#!/usr/bin/env node
/**
 * Health HTTP + optional NATS subscribe.
 * Fleet probes /health. Live NATS is off unless NATS_URL is set.
 */
import http from 'node:http';
import { SUBJECTS } from './subjects.js';
import { handle } from './handle.js';

const port = Number(process.env.FLEET_HEALTH_PORT || process.env.PORT || 13900);
const bind = process.env.FLEET_HEALTH_BIND || '127.0.0.1';
const instance = process.env.FLEET_INSTANCE || 'verae-nats-process-0';
let paused = false;
let processed = 0;

function snapshot() {
  return {
    ok: !paused,
    paused,
    instance,
    role: 'verae-nats-process',
    subjects: { in: SUBJECTS.IN, out: SUBJECTS.OUT, queue: SUBJECTS.QUEUE },
    processed,
  };
}

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, 'http://127.0.0.1');
  const json = (code, obj) => {
    res.writeHead(code, { 'content-type': 'application/json' });
    res.end(JSON.stringify(obj));
  };
  if (url.pathname === '/health' && req.method === 'GET') {
    const s = snapshot();
    return json(s.ok ? 200 : 503, s);
  }
  if (url.pathname === '/pause' && req.method === 'POST') {
    paused = true;
    return json(200, snapshot());
  }
  if (url.pathname === '/resume' && req.method === 'POST') {
    paused = false;
    return json(200, snapshot());
  }
  if (url.pathname === '/message' && req.method === 'POST') {
    const chunks = [];
    for await (const c of req) chunks.push(c);
    let body = {};
    try {
      body = JSON.parse(Buffer.concat(chunks).toString('utf8') || '{}');
    } catch {
      body = {};
    }
    if (paused) return json(503, snapshot());
    try {
      const out = await handle(body);
      processed += 1;
      return json(200, { rttMs: 0, result: out, replyTo: SUBJECTS.reply(out.correlationId) });
    } catch (err) {
      return json(400, { error: err.message });
    }
  }
  json(404, { error: 'not found' });
});

server.listen(port, bind, () => {
  process.stdout.write(`${instance} health http://${bind}:${port}/health in=${SUBJECTS.IN}\n`);
});

process.on('SIGTERM', () => server.close(() => process.exit(0)));