ComponentFactory.h

// Copyright(c) 2019 - 2020, #Momo
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#pragma once

#include "Utilities/STL/MxHashMap.h"
#include "Utilities/String/String.h"
#include "Utilities/AbstractFactory/AbstractFactory.h"
#include "Utilities/ECS/ComponentView.h"

namespace MxEngine
{
    class ComponentFactory
    {
        static constexpr size_t FactorySize = sizeof(FactoryImpl<char>);
    public:
        using FactoryMap = MxHashMap<StringId, std::aligned_storage_t<FactorySize>>;
    private:
        inline static FactoryMap* factories = nullptr;
    public:
        template<typename T>
        static FactoryImpl<T>& GetFactory()
        {
            if (factories->find(T::ComponentId) == factories->end())
            {
                new (&(*factories)[T::ComponentId]) FactoryImpl<T>();
            }
            return *reinterpret_cast<FactoryImpl<T>*>(&(*factories)[T::ComponentId]);
        }

        template<typename T>
        static auto& Get()
        {
            return GetFactory<T>().template GetPool<T>();
        }

        template<typename T>
        static ComponentView<T> GetView()
        {
            return ComponentView{ Get<T>() };
        }

        template<typename T, typename... Args>
        static auto CreateComponent(Args&&... args)
        {
            UUID uuid = UUIDGenerator::Get();
            auto& pool = Get<T>();
            size_t index = pool.Allocate(uuid, std::forward<Args>(args)...);
            return Resource<T, ComponentFactory>(uuid, index);
        }

        template<typename T>
        static void Destroy(Resource<T, ComponentFactory>& resource)
        {
            Get<T>().Deallocate(resource.GetHandle());
        }

        static void Init()
        {
            factories = new FactoryMap(); // static data, so dont care about freeing
        }

        static FactoryMap* GetImpl()
        {
            return factories;
        }

        static void Clone(FactoryMap* other)
        {
            factories = other;
        }
    };

    template<typename T>
    using CResource = Resource<T, ComponentFactory>;
}