#pragma once

#include <unordered_set>

#include <glm/glm.hpp>

#include "Mesh.h"

class Entity {
private:
	glm::mat4 _transform;
	
	glm::mat4 _localToWorld;
	glm::mat4 _worldToLocal;

	Entity* _parent;
	std::unordered_set<Entity*> _children;

	void _UpdateChildTransform() const;

public:
	Entity(Entity* parent);
	virtual ~Entity();
	
	void AddChild(Entity* entity);
	void RemoveChild(Entity* entity);

	Entity* Parent() const { return _parent; }

	void Transform(const glm::mat4& transform);
	void TransformLocal(const glm::mat4& transform);
	void SetTransform(const glm::mat4& transform);
	const glm::mat4& LocalToWorld() const { return _localToWorld; }
	const glm::mat4& WorldToLocal() const { return _worldToLocal; }
	const glm::mat4& LocalObjectTransform() const { return _transform; }

	virtual void Render(DefaultUniform& uniform) { };
	virtual void Update(double deltaTime) { };

};