class EntityOperations

class EntityOperations {
    public function __construct(EntityTypeManagerInterface $entityTypeManager, WorkspaceManagerInterface $workspaceManager, WorkspaceAssociationInterface $workspaceAssociation, WorkspaceInformationInterface $workspaceInfo, WorkspaceRepositoryInterface $workspaceRepository) {
    }
    
    /**
     * Implements hook_entity_preload().
     */
    public function entityPreload(array $ids, string $entity_type_id) : array {
        $entities = [];
        $entity_type = $this->entityTypeManager
            ->getDefinition($entity_type_id);
        if (!$this->workspaceInfo
            ->isEntityTypeSupported($entity_type) || !$this->workspaceManager
            ->hasActiveWorkspace()) {
            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, $ids)) {
            // Bail out early if there are no tracked entities of this type.
            if (!isset($tracked_entities[$entity_type_id])) {
                return $entities;
            }
            
            /** @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;
    }
    
    /**
     * Implements hook_entity_presave().
     */
    public function entityPresave(EntityInterface $entity) : void {
        if ($this->shouldSkipOperations($entity)) {
            return;
        }
        // Disallow any change to an unsupported entity when we are not in the
        // default workspace.
        if (!$this->workspaceInfo
            ->isEntitySupported($entity)) {
            throw new \RuntimeException(sprintf('The "%s" entity type can only be saved in the default workspace.', $entity->getEntityTypeId()));
        }
        
        /** @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);
        }
        // In ::entityFormEntityBuild() we mark the entity as a non-default revision
        // so that validation constraints can rely on $entity->isDefaultRevision()
        // always returning FALSE when an entity form is submitted in a workspace.
        // However, after validation has run, we need to revert that flag so the
        // first revision of a new entity is correctly seen by the system as the
        // default revision.
        if ($entity->isNew()) {
            $entity->isDefaultRevision(TRUE);
        }
        // Track the workspaces in which the new revision was saved.
        if (!$entity->isSyncing()) {
            $field_name = $entity->getEntityType()
                ->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();
        }
    }
    
    /**
     * Implements hook_entity_insert().
     */
    public function entityInsert(EntityInterface $entity) : void {
        if ($entity->getEntityTypeId() === 'workspace') {
            $this->workspaceAssociation
                ->workspaceInsert($entity);
            $this->workspaceRepository
                ->resetCache();
        }
        if ($this->shouldSkipOperations($entity) || !$this->workspaceInfo
            ->isEntitySupported($entity)) {
            return;
        }
        assert($entity instanceof RevisionableInterface && $entity instanceof EntityPublishedInterface);
        $this->workspaceAssociation
            ->trackEntity($entity, $this->workspaceManager
            ->getActiveWorkspace());
        // When a published entity is created in a workspace, it should remain
        // published only in that workspace, and unpublished in the live workspace.
        // It is first saved as unpublished for the default revision, then
        // immediately a second revision is created which is published and attached
        // to the workspace. This ensures that the initial version of the entity
        // does not 'leak' into the live site. This differs from edits to existing
        // entities where there is already a valid default revision for the live
        // workspace.
        if (isset($entity->_initialPublished)) {
            // Ensure that the default revision of an entity saved in a workspace is
            // unpublished.
            if ($entity->isPublished()) {
                throw new \RuntimeException('The default revision of an entity created in a workspace cannot be published.');
            }
            $entity->setPublished();
            $entity->isDefaultRevision(FALSE);
            $entity->save();
        }
    }
    
    /**
     * Implements hook_entity_update().
     */
    public function entityUpdate(EntityInterface $entity) : void {
        if ($entity->getEntityTypeId() === 'workspace') {
            $this->workspaceRepository
                ->resetCache();
        }
        if ($this->shouldSkipOperations($entity) || !$this->workspaceInfo
            ->isEntitySupported($entity)) {
            return;
        }
        // Only track new revisions.
        
