class MenuLinkContent

class MenuLinkContent extends MenuLinkBase implements ContainerFactoryPluginInterface {
    
    /**
     * Entities IDs to load.
     *
     * It is an array of entity IDs keyed by entity IDs.
     *
     * @var array
     */
    protected static $entityIdsToLoad = [];
    
    /**
     * {@inheritdoc}
     */
    protected $overrideAllowed = [
        'menu_name' => 1,
        'parent' => 1,
        'weight' => 1,
        'expanded' => 1,
        'enabled' => 1,
        'title' => 1,
        'description' => 1,
        'route_name' => 1,
        'route_parameters' => 1,
        'url' => 1,
        'options' => 1,
    ];
    
    /**
     * The menu link content entity connected to this plugin instance.
     *
     * @var \Drupal\menu_link_content\MenuLinkContentInterface
     */
    protected $entity;
    
    /**
     * An array of entity operations links.
     *
     * @var array
     */
    protected $listBuilderOperations;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The entity repository.
     *
     * @var \Drupal\Core\Entity\EntityRepositoryInterface
     */
    protected $entityRepository;
    
    /**
     * The language manager.
     *
     * @var \Drupal\Core\Language\LanguageManagerInterface
     */
    protected $languageManager;
    
    /**
     * Constructs a new MenuLinkContent.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin ID for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
     *   The language manager.
     * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
     *   The entity repository.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager, LanguageManagerInterface $language_manager, EntityRepositoryInterface $entity_repository) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        if (!empty($this->pluginDefinition['metadata']['entity_id'])) {
            $entity_id = $this->pluginDefinition['metadata']['entity_id'];
            // Builds a list of entity IDs to take advantage of the more efficient
            // EntityStorageInterface::loadMultiple() in getEntity() at render time.
            static::$entityIdsToLoad[$entity_id] = $entity_id;
        }
        $this->entityTypeManager = $entity_type_manager;
        $this->languageManager = $language_manager;
        $this->entityRepository = $entity_repository;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('entity_type.manager'), $container->get('language_manager'), $container->get('entity.repository'));
    }
    
    /**
     * Loads the entity associated with this menu link.
     *
     * @return \Drupal\menu_link_content\MenuLinkContentInterface
     *   The menu link content entity.
     *
     * @throws \Drupal\Component\Plugin\Exception\PluginException
     *   If the entity ID and UUID are both invalid or missing.
     */
    public function getEntity() : MenuLinkContentInterface {
        if (empty($this->entity)) {
            $entity = NULL;
            $storage = $this->entityTypeManager
                ->getStorage('menu_link_content');
            if (!empty($this->pluginDefinition['metadata']['entity_id'])) {
                $entity_id = $this->pluginDefinition['metadata']['entity_id'];
                // Make sure the current ID is in the list, since each plugin empties
                // the list after calling loadMultiple(). Note that the list may include
                // multiple IDs added earlier in each plugin's constructor.
                static::$entityIdsToLoad[$entity_id] = $entity_id;
                $entities = $storage->loadMultiple(array_values(static::$entityIdsToLoad));
                $entity = $entities[$entity_id] ?? NULL;
                static::$entityIdsToLoad = [];
            }
            if (!$entity) {
                // Fallback to the loading by the UUID.
                $uuid = $this->getUuid();
                $entity = $this->entityRepository
                    ->loadEntityByUuid('menu_link_content', $uuid);
            }
            if (!$entity) {
                throw new PluginException("Entity not found through the menu link plugin definition and could not fallback on UUID '{$uuid}'");
            }
            // Clone the entity object to avoid tampering with the static cache.
            $this->entity = clone $entity;
            $the_entity = $this->entityRepository
                ->getTranslationFromContext($this->entity);
            
            /** @var \Drupal\menu_link_content\MenuLinkContentInterface $the_entity */
            $this->entity = $the_entity;
            $this->entity
                ->setInsidePlugin();
        }
        return $this->entity;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getTitle() {
        // We only need to get the title from the actual entity if it may be a
        // translation based on the current language context. This can only happen
        // if the site is configured to be multilingual.
        if ($this->languageManager
            ->isMultilingual()) {
            return $this->getEntity()
                ->getTitle();
        }
        return $this->pluginDefinition['title'];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDescription() {
        // We only need to get the description from the actual entity if it may be a
        // translation based on the current language context. This can only happen
        // if the site is configured to be multilingual.
        if ($this->languageManager
            ->isMultilingual()) {
            return $this->getEntity()
                ->getDescription();
        }
        return $this->pluginDefinition['description'];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDeleteRoute() {
        $operations = $this->getListBuilderOperations();
        return isset($operations['delete']) ? $operations['delete']['url'] : NULL;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getEditRoute() {
        $operations = $this->getListBuilderOperations();
        return isset($operations['edit']) ? $operations['edit']['url'] : NULL;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getTranslateRoute() {
        $operations = $this->getListBuilderOperations();
        return isset($operations['translate']) ? $operations['translate']['url'] : NULL;
    }
    
    /**
     * Load entity operations from the list builder.
     *
     * @return array
     *   An array of operations.
     */
    protected function getListBuilderOperations() {
        if (is_null($this->listBuilderOperations)) {
            $this->listBuilderOperations = $this->entityTypeManager
                ->getListBuilder($this->getEntity()
                ->getEntityTypeId())
                ->getOperations($this->getEntity());
        }
        return $this->listBuilderOperations;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getOperations() : array {
        return $this->getListBuilderOperations();
    }
    
    /**
     * Returns the unique ID representing the menu link.
     *
     * @return string
     *   The menu link ID.
     */
    protected function getUuid() {
        return $this->getDerivativeId();
    }
    
    /**
     * {@inheritdoc}
     */
    public function updateLink(array $new_definition_values, $persist) {
        // Filter the list of updates to only those that are allowed.
        $overrides = array_intersect_key($new_definition_values, $this->overrideAllowed);
        // Update the definition.
        $this->pluginDefinition = $overrides + $this->getPluginDefinition();
        if ($persist) {
            $entity = $this->getEntity();
            foreach ($overrides as $key => $value) {
                $entity->{$key}->value = $value;
            }
            $entity->save();
        }
        return $this->pluginDefinition;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isDeletable() {
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isTranslatable() {
        return $this->getEntity()
            ->isTranslatable();
    }
    
    /**
     * {@inheritdoc}
     */
    public function deleteLink() {
        $this->getEntity()
            ->delete();
    }

}