#include <Vulkan/Context.h>
#include <Vulkan/Memory.h>

#include <utils.h>
#include <Logger.h>

#include <SDL2/SDL_vulkan.h>

#include <cstring>
#include <cassert>
#include <algorithm>
#include <tuple>


namespace Vulkan {


ContextSettings::ContextSettings() {
}

ContextSettings::~ContextSettings() {
}

bool ContextSettings::debug() const {
    return m_debug;
}

ContextSettings& ContextSettings::with_debug(bool enabled) {
    m_debug = enabled;
    return *this;
}

const std::optional<Uuid>& ContextSettings::physical_device() const {
    return m_physical_device;
}

ContextSettings& ContextSettings::with_physical_device(Uuid uuid) {
    m_physical_device = uuid;
    return *this;
}

const std::vector<ContextSettings::QueueInfo>& ContextSettings::queues() const {
    return m_queues;
}

ContextSettings& ContextSettings::with_queue(
    uint32_t index, VkQueueFlagBits flags, bool use_swapchain_images
) {
    m_queues.emplace_back(QueueInfo { index, flags, use_swapchain_images });
    return *this;
}

SDL_Window* ContextSettings::window() const {
    return m_window;
}

ContextSettings& ContextSettings::with_window(SDL_Window* window) {
    m_window = window;
    return *this;
}


//////////////////////////////////////////////////////////////////////////////
// Context


Context::Context() {
}

Context::~Context() {
    shutdown();
}

VkInstance Context::instance() {
    return m_instance;
}

VkPhysicalDevice Context::physical_device() {
    return m_physical_device;
}

VkDevice Context::device() {
    return m_device;
}

uint32_t Context::queue_family(size_t queue_index) const {
    return m_queue_families[queue_index];
}

uint32_t Context::presentation_queue_family() const {
    return m_presentation_queue_family;
}

VkQueue Context::queue(size_t queue_index) {
    return m_queues[queue_index];
}

VkQueue Context::presentation_queue() {
    return m_presentation_queue;
}

SDL_Window* Context::window() {
    return m_window;
}

VkSurfaceKHR Context::surface() {
    return m_surface;
}

VkSurfaceFormatKHR Context::surface_format() const {
    return m_surface_format;
}

VkPresentModeKHR Context::present_mode() const {
    return m_present_mode;
}

void Context::initialize(const ContextSettings& settings) {
    m_window = settings.window();

    create_instance(settings);
    create_surface(settings);
    choose_physical_device(settings);
    create_device(settings);
    create_internal_objects();

    m_allocator.reset(new Allocator(this));
}

void Context::shutdown() {
    if(!m_instance)
        return;

    vkDeviceWaitIdle(m_device);

    for(auto& callback: m_context_destruction_callbacks)
        callback();

    m_allocator->free_all_pages();
    m_allocator.reset();

    destroy_fence(m_transfer_fence);
    destroy_command_pool(m_transfer_command_pool);

    destroy_device(m_device);
    destroy_surface(m_surface);
    destroy_debug_messenger(m_debug_messenger);
    destroy_instance(m_instance);
}

void Context::register_context_destruction_callback(ContextDestructionCallback callback) {
    m_context_destruction_callbacks.emplace_back(std::move(callback));
}

std::vector<VkExtensionProperties> Context::available_extensions() {
    uint32_t count;
    vkEnumerateInstanceExtensionProperties(nullptr, &count, nullptr);

    std::vector<VkExtensionProperties> extensions(count);
    vkEnumerateInstanceExtensionProperties(nullptr, &count, extensions.data());

    return extensions;
}

std::vector<VkLayerProperties> Context::available_layers() {
    uint32_t count;
    vkEnumerateInstanceLayerProperties(&count, nullptr);

    std::vector<VkLayerProperties> layers(count);
    vkEnumerateInstanceLayerProperties(&count, layers.data());

    return layers;
}

std::vector<const char*> Context::sdl_vulkan_extensions() const {
    unsigned count;
    if(!SDL_Vulkan_GetInstanceExtensions(m_window, &count, nullptr))
        throw std::runtime_error("failed to get window's vulkan extensions");

    std::vector<const char*> extensions(count);
    if(!SDL_Vulkan_GetInstanceExtensions(m_window, &count, extensions.data()))
        throw std::runtime_error("failed to get window's vulkan extensions");

    return extensions;
}

std::vector<VkPhysicalDevice> Context::physical_devices() const {
    uint32_t devices_count = 0;
    vkEnumeratePhysicalDevices(m_instance, &devices_count, nullptr);