        /** @var \Drupal\Core\Entity\RevisionableInterface $entity */
        if ($entity->getLoadedRevisionId() != $entity->getRevisionId()) {
            $this->workspaceAssociation
                ->trackEntity($entity, $this->workspaceManager
                ->getActiveWorkspace());
        }
    }
    
    /**
     * Implements hook_entity_translation_insert().
     */
    public function entityTranslationInsert(EntityInterface $translation) : void {
        if ($this->shouldSkipOperations($translation) || !$this->workspaceInfo
            ->isEntitySupported($translation) || $translation->isSyncing()) {
            return;
        }
        // When a new translation is added to an existing entity, we need to add
        // that translation to the default revision as well, otherwise the new
        // translation wouldn't show up in entity queries or views which use the
        // field data table as the base table.
        $this->workspaceManager
            ->executeOutsideWorkspace(function () use ($translation) {
            $storage = $this->entityTypeManager
                ->getStorage($translation->getEntityTypeId());
            $default_revision = $storage->load($translation->id());
            $langcode = $translation->language()
                ->getId();
            if (!$default_revision->hasTranslation($langcode)) {
                $default_revision_translation = $default_revision->addTranslation($langcode, $translation->toArray());
                $default_revision_translation->setUnpublished();
                $default_revision_translation->setSyncing(TRUE);
                $default_revision_translation->save();
            }
        });
    }
    
    /**
     * Implements hook_entity_predelete().
     */
    public function entityPredelete(EntityInterface $entity) : void {
        if ($entity->getEntityTypeId() === 'workspace') {
            $this->workspaceRepository
                ->resetCache();
        }
        if ($this->shouldSkipOperations($entity)) {
            return;
        }
        // Prevent the entity from being deleted if the entity type does not have
        // support for workspaces, or if the entity has a published default
        // revision.
        $active_workspace = $this->workspaceManager
            ->getActiveWorkspace();
        if (!$this->workspaceInfo
            ->isEntitySupported($entity) || !$this->workspaceInfo
            ->isEntityDeletable($entity, $active_workspace)) {
            throw new \RuntimeException("This {$entity->getEntityType()->getSingularLabel()} can only be deleted in the Live workspace.");
        }
    }
    
    /**
     * Implements hook_entity_delete().
     */
    public function entityDelete(EntityInterface $entity) : void {
        if ($this->workspaceInfo
            ->isEntityTypeSupported($entity->getEntityType())) {
            $this->workspaceAssociation
                ->deleteAssociations(NULL, $entity->getEntityTypeId(), [
                $entity->id(),
            ]);
        }
    }
    
    /**
     * Implements hook_entity_revision_delete().
     */
    public function entityRevisionDelete(EntityInterface $entity) : void {
        if ($this->workspaceInfo
            ->isEntityTypeSupported($entity->getEntityType())) {
            $this->workspaceAssociation
                ->deleteAssociations(NULL, $entity->getEntityTypeId(), [
                $entity->id(),
            ], [
                $entity->getRevisionId(),
            ]);
        }
    }
    
    /**
     * Implements hook_form_alter().
     *
     * Alters entity forms to disallow concurrent editing in multiple workspaces.
     */
    public function entityFormAlter(array &$form, FormStateInterface $form_state, string $form_id) : void {
        if (!$form_state->getFormObject() instanceof EntityFormInterface) {
            return;
        }
        $entity = $form_state->getFormObject()
            ->getEntity();
        if (!$this->workspaceInfo
            ->isEntitySupported($entity) && !$this->workspaceInfo
            ->isEntityIgnored($entity)) {
            return;
        }
        // For supported and ignored entity types, signal the fact that this form is
        // safe to use in a workspace.
        // @see \Drupal\workspaces\Hook\FormOperations::formAlter()
        $form_state->set('workspace_safe', TRUE);
        // There is nothing more to do for ignored entity types.
        if ($this->workspaceInfo
            ->isEntityIgnored($entity)) {
            return;
        }
        // Add an entity builder to the form which marks the edited entity object as
        // a pending revision. This is needed so validation constraints like
        // \Drupal\path\Plugin\Validation\Constraint\PathAliasConstraintValidator
        // know in advance (before hook_entity_presave()) that the new revision will
        // be a pending one.
        if ($this->workspaceManager
            ->hasActiveWorkspace()) {
            $form['#entity_builders'][] = [
                static::class,
                'entityFormEntityBuild',
            ];
        }
    }
    
    /**
     * Entity builder that marks all supported entities as pending revisions.
     */
    public static function entityFormEntityBuild(string $entity_type_id, RevisionableInterface $entity, array &$form, FormStateInterface &$form_state) : void {
        // Ensure that all entity forms are signaling that a new revision will be
        // created.
        $entity->setNewRevision(TRUE);
        // 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 entity operations.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity to check.
     *
     * @return bool
     *   Returns TRUE if entity operations should not be altered, FALSE otherwise.
     */
    protected function shouldSkipOperations(EntityInterface $entity) : bool {
        // We should not react on entity operations when the entity is ignored or
        // when we're not in a workspace context.
        return $this->workspaceInfo
            ->isEntityIgnored($entity) || !$this->workspaceManager
            ->hasActiveWorkspace();
    }

}