var express = require('express');
var router = express.Router();
const redis = require('../../libs/redis');
const { coloringList } = require('./config');

const CACHE_PREFIX = "art_v2";
// const CACHE_EXPIRES = 60; // 60s刷新一次
const CACHE_EXPIRES = 600;


// coloring pages 页路由
router.get('/', function (req, res, next) {
  (async function () {
    let cacheKey = `${CACHE_PREFIX}_coloring-pages`;
    let htmlData = await redis.getAsync(cacheKey);
    // htmlData = null;
    if (!htmlData) {
      let data = {
        uri: req.originalUrl,
        list: coloringList,
      };
      // 渲染EJS模板到内存中
      res.render('v2/coloring-pages', data, async (err, html) => {
        if (err) {
          // 如果渲染出错，调用next()传递错误
          return next(err);
        }

        // 渲染成功，存redis, 发送数据到客户端
        htmlData = html;
        try {
          await redis.set(cacheKey, htmlData, 'EX', CACHE_EXPIRES);
        } catch (e) {
          console.error(e);
        }

        res.send(htmlData);
      });
    } else {
      // 缓存命中， 直接发送缓存数据
      res.set({ 'X-From-Cache': 'true' });
      res.send(htmlData);
    }

  })().catch(next);

});


module.exports = router;