class EntityOperations

class EntityOperations implements ContainerInjectionInterface {
    use StringTranslationTrait;
    
    /**
     * The entity type manager service.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The workspace manager service.
     *
     * @var \Drupal\workspaces\WorkspaceManagerInterface
     */
    protected $workspaceManager;
    
    /**
     * The workspace association service.
     *
     * @var \Drupal\workspaces\WorkspaceAssociationInterface
     */
    protected $workspaceAssociation;
    
    /**
     * Constructs a new EntityOperations instance.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager service.
     * @param \Drupal\workspaces\WorkspaceManagerInterface $workspace_manager
     *   The workspace manager service.
     * @param \Drupal\workspaces\WorkspaceAssociationInterface $workspace_association
     *   The workspace association service.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, WorkspaceManagerInterface $workspace_manager, WorkspaceAssociationInterface $workspace_association) {
        $this->entityTypeManager = $entity_type_manager;
        $this->workspaceManager = $workspace_manager;
        $this->workspaceAssociation = $workspace_association;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_type.manager'), $container->get('workspaces.manager'), $container->get('workspaces.association'));
    }
    
    /**
     * Acts on entity IDs before they are loaded.
     *
     * @see hook_entity_preload()
     */
    public function entityPreload(array $ids, $entity_type_id) {
        $entities = [];
        // Only run if the entity type can belong to a workspace and we are in a
        // non-default workspace.
        if (!$this->workspaceManager
            ->shouldAlterOperations($this->entityTypeManager
            ->getDefinition($entity_type_id))) {
            return $entities;
        }
        // Get a list of revision IDs for entities that have a revision set for the
        // current active workspace. If an entity has multiple revisions set for a
        // workspace, only the one with the highest ID is returned.
        if ($tracked_entities = $this->workspaceAssociation
            ->getTrackedEntities($this->workspaceManager
            ->getActiveWorkspace()
            ->id(), $entity_type_id, $ids)) {
            
            /** @var \Drupal\Core\Entity\RevisionableStorageInterface $storage */
            $storage = $this->entityTypeManager
                ->getStorage($entity_type_id);
            // Swap out every entity which has a revision set for the current active
            // workspace.
            foreach ($storage->loadMultipleRevisions(array_keys($tracked_entities[$entity_type_id])) as $revision) {
                $entities[$revision->id()] = $revision;
            }
        }
        return $entities;
    }
    
    /**
     * Acts on an entity before it is created or updated.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity being saved.
     *
     * @see hook_entity_presave()
     */
    public function entityPresave(EntityInterface $entity) {
        $entity_type = $entity->getEntityType();
        // Only run if we are not dealing with an entity type provided by the
        // Workspaces module, an internal entity type or if we are in a non-default
        // workspace.
        if ($this->shouldSkipPreOperations($entity_type)) {
            return;
        }
        // Disallow any change to an unsupported entity when we are not in the
        // default workspace.
        if (!$this->workspaceManager
            ->isEntityTypeSupported($entity_type)) {
            throw new \RuntimeException('This entity can only be saved in the default workspace.');
        }
        
        /** @var \Drupal\Core\Entity\ContentEntityInterface|\Drupal\Core\Entity\EntityPublishedInterface $entity */
        if (!$entity->isNew() && !$entity->isSyncing()) {
            // Force a new revision if the entity is not replicating.
            $entity->setNewRevision(TRUE);
            // All entities in the non-default workspace are pending revisions,
            // regardless of their publishing status. This means that when creating
            // a published pending revision in a non-default workspace it will also be
            // a published pending revision in the default workspace, however, it will
            // become the default revision only when it is replicated to the default
            // workspace.
            $entity->isDefaultRevision(FALSE);
            // Track the workspaces in which the new revision was saved.
            $field_name = $entity_type->getRevisionMetadataKey('workspace');
            $entity->{$field_name}->target_id = $this->workspaceManager
                ->getActiveWorkspace()
                ->id();
        }
        // When a new published entity is inserted in a non-default workspace, we
        // actually want two revisions to be saved:
        // - An unpublished default revision in the default ('live') workspace.
        // - A published pending revision in the current workspace.
        if ($entity->isNew() && $entity->isPublished()) {
            // Keep track of the publishing status in a dynamic property for
            // ::entityInsert(), then unpublish the default revision.
            // @todo Remove this dynamic property once we have an API for associating
            //   temporary data with an entity: https://www.drupal.org/node/2896474.
            $entity->_initialPublished = TRUE;
            $entity->setUnpublished();
        }
    }
    
    /**
     * Responds to the creation of a new entity.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity that was just saved.
     *
     * @see hook_entity_insert()
     */
    public function entityInsert(EntityInterface $entity) {
        