    std::vector<VkPhysicalDevice> physical_devices(devices_count);
    vkEnumeratePhysicalDevices(m_instance, &devices_count, physical_devices.data());

    return physical_devices;
}

std::vector<VkQueueFamilyProperties> Context::queue_families(VkPhysicalDevice physical_device) const {
    uint32_t queue_families_count = 0;
    vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &queue_families_count, nullptr);

    std::vector<VkQueueFamilyProperties> queue_families(queue_families_count);
    vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &queue_families_count, queue_families.data());

    return queue_families;
}

std::vector<VkExtensionProperties> Context::device_extensions(VkPhysicalDevice physical_device) const {
    uint32_t extensions_count = 0;
    vkEnumerateDeviceExtensionProperties(physical_device, nullptr, &extensions_count, nullptr);

    std::vector<VkExtensionProperties> extensions(extensions_count);
    vkEnumerateDeviceExtensionProperties(physical_device, nullptr, &extensions_count, extensions.data());

    return extensions;
}

std::vector<VkSurfaceFormatKHR> Context::surface_formats(VkPhysicalDevice physical_device) const {
    uint32_t surface_formats_count = 0;
    vkGetPhysicalDeviceSurfaceFormatsKHR(physical_device, m_surface, &surface_formats_count, nullptr);

    std::vector<VkSurfaceFormatKHR> surface_formats(surface_formats_count);
    vkGetPhysicalDeviceSurfaceFormatsKHR(physical_device, m_surface, &surface_formats_count, surface_formats.data());

    return surface_formats;
}

std::vector<VkPresentModeKHR> Context::present_modes(VkPhysicalDevice physical_device) const {
    uint32_t present_modes_count = 0;
    vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, m_surface, &present_modes_count, nullptr);

    std::vector<VkPresentModeKHR> present_modes(present_modes_count);
    vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, m_surface, &present_modes_count, present_modes.data());

    return present_modes;
}


void Context::set_object_name(VkObjectType type, uint64_t object, const char* name) {
    VkDebugUtilsObjectNameInfoEXT name_info {
        .sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT,
        .objectType = type,
        .objectHandle = object,
        .pObjectName = name
    };
    if(setDebugUtilsObjectName(m_device, &name_info) != VK_SUCCESS)
        throw std::runtime_error("failed to set debug name");
}

void Context::set_object_name(VkObjectType type, uint64_t object, const std::string& name) {
    set_object_name(type, object, name.c_str());
}

VkShaderModule Context::create_shader_module(const std::vector<char> bytecode) {
    VkShaderModuleCreateInfo shader_info {
        .sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO,
        .codeSize = bytecode.size(),
        .pCode = reinterpret_cast<const uint32_t*>(bytecode.data()),
    };

    VkShaderModule shader_module = VK_NULL_HANDLE;
    if(vkCreateShaderModule(
        m_device,
        &shader_info,
        nullptr,
        &shader_module
    ) != VK_SUCCESS)
        throw std::runtime_error("failed to create shader module");

    return shader_module;
}

VkShaderModule Context::create_shader_module_from_file(const char* path) {
    auto const bytecode = read_binary_file(path);
    try {
        return create_shader_module(bytecode);
    }
    catch(std::exception err) {
        throw std::runtime_error(cat("failed to create shader '", path, "':\n  ", err.what()));
    }
    return VK_NULL_HANDLE;
}

void Context::copy_buffer(VkBuffer dst, VkBuffer src, uint32_t dst_queue_family, VkDeviceSize size) {
    VkCommandBufferAllocateInfo alloc_info {
        .sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO,
        .commandPool = m_transfer_command_pool,
        .level = VK_COMMAND_BUFFER_LEVEL_PRIMARY,
        .commandBufferCount = 1,
    };

    VkCommandBuffer command_buffer;
    vkAllocateCommandBuffers(m_device, &alloc_info, &command_buffer);
    auto const command_buffer_guard = make_guard([this, command_buffer]() {
        vkFreeCommandBuffers(m_device, m_transfer_command_pool, 1, &command_buffer);
    });

    VkCommandBufferBeginInfo begin_info {
        .sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO,
        .flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT,
    };
    vkBeginCommandBuffer(command_buffer, &begin_info);

    VkBufferCopy region {
        .srcOffset = 0,
        .dstOffset = 0,
        .size = size,
    };
    vkCmdCopyBuffer(command_buffer, src, dst, 1, &region);

