EntityManager.h

//EntityManager.h
#pragma once
#include "ServiceLocator.h"
#include <type_traits>
#include "EntitySystemTypes.h"
#include "ComponentContainer.h"

class EntityManager
{
public:

	EntityManager() {};
	~EntityManager() {};

	template<typename... Args>
	constexpr std::size_t length(Args...)
	{
		std::cout << sizeof...(Args) << '\n';
		return sizeof...(Args);
	}

	template <typename FirstComponent, typename... Components>
	EntityTypeId CreateEntityType() {

		typedef ComponentContainer<FirstComponent, Components...> Container;

		EntityTypeId id = std::numeric_limits<EntityTypeId>::max();

		if (ServiceLocator<Container>::GetService() == nullptr) {

			id = numberOfEntityTypes;

			Container* container = new Container();
			ServiceLocator<Container>::SetService(container);
			numberOfEntityTypes++;
		}
		else {
			std::cout << "Type already exists when CreatingEntityType " << '\n';
		}
		return id;
	}

	template <typename FirstComponent, typename... Components>
	EntityId CreateEntityOfType() {

		typedef ComponentContainer<FirstComponent, Components...> Container;

		Container* container = ServiceLocator<Container>::GetService();

		if (container == nullptr) {
			return std::numeric_limits<EntityId>::max();
		}
		container->AddElements();

		EntityId entityId = std::numeric_limits<EntityTypeId>::max();

		entityId = container->get<0>().size() - 1;

		return entityId;
	}

	template <typename Component, typename FirstComponent, typename... Components>
	Component& GetComponent(EntityId p_entityId) {

		typedef ComponentContainer<FirstComponent, Components...> Container;

		Container* container = ServiceLocator<Container>::GetService();

		return container->GetComponent<Component>(p_entityId);

	}

private:
	EntityTypeId numberOfEntityTypes;
	EntityId numberOfEntities;

};