const axios = require('axios');
const fs = require('fs');
const path = require('path');
var express = require('express');
var router = express.Router();
// 微信小程序的AppID和AppSecret
const appId = 'xxxx';
const appSecret = 'xxxx';
/* GET home page. */
router.get('/', function (req, res, next) {
  res.render('index', { title: 'Express' });
});

//创建二维码
router.get('/createcode/:sid', async (req, res, next) => {

  const qrcode = await generateQrcode('pages/index/index', req.params.sid);//获取流

  res.send(qrcode);

});

// 异步函数获取access_token
async function getAccessToken() {
  const response = await axios({
    url: 'https://api.weixin.qq.com/cgi-bin/token',
    method: 'get',
    params: {
      grant_type: 'client_credential',
      appid: appId,
      secret: appSecret
    }
  });
  return response.data.access_token;
}
// 异步函数生成小程序二维码
async function generateQrcode(pagePath, scene) {
  const accessToken = await getAccessToken(); // 确保已获取access_token
  console.log('accessToken>>>', accessToken);
  const response = await axios({
    url: 'https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=' + accessToken,
    method: 'post',
    responseType: 'arraybuffer',// `responseType` 表示浏览器将要响应的数据类型，选项包括: 'arraybuffer', 'document', 'json', 'text', 'stream'等
    data: {
      scene: scene, //最大32个可见字符
      page: pagePath, // 默认页面路径
      "check_path": false,
      "env_version": "develop",
      width: 430 // 二维码宽度，单位为像素
    }
  });

  if (response.status == 200 && response.data && !response.data.errmsg) {
    const qrcodeBuffer = response.data;
    console.log('是否是buffer>>>>>',Buffer.isBuffer(qrcodeBuffer));
    //转为图片保存 
    fs.writeFile('qrcode1.png',qrcodeBuffer,'binary',(err)=>{
      if(!err){
        console.log('图片保存成功');
      }
    });

    const base64Image = qrcodeBuffer.toString('base64');
    const dataUrl = `data:image/png;base64,${base64Image}`;
    return dataUrl; // 返回图片流
  }

}

module.exports = router;