    VkBufferMemoryBarrier buffer_barrier {
        .sType = VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER,
        .srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT,
        .dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT,
        .srcQueueFamilyIndex = queue_family(VK_QUEUE_TRANSFER_BIT),
        .dstQueueFamilyIndex = dst_queue_family,
        .buffer = dst,
        .offset = 0,
        .size = size,
    };
    vkCmdPipelineBarrier(
        command_buffer,
        VK_PIPELINE_STAGE_TRANSFER_BIT,
        VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
        0,
        0, nullptr,
        1, &buffer_barrier,
        0, nullptr
    );

    vkEndCommandBuffer(command_buffer);

    vkResetFences(m_device, 1, &m_transfer_fence);

    VkSubmitInfo submit_info {
        .sType = VK_STRUCTURE_TYPE_SUBMIT_INFO,
        .commandBufferCount = 1,
        .pCommandBuffers = &command_buffer,
    };
    vkQueueSubmit(
        queue(m_transfer_queue_index),
        1, &submit_info,
        m_transfer_fence
    );
    vkWaitForFences(m_device, 1, &m_transfer_fence, VK_TRUE, UINT64_MAX);
}


void Context::destroy_instance(VkInstance& instance) {
    if(instance == nullptr)
        return;

    vkDestroyInstance(instance, nullptr);
    instance = nullptr;
}

void Context::destroy_debug_messenger(VkDebugUtilsMessengerEXT& debug_messenger) {
    if(debug_messenger == VK_NULL_HANDLE)
        return;

    destroyDebugUtilsMessenger(m_instance, debug_messenger, nullptr);
    debug_messenger = VK_NULL_HANDLE;
}

void Context::destroy_surface(VkSurfaceKHR& surface) {
    if(surface == VK_NULL_HANDLE)
        return;

    vkDestroySurfaceKHR(m_instance, surface, nullptr);
    surface = VK_NULL_HANDLE;
}

void Context::destroy_device(VkDevice& device) {
    if(device == nullptr)
        return;

    vkDestroyDevice(device, nullptr);
    device = nullptr;
}

void Context::destroy_swapchain(VkSwapchainKHR& swapchain) {
    if(swapchain == VK_NULL_HANDLE)
        return;

    vkDestroySwapchainKHR(m_device, swapchain, nullptr);
    swapchain = VK_NULL_HANDLE;
}

void Context::destroy_image(VkImage& image) {
    if(image == VK_NULL_HANDLE)
        return;

    vkDestroyImage(m_device, image, nullptr);
    image = VK_NULL_HANDLE;
}

void Context::destroy_image_view(VkImageView& image_view) {
    if(image_view == VK_NULL_HANDLE)
        return;

    vkDestroyImageView(m_device, image_view, nullptr);
    image_view = VK_NULL_HANDLE;
}

void Context::destroy_framebuffer(VkFramebuffer& framebuffer) {
    if(framebuffer == VK_NULL_HANDLE)
        return;

    vkDestroyFramebuffer(m_device, framebuffer, nullptr);
    framebuffer = VK_NULL_HANDLE;
}

void Context::destroy_buffer(VkBuffer& buffer) {
    if(buffer == VK_NULL_HANDLE)
        return;

    vkDestroyBuffer(m_device, buffer, nullptr);
    buffer = VK_NULL_HANDLE;
}

void Context::destroy_command_pool(VkCommandPool& command_pool) {
    if(command_pool == VK_NULL_HANDLE)
        return;

    vkDestroyCommandPool(m_device, command_pool, nullptr);
    command_pool = VK_NULL_HANDLE;
}

void Context::destroy_descriptor_pool(VkDescriptorPool& descriptor_pool) {
    if(descriptor_pool == VK_NULL_HANDLE)
        return;

    vkDestroyDescriptorPool(m_device, descriptor_pool, nullptr);
    descriptor_pool = VK_NULL_HANDLE;
}

void Context::destroy_render_pass(VkRenderPass& render_pass) {
    if(render_pass == VK_NULL_HANDLE)
        return;

    vkDestroyRenderPass(m_device, render_pass, nullptr);
    render_pass = VK_NULL_HANDLE;
}

void Context::destroy_descriptor_set_layout(VkDescriptorSetLayout& descriptor_set_layout) {
    if(descriptor_set_layout == VK_NULL_HANDLE)
        return;

    vkDestroyDescriptorSetLayout(m_device, descriptor_set_layout, nullptr);
    descriptor_set_layout = VK_NULL_HANDLE;
}

