const crypto = require('crypto');
const http = require('http');

const HMAC_SECRET = 'f6aeeb774a009d7b2a2bea348ea23c5f82de55ca38f3f3a2263ecc3cca1314b1';
const API_KEY = 'f176d279faef1256d209d921e85cd5e27c19ec3b6f057c6829c9ccb18be9af85';
const CENTRIFUGO_PORT = 8787;
const CHANNEL = 'projects-browser';

function createJWT(sub, expSeconds = 86400) {
  const header = { alg: 'HS256', typ: 'JWT' };
  const payload = { sub, exp: Math.floor(Date.now() / 1000) + expSeconds };
  const b64 = (obj) => Buffer.from(JSON.stringify(obj)).toString('base64url');
  const h = b64(header);
  const p = b64(payload);
  const sig = crypto.createHmac('sha256', HMAC_SECRET).update(`${h}.${p}`).digest('base64url');
  return `${h}.${p}.${sig}`;
}

function publish(data) {
  const body = JSON.stringify({ method: 'publish', params: { channel: CHANNEL, data } });

  const req = http.request({
    hostname: '127.0.0.1',
    port: CENTRIFUGO_PORT,
    path: '/api',
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `apikey ${API_KEY}`,
    },
  }, (res) => {
    // drain response
    res.resume();
  });

  req.on('error', (err) => {
    console.error('Centrifugo publish error:', err.message);
  });

  req.write(body);
  req.end();
}

function publishStatus(slug, status, extra = {}) {
  publish({ type: 'status', slug, status, ...extra });
}

function publishScreenshot(slug) {
  publish({ type: 'screenshot', slug, url: `/screenshots/${slug}.png?t=${Date.now()}` });
}

module.exports = { createJWT, publish, publishStatus, publishScreenshot, CHANNEL };