"; print_r( $qo ); die;
        return $qo;
    }

    function readquestions($lines) {
    // parse the array of lines into an array of questions
    // this *could* burn memory - but it won't happen that much
    // so fingers crossed!

        // we just need it as one big string
        $text = implode($lines, " ");
        unset( $lines );

        // this converts xml to big nasty data structure
        // the 0 means keep white space as it is (important for markdown format)
        // print_r it if you want to see what it looks like!
        $xml = xmlize( $text, 0 ); 

        // set up array to hold all our questions
        $questions = array();

        // iterate through questions
        foreach ($xml['quiz']['#']['question'] as $question) {
            $question_type = $question['@']['type'];
            $questiontype = get_string( 'questiontype','quiz',$question_type );
            echo "
$questiontype
"; 

            if ($question_type=='multichoice') {
                $qo = $this->import_multichoice( $question );
            }  
            elseif ($question_type=='truefalse') {
                $qo = $this->import_truefalse( $question );
            }
            elseif ($question_type=='shortanswer') {
                $qo = $this->import_shortanswer( $question );
            }
            elseif ($question_type=='numerical') {
                $qo = $this->import_numerical( $question );
            }
            elseif ($question_type=='matching') {
                $qo = $this->import_matching( $question );
            }
            else {
                $notsupported = get_string( 'xmlnotsupported','quiz',$question_type );
                echo "
$notsupported
";
                $qo = null;
            }

            // stick the result in the $questions array
            if ($qo) {
                $questions[] = $qo;
            }
        }

        return $questions;
    }

    // EXPORT FUNCTIONS START HERE

    function indent_xhtml($source, $indenter = ' ') { 
        // xml tidier-upper
        // (c) Ari Koivula http://ventionline.com
    
        // Remove all pre-existing formatting. 
        // Remove all newlines. 
        $source = str_replace("\n", '', $source); 
        $source = str_replace("\r", '', $source); 
        // Remove all tabs. 
        $source = str_replace("\t", '', $source); 
        // Remove all space after ">" and before "<". 
        $source = ereg_replace(">( )*", ">", $source); 
        $source = ereg_replace("( )*<", "<", $source); 

        // Iterate through the source. 
        $level = 0; 
        $source_len = strlen($source); 
        $pt = 0; 
        while ($pt < $source_len) { 
            if ($source{$pt} === '<') { 
                // We have entered a tag. 
                // Remember the point where the tag starts. 
                $started_at = $pt; 
                $tag_level = 1; 
                // If the second letter of the tag is "/", assume its an ending tag. 
                if ($source{$pt+1} === '/') { 
                    $tag_level = -1; 
                } 
                // If the second letter of the tag is "!", assume its an "invisible" tag. 
                if ($source{$pt+1} === '!') { 
                    $tag_level = 0; 
                } 
                // Iterate throught the source until the end of tag. 
                while ($source{$pt} !== '>') { 
                    $pt++; 
                } 
                // If the second last letter is "/", assume its a self ending tag. 
                if ($source{$pt-1} === '/') { 
                    $tag_level = 0; 
                } 
                $tag_lenght = $pt+1-$started_at; 
             
                // Decide the level of indention for this tag. 
                // If this was an ending tag, decrease indent level for this tag.. 
                if ($tag_level === -1) { 
                    $level--; 
                } 
                // Place the tag in an array with proper indention. 
                $array[] = str_repeat($indenter, $level).substr($source, $started_at, $tag_lenght); 
                // If this was a starting tag, increase the indent level after this tag. 
                if ($tag_level === 1) { 
                    $level++; 
                } 
                // if it was a self closing tag, dont do shit. 
            } 
            // Were out of the tag. 
            // If next letter exists... 
            if (($pt+1) < $source_len) { 
                // ... and its not an "<". 
                if ($source{$pt+1} !== '<') { 
                    $started_at = $pt+1; 
                    // Iterate through the source until the start of new tag or until we reach the end of file. 
                    while ($source{$pt} !== '<' && $pt < $source_len) { 
                         $pt++; 
                    } 
                    // If we found a "<" (we didnt find the end of file) 
                    if ($source{$pt} === '<') { 
                        $tag_lenght = $pt-$started_at; 
                        // Place the stuff in an array with proper indention. 
                        $array[] = str_repeat($indenter, $level).substr($source, $started_at, $tag_lenght); 
                    }  
                // If the next tag is "<", just advance pointer and let the tag indenter take care of it. 
                } else { 
                    $pt++; 
                } 
            // If the next letter doesnt exist... Were done... well, almost.. 
            } else { 
                break; 
            } 
        } 
        // Replace old source with the new one we just collected into our array. 
        $source = implode($array, "\n"); 
        return $source; 
    } 


    function export_file_extension() {
    // override default type so extension is .xml
    
        return ".xml";
    }

    function get_qtype( $type_id ) {
    // translates question type code number into actual name
   
        switch( $type_id ) {
        case TRUEFALSE:
            $name = 'truefalse';
            break;
        case MULTICHOICE:
            $name = 'multichoice';
            break;
        case SHORTANSWER:
            $name = 'shortanswer';
            break;
        case NUMERICAL:
            $name = 'numerical';
            break;
        case MATCH:
            $name = 'matching';
            break;
        case DESCRIPTION:
            $name = 'description';
            break;
        case MULTIANSWER:
            $name = 'cloze';
            break;
        default:
            $name = 'unknown';
        }
        return $name;
    }

    function get_format( $id ) {
    // translates question text format id number into something sensible

        switch( $id ) {
        case 0:
            $name = "moodle_auto_format";
            break;
        case 1:
            $name = "html";
            break;
        case 2:
            $name = "plain_text";
            break;
        case 3:
            $name = "wiki_like";
            break;
        case 4:
            $name = "markdown";
            break;
        default:
            $name = "unknown";
        }
        return $name;
    }

    function get_single( $id ) {
    // translate single value into something sensible

        switch( $id ) {
        case 0:
            $name = "false";
            break;
        case 1:
            $name = "true";
            break;
        default:
            $name = "unknown";
        }
        return $name;
    }

    function writetext( $raw, $ilev=0, $short=true) {
    // generates  tags, processing raw text therein 
    // $ilev is the current indent level
    // $short=true sticks it on one line
        $indent = str_repeat( "  ",$ilev );

