public static string GetReferencingEntityName()

in src/Core/Resolvers/MultipleCreateOrderHelper.cs [45:126]
69 lines of code
8 McCabe index (conditional complexity)

        public static string GetReferencingEntityName(
            IMiddlewareContext context,
            string relationshipName,
            string sourceEntityName,
            string targetEntityName,
            ISqlMetadataProvider metadataProvider,
            Dictionary<string, IValueNode?> columnDataInSourceBody,
            IValueNode? targetNodeValue,
            int nestingLevel,
            bool isMNRelationship = false)
        {
            if (!metadataProvider.GetEntityNamesAndDbObjects().TryGetValue(sourceEntityName, out DatabaseObject? sourceDbObject) ||
                !metadataProvider.GetEntityNamesAndDbObjects().TryGetValue(targetEntityName, out DatabaseObject? targetDbObject))
            {
                // This should not be hit ideally.
                throw new DataApiBuilderException(
                    message: $"Could not determine definition for source: {sourceEntityName} and target: {targetEntityName} entities for " +
                    $"relationship: {relationshipName} at level: {nestingLevel}",
                    statusCode: HttpStatusCode.InternalServerError,
                    subStatusCode: DataApiBuilderException.SubStatusCodes.EntityNotFound);
            }

            if (sourceDbObject.GetType() != typeof(DatabaseTable) || targetDbObject.GetType() != typeof(DatabaseTable))
            {
                throw new DataApiBuilderException(
                message: $"Cannot execute multiple-create for relationship: {relationshipName} at level: {nestingLevel} because currently DAB supports" +
                $"multiple-create only for entities backed by tables.",
                statusCode: HttpStatusCode.BadRequest,
                subStatusCode: DataApiBuilderException.SubStatusCodes.NotSupported);
            }

            DatabaseTable sourceDbTable = (DatabaseTable)sourceDbObject;
            DatabaseTable targetDbTable = (DatabaseTable)targetDbObject;
            if (sourceDbTable.Equals(targetDbTable))
            {
                //  DAB does not yet support multiple-create for self referencing relationships where both the source and
                //  target entities are backed by same database table.
                throw new DataApiBuilderException(
                message: $"Multiple-create for relationship: {relationshipName} at level: {nestingLevel} is not supported because the " +
                $"source entity: {sourceEntityName} and the target entity: {targetEntityName} are backed by the same database table.",
                statusCode: HttpStatusCode.BadRequest,
                subStatusCode: DataApiBuilderException.SubStatusCodes.NotSupported);
            }

            if (isMNRelationship)
            {
                // For M:N relationships, neither the source nor the target entity act as the referencing entity.
                // Instead, the linking table act as the referencing entity.
                return string.Empty;
            }

            if (TryDetermineReferencingEntityBasedOnEntityRelationshipMetadata(
                    sourceEntityName: sourceEntityName,
                    targetEntityName: targetEntityName,
                    sourceDbTable: sourceDbTable,
                    referencingEntityName: out string? referencingEntityNameBasedOnEntityMetadata))
            {
                return referencingEntityNameBasedOnEntityMetadata;
            }
            else
            {
                // Had the target node represented an array value, it would have been an 1:N relationship from (source, target).
                // For that case, we would not hit this code because the entity metadata would have been sufficient to tell us that the target entity
                // is the referencing entity. Hence we conclude that the target node must represent a single input object corresponding to N:1 or 1:1 relationship types.
                ObjectValueNode? objectValueNode = (ObjectValueNode?)targetNodeValue;
                Dictionary<string, IValueNode?> columnDataInTargetBody = GetBackingColumnDataFromFields(
                    context: context,
                    entityName: targetEntityName,
                    fieldNodes: objectValueNode!.Fields,
                    metadataProvider: metadataProvider);

                return DetermineReferencingEntityBasedOnRequestBody(
                    relationshipName: relationshipName,
                    sourceEntityName: sourceEntityName,
                    targetEntityName: targetEntityName,
                    sourceDbObject: sourceDbObject,
                    targetDbObject: targetDbObject,
                    columnDataInSourceBody: columnDataInSourceBody,
                    columnDataInTargetBody: columnDataInTargetBody,
                    nestingLevel: nestingLevel);
            }
        }