void Context::destroy_pipeline_layout(VkPipelineLayout& pipeline_layout) {
    if(pipeline_layout == VK_NULL_HANDLE)
        return;

    vkDestroyPipelineLayout(m_device, pipeline_layout, nullptr);
    pipeline_layout = VK_NULL_HANDLE;
}

void Context::destroy_pipeline(VkPipeline& pipeline) {
    if(pipeline == VK_NULL_HANDLE)
        return;

    vkDestroyPipeline(m_device, pipeline, nullptr);
    pipeline = VK_NULL_HANDLE;
}

void Context::destroy_semaphore(VkSemaphore& semaphore) {
    if(semaphore == VK_NULL_HANDLE)
        return;

    vkDestroySemaphore(m_device, semaphore, nullptr);
    semaphore = VK_NULL_HANDLE;
}

void Context::destroy_fence(VkFence& fence) {
    if(fence == VK_NULL_HANDLE)
        return;

    vkDestroyFence(m_device, fence, nullptr);
    fence = VK_NULL_HANDLE;
}

void Context::free_memory(VkDeviceMemory& memory) {
    if(memory == VK_NULL_HANDLE)
        return;

    vkFreeMemory(m_device, memory, nullptr);
    memory = VK_NULL_HANDLE;
}

void Context::create_instance(const ContextSettings& settings) {
    if(m_instance)
        return;

    char const* const name = "vk_expe";
    uint32_t const version = VK_MAKE_VERSION(0, 1, 0);

    VkApplicationInfo const app_info {
        .sType = VK_STRUCTURE_TYPE_APPLICATION_INFO,
        .pApplicationName = name,
        .applicationVersion = version,
        .pEngineName = name,
        .engineVersion = version,
        .apiVersion = VK_API_VERSION_1_1,
    };

    std::vector<char const*> layers;
    std::vector<char const*> extensions = sdl_vulkan_extensions();

    if(settings.debug()) {
        extensions.push_back(VK_EXT_DEBUG_UTILS_EXTENSION_NAME);

        auto const available_layers = Context::available_layers();

        auto add_layer_if_available = [&](const char* requested_layer) {
            if(std::find_if(
                available_layers.begin(),
                available_layers.end(),
                [requested_layer](const VkLayerProperties& layer) {
                    return std::strcmp(layer.layerName, requested_layer) == 0;
                }
            ) != available_layers.end()) {
                layers.push_back(requested_layer);
            }
            else {
                logger.warning() << "requested layer '" << requested_layer
                    << "' is not available";
            }
        };

        add_layer_if_available("VK_LAYER_KHRONOS_validation");
    }

    VkDebugUtilsMessengerCreateInfoEXT const debug_info {
        .sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT,
        .messageSeverity =
            VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT |
            VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT |
            VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT |
            VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT,
        .messageType =
            VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT |
            VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT |
            VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT,
        .pfnUserCallback = &log_debug_message,
        .pUserData = nullptr,
    };

    VkInstanceCreateInfo const instance_info {
        .sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO,
        .pNext = &debug_info,
        .pApplicationInfo = &app_info,
        .enabledLayerCount = uint32_t(layers.size()),
        .ppEnabledLayerNames = layers.data(),
        .enabledExtensionCount = uint32_t(extensions.size()),
        .ppEnabledExtensionNames = extensions.data(),
    };

    logger.debug() << "Requested extensions:";
    for(char const* extension: extensions)
        logger.debug() << "  " << extension;
    logger.debug() << "Requested layers:";
    for(char const* layer: layers)
        logger.debug() << "  " << layer;

    logger.debug() << "create vulkan instance...";
    if(vkCreateInstance(&instance_info, nullptr, &m_instance) != VK_SUCCESS)
        throw std::runtime_error("failed to create vulkan instance");

    initialize_extension_functions();

    if(settings.debug()) {
        createDebugUtilsMessenger(
            m_instance, &debug_info, nullptr, &m_debug_messenger);
    }
}

void Context::create_surface(const ContextSettings& settings) {
    if(!SDL_Vulkan_CreateSurface(m_window, m_instance, &m_surface))
        throw std::runtime_error("failed to create surface");
}

