#include <cruft/vk/instance.hpp>
#include <cruft/vk/physical_device.hpp>
#include <cruft/vk/queue.hpp>
#include <cruft/vk/device.hpp>
#include <cruft/vk/surface.hpp>
#include <cruft/vk/semaphore.hpp>
#include <cruft/vk/image_view.hpp>
#include <cruft/vk/buffer.hpp>
#include <cruft/vk/render_pass.hpp>
#include <cruft/vk/shader_module.hpp>
#include <cruft/vk/framebuffer.hpp>
#include <cruft/vk/pipeline_layout.hpp>
#include <cruft/vk/command_pool.hpp>
#include <cruft/vk/device_memory.hpp>
#include <cruft/vk/swapchain.hpp>
#include <cruft/vk/pipeline.hpp>
#include <cruft/vk/callback.hpp>

#include <GLFW/glfw3.h>
#include <GLFW/glfw3native.h>

#include <cruft/util/cast.hpp>
#include <cruft/util/extent.hpp>
#include <cruft/util/io.hpp>
#include <cruft/util/log.hpp>
#include <cruft/util/colour.hpp>
#include <cruft/util/point.hpp>

#include <atomic>
#include <mutex>
#include <iostream>
#include <experimental/filesystem>


///////////////////////////////////////////////////////////////////////////////
static VkBool32
vk_debug_callback (VkDebugReportFlagsEXT flags,
                   VkDebugReportObjectTypeEXT objType,
                   uint64_t obj,
                   size_t location,
                   int32_t code,
                   const char* layerPrefix,
                   const char* msg,
                   void* userData)
{
    (void)flags;
    (void)objType;
    (void)obj;
    (void)location;
    (void)code;
    (void)layerPrefix;
    (void)msg;
    (void)userData;

    std::cerr << "validation: " << msg << '\n';

    return VK_FALSE;
}


///////////////////////////////////////////////////////////////////////////////
struct vertex_t {
    util::point2f position;
    util::srgba3f colour;
};


//-----------------------------------------------------------------------------
static constexpr vertex_t VERTICES[] = {
    { { 0.0f, -0.5f }, { 1.0f, 0.0f, 0.0f } },
    { { 0.5f,  0.5f }, { 0.0f, 1.0f, 0.0f } },
    { {-0.5f,  0.5f }, { 0.0f, 0.0f, 1.0f } },
};


namespace glfw {
    namespace detail {
        constexpr const char* error_string (int code) noexcept;
    }


    struct error : public std::exception {
    public:
        static void try_code (int code);
        static void throw_code [[noreturn]] (int code);
        static void throw_code [[noreturn]] (void);

        static void push (int code)
        {
            s_current = code;
        }

    private:
        static std::atomic<int> s_current;
    };


    template <int CodeV>
    struct error_code : public error {
        virtual ~error_code () = default;
        static constexpr const char *message = detail::error_string (CodeV);
    };
}


std::atomic<int> glfw::error::s_current;


void
glfw_error_callback (int code ,const char *description)
{
    LOG_WARN ("glfw: %s", description);
    glfw::error::push (code);
}


namespace glfw {
    class instance {
    public:
        instance ()
        {
            if (std::lock_guard l {s_count.guard}; !s_count.value++)
                glfwInit ();

            glfwSetErrorCallback (glfw_error_callback);

            static constexpr struct {
                int tag;
                int val;
            } HINTS[] {
                { GLFW_CLIENT_API, GLFW_NO_API },
                { GLFW_RESIZABLE,  GLFW_FALSE  },
            };

            for (const auto [tag,val]: HINTS)
                glfwWindowHint (tag, val);
        }


        std::vector<const char*>
        required_extensions (void) const
        {
            unsigned count;
            auto values = glfwGetRequiredInstanceExtensions (&count);

            return {
                values + 0,
                values + count
            };
        }


        void poll_events (void)
        {
            glfwPollEvents ();
        }

        ~instance ()
        {
            if (std::lock_guard l {s_count.guard}; !--s_count.value)
                glfwTerminate ();
        }


    private:
        // TODO: value doesnt' need to be atomic, but it's not performance
        // critical, and I'm not particularly familiar with c++ memory
        // ordering primitives. so it's probably safer this way for now.
        static struct count_t {
            std::mutex guard;
            std::atomic<int> value;
        } s_count;
    };


    class window {
    public:
        using native_t = GLFWwindow*;

        window (util::extent2i resolution, const char *name):
            m_native (glfwCreateWindow (resolution.w, resolution.h, name, nullptr, nullptr))
        {
            if (!m_native)
                error::throw_code ();
        }

        native_t native (void) const { return m_native; }

        bool
        should_close (void) const
        {
            return glfwWindowShouldClose (native ());
        }


    private:
        native_t m_native;
    };
};



