import PgBoss from 'pg-boss';
import { log } from '../log.js';

let boss = null;
const ensuring = new Map();   // name → Promise resolving when the queue is created

export async function start() {
  if (boss) return boss;
  boss = new PgBoss({
    connectionString: process.env.DATABASE_URL,
    newJobCheckIntervalSeconds: 2,
    archiveCompletedAfterSeconds: 86_400,
    deleteAfterDays: 7
  });
  boss.on('error', err => log.error({ err }, 'pg-boss error'));
  await boss.start();
  return boss;
}

export async function stop() {
  if (!boss) return;
  try { await boss.stop({ graceful: true, timeout: 5_000 }); }
  catch (e) { log.warn({ err: e }, 'pg-boss stop'); }
  boss = null;
  ensuring.clear();
}

function ensureQueue(name) {
  if (!ensuring.has(name)) {
    ensuring.set(name, boss.createQueue(name).catch(err => {
      ensuring.delete(name);
      throw err;
    }));
  }
  return ensuring.get(name);
}

export async function enqueue(name, data, opts = {}) {
  if (!boss) throw new Error('queue not started');
  await ensureQueue(name);
  return await boss.send(name, data, opts);
}

export async function subscribe(name, handler, opts = {}) {
  if (!boss) throw new Error('queue not started');
  await ensureQueue(name);
  return await boss.work(name, opts, async (jobs) => {
    const job = Array.isArray(jobs) ? jobs[0] : jobs;
    return handler(job);
  });
}

export function instance() { return boss; }