/***********************************************************************************************************************************************************************
 * File Name    : user_task_overdue_notify.cron.js
 * Type         : Cron Job
 * Description  : Emits a UserNotification for every user who belongs to a group
 *                assigned to a task list that contains a task that JUST flipped
 *                to 'overdue' in the last hour.
 *
 *                Runs 5 minutes after the admin taskOverdue cron (which fires at
 *                the top of each hour) so the status flips are already committed
 *                before this job queries them.
 *
 *                "Just flipped" = status is 'overdue' AND updatedAt is within
 *                the last 65 minutes (1-hour window + 5-min drift buffer).
 *                This prevents re-notifying users for tasks that were already
 *                overdue before this run.
 *
 * Schedule     : 5 minutes past every hour ("5 * * * *"). Registered by
 *                cron/client.cron.js.
 *
 * Author: Kenneth Obsequio (@lash0000)
 * Date Created: Jun. 19, 2026
 ***********************************************************************************************************************************************************************/
const { Op, QueryTypes } = require('sequelize');
const sequelize        = require('../../config/db.config');
const { Task }         = require('../../models/task/task.mdl');
const UserNotification = require('../../models/notifications/user_notification.mdl');
const CronNotificationSetting = require('../../models/notifications/cron_notification_setting.mdl');
const { NOTIFICATION_REGISTRY } = require('../../data/notifications.data');

const WINDOW_MS = 65 * 60 * 1000; // 65-minute lookback

async function run() {
    // Entire job exists to emit this notification — skippable via /admin/notifications/settings.
    const settings = await CronNotificationSetting.findOne({ where: { job_name: 'userNotifications' } });
    if (settings && !settings.enabled) return;

    // ── 1. Find tasks that flipped to overdue in the last 65 minutes ──────────
    let recentlyOverdue;
    try {
        recentlyOverdue = await Task.findAll({
            attributes: ['task_id', 'task_list_id', 'name'],
            where: {
                status:    'overdue',
                updatedAt: { [Op.gte]: new Date(Date.now() - WINDOW_MS) },
            },
            raw: true,
        });
    } catch (err) {
        console.error('[CRON][USER NOTIFY] Failed to query recently overdue tasks:', err);
        return;
    }

    if (recentlyOverdue.length === 0) return;

    console.log(`[CRON][USER NOTIFY] ${recentlyOverdue.length} recently overdue task(s) — resolving affected users.`);

    // ── 2. Resolve affected users via task_list_groups → user_group_members ───
    try {
        const taskListIds = [...new Set(recentlyOverdue.map(t => t.task_list_id))];

        const affectedUsers = await sequelize.query(
            `SELECT DISTINCT ugm.user_id
             FROM   task_list_groups   tlg
             JOIN   user_group_members ugm ON ugm.group_id   = tlg.group_id
                                          AND ugm."deletedAt" IS NULL
             WHERE  tlg.task_list_id IN (:taskListIds)`,
            { replacements: { taskListIds }, type: QueryTypes.SELECT }
        );

        if (affectedUsers.length === 0) return;

        const count  = recentlyOverdue.length;
        const now    = new Date();
        const notify = NOTIFICATION_REGISTRY.user_task_overdue.build({ count, task_list_ids: taskListIds });

        await UserNotification.bulkCreate(
            affectedUsers.map(({ user_id }) => ({
                user_id,
                ...notify,
                seen:      false,
                createdAt: now,
                updatedAt: now,
            })),
            { validate: false }
        );

        console.log(`[CRON][USER NOTIFY] Notified ${affectedUsers.length} user(s) about ${count} overdue task(s).`);
    } catch (err) {
        console.error('[CRON][USER NOTIFY] Failed to emit user notifications:', err);
    }
}

module.exports = {
    name:     'userNotifications',
    schedule: '5 * * * *',
    run,
};