///////////////////////////////////////////////////////////////////////////////
template <typename T>
struct to_format;


#define TO_FORMAT(S,T,VALUE)                        \
template <template <size_t,typename> class KlassT>  \
struct to_format<KlassT<S,T>> {                     \
    static constexpr auto value = VkFormat::VALUE;  \
};


TO_FORMAT(1,float,VK_FORMAT_R32_SFLOAT);
TO_FORMAT(2,float,VK_FORMAT_R32G32_SFLOAT);
TO_FORMAT(3,float,VK_FORMAT_R32G32B32_SFLOAT);
TO_FORMAT(4,float,VK_FORMAT_R32G32B32A32_SFLOAT);


template <typename T>
constexpr auto to_format_v = to_format<T>::value;


///////////////////////////////////////////////////////////////////////////////
struct glfw::instance::count_t glfw::instance::s_count;


///////////////////////////////////////////////////////////////////////////////
constexpr const char*
glfw::detail::error_string (int code) noexcept
{
    switch (code) {
        case GLFW_NOT_INITIALIZED:      return "Not initialised";
        case GLFW_NO_CURRENT_CONTEXT:   return "No current context";
        case GLFW_INVALID_ENUM:         return "Invalid enum";
        case GLFW_INVALID_VALUE:        return "Invalid value";
        case GLFW_OUT_OF_MEMORY:        return "Out of memory";
        case GLFW_API_UNAVAILABLE:      return "API unavailable";
        case GLFW_VERSION_UNAVAILABLE:  return "Version unavailable";
        case GLFW_PLATFORM_ERROR:       return "Platform error";
        case GLFW_FORMAT_UNAVAILABLE:   return "Format unavailable";
        case GLFW_NO_WINDOW_CONTEXT:    return "No window context";
    }

    unhandled (code);
}


//-----------------------------------------------------------------------------
void
glfw::error::try_code (int code)
{
    if (__builtin_expect (code, 0))
        throw_code (code);
}


//-----------------------------------------------------------------------------
void
glfw::error::throw_code [[noreturn]] (int code)
{
    switch (code) {
        case GLFW_NOT_INITIALIZED:      throw error_code<GLFW_NOT_INITIALIZED> {};
        case GLFW_NO_CURRENT_CONTEXT:   throw error_code<GLFW_NO_CURRENT_CONTEXT> {};
        case GLFW_INVALID_ENUM:         throw error_code<GLFW_INVALID_ENUM> {};
        case GLFW_INVALID_VALUE:        throw error_code<GLFW_INVALID_VALUE> {};
        case GLFW_OUT_OF_MEMORY:        throw error_code<GLFW_OUT_OF_MEMORY> {};
        case GLFW_API_UNAVAILABLE:      throw error_code<GLFW_API_UNAVAILABLE> {};
        case GLFW_VERSION_UNAVAILABLE:  throw error_code<GLFW_VERSION_UNAVAILABLE> {};
        case GLFW_PLATFORM_ERROR:       throw error_code<GLFW_PLATFORM_ERROR> {};
        case GLFW_FORMAT_UNAVAILABLE:   throw error_code<GLFW_FORMAT_UNAVAILABLE> {};
        case GLFW_NO_WINDOW_CONTEXT:    throw error_code<GLFW_NO_WINDOW_CONTEXT> {};
    }

    unhandled (code);
}


//-----------------------------------------------------------------------------
void
glfw::error::throw_code [[noreturn]] (void)
{
    throw_code (s_current);
}


///////////////////////////////////////////////////////////////////////////////
class system {
public:
    system ();
};


///////////////////////////////////////////////////////////////////////////////
int
main (void)
{
    LOG_INFO ("intialising glfw");
    glfw::instance glfw_instance;

    util::extent2i resolution { 800, 600 };
    glfw::window window (resolution, "vkcruft-hello");


    auto extensions = glfw_instance.required_extensions ();
    extensions.push_back ("VK_EXT_debug_report");

    const char* layers[] = {
       "VK_LAYER_LUNARG_standard_validation"
    };

    //-------------------------------------------------------------------------
    cruft::vk::instance instance (
        util::make_view (layers),
        util::make_view (extensions.data (), extensions.data () + extensions.size ())
    );

    load_traits (instance);


