#include "vk_engine.h"
#include "vk_images.h"
#include "vk_pipelines.h"
#include <print>

#include <SDL.h>
#include <SDL_vulkan.h>

#include <vk_types.h>
#include <vk_initializers.h>
#include "VkBootstrap.h"

#include <chrono>
#include <thread>
#include "imgui.h"
#include "imgui_impl_sdl2.h"
#include "imgui_impl_vulkan.h"

#define VMA_IMPLEMENTATION
#include "vk_mem_alloc.h"

constexpr bool bUseValidationLayers = true;

VulkanEngine* loadedEngine = nullptr;

VulkanEngine& VulkanEngine::Get() {
  return *loadedEngine;
}

void VulkanEngine::init()
{
  assert(loadedEngine == nullptr);
  loadedEngine = this;

  // We initialize SDL and create a window with it.
  SDL_Init(SDL_INIT_VIDEO);

  SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_VULKAN);

  _window = SDL_CreateWindow(
      "Vulkan Engine",
      SDL_WINDOWPOS_UNDEFINED,
      SDL_WINDOWPOS_UNDEFINED,
      int(_windowExtent.width),
      int(_windowExtent.height),
      window_flags);

  init_vulkan();
  init_swapchain();
  init_commands();
  init_sync_structures();
  init_descriptors();
  init_pipelines();
  init_imgui();

  //everything went fine
  _isInitialized = true;
}

void VulkanEngine::cleanup()
{
  if (_isInitialized) {
    vkDeviceWaitIdle(_device);

    for(size_t i = 0; i < FRAME_OVERLAP; i++) {
      vkDestroyCommandPool(_device, _frames[i]._commandPool, nullptr);

      //destroy sync objects
      vkDestroyFence(_device, _frames[i]._renderFence, nullptr);
      vkDestroySemaphore(_device, _frames[i]._renderSemaphore, nullptr);
      vkDestroySemaphore(_device ,_frames[i]._swapchainSemaphore, nullptr);

      _frames[i]._deletionQueue.flush();
    }

    _mainDeletionQueue.flush();

    destroy_swapchain();

    vkDestroySurfaceKHR(_instance, _surface, nullptr);
    vkDestroyDevice(_device, nullptr);
    vkb::destroy_debug_utils_messenger(_instance, _debug_messenger);
    vkDestroyInstance(_instance, nullptr);
    SDL_DestroyWindow(_window);
  }

  loadedEngine = nullptr;
}

void VulkanEngine::draw()
{
  // wait until the gpu has finished rendering the last frame. Timeout of 1 second
  VK_CHECK(vkWaitForFences(_device, 1, &get_current_frame()._renderFence, true, 1000000000));
  get_current_frame()._deletionQueue.flush();

  VK_CHECK(vkResetFences(_device, 1, &get_current_frame()._renderFence));

  uint32_t swapchainImageIndex = 0;
  VK_CHECK(vkAcquireNextImageKHR(_device, _swapchain, 1000000000, get_current_frame()._swapchainSemaphore, nullptr, &swapchainImageIndex));

  VkCommandBuffer cmd = get_current_frame()._mainCommandBuffer;
  VK_CHECK(vkResetCommandBuffer(cmd, 0));

  VkCommandBufferBeginInfo cmdBeginInfo = vkinit::command_buffer_begin_info(VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT);

  _drawExtent.width = _drawImage.imageExtent.width;
  _drawExtent.height = _drawImage.imageExtent.height;

  VK_CHECK(vkBeginCommandBuffer(cmd, &cmdBeginInfo));

  // transition our main draw image into general layout so we can write into it
  // we will overwrite it all so we dont care about what was the older layout

  vkutil::transition_image(cmd, _drawImage.image, VK_IMAGE_LAYOUT_UNDEFINED, VK_IMAGE_LAYOUT_GENERAL);

  draw_background(cmd);

  vkutil::transition_image(cmd, _drawImage.image, VK_IMAGE_LAYOUT_GENERAL, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL);

  vkutil::transition_image(cmd, _swapchainImages[swapchainImageIndex], VK_IMAGE_LAYOUT_UNDEFINED, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL);

  vkutil::copy_image_to_image(cmd, _drawImage.image,
      _swapchainImages[swapchainImageIndex],
      _drawExtent, _swapchainExtent);

  vkutil::transition_image(cmd, _swapchainImages[swapchainImageIndex], VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);

  draw_imgui(cmd,  _swapchainImageViews[swapchainImageIndex]);

  vkutil::transition_image(cmd, _swapchainImages[swapchainImageIndex], VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, VK_IMAGE_LAYOUT_PRESENT_SRC_KHR);

