const express = require('express');
const puppeteer = require('puppeteer');
const app = express();

const FLAG = process.env.FLAG || 'kalmar{test_flag}';
const CHALLENGE_DOMAIN = process.env.CHALLENGE_DOMAIN || 'http://web:5000/';

app.use(express.json());

function sleep(ms) {
    return new Promise(res => setTimeout(res, ms));
}

async function visitUrl(url) {
  const browser = await puppeteer.launch({
    headless: true,
    args: [
      // this is not a pwn challenge, please don't rce us
      '--disable-extensions',
      '--disable-gpu',
      '--disable-software-rasterizer',
      '--js-flags=--noexpose_wasm,--jitless',
      '--no-sandbox',
    ]
  });

  try {
    const page = await browser.newPage();

    await page.goto(CHALLENGE_DOMAIN, {
      waitUntil: 'networkidle0',
    });

    // Flag is stored in localStorage
    await page.evaluate((flag) => {
        localStorage.setItem("flag", flag);
      }, FLAG);

    await sleep(1000);
    await page.close()

    // now visit reported page
    const page2 = await browser.newPage();
    await page2.goto(url, {waitUntil: []});

    await sleep(5000);
  } catch (err) {
    console.error('Error visiting page:', err);
  } finally {
    await browser.close();
  }
}

app.post('/report', async (req, res) => {
  const { url } = req.body;

  if (!url || typeof url !== 'string' || !url.startsWith(CHALLENGE_DOMAIN + '?')) {
    return res.status(400).json({ error: `Invalid URL. Url should be a string and start with ${CHALLENGE_DOMAIN  + '?'}` });
  }

  try {
    await visitUrl(url);
    res.json({ success: true });
  } catch (err) {
    console.error('Error on /report', err);
    res.status(500).json({ error: 'Failed to visit URL' });
  }
});

const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
  console.log(`Bot listening on port ${PORT}`);
});