#ifndef VKENGINE_H
#define VKENGINE_H

#pragma once

#include <VkTypes.h>

#include <QObject>

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

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

    void flush() {
        // reverse iterate the deletion queue to execute all the functions
        for (auto it = deletors.rbegin(); it != deletors.rend(); it++) {
            (*it)(); //call functors
        }

        deletors.clear();
    }
};


struct FrameData {

    VkCommandPool _commandPool;
    VkCommandBuffer _mainCommandBuffer;

    VkSemaphore _swapchainSemaphore, _renderSemaphore;
    VkFence _renderFence;

    DeletionQueue _deletionQueue;
};

constexpr unsigned int FRAME_OVERLAP = 2;

class VkEngine
{
public:
    VkEngine();

    bool _isInitialized{ false };
    int _frameNumber {0};
    bool stop_rendering{ false };
    VkExtent2D _windowExtent{ 1700 , 900 };

    struct SDL_Window* _window{ nullptr };

    VkInstance _instance;// Vulkan library handle
    VkDebugUtilsMessengerEXT _debug_messenger;// Vulkan debug output handle
    VkPhysicalDevice _chosenGPU;// GPU chosen as the default device
    VkDevice _device; // Vulkan device for commands
    VkSurfaceKHR _surface;// Vulkan window surface

    VkSwapchainKHR _swapchain;
    VkFormat _swapchainImageFormat;

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

    FrameData _frames[FRAME_OVERLAP];

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

    DeletionQueue _mainDeletionQueue;

    VkQueue _graphicsQueue;
    uint32_t _graphicsQueueFamily;

    VmaAllocator _allocator;

    //draw resources
    AllocatedImage _drawImage;
    VkExtent2D _drawExtent;

    static VkEngine& Get();

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

    //shuts down the engine
    void cleanup();

    //draw loop
    void draw();

    //run main loop
    void run();

private:

    void init_vulkan();
    void init_swapchain();
    void init_commands();
    void init_sync_structures();

    void create_swapchain(uint32_t width, uint32_t height);
    void destroy_swapchain();
};

#endif // VKENGINE_H