public function getThumbUrl($size = 'thumb')
    {
        $url = $this->package->config('icons.url');
        $icons = $this->package->config('icons.files');

        if (!$this->metadata->isFile()) {
            return $url . $icons['dir'];
        }

        if ($this->isImage()) {
            $thumbs = $this->getThumbsDetails();

            if (!array_key_exists($size, $thumbs)) {
                return $url . $icons['img'];
            }

            return $thumbs[$size]['url'];
        }

        $mime = $this->getMime();
        if (!array_key_exists($mime, $icons)) {
            $message = sprintf('Configuration file is missing for `%s` file type in `icons.files` array', $mime);
            throw new \Exception($message);
        }

        return $url . $icons[$mime];
    }