namespace OECS;

/// <summary>
/// Marker interface for components that represent a directed relationship
/// between two entities. The component is stored on the <see cref="Source"/>
/// entity and points to the <see cref="Target"/> entity.
///
/// The <see cref="World"/> automatically maintains a reverse index so that
/// all sources pointing to a given target can be looked up efficiently.
/// </summary>
public interface IRelationship
{
    /// <summary>
    /// The entity that owns this relationship component.
    /// </summary>
    Entity Source { get; }

    /// <summary>
    /// The entity that this relationship points to.
    /// </summary>
    Entity Target { get; }
}