// vulkan_guide.h : Include file for standard system include files,
// or project specific include files.

#pragma once

#include <vk_types.h>
#include <vk_descriptors.h>
#include "vk_gui.h"

struct Transaction {
  VkCommandBuffer cmd;
  uint32_t swapchainImageIndex = 0;
};

struct DeletionQueue {
  std::deque<std::function<void()>> deletors;

  void push_function(std::function<void()>&& function) {
    deletors.push_back(function);
  }

  void flush() {
    // reverse itererate the deletion queue
    for(auto it = deletors.rbegin(); it != deletors.rend(); it++) {
      (*it)();
    }

    deletors.clear();
  }
};

struct FrameData {
  VkCommandPool _commandPool;
  VkCommandBuffer _mainCommandBuffer;
  VkSemaphore _swapchainSemaphore;
  VkSemaphore _renderSemaphore;
  VkFence _renderFence;
  DeletionQueue _deletionQueue;
};


class VulkanEngine {
public:
  VkFence _immFence;
  VkCommandBuffer _immCommandBuffer;
  VkCommandPool _immCommandPool;
  VkPipeline _gradientPipeline;
  VkPipelineLayout _gradientPipelineLayout;

  DescriptorAllocator _globalDescriptorAllocator;
  VkDescriptorSet _drawImageDescriptors;
  VkDescriptorSetLayout _drawImageDescriptorLayout;

  // device selection
  VkInstance _instance;
  VkDebugUtilsMessengerEXT _debug_messenger;
  VkPhysicalDevice _chosenGPU;
  VkDevice _device;
  VkSurfaceKHR _surface;

  // swapchain
  VkSwapchainKHR _swapchain;
  VkFormat _swapchainImageFormat;

  std::vector<VkImage> _swapchainImages;
  std::vector<VkImageView> _swapchainImageViews;
  VkExtent2D _swapchainExtent;

  // VMA stuff
  VmaAllocator _allocator;

  // frames/command buffer
  unsigned int _frameNumber = 0;
  FrameData _frames[FRAME_OVERLAP];

  FrameData& get_current_frame() {
    return _frames[_frameNumber % FRAME_OVERLAP];
  }

  VkQueue _graphicsQueue;
  uint32_t _graphicsQueueFamily;

  // draw resources
  AllocatedImage _drawImage;
  VkExtent2D _drawExtent;

  // internal data
  bool _isInitialized{ false };
  VkExtent2D _windowExtent{ 1700 , 900 };
  struct SDL_Window* _window{ nullptr };
  DeletionQueue _mainDeletionQueue;

  // imgui shader stuff
  std::vector<ComputeEffect> backgroundEffects;
  int currentBackgroundEffect{0};
  
  // ZED's REFACTOR
  VkGUI _gui;

  static VulkanEngine& Get();

  //initializes everything in the engine
  void init();

  //shuts down the engine
  void cleanup();

  //draw loop
  void draw();

  //run main loop
  void run();

  void immediate_submit(std::function<void(VkCommandBuffer cmd)>&& function);

  Transaction begin_transaction();
  void commit_transaction(Transaction& cmd);

private:
  void init_vulkan();
  void init_swapchain();
  void init_commands();
  void init_sync_structures();
  void init_descriptors();
  void init_pipelines();
  void init_background_pipelines();
  void init_shaders();
  void load_shader(const char *file_name, const char *entry_point, ComputeEffect data);

  void create_swapchain(uint32_t width, uint32_t height);
  void destroy_swapchain();
  void draw_background(VkCommandBuffer cmd);
};