class NodeRevisionDeleteForm

class NodeRevisionDeleteForm extends ConfirmFormBase {
  
  /**
   * The node revision.
   *
   * @var \Drupal\node\NodeInterface
   */
  protected $revision;
  
  /**
   * The node storage.
   *
   * @var \Drupal\Core\Entity\EntityStorageInterface
   */
  protected $nodeStorage;
  
  /**
   * The node type storage.
   *
   * @var \Drupal\Core\Entity\EntityStorageInterface
   */
  protected $nodeTypeStorage;
  
  /**
   * The database connection.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $connection;
  
  /**
   * The date formatter service.
   *
   * @var \Drupal\Core\Datetime\DateFormatterInterface
   */
  protected $dateFormatter;
  
  /**
   * Constructs a new NodeRevisionDeleteForm.
   *
   * @param \Drupal\Core\Entity\EntityStorageInterface $node_storage
   *   The node storage.
   * @param \Drupal\Core\Entity\EntityStorageInterface $node_type_storage
   *   The node type storage.
   * @param \Drupal\Core\Database\Connection $connection
   *   The database connection.
   * @param \Drupal\Core\Datetime\DateFormatterInterface $date_formatter
   *   The date formatter service.
   */
  public function __construct(EntityStorageInterface $node_storage, EntityStorageInterface $node_type_storage, Connection $connection, DateFormatterInterface $date_formatter) {
    $this->nodeStorage = $node_storage;
    $this->nodeTypeStorage = $node_type_storage;
    $this->connection = $connection;
    $this->dateFormatter = $date_formatter;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    $entity_type_manager = $container->get('entity_type.manager');
    return new static($entity_type_manager->getStorage('node'), $entity_type_manager->getStorage('node_type'), $container->get('database'), $container->get('date.formatter'));
  }
  
  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'node_revision_delete_confirm';
  }
  
  /**
   * {@inheritdoc}
   */
  public function getQuestion() {
    return $this->t('Are you sure you want to delete the revision from %revision-date?', [
      '%revision-date' => $this->dateFormatter
        ->format($this->revision
        ->getRevisionCreationTime()),
    ]);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCancelUrl() {
    return new Url('entity.node.version_history', [
      'node' => $this->revision
        ->id(),
    ]);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getConfirmText() {
    return $this->t('Delete');
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, NodeInterface $node_revision = NULL) {
    $this->revision = $node_revision;
    $form = parent::buildForm($form, $form_state);
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $this->nodeStorage
      ->deleteRevision($this->revision
      ->getRevisionId());
    $this->logger('content')
      ->notice('@type: deleted %title revision %revision.', [
      '@type' => $this->revision
        ->bundle(),
      '%title' => $this->revision
        ->label(),
      '%revision' => $this->revision
        ->getRevisionId(),
    ]);
    $node_type = $this->nodeTypeStorage
      ->load($this->revision
      ->bundle())
      ->label();
    $this->messenger()
      ->addStatus($this->t('Revision from %revision-date of @type %title has been deleted.', [
      '%revision-date' => $this->dateFormatter
        ->format($this->revision
        ->getRevisionCreationTime()),
      '@type' => $node_type,
      '%title' => $this->revision
        ->label(),
    ]));
    $form_state->setRedirect('entity.node.canonical', [
      'node' => $this->revision
        ->id(),
    ]);
    if ($this->connection
      ->query('SELECT COUNT(DISTINCT [vid]) FROM {node_field_revision} WHERE [nid] = :nid', [
      ':nid' => $this->revision
        ->id(),
    ])
      ->fetchField() > 1) {
      $form_state->setRedirect('entity.node.version_history', [
        'node' => $this->revision
          ->id(),
      ]);
    }
  }

}