        // encode the text to 'disguise' HTML content 
        $raw = htmlspecialchars( $raw );

        if ($short) {
            $xml = "$indent$raw\n";
        }
        else {
            $xml = "$indent\n$raw\n$indent\n";
        }

        return $xml;
    }

    function presave_process( $content ) {
    // override method to allow us to add xml headers and footers

        $content = "\n" .
                       "\n" .
                       $content . "\n" .
                       "";

        return $content;
    }

    function writeimage( $imagepath ) {
    // includes image in base64
        global $CFG;
   
        if (empty($imagepath)) {
            return '';
        }

        $courseid = $this->course->id;
        if (!$binary = file_get_contents( "{$CFG->dataroot}/$courseid/$imagepath" )) {
            return '';
        }

        $content = "    \n".addslashes(base64_encode( $binary ))."\n".
            "\n    \n";
        return $content;
    }

    function writequestion( $question ) {
    // turns question into string
    // question reflects database fields for general question and specific to type

        // initial string;
        $expout = "";

        // add comment
        $expout .= "\n\n\n";

        // add opening tag
        $question_type = $this->get_qtype( $question->qtype );
        $name_text = $this->writetext( $question->name );
        $qtformat = $this->get_format($question->questiontextformat);
        $question_text = $this->writetext( $question->questiontext );
        $expout .= "  \n";   
        $expout .= "    $name_text\n";
        $expout .= "    \n";
        $expout .= $question_text;
        $expout .= "    \n";   
        $expout .= "    {$question->image}\n";
        $expout .= $this->writeimage($question->image);
        $expout .= "    {$question->penalty}\n";
        $expout .= "    {$question->hidden}\n";
        if (!empty($question->options->shuffleanswers)) {
            $expout .= "    {$question->options->shuffleanswers}\n";
        }
        else {
            $expout .= "    0\n";
        }

        // output depends on question type
        switch($question->qtype) {
        case TRUEFALSE:
            $answer = $question->options->answers;
            $true_percent = round( $answer['true']->fraction * 100 );
            $false_percent = round( $answer['false']->fraction * 100 );
            // true answer
            $expout .= "    \n";
            $expout .= $this->writetext("true",3)."\n";
            $expout .= "      \n";
            $expout .= $this->writetext( $answer['true']->feedback,4,false );
            $expout .= "      \n";
            $expout .= "    \n";

            // false answer
            $expout .= "    \n";
            $expout .= $this->writetext("false")."\n";
            $expout .= "      \n";
            $expout .= $this->writetext( $answer['false']->feedback,4,false );
            $expout .= "      \n";
            $expout .= "    \n";
            break;
        case MULTICHOICE:
            $expout .= "    ".$this->get_single($question->options->single)."\n";
            foreach($question->options->answers as $answer) {
                $percent = $answer->fraction * 100;
                $expout .= "      \n";
                $expout .= $this->writetext( $answer->answer,4,false );
                $expout .= "      \n";
                $expout .= $this->writetext( $answer->feedback,4,false );
                $expout .= "      \n";
                $expout .= "    \n";
                }
            break;
        case SHORTANSWER:
        $expout .= "    {$question->options->usecase}\n ";
            foreach($question->options->answers as $answer) {
                $percent = 100 * $answer->fraction;
                $expout .= "    \n";
                $expout .= $this->writetext( $answer->answer,3,false );
                $expout .= "      \n";
                $expout .= $this->writetext( $answer->feedback,4,false );
                $expout .= "      \n";
                $expout .= "    \n";
            }
            break;
        case NUMERICAL:
            foreach ($question->options->answers as $answer) {
                $tolerance = $answer->tolerance;
                $expout .= "\n";
                $expout .= "    {$answer->answer}\n";
                $expout .= "    $tolerance\n";
                $expout .= "    ".$this->writetext( $answer->feedback )."\n";
                $expout .= "    {$answer->fraction}\n";
                $expout .= "\n";
            }

            $units = $question->options->units;
            if (count($units)) {
                $expout .= "\n";
                foreach ($units as $unit) {
                    $expout .= "  \n";
                    $expout .= "    {$unit->multiplier}\n";
                    $expout .= "    {$unit->unit}\n";
                    $expout .= "  \n";
                }
                $expout .= "\n";
            }
            break;
        case MATCH:
            foreach($question->options->subquestions as $subquestion) {
                $expout .= "\n";
                $expout .= $this->writetext( $subquestion->questiontext );
                $expout .= "".$this->writetext( $subquestion->answertext )."\n";
                $expout .= "\n";
            }
            break;
        case DESCRIPTION:
            // nothing more to do for this type
            break;
        case MULTIANSWER:
            $expout .= "\n";
            break;
        default:
            $expout .= "\n";
        }

        // close the question tag
        $expout .= "\n";

        // run through xml tidy function
        // $tidy_expout = $this->indent_xhtml( $expout, '    ' ) . "\n\n";

        return $expout;
    }
}

?>