/*********************************************************************
 * \file   SHSystemManager.h
 * \author Daniel Chua Yee Chen
 * \brief  Declaration for the SHSystemManager class.
 * SHSystemManager is the interface class where users of the engine create
 * the systems that gives the components their functionality. This also ensures that the Init and Exit functions are ran at the appropriate time
 *
 * \copyright Copyright (c) 2021 DigiPen Institute of Technology. Reproduction
	 or disclosure of this file or its contents without the prior written
	 consent of DigiPen Institute of Technology is prohibited.
 *********************************************************************/


#ifndef SH_SYSTEM_MANAGER_H
#define SH_SYSTEM_MANAGER_H


#include <unordered_map>
#include <memory>
#include <string>
#include <cassert>
#include <climits>
#include "../System/SHSystem.h"
#include "../General/SHFamily.h"

namespace SHADE
{

	typedef uint32_t SystemTypeID;
	typedef uint32_t SystemVersionID;
	typedef uint64_t SystemID;
	typedef SHFamilyID<SHSystem> SystemFamily;

	class SHSystemManager
	{
		//type definition for the container we use to store our system
		using SystemContainer = std::unordered_map<SystemID, std::unique_ptr<SHSystem>>;

	private:
		static SystemContainer systemContainer;


	public:
		/*!*************************************************************************
		 * This class is used as a static class.
		 * No objects of this type should be created
		***************************************************************************/
		SHSystemManager() = delete;
		~SHSystemManager() = delete;

		/**************************************************************************
		 * \brief 
		 * Create a system of type T and map it to a name.
		 * throws an error if a system with the same name already exists.
		 * \param name
		 * name of the system
		 * \return 
		 * none
		***************************************************************************/
		template<typename T>
		static std::enable_if_t<std::is_base_of_v<SHSystem, T>, void> CreateSystem()
		{
			SystemTypeID typeID = SystemFamily::GetID<T>();

			SystemVersionID version = 0;
			SystemID id = ((SystemID)version << sizeof(SystemVersionID) * CHAR_BIT)  + typeID;
			while (systemContainer.find(id) != systemContainer.end())
			{
				++version;
				SystemID id = ((SystemID)version << sizeof(SystemVersionID) * CHAR_BIT) + typeID;
			}
			systemContainer.emplace(id, std::make_unique<T>());


		}

		/**************************************************************************
		 * \brief 
		 * Get a pointer to the System with a specified name.
		 * \param name
		 * Name of the system in the map
		 * \return 
		 * Base System pointer.
		***************************************************************************/
		template<typename T>
		static std::enable_if_t<std::is_base_of_v<SHSystem, T>, T*> GetSystem(SystemVersionID version = 0)
		{
			SystemTypeID typeID = SystemFamily::GetID<T>();

			SystemID id = ((SystemID)version << sizeof(SystemVersionID) * CHAR_BIT) + typeID;

			if (systemContainer.find(id) == systemContainer.end())
			{
				std::cout << "System Manager error: System Version " << version << " does not exit." << std::endl;
				return nullptr;
			}

			return (T*)systemContainer.find(id)->second.get();
		}

		/**************************************************************************
		 * \brief 
		 * Call the Init function of all systems.
		 * \return 
		 * none
		***************************************************************************/
		static void Init() noexcept;

		/**************************************************************************
		 * \brief 
		 * Call the Exit function of all systems.
		 * \return 
		***************************************************************************/
		static void Exit() noexcept;


	protected:


	};

}



#endif