void Context::choose_physical_device(const ContextSettings& settings) {
    auto physical_devices = this->physical_devices();
    if(settings.physical_device()) {
        auto const device_it = std::find_if(
            physical_devices.begin(),
            physical_devices.end(),
            [&settings] (VkPhysicalDevice physical_device) {
                VkPhysicalDeviceProperties device_properties;
                vkGetPhysicalDeviceProperties(physical_device, &device_properties);
                return make_uuid(device_properties.pipelineCacheUUID)
                    == *settings.physical_device();
            }
        );
        if(device_it != physical_devices.end()) {
            using std::swap;
            swap(physical_devices[0], *device_it);
        }
    }

    for(auto const physical_device: physical_devices) {
        auto maybe_properties = select_physical_device(physical_device, settings);
        if(maybe_properties) {
            m_physical_device = physical_device;
            m_physical_device_properties = *maybe_properties;
            vkGetPhysicalDeviceMemoryProperties(m_physical_device, &m_memory_properties);
            break;
        }
    }

    if(!m_physical_device)
        throw std::runtime_error("failed to find suitable physical device");

    logger.info() << "use suitable device: " << m_physical_device_properties.deviceName;
    logger.debug() << "swapchain format: " << m_surface_format.format;
    logger.debug() << "present mode: " << m_present_mode;
}

std::optional<VkPhysicalDeviceProperties> Context::select_physical_device(
    VkPhysicalDevice physical_device,
    const ContextSettings& settings
) {
    VkPhysicalDeviceProperties device_properties;
    vkGetPhysicalDeviceProperties(physical_device, &device_properties);

    VkPhysicalDeviceFeatures available_features;
    vkGetPhysicalDeviceFeatures(physical_device, &available_features);

    if (!available_features.geometryShader)
        return std::nullopt;


    m_transfer_queue_index = settings.queues().size();
    m_queue_families.assign(settings.queues().size() + 1, INVALID_QUEUE_FAMILY);
    m_presentation_queue_family = INVALID_QUEUE_FAMILY;

    auto const queue_families = this->queue_families(physical_device);
    uint32_t queue_family_index = 0;
    for(auto const& queue_family: queue_families) {
        if(m_window != nullptr) {
            VkBool32 support_surface = false;
            vkGetPhysicalDeviceSurfaceSupportKHR(
                physical_device,
                queue_family_index,
                m_surface,
                &support_surface
            );
            if(support_surface)
                m_presentation_queue_family = queue_family_index;
        }

        for(auto const queue_info: settings.queues()) {
            uint32_t const index = queue_info.index;
            VkQueueFlagBits flags = queue_info.flags;

            if(m_queue_families[index] != INVALID_QUEUE_FAMILY)
                continue;

            if((queue_family.queueFlags & flags) == flags)
                m_queue_families[index] = queue_family_index;
        }

        if(m_queue_families[m_transfer_queue_index] == INVALID_QUEUE_FAMILY
                && queue_family.queueFlags == VK_QUEUE_TRANSFER_BIT)
            m_queue_families[m_transfer_queue_index] = queue_family_index;

        queue_family_index += 1;
    }

    for(auto const queue_family: m_queue_families) {
        if(queue_family == INVALID_QUEUE_FAMILY)
            return std::nullopt;
    }

    auto const available_extensions = this->device_extensions(physical_device);
    auto has_extension = [&available_extensions](const char* required_extension) {
        return std::find_if(
            available_extensions.begin(),
            available_extensions.end(),
            [required_extension](const VkExtensionProperties& extension) {
                return strcmp(extension.extensionName, required_extension) == 0;
            }
        ) != available_extensions.end();
    };

    if(m_window) {
        if(!has_extension(VK_KHR_SWAPCHAIN_EXTENSION_NAME))
            return std::nullopt;

        auto const surface_formats = this->surface_formats(physical_device);
        if(surface_formats.empty())
            return std::nullopt;

        auto const present_modes = this->present_modes(physical_device);
        if(present_modes.empty())
            return std::nullopt;

        auto const surface_format_it = std::find_if(
            surface_formats.begin(),
            surface_formats.end(),
            [](const VkSurfaceFormatKHR& surface_format) {
                return surface_format.format == VK_FORMAT_B8G8R8A8_SRGB
                    && surface_format.colorSpace == VK_COLOR_SPACE_SRGB_NONLINEAR_KHR;
            }
        );
        m_surface_format = (surface_format_it != surface_formats.end())?
            *surface_format_it:
            surface_formats[0];

        m_present_mode = VK_PRESENT_MODE_FIFO_KHR;
        // m_present_mode = VK_PRESENT_MODE_IMMEDIATE_KHR;
    }

