private function fileRename() {
    $filename = $this->filename_new;
    $extension = '.' . File::extension($this->filename_new);
    $basename = rtrim($filename, $extension);

    $increment = 0;

    while (File::exists($this->directory . $filename)) {
      $filename = $basename . '_' . ++$increment . $extension;
    }

    return $this->filename_new = $filename;
  }