/***********************************************************************************************************************************************************************
 * File Name    : retry_stuck_transcodes.cron.js
 * Type         : Cron Job
 * Description  : Safety net for the .mov/.mkv -> faststart .mp4 background
 *                remux (see services/assetTranscode.service.js). Picks up:
 *                  - "pending"    — the fire-and-forget call in
 *                                   assets.controller.js#finalizeAssetFromStorage
 *                                   never actually started (e.g. this process
 *                                   crashed between the DB commit and the call).
 *                  - "processing" for over 30 minutes — the job itself was
 *                                   running when the process restarted/crashed
 *                                   mid-remux and never got to flip the status.
 *
 *                Processes at most 3 per run, sequentially — this runs on a
 *                small droplet, and remuxing is disk/CPU-bound; no reason to
 *                pile up concurrent ffmpeg processes for a background sweep.
 *
 * Schedule     : Every 10 minutes ("*\/10 * * * *"). Registered by
 *                cron/admin.cron.js.
 *
 * Author: Kenneth Obsequio
 * Date Created: Aug. 1, 2026
 ***********************************************************************************************************************************************************************/
const { Op } = require('sequelize');
const mdl_Assets = require('../../models/assets/assets.mdl');
const { transcodeAsset } = require('../../services/assetTranscode.service');

const MAX_PER_RUN = 3;
const STUCK_PROCESSING_MINUTES = 30;

async function run() {
    try {
        const stuckSince = new Date(Date.now() - STUCK_PROCESSING_MINUTES * 60 * 1000);

        // Demote stale "processing" rows back to "pending" so transcodeAsset()'s
        // own claim step (pending/failed -> processing) can pick them up again —
        // it never claims an in-progress "processing" row, by design (avoids
        // double-processing a job that's actually still running elsewhere).
        await mdl_Assets.update(
            { transcode_status: 'pending' },
            { where: { transcode_status: 'processing', updatedAt: { [Op.lt]: stuckSince } } },
        );

        const candidates = await mdl_Assets.findAll({
            where: { deletedAt: null, transcode_status: 'pending' },
            limit: MAX_PER_RUN,
        });

        if (!candidates.length) return;

        for (const asset of candidates) {
            await transcodeAsset(asset);
        }

        console.log(`[CRON][RETRY STUCK TRANSCODES] Processed ${candidates.length} asset(s).`);
    } catch (err) {
        console.error('[CRON][RETRY STUCK TRANSCODES] Failed:', err);
    }
}

module.exports = {
    name:     'retryStuckTranscodes',
    schedule: '*/10 * * * *',
    run,
};