package synchronizator

// A user representation of a relationship, this interface should be implemented by the user
// to provide the ability to parse the database relationship into a user defined
// struct that fulfills it's requirements.
//
// Example usage:
//
//	type collection_relation struct{}
//
//	func (collection *collection_relation) ToRelationship() (string, []byte, error) {
//		return "COLLECTION_HAS", nil, nil
//	}
//
//	func (collection *collection_relation) FromRelationship(_class string, metadata []byte) error {
//		if _class != "COLLECTION_HAS" {
//			return fmt.Errorf("invalid class %s", _class)
//		}
//		return nil
//	}
type StandardRelationship interface {
	// How to transform the struct into a collection. It needs to return the class,
	// and a []byte representation of the metadata.
	//
	// - class: Is used for classification and query pourposes. It's recomended to provide a constante string to increase consistency.
	// - metadata: Arbitrary data. This will be stored as a jsonb in the database
	//
	ToRelationship() (string, []byte, error)

	// How to transform a relationship into the struct. This method should modify the
	// struct directly as it receives a pointer.
	//
	// - class: Is used for classification and query pourposes.
	// - metadata: Arbitrary data. This is stored as a jsonb in the database
	FromRelationship(string, []byte) error
}

// A relationship in the database.
// It adds some helper methods to easily manage the node.
type Relationship struct {
	_conn    *DB    // Underlaying connection to the database.
	_class   string // The class of the node, should not be modified to avoid inconsistencies.
	From     int64  // From what node this relation comes from
	To       int64  // To what node this relation goes to
	Metadata []byte // Arbitrary data. This is stored as a jsonb in the database
}