#pragma once

#if !defined(MIJIN_MEMORY_OBJECT_POOL_HPP_INCLUDED)
#define MIJIN_MEMORY_OBJECT_POOL_HPP_INCLUDED 1

#include <array>
#include <cstddef>
#include <cstdint>
#include <limits>
#include <memory>
#include <vector>
#include "../debug/assert.hpp"

namespace mijin
{
template<typename TObject, std::size_t OBJECTS_PER_PAGE = 1024>
class ObjectPool
{
private:
    struct GapInfo
    {
        std::uint32_t objectCount;
        std::uint32_t nextGap;
    };
    static constexpr std::size_t ALIGN = std::max(alignof(TObject), alignof(GapInfo));

    struct alignas(ALIGN) ObjectData
    {
        std::array<std::byte, sizeof(TObject)> bytes;
    };
    struct Page
    {
        std::uint32_t freeOffset = 0;
        std::array<ObjectData, OBJECTS_PER_PAGE> data;
    };

    std::vector<std::unique_ptr<Page>> pages;
public:
    [[nodiscard]] TObject* allocate(std::size_t count = 1) noexcept;
    void free(TObject* object, std::size_t count = 1) noexcept;
};

template<typename TObject, std::size_t OBJECTS_PER_PAGE>
TObject* ObjectPool<TObject, OBJECTS_PER_PAGE>::allocate(std::size_t count) noexcept
{
    MIJIN_ASSERT(count <= OBJECTS_PER_PAGE, "Cannot allocate more than OBJECTS_PER_PAGE elements at once!");
    // first try to find a free spot in the existing pages

    for (std::unique_ptr<Page>& page : pages)
    {
        std::uint32_t offset = page->freeOffset;
        while (offset < OBJECTS_PER_PAGE)
        {
            GapInfo& gapInfo = *std::bit_cast<GapInfo*>(&page->data[offset]);
            
        }
    }
}
} // namespace mijin

#endif // !defined(MIJIN_MEMORY_OBJECT_POOL_HPP_INCLUDED)