'use strict';

/**
 * snapshotScheduler — in-process snapshot cron (Session 45).
 *
 * No new dependency: a 1-minute unref'd interval that fires `runAllSnapshots`
 * at the configured UTC hours (default 14,19,22,1,3 = 10AM/3PM/6PM/9PM/11PM ET,
 * matching the sports cycle — morning research, afternoon news, pre-game lock,
 * in-game). Gated on SNAPSHOT_CRON=1 so it never runs in dev/test or on a
 * container that shouldn't own the schedule. Prefer an EXTERNAL cron (n8n) hitting
 * POST /api/internal/snapshot/all when running multiple API replicas — this
 * in-process variant assumes a single scheduler instance.
 */

const HOURS_UTC = (process.env.SNAPSHOT_HOURS_UTC || '14,19,22,1,3')
  .split(',')
  .map((n) => parseInt(n, 10))
  .filter((n) => Number.isInteger(n) && n >= 0 && n <= 23);

function startSnapshotScheduler(opts = {}) {
  if (process.env.SNAPSHOT_CRON !== '1') return null;
  const runAll = opts.runAllSnapshots || require('./services/snapshotService').runAllSnapshots;
  const now = opts.now || (() => new Date());
  let lastFiredSlot = null;

  const tick = async () => {
    const d = now();
    if (d.getUTCMinutes() !== 0) return;
    const h = d.getUTCHours();
    if (!HOURS_UTC.includes(h)) return;
    const slot = `${d.getUTCFullYear()}-${d.getUTCMonth()}-${d.getUTCDate()}-${h}`;
    if (slot === lastFiredSlot) return; // fire once per slot
    lastFiredSlot = slot;
    try {
      const results = await runAll();
      const ok = results.filter((r) => r.status === 'ok');
      console.log(`[snapshot] cron fired ${h}:00 UTC — ${ok.length}/${results.length} sports graded`);
    } catch (e) {
      console.warn('[snapshot] cron run failed:', e.message);
    }
  };

  const interval = setInterval(tick, 60_000);
  if (interval.unref) interval.unref();
  console.log(`[snapshot] scheduler armed for UTC hours: ${HOURS_UTC.join(', ')}`);
  return { interval, tick };
}

module.exports = { startSnapshotScheduler, HOURS_UTC };