// =============================================
//  Aster: pipeline_utils.h
//  Copyright (c) 2020-2024 Anish Bhobe
// =============================================

#pragma once

#include "global.h"

#include <EASTL/deque.h>
#include <EASTL/stack.h>

struct Device;
struct Texture;
struct UniformStorageBuffer;

struct RenderResourceManager;

struct Handle
{
    u32 m_Index;
};

struct BufferHandle : Handle
{
};

struct TextureHandle : Handle
{
};

struct FreeList
{
    eastl::stack<u32, eastl::deque<u32>> m_List;
    u32 m_MaxVisited = 0;
    u32 m_MaxCapacity = 16;

    void
    Init(u32 maxCapacity)
    {
        m_MaxCapacity = maxCapacity;
    }

    [[nodiscard]] u32
    Alloc()
    {
        if (!m_List.empty())
        {
            const u32 value = m_List.top();
            m_List.pop();
            return value;
        }
        if (m_MaxVisited < m_MaxCapacity)
        {
            return m_MaxVisited++;
        }
        ERROR("Out of Handles.") THEN_ABORT(-1);
    }

    void
    Free(u32 index)
    {
        WARN_IF(index >= m_MaxCapacity, "Trying to free an out-of-bounds index.");

        if (index < m_MaxCapacity)
            m_List.push(index);
    }
};

struct RenderResourceManager
{
  private:
    union WriteInfo {
        vk::DescriptorBufferInfo uBufferInfo;
        vk::DescriptorImageInfo uImageInfo;
        vk::BufferView uBufferView;

        explicit WriteInfo(vk::DescriptorBufferInfo info);
        explicit WriteInfo(vk::DescriptorImageInfo info);
        explicit WriteInfo(vk::BufferView info);
    };

    eastl::deque<WriteInfo> m_WriteInfos;
    eastl::vector<vk::WriteDescriptorSet> m_Writes;

    vk::Sampler m_Sampler;

    FreeList m_BufferFreeList;
    FreeList m_TextureFreeList;

  public:
    const Device *m_Device;

    constexpr static u32 BUFFER_BINDING_INDEX = 0;
    constexpr static u32 TEXTURE_BINDING_INDEX = 1;

    vk::DescriptorPool m_DescriptorPool;
    vk::DescriptorSetLayout m_SetLayout;
    vk::DescriptorSet m_DescriptorSet;

    BufferHandle Commit(const UniformStorageBuffer *storageBuffer);
    TextureHandle Commit(const Texture *texture);

    void Update();

    // Ctor/Dtor
    explicit RenderResourceManager(const Device *device, u16 maxSize);
    ~RenderResourceManager();
};