public function details()
  {
    $file = $this->file;

    if (file_exists($file)) {
      $data = unserialize($this->decrypt(file_get_contents($file)));

      return [
        'records' => count($data),
        'size' => round(filesize($file) / 1024, 1),
        'updated_at' => date('Y-m-d h:i:s', filemtime($file))
      ];
    }

    return null;
  }