  VK_CHECK(vkEndCommandBuffer(cmd));

  //prepare the submission to the queue.
  //we want to wait on the _presentSemaphore, as that semaphore is signaled when the swapchain is ready
  //we will signal the _renderSemaphore, to signal that rendering has finished

  VkCommandBufferSubmitInfo cmdinfo = vkinit::command_buffer_submit_info(cmd);

  VkSemaphoreSubmitInfo waitInfo = vkinit::semaphore_submit_info(VK_PIPELINE_STAGE_2_COLOR_ATTACHMENT_OUTPUT_BIT_KHR,get_current_frame()._swapchainSemaphore);
  VkSemaphoreSubmitInfo signalInfo = vkinit::semaphore_submit_info(VK_PIPELINE_STAGE_2_ALL_GRAPHICS_BIT, get_current_frame()._renderSemaphore);

  VkSubmitInfo2 submit = vkinit::submit_info(&cmdinfo,&signalInfo,&waitInfo);

  //submit command buffer to the queue and execute it.
  // _renderFence will now block until the graphic commands finish execution
  VK_CHECK(vkQueueSubmit2(_graphicsQueue, 1, &submit, get_current_frame()._renderFence));

  //prepare present
  // this will put the image we just rendered to into the visible window.
  // we want to wait on the _renderSemaphore for that,
  // as its necessary that drawing commands have finished before the image is displayed to the user
  VkPresentInfoKHR presentInfo{
    .sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR,
    .pNext = nullptr,
    .waitSemaphoreCount = 1,
    .pWaitSemaphores = &get_current_frame()._renderSemaphore,
    .swapchainCount = 1,
    .pSwapchains = &_swapchain,
    .pImageIndices = &swapchainImageIndex,
  };

  VK_CHECK(vkQueuePresentKHR(_graphicsQueue, &presentInfo));

  //increase the number of frames drawn
  _frameNumber++;
}

void VulkanEngine::run()
{
  SDL_Event e;
  bool bQuit = false;
  bool stop_rendering = false;

  //main loop
  while(!bQuit)
  {
    //Handle events on queue
    while(SDL_PollEvent(&e) != 0)
    {
      //close the window when user alt-f4s or clicks the X button
      if(e.type == SDL_QUIT) {
        bQuit = true;
      }

      if(e.type == SDL_WINDOWEVENT) {
        if(e.window.event == SDL_WINDOWEVENT_MINIMIZED) {
          stop_rendering = true;
        }

        if(e.window.event == SDL_WINDOWEVENT_RESTORED) {
          stop_rendering = false;
        }
      }

      ImGui_ImplSDL2_ProcessEvent(&e);
    }

    if(stop_rendering) {
      std::this_thread::sleep_for(std::chrono::milliseconds(100));
      continue;
    }

    render_imgui();
    draw();
  }
}

void VulkanEngine::render_imgui() {
  ImGui_ImplVulkan_NewFrame();
  ImGui_ImplSDL2_NewFrame();

  ImGui::NewFrame();

  if (ImGui::Begin("background")) {

    ComputeEffect& selected = backgroundEffects[currentBackgroundEffect];

    ImGui::Text("Selected effect: %s", selected.name);

    ImGui::SliderInt("Effect Index", &currentBackgroundEffect,0, backgroundEffects.size() - 1);

    ImGui::InputFloat4("data1",(float*)& selected.data.data1);
    ImGui::InputFloat4("data2",(float*)& selected.data.data2);
    ImGui::InputFloat4("data3",(float*)& selected.data.data3);
    ImGui::InputFloat4("data4",(float*)& selected.data.data4);
  }
  ImGui::End();

  ImGui::Render();
}

void VulkanEngine::init_vulkan() {
  vkb::InstanceBuilder builder;

