class ReindexConfirm

class ReindexConfirm extends ConfirmFormBase {
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'search_reindex_confirm';
    }
    
    /**
     * {@inheritdoc}
     */
    public function getQuestion() {
        return $this->t('Are you sure you want to re-index the site?');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDescription() {
        return $this->t("This will re-index content in the search indexes of all active search pages. Searching will continue to work, but new content won't be indexed until all existing content has been re-indexed. This action cannot be undone.");
    }
    
    /**
     * {@inheritdoc}
     */
    public function getConfirmText() {
        return $this->t('Re-index site');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCancelText() {
        return $this->t('Cancel');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCancelUrl() {
        return new Url('entity.search_page.collection');
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        if ($form['confirm']) {
            // Ask each active search page to mark itself for re-index.
            $search_page_repository = \Drupal::service('search.search_page_repository');
            foreach ($search_page_repository->getIndexableSearchPages() as $entity) {
                $entity->getPlugin()
                    ->markForReindex();
            }
            $this->messenger()
                ->addStatus($this->t('All search indexes will be rebuilt.'));
            $form_state->setRedirectUrl($this->getCancelUrl());
        }
    }

}