import net from 'node:net';
import * as services from '../../db/repos/monitored_services.js';
import { log } from '../../log.js';

export const NAME = 'discover.lan';

// Common homelab web/service ports to probe.
const PORTS = [80, 81, 443, 2424, 3000, 3001, 5000, 5055, 6767, 6875, 7878, 8000,
  8006, 8080, 8081, 8096, 8123, 8265, 8384, 8443, 8989, 9000, 9090, 9696, 11434, 19999, 32400, 60072];
const HTTPS_PORTS = new Set([443, 8443, 8006]);

function tcpOpen(host, port, timeoutMs = 350) {
  return new Promise(resolve => {
    const sock = net.connect({ host, port });
    let done = false;
    const finish = (ok) => { if (!done) { done = true; sock.destroy(); resolve(ok); } };
    sock.setTimeout(timeoutMs);
    sock.on('connect', () => finish(true));
    sock.on('timeout', () => finish(false));
    sock.on('error', () => finish(false));
  });
}

async function httpTitle(url) {
  try {
    const res = await fetch(url, { redirect: 'manual', signal: AbortSignal.timeout(2500) });
    let title = '';
    if (res.status >= 200 && res.status < 400) {
      const html = await res.text().catch(() => '');
      const m = html.match(/<title>([^<]{1,80})/i);
      title = m ? m[1].trim().replace(/\s+/g, ' ') : '';
    }
    return { code: res.status, title };
  } catch { return null; }
}

// Test seam.
let _tcp = tcpOpen, _http = httpTitle;
export function _setProbes({ tcp, http } = {}) { _tcp = tcp || tcpOpen; _http = http || httpTitle; }

async function mapPool(items, concurrency, fn) {
  const out = new Array(items.length);
  let i = 0;
  await Promise.all(Array.from({ length: Math.min(concurrency, items.length) }, async () => {
    while (i < items.length) { const idx = i++; out[idx] = await fn(items[idx]); }
  }));
  return out;
}

export async function handler(job) {
  const subnet = job?.data?.subnet || process.env.DISCOVER_SUBNET || '192.168.1';
  const targets = [];
  for (let h = 1; h <= 254; h++) for (const port of PORTS) targets.push({ host: `${subnet}.${h}`, port });

  // 1) TCP sweep → live host:ports
  const open = (await mapPool(targets, 120, async (t) => (await _tcp(t.host, t.port)) ? t : null)).filter(Boolean);

  // 2) HTTP-probe each, build + upsert discovered candidates (no-clobber in the repo)
  let added = 0;
  for (const { host, port } of open) {
    const scheme = HTTPS_PORTS.has(port) ? 'https' : 'http';
    const url = `${scheme}://${host}:${port}`;
    const probe = await _http(url);
    const name = (probe && probe.title) || `${host}:${port}`;
    const id = `disc-${host.replace(/\./g, '-')}-${port}`;
    const check = scheme === 'https' ? { type: 'tcp' } : { type: 'http' };
    const r = await services.upsertDiscovered({ id, name, category: 'other', host, url, check });
    if (r) added++;
  }
  log.info({ open: open.length, added }, 'lan discovery complete');
  return { open: open.length, added };
}