  // make the vulkan instance, with basic debug features

  auto inst_ret = builder.set_app_name("Example Vulkan Application")
    .request_validation_layers(bUseValidationLayers)
    .use_default_debug_messenger()
    .require_api_version(1, 3, 0)
    .build();

  vkb::Instance vkb_inst = inst_ret.value();

  // grab the instance
  _instance = vkb_inst.instance;
  _debug_messenger = vkb_inst.debug_messenger;

  SDL_Vulkan_CreateSurface(_window, _instance, &_surface);

  //vulkan 1.3 features
  VkPhysicalDeviceVulkan13Features features13{
    .sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_3_FEATURES,
      .synchronization2 = true,
      .dynamicRendering = true,
  };
  
  //vulkan 1.2 features
  VkPhysicalDeviceVulkan12Features features12{
    .sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_2_FEATURES,
      .descriptorIndexing = true,
      .bufferDeviceAddress = true,
  };
  
  // use vkbootstrap to select a gpu
  // We want a gpu that can write to the SDL surface
  vkb::PhysicalDeviceSelector selector{ vkb_inst };
  auto physicalDevice = selector
    .set_minimum_version(1, 3)
    .set_required_features_13(features13)
    .set_required_features_12(features12)
    .set_surface(_surface)
    .select()
    .value();

  vkb::DeviceBuilder deviceBuilder{physicalDevice};
  vkb::Device vkbDevice = deviceBuilder.build().value();

  _device = vkbDevice.device;
  _chosenGPU = physicalDevice.physical_device;

  _graphicsQueue = vkbDevice.get_queue(vkb::QueueType::graphics).value();
  _graphicsQueueFamily = vkbDevice.get_queue_index(vkb::QueueType::graphics).value();

  // initialize the memory allocator
  VmaAllocatorCreateInfo allocatorInfo{
    .flags = VMA_ALLOCATOR_CREATE_BUFFER_DEVICE_ADDRESS_BIT,
    .physicalDevice = _chosenGPU,
    .device = _device,
    .instance = _instance,
  };
  
  vmaCreateAllocator(&allocatorInfo, &_allocator);

  _mainDeletionQueue.push_function([&]() {
      vmaDestroyAllocator(_allocator);
  });
}

void VulkanEngine::create_swapchain(uint32_t width, uint32_t height) {
  vkb::SwapchainBuilder swapchainBuilder{ _chosenGPU, _device, _surface};

  _swapchainImageFormat = VK_FORMAT_B8G8R8A8_UNORM;
  VkSurfaceFormatKHR surfaceFormat{};
  surfaceFormat.format=_swapchainImageFormat;

  vkb::Swapchain vkbSwapchain = swapchainBuilder
    //.use_default_format_selection()
    .set_desired_format(surfaceFormat)
    // use vsync present mode
    .set_desired_present_mode(VK_PRESENT_MODE_FIFO_KHR)
    .set_desired_extent(width, height)
    .add_image_usage_flags(VK_IMAGE_USAGE_TRANSFER_DST_BIT)
    .build()
    .value();

  _swapchainExtent = vkbSwapchain.extent;
  _swapchain = vkbSwapchain.swapchain;
  _swapchainImages = vkbSwapchain.get_images().value();
  _swapchainImageViews = vkbSwapchain.get_image_views().value();
}

void VulkanEngine::destroy_swapchain() {
  vkDestroySwapchainKHR(_device, _swapchain, nullptr);

  for(auto& view : _swapchainImageViews) {
    vkDestroyImageView(_device, view, nullptr);
  }
}

void VulkanEngine::init_swapchain() {
  create_swapchain(_windowExtent.width, _windowExtent.height);

  VkExtent3D drawImageExtent = {
    _windowExtent.width,
    _windowExtent.height,
    1
  };

  _drawImage.imageFormat =  VK_FORMAT_R16G16B16A16_SFLOAT;
  _drawImage.imageExtent = drawImageExtent;

  VkImageUsageFlags drawImageUsages = 
    VK_IMAGE_USAGE_TRANSFER_SRC_BIT
    | VK_IMAGE_USAGE_TRANSFER_DST_BIT
    | VK_IMAGE_USAGE_STORAGE_BIT
    | VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;

  VkImageCreateInfo rimg_info = vkinit::image_create_info(_drawImage.imageFormat, drawImageUsages, drawImageExtent);