        /** @var \Drupal\Core\Entity\RevisionableInterface|\Drupal\Core\Entity\EntityPublishedInterface $entity */
        // Only run if the entity type can belong to a workspace and we are in a
        // non-default workspace.
        if (!$this->workspaceManager
            ->shouldAlterOperations($entity->getEntityType())) {
            return;
        }
        $this->workspaceAssociation
            ->trackEntity($entity, $this->workspaceManager
            ->getActiveWorkspace());
        // When an entity is newly created in a workspace, it should be published in
        // that workspace, but not yet published on the live workspace. It is first
        // saved as unpublished for the default revision, then immediately a second
        // revision is created which is published and attached to the workspace.
        // This ensures that the published version of the entity does not 'leak'
        // into the live site. This differs from edits to existing entities where
        // there is already a valid default revision for the live workspace.
        if (isset($entity->_initialPublished)) {
            // Operate on a clone to avoid changing the entity prior to subsequent
            // hook_entity_insert() implementations.
            $pending_revision = clone $entity;
            $pending_revision->setPublished();
            $pending_revision->isDefaultRevision(FALSE);
            $pending_revision->save();
        }
    }
    
    /**
     * Responds to updates to an entity.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity that was just saved.
     *
     * @see hook_entity_update()
     */
    public function entityUpdate(EntityInterface $entity) {
        // Only run if the entity type can belong to a workspace and we are in a
        // non-default workspace.
        if (!$this->workspaceManager
            ->shouldAlterOperations($entity->getEntityType())) {
            return;
        }
        // Only track new revisions.
        
        /** @var \Drupal\Core\Entity\RevisionableInterface $entity */
        if ($entity->getLoadedRevisionId() != $entity->getRevisionId()) {
            $this->workspaceAssociation
                ->trackEntity($entity, $this->workspaceManager
                ->getActiveWorkspace());
        }
    }
    
    /**
     * Acts on an entity before it is deleted.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity being deleted.
     *
     * @see hook_entity_predelete()
     */
    public function entityPredelete(EntityInterface $entity) {
        $entity_type = $entity->getEntityType();
        // Only run if we are not dealing with an entity type provided by the
        // Workspaces module, an internal entity type or if we are in a non-default
        // workspace.
        if ($this->shouldSkipPreOperations($entity_type)) {
            return;
        }
        // Disallow any change to an unsupported entity when we are not in the
        // default workspace.
        if (!$this->workspaceManager
            ->isEntityTypeSupported($entity_type)) {
            throw new \RuntimeException('This entity can only be deleted in the default workspace.');
        }
    }
    
    /**
     * Alters entity forms to disallow concurrent editing in multiple workspaces.
     *
     * @param array $form
     *   An associative array containing the structure of the form.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     * @param string $form_id
     *   The form ID.
     *
     * @see hook_form_alter()
     */
    public function entityFormAlter(array &$form, FormStateInterface $form_state, $form_id) {
        
        /** @var \Drupal\Core\Entity\RevisionableInterface $entity */
        $entity = $form_state->getFormObject()
            ->getEntity();
        if (!$this->workspaceManager
            ->isEntityTypeSupported($entity->getEntityType())) {
            return;
        }
        // For supported entity types, signal the fact that this form is safe to use
        // in a non-default workspace.
        // @see \Drupal\workspaces\FormOperations::validateForm()
        $form_state->set('workspace_safe', TRUE);
        // Add an entity builder to the form which marks the edited entity object as
        // a pending revision. This is needed so validation constraints like
        // \Drupal\path\Plugin\Validation\Constraint\PathAliasConstraintValidator
        // know in advance (before hook_entity_presave()) that the new revision will
        // be a pending one.
        if ($this->workspaceManager
            ->hasActiveWorkspace()) {
            $form['#entity_builders'][] = [
                static::class,
                'entityFormEntityBuild',
            ];
        }
        // Run the workspace conflict validation constraint when the entity form is
        // being built so we can "disable" it early and display a message to the
        // user, instead of allowing them to enter data that can never be saved.
        foreach ($entity->validate()
            ->getEntityViolations() as $violation) {
            if ($violation->getConstraint() instanceof EntityWorkspaceConflictConstraint) {
                $form['#markup'] = $violation->getMessage();
                $form['#access'] = FALSE;
                continue;
            }
        }
    }
    
    /**
     * Entity builder that marks all supported entities as pending revisions.
     */
    public static function entityFormEntityBuild($entity_type_id, RevisionableInterface $entity, &$form, FormStateInterface &$form_state) {
        // Set the non-default revision flag so that validation constraints are also
        // aware that a pending revision is about to be created.
        $entity->isDefaultRevision(FALSE);
    }
    
    /**
     * Determines whether we need to react on pre-save or pre-delete operations.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type to check.
     *
     * @return bool
     *   Returns TRUE if the pre-save or pre-delete entity operations should not
     *   be altered in the current request, FALSE otherwise.
     */
    protected function shouldSkipPreOperations(EntityTypeInterface $entity_type) {
        // We should not react on pre-save and pre-delete entity operations if one
        // of the following conditions are met:
        // - the entity type is provided by the Workspaces module;
        // - the entity type is internal, which means that it should not affect
        //   anything in the default (Live) workspace;
        // - we are in the default workspace.
        return $entity_type->getProvider() === 'workspaces' || $entity_type->isInternal() || !$this->workspaceManager
            ->hasActiveWorkspace();
    }

}