class EntityTypeInfo

class EntityTypeInfo implements ContainerInjectionInterface {
    
    /**
     * The entity type manager service.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The workspace manager service.
     *
     * @var \Drupal\workspaces\WorkspaceManagerInterface
     */
    protected $workspaceManager;
    
    /**
     * Constructs a new EntityTypeInfo instance.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager service.
     * @param \Drupal\workspaces\WorkspaceManagerInterface $workspace_manager
     *   The workspace manager service.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, WorkspaceManagerInterface $workspace_manager) {
        $this->entityTypeManager = $entity_type_manager;
        $this->workspaceManager = $workspace_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_type.manager'), $container->get('workspaces.manager'));
    }
    
    /**
     * Adds the "EntityWorkspaceConflict" constraint to eligible entity types.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface[] $entity_types
     *   An associative array of all entity type definitions, keyed by the entity
     *   type name. Passed by reference.
     *
     * @see hook_entity_type_build()
     */
    public function entityTypeBuild(array &$entity_types) {
        foreach ($entity_types as $entity_type) {
            if ($this->workspaceManager
                ->isEntityTypeSupported($entity_type)) {
                $entity_type->addConstraint('EntityWorkspaceConflict');
                $entity_type->setRevisionMetadataKey('workspace', 'workspace');
            }
        }
    }
    
    /**
     * Removes the 'latest-version' link template provided by Content Moderation.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface[] $entity_types
     *   An array of entity types.
     *
     * @see hook_entity_type_alter()
     */
    public function entityTypeAlter(array &$entity_types) {
        foreach ($entity_types as $entity_type_id => $entity_type) {
            // Non-default workspaces display the active revision on the canonical
            // route of an entity, so the latest version route is no longer needed.
            $link_templates = $entity_type->get('links');
            unset($link_templates['latest-version']);
            $entity_type->set('links', $link_templates);
        }
    }
    
    /**
     * Alters field plugin definitions.
     *
     * @param array[] $definitions
     *   An array of field plugin definitions.
     *
     * @see hook_field_info_alter()
     */
    public function fieldInfoAlter(&$definitions) {
        if (isset($definitions['entity_reference'])) {
            $definitions['entity_reference']['constraints']['EntityReferenceSupportedNewEntities'] = [];
        }
        // Allow path aliases to be changed in workspace-specific pending revisions.
        if (isset($definitions['path'])) {
            unset($definitions['path']['constraints']['PathAlias']);
        }
    }
    
    /**
     * Provides custom base field definitions for a content entity type.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface[]
     *   An array of field definitions, keyed by field name.
     *
     * @see hook_entity_base_field_info()
     */
    public function entityBaseFieldInfo(EntityTypeInterface $entity_type) {
        if ($this->workspaceManager
            ->isEntityTypeSupported($entity_type)) {
            // Disable the BC layer to prevent a recursion, this only needs the
            // workspace key that is always set.
            $field_name = $entity_type->getRevisionMetadataKeys(FALSE)['workspace'];
            $fields[$field_name] = BaseFieldDefinition::create('entity_reference')->setLabel(new TranslatableMarkup('Workspace'))
                ->setDescription(new TranslatableMarkup('Indicates the workspace that this revision belongs to.'))
                ->setSetting('target_type', 'workspace')
                ->setInternal(TRUE)
                ->setTranslatable(FALSE)
                ->setRevisionable(TRUE);
            return $fields;
        }
    }

}