using System;
using static flecs_hub.flecs;

namespace gaemstone.ECS;

public readonly struct Id
	: IEquatable<Id>
{
	public readonly ecs_id_t Value;
	public IdFlags Flags => (IdFlags)(Value & ECS_ID_FLAGS_MASK);

	public bool IsPair     => ecs_id_is_pair(this);
	public bool IsWildcard => ecs_id_is_wildcard(this);

	public Entity RelationUnsafe => new(new() { Data = (Value & ECS_COMPONENT_MASK) >> 32 });
	public Entity TargetUnsafe   => new(new() { Data =  Value & ECS_ENTITY_MASK });

	public Id(ecs_id_t value) => Value = value;

	public static Id Pair(Entity relation, Entity target)
		=> new(ecs_make_pair(relation, target));

	public bool Equals(Id other) => Value.Data == other.Value.Data;
	public override bool Equals(object? obj) => (obj is Id other) && Equals(other);
	public override int GetHashCode() => Value.Data.GetHashCode();
	public override string? ToString()
		=> (Flags != default) ? $"Id({Value.Data}, Flags={Flags})"
		                      : $"Id({Value.Data})";

	public static bool operator ==(Id left, Id right) =>  left.Equals(right);
	public static bool operator !=(Id left, Id right) => !left.Equals(right);

	public static implicit operator ecs_id_t(Id id) => id.Value;

	public static implicit operator Term(Id id) => new(id);
}