public function getSortFieldName(
        SortClause $sortClause,
        $contentTypeIdentifier,
        $fieldDefinitionIdentifier,
        $name = null
    ) {
        $fieldMap = $this->getSearchableFieldMap();

        // First check if field exists in type, there is nothing to do if it doesn't
        if (!isset($fieldMap[$contentTypeIdentifier][$fieldDefinitionIdentifier])) {
            return null;
        }

        $fieldName = array_keys($this->getIndexFieldName(
            $sortClause,
            $contentTypeIdentifier,
            $fieldDefinitionIdentifier,
            $fieldMap[$contentTypeIdentifier][$fieldDefinitionIdentifier]['field_type_identifier'],
            $name,
            true
        ));

        return reset($fieldName);
    }