'use strict';

const http = require('http');
const { settings, validate } = require('./src/settings');
const {
  probeCycle,
  startProbing,
  stopProbing,
} = require('./src/upstreams');
const { handleProxy } = require('./src/proxy');
const { healthPayload } = require('./src/health');
const { sendText, sendJson } = require('./src/http-utils');

const HEALTH_PATHS = new Set(['/health', '/healthz']);

const server = http.createServer((req, res) => {
  let reqUrl;
  try {
    reqUrl = new URL(req.url, 'http://proxy.invalid');
  } catch {
    sendText(res, 400, 'Bad request');
    return;
  }

  if (req.method === 'GET' && HEALTH_PATHS.has(reqUrl.pathname)) {
    sendJson(res, 200, healthPayload());
    return;
  }

  handleProxy(req, res, reqUrl);
});

function shutdown(signal) {
  console.log(`Received ${signal}, shutting down`);
  stopProbing();
  server.close(() => process.exit(0));
  setTimeout(() => process.exit(0), 5000).unref();
}

process.on('SIGTERM', () => shutdown('SIGTERM'));
process.on('SIGINT', () => shutdown('SIGINT'));

async function main() {
  try {
    validate();
  } catch (e) {
    console.error(e.message);
    process.exit(1);
  }

  await probeCycle();

  server.listen(settings.listenPort, () => {
    console.log(`Xtream proxy listening on :${settings.listenPort}`);
    console.log(`Config file: ${settings.configFile}`);
    console.log(
      `Probe interval: ${settings.probeIntervalSec}s, probe timeout: ${settings.probeTimeoutMs}ms`
    );
    startProbing();
  });
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});