  VmaAllocationCreateInfo rimg_allocinfo{
    .usage = VMA_MEMORY_USAGE_GPU_ONLY,
      .requiredFlags = VkMemoryPropertyFlags(VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT),
  };
  
  //allocate and create the image
  vmaCreateImage(_allocator, &rimg_info, &rimg_allocinfo, &_drawImage.image, &_drawImage.allocation, nullptr);

  //build a image-view for the draw image to use for rendering
  VkImageViewCreateInfo rview_info = vkinit::imageview_create_info(_drawImage.imageFormat, _drawImage.image, VK_IMAGE_ASPECT_COLOR_BIT);

  VK_CHECK(vkCreateImageView(_device, &rview_info, nullptr, &_drawImage.imageView));

  //add to deletion queues
  _mainDeletionQueue.push_function([=, this]() {
      vkDestroyImageView(_device, _drawImage.imageView, nullptr);
      vmaDestroyImage(_allocator, _drawImage.image, _drawImage.allocation);
  });
}

void VulkanEngine::init_commands() {
  	//create a command pool for commands submitted to the graphics queue.
	//we also want the pool to allow for resetting of individual command buffers
	VkCommandPoolCreateInfo commandPoolInfo = vkinit::command_pool_create_info(_graphicsQueueFamily, VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT);

	for (size_t i = 0; i < FRAME_OVERLAP; i++) {

		VK_CHECK(vkCreateCommandPool(_device, &commandPoolInfo, nullptr, &_frames[i]._commandPool));

		// allocate the default command buffer that we will use for rendering
		VkCommandBufferAllocateInfo cmdAllocInfo = vkinit::command_buffer_allocate_info(_frames[i]._commandPool, 1);

		VK_CHECK(vkAllocateCommandBuffers(_device, &cmdAllocInfo, &_frames[i]._mainCommandBuffer));
	}

    VK_CHECK(vkCreateCommandPool(_device, &commandPoolInfo, nullptr, &_immCommandPool));

    VkCommandBufferAllocateInfo cmdAllocInfo = vkinit::command_buffer_allocate_info(_immCommandPool, 1);

    VK_CHECK(vkAllocateCommandBuffers(_device, &cmdAllocInfo, &_immCommandBuffer));

    _mainDeletionQueue.push_function([=,this]() {
        vkDestroyCommandPool(_device, _immCommandPool, nullptr);
    });
}

void VulkanEngine::init_sync_structures() {
  VkFenceCreateInfo fenceCreateInfo = vkinit::fence_create_info(VK_FENCE_CREATE_SIGNALED_BIT);
  VkSemaphoreCreateInfo semaphoreCreateInfo = vkinit::semaphore_create_info();

  for (size_t i = 0; i < FRAME_OVERLAP; i++) {
    VK_CHECK(vkCreateFence(_device, &fenceCreateInfo, nullptr, &_frames[i]._renderFence));

    VK_CHECK(vkCreateSemaphore(_device, &semaphoreCreateInfo, nullptr, &_frames[i]._swapchainSemaphore));
    VK_CHECK(vkCreateSemaphore(_device, &semaphoreCreateInfo, nullptr, &_frames[i]._renderSemaphore));
  }

  VK_CHECK(vkCreateFence(_device, &fenceCreateInfo, nullptr, &_immFence));

  _mainDeletionQueue.push_function([=,this]() {
      vkDestroyFence(_device, _immFence, nullptr);
  });
}

void VulkanEngine::draw_background(VkCommandBuffer cmd)
{
  ComputeEffect &effect = backgroundEffects[currentBackgroundEffect];

  vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_COMPUTE, effect.pipeline);

  vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_COMPUTE, _gradientPipelineLayout, 0, 1, &_drawImageDescriptors, 0, nullptr);

  vkCmdPushConstants(cmd, _gradientPipelineLayout, VK_SHADER_STAGE_COMPUTE_BIT, 0, sizeof(ComputePushConstants), &effect.data);

  vkCmdDispatch(cmd, std::ceil(_drawExtent.width / 16.0), std::ceil(_drawExtent.height / 16.0), 1);
}


void VulkanEngine::init_descriptors() {
  std::vector<DescriptorAllocator::PoolSizeRatio> sizes =
  {
    { VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, 1 }
  };

  globalDescriptorAllocator.init_pool(_device, 10, sizes);

