<?php
// This file is part of the customcert module for 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/>.

/**
 * This file contains the customcert element teachername's core interaction API.
 *
 * @package    customcertelement_teachername
 * @copyright  2013 Mark Nelson <markn@moodle.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

namespace customcertelement_teachername;

/**
 * The customcert element teachername's core interaction API.
 *
 * @package    customcertelement_teachername
 * @copyright  2013 Mark Nelson <markn@moodle.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class element extends \mod_customcert\element {
    /**
     * This function renders the form elements when adding a customcert element.
     *
     * @param \MoodleQuickForm $mform the edit_form instance
     */
    public function render_form_elements($mform) {
        $mform->addElement(
            'select',
            'teacher',
            get_string('teacher', 'customcertelement_teachername'),
            $this->get_list_of_teachers()
        );
        $mform->addHelpButton('teacher', 'teacher', 'customcertelement_teachername');

        parent::render_form_elements($mform);
    }

    /**
     * This will handle how form data will be saved into the data column in the
     * customcert_elements table.
     *
     * @param \stdClass $data the form data
     * @return string the text
     */
    public function save_unique_data($data) {
        if (!empty($data->teacher)) {
            return $data->teacher;
        }
    }

    /**
     * Handles rendering the element on the pdf.
     *
     * @param \pdf $pdf the pdf object
     * @param bool $preview true if it is a preview, false otherwise
     * @param \stdClass $user the user we are rendering this for
     */
    public function render($pdf, $preview, $user) {
        global $DB;

        $teacher = $DB->get_record('user', ['id' => $this->get_data()]);
        $teachername = fullname($teacher);

        \mod_customcert\element_helper::render_content($pdf, $this, $teachername);
    }

    /**
     * Render the element in html.
     *
     * This function is used to render the element when we are using the
     * drag and drop interface to position it.
     *
     * @return string the html
     */
    public function render_html() {
        global $DB;

        $teacher = $DB->get_record('user', ['id' => $this->get_data()]);
        $teachername = fullname($teacher);

        return \mod_customcert\element_helper::render_html_content($this, $teachername);
    }

    /**
     * Helper function to return the teachers for this course.
     *
     * @return array the list of teachers
     */
    protected function get_list_of_teachers() {
        global $PAGE;

        // Return early if we are in a site template.
        if ($PAGE->context->id == \context_system::instance()->id) {
            return [];
        }

        // The list of teachers to return.
        $teachers = [];

        // Now return all users who can manage the customcert in this context.
        if ($users = get_enrolled_users($PAGE->context, 'mod/customcert:manage')) {
            foreach ($users as $user) {
                $teachers[$user->id] = fullname($user);
            }
        }

        return $teachers;
    }

    /**
     * Sets the data on the form when editing an element.
     *
     * @param \MoodleQuickForm $mform the edit_form instance
     */
    public function definition_after_data($mform) {
        if (!empty($this->get_data())) {
            $element = $mform->getElement('teacher');
            $element->setValue($this->get_data());
        }
        parent::definition_after_data($mform);
    }
}
