class WorkspaceAssociation

class WorkspaceAssociation implements WorkspaceAssociationInterface {
    
    /**
     * The table for the workspace association storage.
     */
    const TABLE = 'workspace_association';
    
    /**
     * The database connection.
     *
     * @var \Drupal\Core\Database\Connection
     */
    protected $database;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The workspace repository service.
     *
     * @var \Drupal\workspaces\WorkspaceRepositoryInterface
     */
    protected $workspaceRepository;
    
    /**
     * Constructs a WorkspaceAssociation object.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   A database connection for reading and writing path aliases.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager for querying revisions.
     * @param \Drupal\workspaces\WorkspaceRepositoryInterface $workspace_repository
     *   The Workspace repository service.
     */
    public function __construct(Connection $connection, EntityTypeManagerInterface $entity_type_manager, WorkspaceRepositoryInterface $workspace_repository) {
        $this->database = $connection;
        $this->entityTypeManager = $entity_type_manager;
        $this->workspaceRepository = $workspace_repository;
    }
    
    /**
     * {@inheritdoc}
     */
    public function trackEntity(RevisionableInterface $entity, WorkspaceInterface $workspace) {
        // Determine all workspaces that might be affected by this change.
        $affected_workspaces = $this->workspaceRepository
            ->getDescendantsAndSelf($workspace->id());
        // Get the currently tracked revision for this workspace.
        $tracked = $this->getTrackedEntities($workspace->id(), $entity->getEntityTypeId(), [
            $entity->id(),
        ]);
        $tracked_revision_id = NULL;
        if (isset($tracked[$entity->getEntityTypeId()])) {
            $tracked_revision_id = key($tracked[$entity->getEntityTypeId()]);
        }
        try {
            $transaction = $this->database
                ->startTransaction();
            // Update all affected workspaces that were tracking the current revision.
            // This means they are inheriting content and should be updated.
            if ($tracked_revision_id) {
                $this->database
                    ->update(static::TABLE)
                    ->fields([
                    'target_entity_revision_id' => $entity->getRevisionId(),
                ])
                    ->condition('workspace', $affected_workspaces, 'IN')
                    ->condition('target_entity_type_id', $entity->getEntityTypeId())
                    ->condition('target_entity_id', $entity->id())
                    ->condition('target_entity_revision_id', $tracked_revision_id)
                    ->execute();
            }
            // Insert a new index entry for each workspace that is not tracking this
            // entity yet.
            $missing_workspaces = array_diff($affected_workspaces, $this->getEntityTrackingWorkspaceIds($entity));
            if ($missing_workspaces) {
                $insert_query = $this->database
                    ->insert(static::TABLE)
                    ->fields([
                    'workspace',
                    'target_entity_revision_id',
                    'target_entity_type_id',
                    'target_entity_id',
                ]);
                foreach ($missing_workspaces as $workspace_id) {
                    $insert_query->values([
                        'workspace' => $workspace_id,
                        'target_entity_type_id' => $entity->getEntityTypeId(),
                        'target_entity_id' => $entity->id(),
                        'target_entity_revision_id' => $entity->getRevisionId(),
                    ]);
                }
                $insert_query->execute();
            }
        } catch (\Exception $e) {
            if (isset($transaction)) {
                $transaction->rollBack();
            }
            watchdog_exception('workspaces', $e);
            throw $e;
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function workspaceInsert(WorkspaceInterface $workspace) {
        // When a new workspace has been saved, we need to copy all the associations
        // of its parent.
        if ($workspace->hasParent()) {
            $this->initializeWorkspace($workspace);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getTrackedEntities($workspace_id, $entity_type_id = NULL, $entity_ids = NULL) {
        $query = $this->database
            ->select(static::TABLE);
        $query->fields(static::TABLE, [
            'target_entity_type_id',
            'target_entity_id',
            'target_entity_revision_id',
        ])
            ->orderBy('target_entity_revision_id', 'ASC')
            ->condition('workspace', $workspace_id);
        if ($entity_type_id) {
            $query->condition('target_entity_type_id', $entity_type_id, '=');
            if ($entity_ids) {
                $query->condition('target_entity_id', $entity_ids, 'IN');
            }
        }
        $tracked_revisions = [];
        foreach ($query->execute() as $record) {
            $tracked_revisions[$record->target_entity_type_id][$record->target_entity_revision_id] = $record->target_entity_id;
        }
        return $tracked_revisions;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAssociatedRevisions($workspace_id, $entity_type_id, $entity_ids = NULL) {
        