  // make the descriptor set layout for our compute draw
  {
    DescriptorLayoutBuilder builder;
    builder.add_binding(0, VK_DESCRIPTOR_TYPE_STORAGE_IMAGE);
    _drawImageDescriptorLayout = builder.build(_device, VK_SHADER_STAGE_COMPUTE_BIT);
  }

  // other code
  //allocate a descriptor set for our draw image
  _drawImageDescriptors = globalDescriptorAllocator.allocate(_device,_drawImageDescriptorLayout);

  VkDescriptorImageInfo imgInfo{
    .imageView = _drawImage.imageView,
    .imageLayout = VK_IMAGE_LAYOUT_GENERAL,
  };
  
  VkWriteDescriptorSet drawImageWrite = {
    .sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET,
    .dstSet = _drawImageDescriptors,
    .dstBinding = 0,
    .descriptorCount = 1,
    .descriptorType = VK_DESCRIPTOR_TYPE_STORAGE_IMAGE,
    .pImageInfo = &imgInfo,
  };

  vkUpdateDescriptorSets(_device, 1, &drawImageWrite, 0, nullptr),

  //make sure both the descriptor allocator and the new layout get cleaned up properly
  _mainDeletionQueue.push_function([&]() {
      globalDescriptorAllocator.destroy_pool(_device);

      vkDestroyDescriptorSetLayout(_device, _drawImageDescriptorLayout, nullptr);
    });
}

void VulkanEngine::init_pipelines()
{
  init_background_pipelines();
}

void VulkanEngine::init_background_pipelines()
{
  VkPushConstantRange pushConstant{
    .stageFlags = VK_SHADER_STAGE_COMPUTE_BIT,
      .offset = 0,
      .size = sizeof(ComputePushConstants) ,
  };
  
  VkPipelineLayoutCreateInfo computeLayout{
    .sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO,
      .setLayoutCount = 1,
      .pSetLayouts = &_drawImageDescriptorLayout,
      .pushConstantRangeCount = 1,
      .pPushConstantRanges = &pushConstant,
  };
  
  VK_CHECK(vkCreatePipelineLayout(_device, &computeLayout, nullptr, &_gradientPipelineLayout));

  VkShaderModule gradientShader;
  bool good = vkutil::load_shader_module("gradient_color.comp.spv", _device, &gradientShader);
  assert(good && "failed to load gradient_color.comp.spv");

  VkShaderModule skyShader;
  good = vkutil::load_shader_module("sky.comp.spv", _device, &skyShader);

  VkPipelineShaderStageCreateInfo stageinfo{
    .sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO,
      .stage = VK_SHADER_STAGE_COMPUTE_BIT,
      .module = gradientShader,
      .pName = "main",
  };
  
  VkComputePipelineCreateInfo computePipelineCreateInfo{
    .sType = VK_STRUCTURE_TYPE_COMPUTE_PIPELINE_CREATE_INFO,
      .stage = stageinfo,
      .layout = _gradientPipelineLayout,
  };
  
  ComputeEffect gradient{
    .name = "gradient",
    .layout = _gradientPipelineLayout,
    .data = {
      .data1 = glm::vec4(1, 0, 0, 1),
      .data2 = glm::vec4(0, 0, 1, 1),
    },
  };
  

  VK_CHECK(vkCreateComputePipelines(_device, VK_NULL_HANDLE, 1, &computePipelineCreateInfo, nullptr, &gradient.pipeline));

  // change the shader module only to create the sky
  computePipelineCreateInfo.stage.module = skyShader;

  ComputeEffect sky{
    .name = "sky",
    .layout = _gradientPipelineLayout,
    .data{.data1 = glm::vec4(0.1, 0.2, 0.4, 0.97)},
  };
  
  VK_CHECK(vkCreateComputePipelines(_device, VK_NULL_HANDLE, 1, &computePipelineCreateInfo, nullptr, &sky.pipeline));

  backgroundEffects.push_back(gradient);
  backgroundEffects.push_back(sky);
  
  vkDestroyShaderModule(_device, gradientShader, nullptr);
  vkDestroyShaderModule(_device, skyShader, nullptr);

