// Blaze.cpp : This file contains the 'main' function. Program execution begins and ends there.
//


#include <array>
#include <cassert>
#include <span>

#include <volk.h>

#define SDL_MAIN_USE_CALLBACKS 1
#include <memory>
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>
#include <SDL3/SDL_filesystem.h>
#include <SDL3/SDL_vulkan.h>

#include "AppState.h"
#include "Frame.h"
#include "GlobalMemory.h"
#include "MacroUtils.h"
#include "MathUtil.h"
#include "RenderDevice.h"
#include "MiscData.h"

constexpr uint32_t WIDTH      = 1280;
constexpr uint32_t HEIGHT     = 720;
constexpr uint32_t NUM_FRAMES = 3;

using Byte = uint8_t;

constexpr size_t operator ""_KiB( size_t const value )
{
  return value * 1024;
}

constexpr size_t operator ""_MiB( size_t const value )
{
  return value * 1024_KiB;
}

constexpr size_t operator ""_GiB( size_t const value )
{
  return value * 1024_MiB;
}

namespace Blaze::Global
{
GlobalMemory g_Memory;
}

SDL_AppResult SDL_AppInit( void** pAppState, int, char** )
{
  SDL_Init( SDL_INIT_VIDEO | SDL_INIT_EVENTS );

  Blaze::Global::g_Memory.init( 128_MiB );

  *pAppState = CreateAppState( &Blaze::Global::g_Memory, WIDTH, HEIGHT );
  if ( !*pAppState ) return SDL_APP_FAILURE;

  AppState& appState = *static_cast<AppState*>(*pAppState);

  if ( !appState.isInit() )
  {
    return SDL_APP_FAILURE;
  }

  return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppIterate( void* appstate )
{
  AppState&     appState     = *static_cast<AppState*>(appstate);
  RenderDevice& renderDevice = *appState.renderDevice;
  MiscData&     misc         = *appState.miscData;
  Frame&        currentFrame = renderDevice.frames[renderDevice.frameIndex];

  VK_CHECK(
    vkWaitForFences(renderDevice.device, 1, &currentFrame.frameReadyToReuse, VK_TRUE, std::numeric_limits<uint32_t>::max
      ()) );
  // All resources of frame 'frameIndex' are free.

  uint32_t currentImageIndex;
  VK_CHECK(
    vkAcquireNextImageKHR(renderDevice.device, renderDevice.swapchain, std::numeric_limits<uint32_t>::max(),
      currentFrame.imageAcquiredSemaphore, nullptr, &currentImageIndex) );

  VK_CHECK( vkResetFences(renderDevice.device, 1, &currentFrame.frameReadyToReuse) );
  VK_CHECK( vkResetCommandPool(renderDevice.device, currentFrame.commandPool, 0) );

  misc.acquireToRenderBarrier.image = renderDevice.swapchainImages[currentImageIndex];
  misc.renderToPresentBarrier.image = renderDevice.swapchainImages[currentImageIndex];

  VkCommandBuffer cmd = currentFrame.commandBuffer;

  VkCommandBufferBeginInfo constexpr beginInfo = {
    .sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO,
    .pNext = nullptr,
    .flags = 0,
    .pInheritanceInfo = nullptr,
  };

  VkClearColorValue constexpr static BLACK_CLEAR = {
    .float32 = { 0.0f, 0.0f, 0.0f, 1.0f },
  };

  VK_CHECK( vkBeginCommandBuffer(cmd, &beginInfo) );
  {
    VkRenderingAttachmentInfo const attachmentInfo = {
      .sType = VK_STRUCTURE_TYPE_RENDERING_ATTACHMENT_INFO,
      .pNext = nullptr,
      .imageView = renderDevice.swapchainViews[currentImageIndex],
      .imageLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
      .resolveMode = VK_RESOLVE_MODE_NONE,
      .resolveImageView = nullptr,
      .resolveImageLayout = VK_IMAGE_LAYOUT_UNDEFINED,
      .loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR,
      .storeOp = VK_ATTACHMENT_STORE_OP_STORE,
      .clearValue = { .color = BLACK_CLEAR },
    };

    VkRenderingInfo renderingInfo = {
      .sType = VK_STRUCTURE_TYPE_RENDERING_INFO,
      .pNext = nullptr,
      .flags = 0,
      .renderArea = { .offset = { 0, 0 }, .extent = renderDevice.swapchainExtent },
      .layerCount = 1,
      .viewMask = 0,
      .colorAttachmentCount = 1,
      .pColorAttachments = &attachmentInfo,
      .pDepthAttachment = nullptr,
      .pStencilAttachment = nullptr,
    };

    vkCmdPipelineBarrier2( cmd, &misc.acquireToRenderDependency );
    vkCmdBeginRendering( cmd, &renderingInfo );
    {
      VkViewport viewport = {
        .x = 0,
        .y = static_cast<float>(renderDevice.swapchainExtent.height),
        .width = static_cast<float>(renderDevice.swapchainExtent.width),
        .height = -static_cast<float>(renderDevice.swapchainExtent.height),
        .minDepth = 0.0f,
        .maxDepth = 1.0f,
      };
      vkCmdSetViewport( cmd, 0, 1, &viewport );
      VkRect2D scissor = {
        .offset = { 0, 0 },
        .extent = renderDevice.swapchainExtent,
      };
      vkCmdSetScissor( cmd, 0, 1, &scissor );

      // Render Something?
      vkCmdBindPipeline( cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, misc.trianglePipeline );
      vkCmdDraw( cmd, 3, 1, 0, 0 );
    }
    vkCmdEndRendering( cmd );
    vkCmdPipelineBarrier2( cmd, &misc.renderToPresentDependency );
  }
  VK_CHECK( vkEndCommandBuffer(cmd) );

  VkPipelineStageFlags stageMask  = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
  VkSubmitInfo const   submitInfo = {
    .sType = VK_STRUCTURE_TYPE_SUBMIT_INFO,
    .pNext = nullptr,
    .waitSemaphoreCount = 1,
    .pWaitSemaphores = &currentFrame.imageAcquiredSemaphore,
    .pWaitDstStageMask = &stageMask,
    .commandBufferCount = 1,
    .pCommandBuffers = &cmd,
    .signalSemaphoreCount = 1,
    .pSignalSemaphores = &currentFrame.renderFinishedSemaphore,
  };
  VK_CHECK( vkQueueSubmit(renderDevice.directQueue, 1, &submitInfo, currentFrame.frameReadyToReuse) );

  VkPresentInfoKHR const presentInfo = {
    .sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR,
    .pNext = nullptr,
    .waitSemaphoreCount = 1,
    .pWaitSemaphores = &currentFrame.renderFinishedSemaphore,
    .swapchainCount = 1,
    .pSwapchains = &renderDevice.swapchain,
    .pImageIndices = &currentImageIndex,
    .pResults = nullptr,
  };

  VK_CHECK( vkQueuePresentKHR(renderDevice.directQueue, &presentInfo) );

  renderDevice.frameIndex = (renderDevice.frameIndex + 1) % NUM_FRAMES;

  return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppEvent( void*, SDL_Event* event )
{
  if ( event->type == SDL_EVENT_QUIT )
  {
    return SDL_APP_SUCCESS;
  }

  return SDL_APP_CONTINUE;
}

void SDL_AppQuit( void* appstate, SDL_AppResult )
{
  AppState* appState = static_cast<AppState*>(appstate);

  appState->destroy();

  Blaze::Global::g_Memory.destroy();
}