edit_multichoice_form.php

<?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/>.

defined('MOODLE_INTERNAL') || die();

/**
 * Defines the editing form for the multiple choice question type.
 *
 * @package qtype
 * @subpackage multichoice
 * @copyright &copy; 2007 Jamie Pratt
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * Multiple choice editing form definition.
 *
 * @copyright &copy; 2007 Jamie Pratt
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class question_edit_multichoice_form extends question_edit_form {
    /**
     * Add question-type specific form fields.
     *
     * @param object $mform the form being built.
     */
    protected function definition_inner($mform) {
        global $QTYPES;

        $menu = array(get_string('answersingleno', 'qtype_multichoice'), get_string('answersingleyes', 'qtype_multichoice'));
        $mform->addElement('select', 'single', get_string('answerhowmany', 'qtype_multichoice'), $menu);
        $mform->setDefault('single', 1);

        $mform->addElement('advcheckbox', 'shuffleanswers', get_string('shuffleanswers', 'qtype_multichoice'), null, null, array(0,1));
        $mform->addHelpButton('shuffleanswers', 'shuffleanswers', 'qtype_multichoice');
        $mform->setDefault('shuffleanswers', 1);

        $mform->addElement('select', 'answernumbering', get_string('answernumbering', 'qtype_multichoice'),
                qtype_multichoice::get_numbering_styles());
        $mform->setDefault('answernumbering', 'abc');

        $creategrades = get_grade_options();
        $this->add_per_answer_fields($mform, get_string('choiceno', 'qtype_multichoice', '{no}'),
                $creategrades->gradeoptionsfull, max(5, QUESTION_NUMANS_START));

        $this->add_combined_feedback_fields(true);
        $mform->disabledIf('shownumcorrect', 'single', 'eq', 1);

        $this->add_interactive_settings(true, true);
    }

    function data_preprocessing($question) {
        $question = parent::data_preprocessing($question);
        $question = $this->data_preprocessing_answers($question, true);
        $question = $this->data_preprocessing_combined_feedback($question, true);
        $question = $this->data_preprocessing_hints($question);

        if (!empty($question->options)) {
            $question->single =  $question->options->single;
            $question->shuffleanswers =  $question->options->shuffleanswers;
            $question->answernumbering =  $question->options->answernumbering;
        }

        return $question;
    }

    public function validation($data, $files) {
        $errors = parent::validation($data, $files);
        $answers = $data['answer'];
        $answercount = 0;

        $totalfraction = 0;
        $maxfraction = -1;

        foreach ($answers as $key => $answer) {
            //check no of choices
            $trimmedanswer = trim($answer);
            if (empty($trimmedanswer)) {
                continue;
            }

            $answercount++;

            //check grades
            if ($data['fraction'][$key] > 0) {
                $totalfraction += $data['fraction'][$key];
            }
            if ($data['fraction'][$key] > $maxfraction) {
                $maxfraction = $data['fraction'][$key];
            }
        }

        if ($answercount == 0) {
            $errors['answer[0]'] = get_string('notenoughanswers', 'qtype_multichoice', 2);
            $errors['answer[1]'] = get_string('notenoughanswers', 'qtype_multichoice', 2);
        } elseif ($answercount == 1) {
            $errors['answer[1]'] = get_string('notenoughanswers', 'qtype_multichoice', 2);

        }

        /// Perform sanity checks on fractional grades
        if ($data['single']) {
            if ($maxfraction != 1) {
                $maxfraction = $maxfraction * 100;
                $errors['fraction[0]'] = get_string('errfractionsnomax', 'qtype_multichoice', $maxfraction);
            }
        } else {
            $totalfraction = round($totalfraction,2);
            if ($totalfraction != 1) {
                $totalfraction = $totalfraction * 100;
                $errors['fraction[0]'] = get_string('errfractionsaddwrong', 'qtype_multichoice', $totalfraction);
            }
        }
        return $errors;
    }

    public function qtype() {
        return 'multichoice';
    }
}