// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "pma/PolyAllocator.h"

#ifdef _MSC_VER
    #pragma warning(push)
    #pragma warning(disable : 4365 4987)
#endif
#include <functional>
#include <memory>
#include <utility>
#ifdef _MSC_VER
    #pragma warning(pop)
#endif

namespace pma {

class MemoryResource;

namespace impl {

template<class TPointer, class TTarget, class TBase = TTarget>
class ManagedInstance {
    public:
        using PointerType = TPointer;

    private:
        explicit ManagedInstance(MemoryResource* memRes) : pMemRes{memRes} {
        }

    public:
        static ManagedInstance with(MemoryResource* memRes) {
            return ManagedInstance{memRes};
        }

        template<typename ... Args>
        PointerType create(Args&& ... args) {
            pma::PolyAllocator<TTarget> alloc{pMemRes};
            auto deleter = [alloc](TBase* ptr) mutable {
                    alloc.deleteObject(static_cast<TTarget*>(ptr));
                };
            return {alloc.newObject(std::forward<Args>(args)...), deleter};
        }

    private:
        MemoryResource* pMemRes;

};

}  // namespace impl

template<class TTarget, class TBase = TTarget>
using UniqueInstance = impl::ManagedInstance<std::unique_ptr<TBase, std::function<void (TBase*)> >, TTarget, TBase>;

template<class TTarget, class TBase = TTarget>
using SharedInstance = impl::ManagedInstance<std::shared_ptr<TBase>, TTarget, TBase>;

}  // namespace pma