tag
     * 
     * @param $input The text inside the custom tag
     * @param array $args Any attributes given in the tag
     * @param Parser $parser The parser object
     * @param PPFrame $frame The parent frame calling the parser
     * @return string HTML string of output
     */
    static function renderConfigTag( $input, array $args, $parser, $frame ) {
		return '
' . $input . '
';
	}

    /**
     * MWHook: Load the js and css modules if model-viewer element is found in the html output
     * 
     * @see https://www.mediawiki.org/wiki/Manual:Hooks/BeforePageDisplay
     * 
     * @param OutputPage $out compiled page html and manipulation methods
     */
    public static function onBeforePageDisplay($out) {
    preg_match('/(getHTML(),$findGltf);
        if ($findGltf[0]) {
       
                $out->addHeadItems(
                Html::rawElement(
                    'script',
                    array(
                        'src' => 'https://ajax.googleapis.com/ajax/libs/model-viewer/3.5.0/model-viewer.min.js',
                        'type' => 'module'
                    )
                )
            );
            $out->addModules('ext.glmv');
        }
    }

    /**
     * MWHook: Display model when model file page edits are previewed
     * 
     * @see https://www.mediawiki.org/wiki/Manual:Hooks/AlternateEditPreview
     * 
     * @param EditPage $editor access to information about the edit page itself
     * @param Content $content access to the current content of the editor
     * @param string &$previewHTML by reference access to the resultant compiled preview html
     * @param ?ParserOutput &$parserOutput
     * @return bool|void True to continue default processing or false to abort for custom processing
     */
    public static function onAlternateEditPreview( $editor, $content, string &$previewHTML, ?ParserOutput &$parserOutput ) {
        $title = $editor->getTitle();
        $file = MediaWikiServices::getInstance()->getRepoGroup()->findFile($title);
        if (!$file || $file->getMimeType() !== 'model/gltf-binary') {
            return true;
        }

        $out = $editor->getContext()->getOutput();
        $out->addModules('ext.glmv.prev');

        $mvTransform = $file->transform([ 'width' => '800', 'hight' => '600', 'view' => 'test']);
        $previewViewer = $mvTransform->toHtml([ 'preview' => true]);

        $previewHTML = Html::rawElement('div',NULL,$previewViewer);
        return false;
    }

    /**
     * MWHook: Occurs after the descriptor for the upload form as been assembled.
     * 
     * @param $descriptor the HTMLForm descriptor
     */
    public static function onUploadFormInitDescriptor( $descriptor ) {
        $context = RequestContext::getMain();
        $out = $context->getOutput();
        $mvScriptAttr = array(
            'src' => 'https://ajax.googleapis.com/ajax/libs/model-viewer/3.5.0/model-viewer.min.js',
            'type' => 'module'
            );
        $out->addHeadItems(Html::rawElement('script',$mvScriptAttr));
        $out->addModules('ext.glmv.upl');
    }

    /**
     * Perform upload verification, based on both file properties like MIME type
     * (same as UploadVerifyFile) and the information entered by the user (upload
     * comment, file page contents etc.).
     * 
     * @param UploadBase $upload Instance of UploadBase, with all info about the upload
     * @param User $user User uploading this file
     * @param array | null $props File properties, as returned by MWFileProps::getPropsFromPath()
     * @param string $comment Upload log comment (also used as edit summary)
     * @param string | false $pageText File description page text (only used for new uploads)
     * @param array | MessageSpecifier | null &$error Output: If the file upload should be prevented, set this to the reason
     * @return bool|void True or no return value to continue or false to abort
     */
    public static function onUploadVerifyUpload	($upload, $user, ?array	$props, $comment, $pageText, &$error) {
        if ($props['mime'] != 'model/gltf-binary') {
            return true;
        } else {
            $path = $upload->getTempPath();
            $gltf = fopen($path, 'r');
            $glHeader = fread($gltf, 4);
            fclose($gltf);

            if ($glHeader == 'glTF') {
                return true;
            } else {
                $error = array(
                    "glmv-load-error-format",
                    $upload->getTitle()->getRootText()
                );
                return false;
            }
        }
    }
    

    /**
     * MWHook: Called just before the upload data, like wpUploadDescription, are processed, so extensions get a chance to manipulate them.
     * 
     * @param SpecialUpload $uploadFormObj current SpecialUpload object
     */
    public static function onUploadFormBeforeProcessing( $uploadFormObj ) {
        preg_match('/(glb|gltf)$/', $uploadFormObj->mUpload->getTitle(), $isGltf);
        if ($isGltf) {
            $uploadFormObj->mComment .= <<
                [viewerConfig.default]
                camera-controls = true
            
            CONF;
        }

        return true;
    }

    /**
     * Small helper function to display information on the browser console
     * 
     * Usage:
     * echo '';
     * 
     * @param $data information to display
     * @param bool $add_script_tags true to put information is inside complete script tag
     */
    public static function console_log($data, $add_script_tags = false) {
        $command = 'console.log('. json_encode($data, JSON_HEX_TAG).');';
        if ($add_script_tags) {
            $command = '';
        }
        echo $command;
    }
}