<?php
// 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/>.

namespace qbank_statistics\columns;

use core_question\local\bank\column_base;

/**
 * This columns shows a message about whether this question is OK or needs revision.
 *
 * This is based on the average discrimination index.
 *
 * @package    qbank_statistics
 * @copyright  2021 Catalyst IT Australia Pty Ltd
 * @author     Nathan Nguyen <nathannguyen@catalyst-au.net>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class discrimination_index extends column_base {

    public function get_title(): string {
        return get_string('discrimination_index', 'qbank_statistics');
    }

    public function help_icon(): ?\help_icon {
        return new \help_icon('discrimination_index', 'qbank_statistics');
    }

    public function get_name(): string {
        return 'discrimination_index';
    }

    public function get_required_statistics_fields(): array {
        return ['discriminationindex'];
    }

    protected function display_content($question, $rowclasses) {
        global $PAGE;

        $discriminationindex = $this->qbank->get_aggregate_statistic($question->id, 'discriminationindex');
        echo $PAGE->get_renderer('qbank_statistics')->render_discrimination_index($discriminationindex);
    }


>     public function display_preview(\stdClass $question, string $rowclasses): void {
    public function get_extra_classes(): array {
>         global $PAGE;
        return ['pr-3'];
> 
    }
>         $this->display_start($question, $rowclasses);

>         echo $PAGE->get_renderer('qbank_statistics')->render_discrimination_index(50.00);
}
>         $this->display_end($question, $rowclasses);;
>     }
>