#!/usr/bin/env node

// Wrapper around `ng serve` that resolves the best binding:
//   1. https://stella-ops.local  (port 443) — if hostname resolves and port is free
//   2. https://localhost:10000                — always available fallback
//
// Additionally binds http://stella-ops.local (port 80) as a redirect to HTTPS
// when the hostname resolves and port 80 is available.

const { spawn } = require('child_process');
const http = require('http');
const dns = require('dns');
const net = require('net');
const path = require('path');

const HOSTNAME = 'stella-ops.local';
const HTTPS_PORT = 443;
const HTTP_PORT = 80;
const DEV_PORT = 10000;
const SETUP_DOC = 'docs/technical/architecture/port-registry.md';

function isWindows() {
  return process.platform === 'win32';
}

function hostsFilePath() {
  return isWindows()
    ? 'C:\\Windows\\System32\\drivers\\etc\\hosts'
    : '/etc/hosts';
}

function resolveHostnameIp(hostname) {
  return new Promise((resolve) => {
    dns.lookup(hostname, { family: 4 }, (err, address) => {
      if (err) return resolve(null);
      resolve(address);
    });
  });
}

function isPortAvailable(port, ip) {
  return new Promise((resolve) => {
    const server = net.createServer();
    server.once('error', () => resolve(false));
    server.once('listening', () => {
      server.close(() => resolve(true));
    });
    server.listen(port, ip);
  });
}

function startHttpRedirect(httpsHost, httpsPort, bindIp) {
  return new Promise((resolve) => {
    const server = http.createServer((req, res) => {
      const location = `https://${httpsHost}${httpsPort === 443 ? '' : ':' + httpsPort}${req.url}`;
      res.writeHead(301, { Location: location });
      res.end();
    });

    server.on('error', (err) => {
      console.warn(`  HTTP redirect on port ${HTTP_PORT} failed: ${err.message}`);
      resolve(false);
    });

    server.listen(HTTP_PORT, bindIp, () => {
      console.log(`  HTTP redirect active: http://${HOSTNAME} -> https://${httpsHost}${httpsPort === 443 ? '' : ':' + httpsPort}`);
      console.log(`  Bound to ${bindIp}:${HTTP_PORT}`);
      resolve(true);
    });
  });
}

async function main() {
  const extraArgs = process.argv.slice(2);
  const resolvedIp = await resolveHostnameIp(HOSTNAME);
  const hostnameOk = !!resolvedIp;
  const port443Free = hostnameOk ? await isPortAvailable(HTTPS_PORT, resolvedIp) : false;
  const port80Free = hostnameOk ? await isPortAvailable(HTTP_PORT, resolvedIp) : false;

  let host, port;

  if (hostnameOk && port443Free) {
    host = HOSTNAME;
    port = HTTPS_PORT;
    console.log('');
    console.log(`  ${HOSTNAME} resolves to ${resolvedIp}; port ${HTTPS_PORT} is available.`);
    console.log(`  Dev server binding to https://${HOSTNAME}`);
    console.log(`  Also accessible at https://localhost:${DEV_PORT}`);

    if (port80Free) {
      const redirectOk = await startHttpRedirect(HOSTNAME, HTTPS_PORT, resolvedIp);
      if (redirectOk) {
        console.log(`  Also accessible at http://${HOSTNAME} (redirects to HTTPS)`);
      } else {
        console.warn(`  Failed to start HTTP redirect on ${resolvedIp}:${HTTP_PORT}`);
      }
    } else {
      console.warn(`  Port ${HTTP_PORT} on ${resolvedIp} is unavailable; skipping http://${HOSTNAME} redirect.`);
    }

    console.log('');
  } else if (hostnameOk) {
    host = HOSTNAME;
    port = DEV_PORT;
    console.warn('');
    console.warn(`  ${HOSTNAME} resolves to ${resolvedIp} but port ${HTTPS_PORT} is unavailable`);
    console.warn(`  (requires elevated privileges or is already in use).`);
    console.warn(`  Dev server binding to https://${HOSTNAME}:${DEV_PORT}`);
    console.warn('');
  } else {
    host = 'localhost';
    port = DEV_PORT;
    console.warn('');
    console.warn(`  WARNING: ${HOSTNAME} does not resolve.`);
    console.warn(`  Dev server binding to https://localhost:${DEV_PORT}`);
    console.warn('');
    console.warn(`  To use https://${HOSTNAME}, add to ${hostsFilePath()}:`);
    console.warn('');
    console.warn(`    127.1.0.1 ${HOSTNAME}  # or your preferred IP`);
    console.warn('');
    console.warn(`  See ${SETUP_DOC} for the full list of hostnames.`);
    console.warn('');
  }

  runNgServe(host, port, extraArgs);
}

function runNgServe(host, port, extraArgs) {
  const cwd = path.resolve(__dirname, '..');
  const ngCli = path.resolve(cwd, 'node_modules', '@angular', 'cli', 'bin', 'ng.js');
  // Pass the hostname (not IP) so Vite resolves it for both HTTPS and HMR websocket.
  // The hostname resolves to a unique loopback IP via the hosts file, so ports
  // won't collide with other services.
  const args = ['serve', '--host', host, '--port', String(port), '--ssl', ...extraArgs];

  console.log(`  ng serve binding to ${host}:${port}`);

  const child = spawn(process.execPath, [ngCli, ...args], {
    stdio: 'inherit',
    cwd,
  });

  child.on('exit', (code) => process.exit(code ?? 1));
}

main();