public function getHTMLFiles($directory)
    {
        try {
            $dir = new RecursiveDirectoryIterator($directory, RecursiveDirectoryIterator::SKIP_DOTS | RecursiveDirectoryIterator::NEW_CURRENT_AND_KEY);
            $files = new \RecursiveIteratorIterator($dir);

            $allowedExtensions = ['htm', 'html'];

            $list = [];
            foreach ($files as $file) {
                if (in_array($file->getExtension(), $allowedExtensions)) {
                    // HTML File found
                    $relativePath = str_replace($directory, '', $file->getPathname());
                    $list[] = ltrim($relativePath, '\\/');
                }
            }

            return $list;
        } catch (\Exception $e) {
            return [];
        }
    }