/***********************************************************************************************************************************************************************
 * File Name    : cronRegistry.util.js
 * Type         : Utility
 * Description  : Shared machinery for settings-backed cron jobs (the 4 jobs
 *                that emit notifications and are configurable from
 *                /admin/notifications/settings). Not every cron job in the
 *                app goes through this — jobs with no notification tied to
 *                them (e.g. lift_expired_bans) keep using node-cron directly.
 *
 *                startSettingsBackedJobs() reads each job's schedule from
 *                cron_notification_settings (falling back to — and seeding —
 *                the job's own hardcoded default on first boot), then keeps
 *                a live reference to the scheduled task so it can be swapped
 *                out later via rescheduleJob() without a server restart.
 *
 * Author: Kenneth Obsequio (@lash0000)
 * Date Created: Jul. 2, 2026
 ***********************************************************************************************************************************************************************/
'use strict';

const cron = require('node-cron');
const CronNotificationSetting = require('../models/notifications/cron_notification_setting.mdl');

// job_name -> { task: ScheduledTask, run: fn }
const runningTasks = new Map();

// CockroachDB can't run Sequelize's findOrCreate() — it wraps the insert in a
// pg_temp PL/pgSQL function to atomically catch unique_violation, which
// CockroachDB rejects ("cannot create user-defined functions under a temporary
// schema"). Plain findOne-then-create sidesteps it; the race window (two boots
// racing to seed the same job_name) is a non-issue here — jobs are seeded once.
async function getOrCreateSetting(jobName, defaultSchedule) {
    let row = await CronNotificationSetting.findOne({ where: { job_name: jobName } });
    if (row) return row;

    try {
        row = await CronNotificationSetting.create({ job_name: jobName, enabled: true, schedule: defaultSchedule });
    } catch (err) {
        row = await CronNotificationSetting.findOne({ where: { job_name: jobName } });
        if (!row) throw err;
    }
    return row;
}

async function startSettingsBackedJobs(jobs, scopeLabel) {
    const registered = [];

    for (const { name, schedule: defaultSchedule, run } of jobs) {
        let schedule = defaultSchedule;
        try {
            const settings = await getOrCreateSetting(name, defaultSchedule);
            schedule = settings.schedule || defaultSchedule;
        } catch (err) {
            console.error(`[CRON][${scopeLabel}] Failed to load settings for "${name}", using hardcoded default:`, err);
        }

        if (!cron.validate(schedule)) {
            console.error(`[CRON][${scopeLabel}] Invalid schedule for "${name}": "${schedule}" — skipped.`);
            continue;
        }

        const task = cron.schedule(schedule, run);
        runningTasks.set(name, { task, run });
        registered.push({ name, scope: scopeLabel, schedule });
    }

    return registered;
}

// Live-swap a running job's schedule — used by notificationSettings.controller.js
// after an admin picks a new preset. No server restart required.
function rescheduleJob(jobName, newSchedule) {
    const entry = runningTasks.get(jobName);
    if (!entry) throw new Error(`No running cron task found for "${jobName}".`);
    if (!cron.validate(newSchedule)) throw new Error(`Invalid cron schedule: "${newSchedule}".`);

    entry.task.stop();
    const task = cron.schedule(newSchedule, entry.run);
    runningTasks.set(jobName, { task, run: entry.run });
}

module.exports = { startSettingsBackedJobs, rescheduleJob, getOrCreateSetting };