#pragma once

#include <cstddef>
#include <tuple>
#include <vector>

#include <Entities/Components.h>
#include <Entities/Entity.h>

using ComponentVectorTuple = std::tuple
<
	std::vector<Transform>,
	std::vector<Texture>,
	std::vector<BoundingBox>
>;

class EntityMemoryPool
{
private:
	ComponentVectorTuple m_components;
	std::vector<EntityTag> m_tags;
	std::vector<bool> m_aliveStates;
	size_t m_entityCount; // for debugging purposes, should not be included in release version
	bool m_holePresent{false};

private:
	EntityMemoryPool();

	EntityMemoryPool(const EntityMemoryPool&) = delete;

public:
  static EntityMemoryPool& instance();

  template<typename T>
  bool hasComponent(EntityIndex) const;
  
  template<typename T>
  T& getComponent(EntityIndex) const;

  template<typename T>
  T& getComponent(EntityIndex);

  EntityTag getTag(EntityIndex) const;

  bool getAlive(EntityIndex) const;

  void removeEntity(EntityIndex);
};