    return device_properties;
}

void Context::create_device(const ContextSettings& settings) {
    std::vector<uint32_t> queue_families = m_queue_families;
    std::sort(queue_families.begin(), queue_families.end());
    queue_families.erase(
        std::unique(queue_families.begin(), queue_families.end()),
        queue_families.end()
    );

    float const queue_priority = 1.0f;
    std::vector<VkDeviceQueueCreateInfo> queue_infos;
    for(uint32_t queue_family: queue_families) {
        queue_infos.emplace_back(VkDeviceQueueCreateInfo {
            .sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO,
            .queueFamilyIndex = queue_family,
            .queueCount = 1,
            .pQueuePriorities = &queue_priority,
        });
    }

    VkPhysicalDeviceFeatures const device_features {
        .geometryShader = true,
    };

    std::vector<const char*> extensions;
    if(m_window) {
        extensions.push_back(VK_KHR_SWAPCHAIN_EXTENSION_NAME);
    };

    VkDeviceCreateInfo const device_info {
        .sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO,
        .queueCreateInfoCount = uint32_t(queue_infos.size()),
        .pQueueCreateInfos = queue_infos.data(),
        .enabledExtensionCount = uint32_t(extensions.size()),
        .ppEnabledExtensionNames = extensions.data(),
        .pEnabledFeatures = &device_features,
    };

    logger.debug() << "create vulkan device...";
    if(vkCreateDevice(
        m_physical_device,
        &device_info,
        nullptr,
        &m_device
    ) != VK_SUCCESS)
        throw std::runtime_error("failed to create logical device");

    m_queues.resize(m_queue_families.size());
    for(size_t index = 0; index < m_queue_families.size(); ++index) {
        vkGetDeviceQueue(
            m_device,
            m_queue_families[index],
            0,
            &m_queues[index]
        );
    }
    vkGetDeviceQueue(m_device, m_presentation_queue_family, 0, &m_presentation_queue);
}

void Context::create_internal_objects() {
    VkCommandPoolCreateInfo pool_info {
        .sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO,
        .flags = 0,
        .queueFamilyIndex = queue_family(m_transfer_queue_index),
    };
    if(vkCreateCommandPool(
        m_device,
        &pool_info,
        nullptr,
        &m_transfer_command_pool
    ) != VK_SUCCESS) {
        throw std::runtime_error("failed to create command pool");
    }

    VkFenceCreateInfo fence_info {
        .sType = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO,
    };
    if(vkCreateFence(m_device, &fence_info, nullptr, &m_transfer_fence) != VK_SUCCESS)
        throw std::runtime_error("failed to create fence");
}

void Context::initialize_extension_functions() {
    uint32_t errors_count = 0;

    #define GET_PROC_ADDR(ptr_name, func_name) \
        ptr_name = (PFN_vk ## func_name)vkGetInstanceProcAddr( \
            m_instance, "vk" #func_name); \
        if(ptr_name == nullptr) \
        { \
            logger.error() << "failed to load extension function 'vk" #func_name "'"; \
            errors_count += 1; \
        }

    GET_PROC_ADDR(createDebugUtilsMessenger, CreateDebugUtilsMessengerEXT)
    GET_PROC_ADDR(destroyDebugUtilsMessenger, DestroyDebugUtilsMessengerEXT)
    GET_PROC_ADDR(setDebugUtilsObjectName, SetDebugUtilsObjectNameEXT)

    if(errors_count != 0)
        throw std::runtime_error("failed to load extensions");
}

VKAPI_ATTR VkBool32 VKAPI_CALL Context::log_debug_message(
        VkDebugUtilsMessageSeverityFlagBitsEXT severity,
        VkDebugUtilsMessageTypeFlagsEXT type,
        const VkDebugUtilsMessengerCallbackDataEXT* data,
        void* user_data
) {
    {
        auto stream = [severity]() {
            switch(severity) {
            case VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT:
                return logger.debug();
            case VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT:
                return logger.info();
            case VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT:
                return logger.warning();
            case VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT:
                return logger.error();
            }
            return logger.debug();
        }();

        switch(type) {
        case VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT:
            stream << "[vk:general] ";
            break;
        case VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT:
            stream << "[vk:validation] ";
            break;
        case VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT:
            stream << "[vk:performance] ";
            break;
        }

        stream << data->pMessage;
    }

    if(severity == VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT
        && data->messageIdNumber != 2094043421 // wrong swapchain extent
    )
        abort();

    return VK_FALSE;
}


}