<?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/>.

/**
 * Drag-and-drop words into sentences question renderer class.
 *
 * @package   qtype_ddwtos
 * @copyright 2010 The Open University
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */


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

require_once($CFG->dirroot . '/question/type/gapselect/rendererbase.php');


/**
 * Generates the output for drag-and-drop words into sentences questions.
 *
 * @copyright  2010 The Open University
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class qtype_ddwtos_renderer extends qtype_elements_embedded_in_question_text_renderer {

    public function formulation_and_controls(question_attempt $qa,
            question_display_options $options) {
        global $PAGE;

        $result = parent::formulation_and_controls($qa, $options);

        $PAGE->requires->js_call_amd('qtype_ddwtos/ddwtos', 'init',
                ['q' . $qa->get_slot(), $options->readonly]);
        return $result;
    }

    protected function post_qtext_elements(question_attempt $qa,
            question_display_options $options) {
        $result = '';
        $question = $qa->get_question();

        $dragboxs = '';
        foreach ($question->choices as $group => $choices) {
            $dragboxs .= $this->drag_boxes($qa, $group,
                    $question->get_ordered_choices($group), $options);
        }

        $classes = array('answercontainer');
        if ($options->readonly) {
            $classes[] = 'readonly';
        }
        $result .= html_writer::tag('div', $dragboxs, array('class' => implode(' ', $classes)));

        $classes = array('drags');
        if ($options->readonly) {
            $classes[] = 'readonly';
        }
        $result .= html_writer::tag('div', '', array('class' => implode(' ', $classes)));

        // We abuse the clear_wrong method to output the hidden form fields we
        // want irrespective of whether we are actually clearing the wrong
        // bits of the response.
        if (!$options->clearwrong) {
            $result .= $this->clear_wrong($qa, false);
        }
        return $result;
    }

    protected function embedded_element(question_attempt $qa, $place,
            question_display_options $options) {
        $question = $qa->get_question();
        $group = $question->places[$place];
        $boxcontents = '&#160;' . html_writer::tag('span',
                get_string('blank', 'qtype_ddwtos'), array('class' => 'accesshide'));

        $value = $qa->get_last_qt_var($question->field($place));

        $attributes = array(
            'class' => 'place' . $place . ' drop group' . $group
        );

        if ($options->readonly) {
            $attributes['class'] .= ' readonly';
        } else {
            $attributes['tabindex'] = '0';
        }

        $feedbackimage = '';
        if ($options->correctness) {
            $response = $qa->get_last_qt_data();
            $fieldname = $question->field($place);
            if (array_key_exists($fieldname, $response)) {
                $fraction = (int) ($response[$fieldname] ==
                        $question->get_right_choice_for($place));
                $feedbackimage = $this->feedback_image($fraction);
            }
        }

        return html_writer::tag('span', $boxcontents, $attributes) . ' ' . $feedbackimage;
    }

    protected function drag_boxes($qa, $group, $choices, question_display_options $options) {
        $boxes = '';
        foreach ($choices as $key => $choice) {
            // Bug 8632: long text entry causes bug in drag and drop field in IE.
            $content = str_replace('-', '&#x2011;', $choice->text);
            $content = str_replace(' ', '&#160;', $content);

            $infinite = '';
            if ($choice->infinite) {
                $infinite = ' infinite';
            }

            $boxes .= html_writer::tag('span', $content, array(
                    'class' => 'draghome choice' . $key . ' group' .
                            $choice->draggroup . $infinite)) . ' ';
        }

        return html_writer::nonempty_tag('div', $boxes,
                array('class' => 'draggrouphomes' . $choice->draggroup));
    }

    /**
     * Actually, this question type abuses this method to always output the
     * hidden fields it needs.
     *
     * @param question_attempt $qa the question attempt.
     * @param bool $reallyclear whether we are really clearing the responses, or just outputting them.
     * @return string HTML to output.
     */
    public function clear_wrong(question_attempt $qa, $reallyclear = true) {
        $question = $qa->get_question();
        $response = $qa->get_last_qt_data();

        if (!empty($response) && $reallyclear) {
            $cleanresponse = $question->clear_wrong_from_response($response);
        } else {
            $cleanresponse = $response;
        }

        $output = '';
        foreach ($question->places as $place => $group) {
            $fieldname = $question->field($place);
            if (array_key_exists($fieldname, $response)) {
                $value = (string) $response[$fieldname];
            } else {
                $value = '0';
            }
            if (array_key_exists($fieldname, $cleanresponse)) {
                $cleanvalue = (string) $cleanresponse[$fieldname];
            } else {
                $cleanvalue = '0';
            }
            if ($cleanvalue === $value) {
                // Normal case: just one hidden input, to store the
                // current value and be the value submitted.
                $output .= html_writer::empty_tag('input', array(
                        'type' => 'hidden',
                        'id' => $this->box_id($qa, 'p' . $place),
                        'class' => 'placeinput place' . $place . ' group' . $group,
                        'name' => $qa->get_qt_field_name($fieldname),
                        'value' => s($value)));
            } else {
                // The case, which only happens when the question is read-only, where
                // we want to show the drag item in a given place (first hidden input),
                // but when submitted, we want it to go to a different place (second input).
                $output .= html_writer::empty_tag('input', array(
                        'type' => 'hidden',
                        'id' => $this->box_id($qa, 'p' . $place),
                        'class' => 'placeinput place' . $place . ' group' . $group,
                        'value' => s($value))) .
                        html_writer::empty_tag('input', array(
                        'type' => 'hidden',
                        'name' => $qa->get_qt_field_name($fieldname),
                        'value' => s($cleanvalue)));
            }
        }
        return $output;
    }

}
