class ConfigImportForm

class ConfigImportForm extends FormBase {
  
  /**
   * The configuration storage.
   *
   * @var \Drupal\Core\Config\StorageInterface
   */
  protected $configStorage;
  
  /**
   * The file system service.
   *
   * @var \Drupal\Core\File\FileSystemInterface
   */
  protected $fileSystem;
  
  /**
   * The settings object.
   *
   * @var \Drupal\Core\Site\Settings
   */
  protected $settings;
  
  /**
   * Constructs a new ConfigImportForm.
   *
   * @param \Drupal\Core\Config\StorageInterface $config_storage
   *   The configuration storage.
   * @param \Drupal\Core\File\FileSystemInterface $file_system
   *   The file system service.
   * @param \Drupal\Core\Site\Settings $settings
   *   The settings object.
   */
  public function __construct(StorageInterface $config_storage, FileSystemInterface $file_system = NULL, Settings $settings = NULL) {
    $this->configStorage = $config_storage;
    if (!isset($file_system)) {
      @trigger_error('The $file_system parameter was added in Drupal 8.8.0 and will be required in 9.0.0. See https://www.drupal.org/node/3021434.', E_USER_DEPRECATED);
      $file_system = \Drupal::service('file_system');
    }
    $this->fileSystem = $file_system;
    if (!isset($settings)) {
      @trigger_error('The $settings parameter was added in Drupal 8.8.0 and will be required in 9.0.0. See https://www.drupal.org/node/2980712.', E_USER_DEPRECATED);
      $settings = \Drupal::service('settings');
    }
    $this->settings = $settings;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container->get('config.storage.sync'), $container->get('file_system'), $container->get('settings'));
  }
  
  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'config_import_form';
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $directory = $this->settings
      ->get('config_sync_directory');
    $directory_is_writable = is_writable($directory);
    if (!$directory_is_writable) {
      $this->messenger()
        ->addError($this->t('The directory %directory is not writable.', [
        '%directory' => $directory,
      ]));
    }
    $form['import_tarball'] = [
      '#type' => 'file',
      '#title' => $this->t('Configuration archive'),
      '#description' => $this->t('Allowed types: @extensions.', [
        '@extensions' => 'tar.gz tgz tar.bz2',
      ]),
    ];
    $form['submit'] = [
      '#type' => 'submit',
      '#value' => $this->t('Upload'),
      '#disabled' => !$directory_is_writable,
    ];
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function validateForm(array &$form, FormStateInterface $form_state) {
    $all_files = $this->getRequest()->files
      ->get('files', []);
    if (!empty($all_files['import_tarball'])) {
      $file_upload = $all_files['import_tarball'];
      if ($file_upload->isValid()) {
        $form_state->setValue('import_tarball', $file_upload->getRealPath());
        return;
      }
    }
    $form_state->setErrorByName('import_tarball', $this->t('The file could not be uploaded.'));
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    if ($path = $form_state->getValue('import_tarball')) {
      $this->configStorage
        ->deleteAll();
      try {
        $archiver = new ArchiveTar($path, 'gz');
        $files = [];
        foreach ($archiver->listContent() as $file) {
          $files[] = $file['filename'];
        }
        $archiver->extractList($files, $this->settings
          ->get('config_sync_directory'), '', FALSE, FALSE);
        $this->messenger()
          ->addStatus($this->t('Your configuration files were successfully uploaded and are ready for import.'));
        $form_state->setRedirect('config.sync');
      } catch (\Exception $e) {
        $this->messenger()
          ->addError($this->t('Could not extract the contents of the tar file. The error message is <em>@message</em>', [
          '@message' => $e->getMessage(),
        ]));
      }
      $this->fileSystem
        ->unlink($path);
    }
  }

}