class.ilAssSelfAssessmentQuestionFormatter.php

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<?php
/* Copyright (c) 1998-2017 ILIAS open source, Extended GPL, see docs/LICENSE */

require_once 'Modules/TestQuestionPool/interfaces/interface.ilAssSelfAssessmentMigrator.php';

class ilAssSelfAssessmentQuestionFormatter implements ilAssSelfAssessmentMigrator
{
    public function format($string)
    {
        $string = $this->handleLineBreaks($string);

        require_once 'Services/RTE/classes/class.ilRTE.php';
        $string = (string) ilRTE::_replaceMediaObjectImageSrc($string, 1);

        $string = str_replace("</li><br />", "</li>", $string);
        $string = str_replace("</li><br>", "</li>", $string);

        require_once 'Services/MathJax/classes/class.ilMathJax.php';
        $string = ilMathJax::getInstance()->insertLatexImages($string, "\[tex\]", "\[\/tex\]");
        $string = ilMathJax::getInstance()->insertLatexImages($string, "<span class\=\"latex\">", "<\/span>");

        $string = str_replace('{', '&#123;', $string);
        $string = str_replace('}', '&#125;', $string);

        return $string;
    }

    protected function handleLineBreaks($string)
    {
        if (!ilUtil::isHTML($string)) {
            $string = nl2br($string);
        }

        return $string;
    }
    
    protected function convertLatexSpanToTex($string)
    {
        // we try to save all latex tags
        $try = true;
        $ls = '<span class="latex">';
        $le = '</span>';
        while ($try) {
            // search position of start tag
            $pos1 = strpos($string, $ls);
            if (is_int($pos1)) {
                $pos2 = strpos($string, $le, $pos1);
                if (is_int($pos2)) {
                    // both found: replace end tag
                    $string = substr($string, 0, $pos2) . "[/tex]" . substr($string, $pos2 + 7);
                    $string = substr($string, 0, $pos1) . "[tex]" . substr($string, $pos1 + 20);
                } else {
                    $try = false;
                }
            } else {
                $try = false;
            }
        }

        return $string;
    }
    
    protected function stripHtmlExceptSelfAssessmentTags($string)
    {
        $tags = self::getSelfAssessmentTags();

        $tstr = "";
        
        foreach ($tags as $t) {
            $tstr .= "<" . $t . ">";
        }

        $string = ilUtil::secureString($string, true, $tstr);

        return $string;
    }
    
    public function migrateToLmContent($string)
    {
        $string = $this->convertLatexSpanToTex($string);
        $string = $this->stripHtmlExceptSelfAssessmentTags($string);
        return $string;
    }
    
    public static function prepareQuestionForLearningModule(assQuestion $question)
    {
        $question->migrateContentForLearningModule(new self());
    }
    
    public static function getSelfAssessmentTags()
    {
        // set tags we allow in self assessment mode
        $st = ilUtil::getSecureTags();
        
        // we allow these tags, since they are typically used in the Tiny Assessment editor
        // and should not be deleted, if questions are copied from pools to learning modules
        $not_supported = array("img", "p");
        $tags = array();
        
        $tags[] = 'p';
        
        foreach ($st as $s) {
            if (!in_array($s, $not_supported)) {
                $tags[] = $s;
            }
        }
        
        return $tags;
    }
}