const fs = require("fs");
const express = require("express");
const fetch = require("node-fetch");
const htmlParser = require("node-html-parser");
const { URL } = require("url");

// Array of hostnames that will be proxied
const URL_WHITELIST = [
  'i.ytimg.com',
  'yt3.googleusercontent.com',
  'cdn.glitch.global',
  'cdn.statically.io',
  'site-assets.fontawesome.com',
  'fonts.gstatic.com',
  'yt3.ggpht.com',
  'tube.kuylar.dev',
  'lh3.googleusercontent.com',
  'is4-ssl.mzstatic.com',
  'twemoji.maxcdn.com',
  'unpkg.com',
];

const app = express();

app.use(express.json()); // for parsing application/json
app.use(express.urlencoded({ extended: true })); // for parsing application/x-www-form-urlencoded

app.use(function (req, res, next) {
  console.log(`=> ${req.method} ${req.originalUrl.slice(1)}`)
  next();
});

app.use(function (req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  next();
});

/**
 * @param {express.Request} req 
 * @param {express.Response} res 
 */
const proxy = async (req, res) => {
  try {
    let url;

    try {
      url = new URL("https://" + req.originalUrl.slice(1));
    } catch(e) {
      console.log('==> Cannot parse URL: ' + e);
      return res.status(400).send('Malformed URL');
    }

    if (!URL_WHITELIST.includes(url.host)) {
      console.log(`==> Refusing to proxy host ${url.host}`);
      res.status(401).send(`Hostname '${url.host}' is not permitted`);
      return;
    }

    console.log(`==> Proxying request`);

    let f = await fetch(url, {
      method: req.method,
    });

    f.body.pipe(res);
  } catch(e) {
    console.log(`==> Error: ${e}`);
    res.status(500).send('Internal server error');
  }
};

const listener = (req, res) => {
  proxy(req, res);
};

app.get("/", (req, res) =>
  res.redirect(`https://poketube.fun/watch?v=l3eww1dnd0k`)
);

app.all("/*", listener);

app.listen(3000, () => console.log('Listening on 0.0.0.0:3000'));