public function parse($value, $sub)
    {
        if (substr($value, 0, 2) == '//') {
            $value = StringHelper::replaceFirst('//', Url::base(true) . '/', $value);
            $external = false;
        } else {
            $external = true;
        }
        
        $value = Url::ensureHttp($value);
        $label = empty($sub) ? $value : $sub;
        
        return Html::a($label, $value, ['class' => $external ? 'link-external' : 'link-internal', 'target' => $external ? '_blank' : null]);
    }