  _mainDeletionQueue.push_function([=,this]() {
      vkDestroyPipelineLayout(_device, _gradientPipelineLayout, nullptr);
      vkDestroyPipeline(_device, sky.pipeline, nullptr);
      vkDestroyPipeline(_device, sky.pipeline, nullptr);
  });
}


void VulkanEngine::immediate_submit(std::function<void(VkCommandBuffer cmd)>&& function)
{
  VK_CHECK(vkResetFences(_device, 1, &_immFence));
  VK_CHECK(vkResetCommandBuffer(_immCommandBuffer, 0));

  VkCommandBuffer cmd = _immCommandBuffer;

  VkCommandBufferBeginInfo cmdBeginInfo = vkinit::command_buffer_begin_info(VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT);

  VK_CHECK(vkBeginCommandBuffer(cmd, &cmdBeginInfo));

  function(cmd);

  VK_CHECK(vkEndCommandBuffer(cmd));

  VkCommandBufferSubmitInfo cmdinfo = vkinit::command_buffer_submit_info(cmd);
  VkSubmitInfo2 submit = vkinit::submit_info(&cmdinfo, nullptr, nullptr);

  VK_CHECK(vkQueueSubmit2(_graphicsQueue, 1, &submit, _immFence));
  VK_CHECK(vkWaitForFences(_device, 1, &_immFence, true,9999999999)); 

}


void VulkanEngine::init_imgui()
{
// 1: create descriptor pool for IMGUI
	//  the size of the pool is very oversize, but it's copied from imgui demo
	//  itself.
	VkDescriptorPoolSize pool_sizes[] = {
      { VK_DESCRIPTOR_TYPE_SAMPLER, 1000 },
      { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1000 },
      { VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, 1000 },
      { VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, 1000 },
      { VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER, 1000 },
      { VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, 1000 },
      { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1000 },
      { VK_DESCRIPTOR_TYPE_STORAGE_BUFFER, 1000 },
      { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC, 1000 },
      { VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC, 1000 },
      { VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT, 1000 }
    };
 
    VkDescriptorPoolCreateInfo pool_info{
      .sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO,
        .flags = VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT,
        .maxSets = 1000,
        .poolSizeCount = (uint32_t)std::size(pool_sizes),
        .pPoolSizes = pool_sizes,
    };
    
    VkDescriptorPool imguiPool;
    VK_CHECK(vkCreateDescriptorPool(_device, &pool_info, nullptr, &imguiPool));

    // 2: initialize the imgui library
    ImGui::CreateContext();

    ImGui_ImplSDL2_InitForVulkan(_window);

    ImGui_ImplVulkan_InitInfo init_info{
      .Instance = _instance,
        .PhysicalDevice = _chosenGPU,
        .Device = _device,
        .Queue = _graphicsQueue,
        .DescriptorPool = imguiPool,
        .MinImageCount = 3,
        .ImageCount = 3,
        .MSAASamples = VK_SAMPLE_COUNT_1_BIT,
        .UseDynamicRendering = true,
        .PipelineRenderingCreateInfo = {
          .sType = VK_STRUCTURE_TYPE_PIPELINE_RENDERING_CREATE_INFO,
          .colorAttachmentCount = 1,
          .pColorAttachmentFormats = &_swapchainImageFormat,
        },
    };

    ImGui_ImplVulkan_Init(&init_info);
    ImGui_ImplVulkan_CreateFontsTexture();

    _mainDeletionQueue.push_function([=,this]() {
        ImGui_ImplVulkan_Shutdown();
        vkDestroyDescriptorPool(_device, imguiPool, nullptr);
    });
}


void VulkanEngine::draw_imgui(VkCommandBuffer cmd, VkImageView targetImageView)
{
  VkRenderingAttachmentInfo colorAttachment = vkinit::attachment_info(targetImageView, nullptr, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);

  VkRenderingInfo renderInfo = vkinit::rendering_info(_swapchainExtent, &colorAttachment, nullptr);

  vkCmdBeginRendering(cmd, &renderInfo);

  ImGui_ImplVulkan_RenderDrawData(ImGui::GetDrawData(), cmd);

  vkCmdEndRendering(cmd);
}