        /** @var \Drupal\Core\Entity\EntityStorageInterface $storage */
        $storage = $this->entityTypeManager
            ->getStorage($entity_type_id);
        // If the entity type is not using core's default entity storage, we can't
        // assume the table mapping layout so we have to return only the latest
        // tracked revisions.
        if (!$storage instanceof SqlContentEntityStorage) {
            return $this->getTrackedEntities($workspace_id, $entity_type_id, $entity_ids)[$entity_type_id];
        }
        $entity_type = $storage->getEntityType();
        $table_mapping = $storage->getTableMapping();
        $workspace_field = $table_mapping->getColumnNames($entity_type->get('revision_metadata_keys')['workspace'])['target_id'];
        $id_field = $table_mapping->getColumnNames($entity_type->getKey('id'))['value'];
        $revision_id_field = $table_mapping->getColumnNames($entity_type->getKey('revision'))['value'];
        $query = $this->database
            ->select($entity_type->getRevisionTable(), 'revision');
        $query->leftJoin($entity_type->getBaseTable(), 'base', "[revision].[{$id_field}] = [base].[{$id_field}]");
        $query->fields('revision', [
            $revision_id_field,
            $id_field,
        ])
            ->condition("revision.{$workspace_field}", $workspace_id)
            ->where("[revision].[{$revision_id_field}] > [base].[{$revision_id_field}]")
            ->orderBy("revision.{$revision_id_field}", 'ASC');
        // Restrict the result to a set of entity ID's if provided.
        if ($entity_ids) {
            $query->condition("revision.{$id_field}", $entity_ids, 'IN');
        }
        return $query->execute()
            ->fetchAllKeyed();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getEntityTrackingWorkspaceIds(RevisionableInterface $entity) {
        $query = $this->database
            ->select(static::TABLE)
            ->fields(static::TABLE, [
            'workspace',
        ])
            ->condition('target_entity_type_id', $entity->getEntityTypeId())
            ->condition('target_entity_id', $entity->id());
        return $query->execute()
            ->fetchCol();
    }
    
    /**
     * {@inheritdoc}
     */
    public function postPublish(WorkspaceInterface $workspace) {
        $this->deleteAssociations($workspace->id());
    }
    
    /**
     * {@inheritdoc}
     */
    public function deleteAssociations($workspace_id, $entity_type_id = NULL, $entity_ids = NULL) {
        $query = $this->database
            ->delete(static::TABLE)
            ->condition('workspace', $workspace_id);
        if ($entity_type_id) {
            $query->condition('target_entity_type_id', $entity_type_id, '=');
            if ($entity_ids) {
                $query->condition('target_entity_id', $entity_ids, 'IN');
            }
        }
        $query->execute();
    }
    
    /**
     * {@inheritdoc}
     */
    public function initializeWorkspace(WorkspaceInterface $workspace) {
        if ($parent_id = $workspace->parent->target_id) {
            $indexed_rows = $this->database
                ->select(static::TABLE);
            $indexed_rows->addExpression(':new_id', 'workspace', [
                ':new_id' => $workspace->id(),
            ]);
            $indexed_rows->fields(static::TABLE, [
                'target_entity_type_id',
                'target_entity_id',
                'target_entity_revision_id',
            ]);
            $indexed_rows->condition('workspace', $parent_id);
            $this->database
                ->insert(static::TABLE)
                ->from($indexed_rows)
                ->execute();
        }
    }

}