class DefaultsEntityForm

class DefaultsEntityForm extends EntityForm {
  use PreviewToggleTrait;
  use LayoutBuilderEntityFormTrait;

  /**
   * Layout tempstore repository.
   *
   * @var \Drupal\layout_builder\LayoutTempstoreRepositoryInterface
   */
  protected $layoutTempstoreRepository;

  /**
   * The entity type bundle info service.
   *
   * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
   */
  protected $entityTypeBundleInfo;

  /**
   * The section storage.
   *
   * @var \Drupal\layout_builder\SectionStorageInterface
   */
  protected $sectionStorage;

  /**
   * Constructs a new DefaultsEntityForm.
   *
   * @param \Drupal\layout_builder\LayoutTempstoreRepositoryInterface $layout_tempstore_repository
   *   The layout tempstore repository.
   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
   *   The entity type bundle info service.
   */
  public function __construct(LayoutTempstoreRepositoryInterface $layout_tempstore_repository, EntityTypeBundleInfoInterface $entity_type_bundle_info) {
    $this->layoutTempstoreRepository = $layout_tempstore_repository;
    $this->entityTypeBundleInfo = $entity_type_bundle_info;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container
      ->get('layout_builder.tempstore_repository'), $container
      ->get('entity_type.bundle.info'));
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, SectionStorageInterface $section_storage = NULL) {
    $form['#attributes']['class'][] = 'layout-builder-form';
    $form['layout_builder'] = [
      '#type' => 'layout_builder',
      '#section_storage' => $section_storage,
      '#process' => [
        [
          static::class,
          'layoutBuilderElementGetKeys',
        ],
      ],
    ];
    $form['layout_builder_message'] = $this
      ->buildMessage($section_storage
      ->getContextValue('display'));
    $this->sectionStorage = $section_storage;
    return parent::buildForm($form, $form_state);
  }

  /**
   * Form element #process callback.
   *
   * Save the layout builder element array parents as a property on the top form
   * element so that they can be used to access the element within the whole
   * render array later.
   *
   * @see \Drupal\layout_builder\Controller\LayoutBuilderHtmlEntityFormController
   */
  public static function layoutBuilderElementGetKeys(array $element, FormStateInterface $form_state, &$form) {
    $form['#layout_builder_element_keys'] = $element['#array_parents'];
    return $element;
  }

  /**
   * Renders a message to display at the top of the layout builder.
   *
   * @param \Drupal\layout_builder\Entity\LayoutEntityDisplayInterface $entity
   *   The entity view display being edited.
   *
   * @return array
   *   A renderable array containing the message.
   */
  protected function buildMessage(LayoutEntityDisplayInterface $entity) {
    $entity_type_id = $entity
      ->getTargetEntityTypeId();
    $entity_type = $this->entityTypeManager
      ->getDefinition($entity_type_id);
    $bundle_info = $this->entityTypeBundleInfo
      ->getBundleInfo($entity_type_id);
    $args = [
      '@bundle' => $bundle_info[$entity
        ->getTargetBundle()]['label'],
      '@plural_label' => $entity_type
        ->getPluralLabel(),
    ];
    if ($entity_type
      ->hasKey('bundle')) {
      $message = $this
        ->t('You are editing the layout template for all @bundle @plural_label.', $args);
    }
    else {
      $message = $this
        ->t('You are editing the layout template for all @plural_label.', $args);
    }
    return $this
      ->buildMessageContainer($message, 'defaults');
  }

  /**
   * {@inheritdoc}
   */
  public function buildEntity(array $form, FormStateInterface $form_state) {

    // \Drupal\Core\Entity\EntityForm::buildEntity() clones the entity object.
    // Keep it in sync with the one used by the section storage.
    $this
      ->setEntity($this->sectionStorage
      ->getContextValue('display'));
    $entity = parent::buildEntity($form, $form_state);
    $this->sectionStorage
      ->setContextValue('display', $entity);
    return $entity;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityFromRouteMatch(RouteMatchInterface $route_match, $entity_type_id) {
    $route_parameters = $route_match
      ->getParameters()
      ->all();
    return $this->entityTypeManager
      ->getStorage('entity_view_display')
      ->load($route_parameters['entity_type_id'] . '.' . $route_parameters['bundle'] . '.' . $route_parameters['view_mode_name']);
  }

  /**
   * {@inheritdoc}
   */
  protected function actions(array $form, FormStateInterface $form_state) {
    $actions = parent::actions($form, $form_state);
    return $this
      ->buildActions($actions);
  }

  /**
   * {@inheritdoc}
   */
  public function save(array $form, FormStateInterface $form_state) {
    $return = $this->sectionStorage
      ->save();
    $this
      ->saveTasks($form_state, $this
      ->t('The layout has been saved.'));
    return $return;
  }

}