const express = require('express');
const axios = require('axios');
const app = express();
app.use(express.json());

const APP_ID = 'wx364b8ebf17fe45fe';
const APP_SECRET = '9b7476020991a2c71f1416da7f011d31'; // ⚠️ 安全存储在后端

// 前端发送 code 到这里
app.post('/api/wechat-login', async (req, res) => {
  const { code } = req.body;
  if (!code) return res.status(400).json({ error: 'code is required' });

  try {
    // 1️⃣ 换取 access_token
    const tokenResp = await axios.get('https://api.weixin.qq.com/sns/oauth2/access_token', {
      params: {
        appid: APP_ID,
        secret: APP_SECRET,
        code,
        grant_type: 'authorization_code'
      }
    });

    const tokenData = tokenResp.data;
    const accessToken = tokenData.access_token;
    const openid = tokenData.openid;

    if (!accessToken || !openid) {
      return res.status(400).json({ error: 'Failed to get access_token or openid', data: tokenData });
    }

    // 2️⃣ 获取用户信息
    const userResp = await axios.get('https://api.weixin.qq.com/sns/userinfo', {
      params: { access_token: accessToken, openid }
    });

    const userInfo = userResp.data;

    // 3️⃣ 可生成网站登录态（JWT 或 session），这里演示直接返回
    res.json({ userInfo });

  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'WeChat login failed' });
  }
});

app.listen(3001, () => {
  console.log('Server running on http://localhost:3001');
});