class NodeRevisionRevertForm

class NodeRevisionRevertForm extends ConfirmFormBase {
    
    /**
     * The node revision.
     *
     * @var \Drupal\node\NodeInterface
     */
    protected $revision;
    
    /**
     * The node storage.
     *
     * @var \Drupal\node\NodeStorageInterface
     */
    protected $nodeStorage;
    
    /**
     * The date formatter service.
     *
     * @var \Drupal\Core\Datetime\DateFormatterInterface
     */
    protected $dateFormatter;
    
    /**
     * The time service.
     *
     * @var \Drupal\Component\Datetime\TimeInterface
     */
    protected $time;
    
    /**
     * Constructs a new NodeRevisionRevertForm.
     *
     * @param \Drupal\Core\Entity\EntityStorageInterface $node_storage
     *   The node storage.
     * @param \Drupal\Core\Datetime\DateFormatterInterface $date_formatter
     *   The date formatter service.
     * @param \Drupal\Component\Datetime\TimeInterface $time
     *   The time service.
     */
    public function __construct(EntityStorageInterface $node_storage, DateFormatterInterface $date_formatter, TimeInterface $time) {
        $this->nodeStorage = $node_storage;
        $this->dateFormatter = $date_formatter;
        $this->time = $time;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_type.manager')
            ->getStorage('node'), $container->get('date.formatter'), $container->get('datetime.time'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'node_revision_revert_confirm';
    }
    
    /**
     * {@inheritdoc}
     */
    public function getQuestion() {
        return $this->t('Are you sure you want to revert to 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('Revert');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDescription() {
        return '';
    }
    
    /**
     * {@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) {
        // The revision timestamp will be updated when the revision is saved. Keep
        // the original one for the confirmation message.
        $original_revision_timestamp = $this->revision
            ->getRevisionCreationTime();
        $this->revision = $this->prepareRevertedRevision($this->revision, $form_state);
        $this->revision->revision_log = $this->t('Copy of the revision from %date.', [
            '%date' => $this->dateFormatter
                ->format($original_revision_timestamp),
        ]);
        $this->revision
            ->setRevisionUserId($this->currentUser()
            ->id());
        $this->revision
            ->setRevisionCreationTime($this->time
            ->getRequestTime());
        $this->revision
            ->setChangedTime($this->time
            ->getRequestTime());
        $this->revision
            ->save();
        $this->logger('content')
            ->notice('@type: reverted %title revision %revision.', [
            '@type' => $this->revision
                ->bundle(),
            '%title' => $this->revision
                ->label(),
            '%revision' => $this->revision
                ->getRevisionId(),
        ]);
        $this->messenger()
            ->addStatus($this->t('@type %title has been reverted to the revision from %revision-date.', [
            '@type' => node_get_type_label($this->revision),
            '%title' => $this->revision
                ->label(),
            '%revision-date' => $this->dateFormatter
                ->format($original_revision_timestamp),
        ]));
        $form_state->setRedirect('entity.node.version_history', [
            'node' => $this->revision
                ->id(),
        ]);
    }
    
    /**
     * Prepares a revision to be reverted.
     *
     * @param \Drupal\node\NodeInterface $revision
     *   The revision to be reverted.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     *
     * @return \Drupal\node\NodeInterface
     *   The prepared revision ready to be stored.
     */
    protected function prepareRevertedRevision(NodeInterface $revision, FormStateInterface $form_state) {
        $revision->setNewRevision();
        $revision->isDefaultRevision(TRUE);
        return $revision;
    }

}