcode"] != 0:
                    logger.error(f"微信登录失败: {data.get('errmsg')}")
                    return None
                
                return {
                    "openid": data.get("openid"),
                    "session_key": data.get("session_key"),
                    "unionid": data.get("unionid")
                }
        except Exception as e:
            logger.exception(f"微信登录异常: {e}")
            return None
    
    @staticmethod
    async def get_phone_number(phone_code: str) -> Optional[str]:
        """
        通过手机号授权码获取用户手机号
        
        微信新版 API，使用 getPhoneNumber 返回的 code 获取手机号
        
        Args:
            phone_code: 手机号授权码 (getPhoneNumber 返回的 code)
            
        Returns:
            str: 用户手机号，失败返回 None
        """
        if not settings.wechat_app_id or not settings.wechat_app_secret:
            logger.error("微信小程序配置缺失")
            return None
        
        access_token = await WechatService._get_access_token()
        if not access_token:
            return None
        
        url = "https://api.weixin.qq.com/wxa/business/getuserphonenumber"
        
        try:
            async with httpx.AsyncClient() as client:
                response = await client.post(
                    url,
                    params={"access_token": access_token},
                    json={"code": phone_code}
                )
                data = response.json()
                
                if data.get("errcode", 0) != 0:
                    logger.error(f"获取手机号失败: {data.get('errmsg')}")
                    return None
                
                phone_info = data.get("phone_info", {})
                return phone_info.get("purePhoneNumber") or phone_info.get("phoneNumber")
        except Exception as e:
            logger.exception(f"获取手机号异常: {e}")
            return None
    
    @staticmethod
    async def _get_access_token() -> Optional[str]:
        """
        获取微信小程序 access_token
        
        注意：生产环境应缓存 access_token，有效期 2 小时
        """
        url = "https://api.weixin.qq.com/cgi-bin/token"
        params = {
            "grant_type": "client_credential",
            "appid": settings.wechat_app_id,
            "secret": settings.wechat_app_secret
        }
        
        try:
            async with httpx.AsyncClient() as client:
                response = await client.get(url, params=params)
                data = response.json()
                
                if "access_token" in data:
                    return data["access_token"]
                
                logger.error(f"获取 access_token 失败: {data.get('errmsg')}")
                return None
        except Exception as e:
            logger.exception(f"获取 access_token 异常: {e}")
            return None