// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

import * as formSubmit from 'core_form/submit';

/**
 * Module for the quick grading functionality on the submissions page.
 *
 * @module     mod_assign/quick_grading
 * @copyright  2024 Mihail Geshoski <mihail@moodle.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/** @constant {Object} The object containing the relevant selectors. */
const Selectors = {
    quickGradingSaveRegion: '[data-region="quick-grading-save"]',
    notifyStudentsCheckbox: 'input[type="checkbox"][name="sendstudentnotifications"]',
    notifyStudentsHidden: 'input[type="hidden"][name="sendstudentnotifications"]',
    saveButton: 'button[type="submit"]'
};

/**
 * Initialize module.
 */
export const init = () => {
    const quickGradingSaveRegion = document.querySelector(Selectors.quickGradingSaveRegion);
    if (quickGradingSaveRegion) {
        const quickGradingSaveButton = quickGradingSaveRegion.querySelector(Selectors.saveButton);
        // Initialize the submit button.
        formSubmit.init(quickGradingSaveButton);
        // Add 'change' event listener to the quick grading save region.
        quickGradingSaveRegion.addEventListener('change', e => {
            const notifyStudentsCheckbox = e.target.closest(Selectors.notifyStudentsCheckbox);
            // The target is the 'Notify student' checkbox.
            if (notifyStudentsCheckbox) {
                // The 'Notify student' option uses a hidden input and a checkbox. The hidden input is used to submit '0'
                // as a workaround when the checkbox is unchecked since unchecked checkboxes are not submitted with the
                // form. Therefore, we need to enable or disable the hidden input based on the checkbox state.
                const notifyStudentsHidden = notifyStudentsCheckbox.parentNode.querySelector(Selectors.notifyStudentsHidden);
                notifyStudentsHidden.disabled = notifyStudentsCheckbox.checked;
            }
        });
    }
};