public static function getFiles($folder, $excludeFolders = self::INCLUDE_FOLDERS)
    {
        $files = [];

        if (false === is_dir($folder)) {
            return [];
        }

        $handle = opendir($folder);
        while (false !== ($entry = readdir($handle))) {
            if (true === in_array($entry, self::getDirSymbols())) {
                continue;
            }

            if (self::EXCLUDE_FOLDERS === $excludeFolders && true === is_dir(sprintf('%s/%s', $folder, $entry))) {
                continue;
            }

            $files[] = $entry;
        }

        closedir($handle);

        return $files;
    }