class DiscardLayoutChangesForm

class DiscardLayoutChangesForm extends ConfirmFormBase {
    
    /**
     * The layout tempstore repository.
     *
     * @var \Drupal\layout_builder\LayoutTempstoreRepositoryInterface
     */
    protected $layoutTempstoreRepository;
    
    /**
     * The messenger service.
     *
     * @var \Drupal\Core\Messenger\MessengerInterface
     */
    protected $messenger;
    
    /**
     * The section storage.
     *
     * @var \Drupal\layout_builder\SectionStorageInterface
     */
    protected $sectionStorage;
    
    /**
     * Constructs a new DiscardLayoutChangesForm.
     *
     * @param \Drupal\layout_builder\LayoutTempstoreRepositoryInterface $layout_tempstore_repository
     *   The layout tempstore repository.
     * @param \Drupal\Core\Messenger\MessengerInterface $messenger
     *   The messenger service.
     */
    public function __construct(LayoutTempstoreRepositoryInterface $layout_tempstore_repository, MessengerInterface $messenger) {
        $this->layoutTempstoreRepository = $layout_tempstore_repository;
        $this->messenger = $messenger;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('layout_builder.tempstore_repository'), $container->get('messenger'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'layout_builder_discard_changes';
    }
    
    /**
     * {@inheritdoc}
     */
    public function getQuestion() {
        return $this->t('Are you sure you want to discard your layout changes?');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCancelUrl() {
        return $this->sectionStorage
            ->getRedirectUrl();
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state, SectionStorageInterface $section_storage = NULL) {
        $this->sectionStorage = $section_storage;
        // Mark this as an administrative page for JavaScript ("Back to site" link).
        $form['#attached']['drupalSettings']['path']['currentPathIsAdmin'] = TRUE;
        return parent::buildForm($form, $form_state);
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $this->layoutTempstoreRepository
            ->delete($this->sectionStorage);
        $this->messenger
            ->addMessage($this->t('The changes to the layout have been discarded.'));
        $form_state->setRedirectUrl($this->getCancelUrl());
    }

}