    //-------------------------------------------------------------------------
    VkDebugReportCallbackCreateInfoEXT debug_info {};
    debug_info.sType = cruft::vk::structure_type_v<VkDebugReportCallbackCreateInfoEXT>;
    debug_info.flags =
        //VK_DEBUG_REPORT_INFORMATION_BIT_EXT |
        VK_DEBUG_REPORT_WARNING_BIT_EXT |
        VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT |
        VK_DEBUG_REPORT_ERROR_BIT_EXT
        //VK_DEBUG_REPORT_DEBUG_BIT_EXT |
        ;

    debug_info.pfnCallback = vk_debug_callback;
    auto debug_callback = cruft::vk::make_owned<cruft::vk::debug_report> (
        instance, &debug_info, nullptr
    );


    //-------------------------------------------------------------------------
    auto pdevices = cruft::vk::physical_device::find (instance);
    auto &pdevice = pdevices[0];


    //-------------------------------------------------------------------------
    auto surface = cruft::vk::make_owned<cruft::vk::surface> (
        cruft::vk::error::try_query (
            glfwCreateWindowSurface, instance.native (), window.native (), nullptr
        ),
        instance
    );

    auto surface_capabilities = capabilities (pdevice, surface);
    auto surface_formats = formats (pdevice, surface);
    auto surface_modes = present_modes (pdevice, surface);

    auto queues = pdevice.queue_families ();
    int graphics_queue_id = -1, present_queue_id = -1;

    for (int i = 0, last = util::cast::lossless<int> (queues.size ()); i != last; ++i)
        if (queues[i].queueCount > 0 && queues[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) {
            graphics_queue_id = i;
            break;
        }

    for (uint32_t i = 0, last = util::cast::narrow<uint32_t> (queues.size ()); i != last; ++i) {
        if (cruft::vk::error::try_query (vkGetPhysicalDeviceSurfaceSupportKHR,
                                         pdevice.native (), i, surface)) {
            present_queue_id = i;
            break;
        }
    }

    if (graphics_queue_id == -1 || present_queue_id == -1) {
        std::cerr << "unable to find useful queues\n";
        return EXIT_FAILURE;
    }

    float priority = 1.f;
    VkDeviceQueueCreateInfo device_queues[] =
    {
        {
            .sType = cruft::vk::structure_type_v<VkDeviceQueueCreateInfo>,
            .pNext = nullptr,
            .flags = 0,
            .queueFamilyIndex = unsigned (graphics_queue_id),
            .queueCount = 1,
            .pQueuePriorities = &priority,
        },
        {
            .sType = cruft::vk::structure_type_v<VkDeviceQueueCreateInfo>,
            .pNext = nullptr,
            .flags = 0,
            .queueFamilyIndex = unsigned (present_queue_id),
            .queueCount = 1,
            .pQueuePriorities = &priority
        }
    };

    const char *device_extensions[] = {
        "VK_KHR_swapchain"
    };

    VkPhysicalDeviceFeatures device_features {};

    VkDeviceCreateInfo device_info {};
    device_info.sType = cruft::vk::structure_type_v<VkDeviceCreateInfo>;
    device_info.pQueueCreateInfos = std::data (device_queues);
    device_info.queueCreateInfoCount = graphics_queue_id == present_queue_id ? 1 : 2;
    device_info.pEnabledFeatures = &device_features;
    device_info.enabledLayerCount = std::size (layers);
    device_info.ppEnabledLayerNames = layers;
    device_info.enabledExtensionCount = std::size (device_extensions);
    device_info.ppEnabledExtensionNames = std::data (device_extensions);

    cruft::vk::device ldevice (pdevice, device_info);


    //-------------------------------------------------------------------------
#if 0
    VkSurfaceFormatKHR surface_format =
        (surface_formats.size () == 1 && surface_formats[0].format == VK_FORMAT_UNDEFINED)
            ? { VK_FORMAT_B8G8R8A8_UNORM, VK_COLOR_SPACE_SRGB_NONLINEAR_KHR }
            : surface_formats[0];
#endif
    VkSurfaceFormatKHR surface_format { VK_FORMAT_B8G8R8A8_UNORM, VK_COLOR_SPACE_SRGB_NONLINEAR_KHR };
    VkPresentModeKHR present_mode = VK_PRESENT_MODE_FIFO_KHR;
    VkExtent2D present_extent {
        .width = util::limit (
            unsigned (resolution.w),
            surface_capabilities.minImageExtent.width,
            surface_capabilities.maxImageExtent.width
        ),
        .height = util::limit (
            unsigned (resolution.h),
            surface_capabilities.minImageExtent.height,
            surface_capabilities.maxImageExtent.height
        )
    };

    uint32_t image_count = surface_capabilities.minImageCount;

    VkSwapchainCreateInfoKHR swap_create_info {
        .sType = cruft::vk::structure_type_v<VkSwapchainCreateInfoKHR>,
        .pNext = nullptr,
        .flags = {},
        .surface = surface->native (),
        .minImageCount = image_count,
        .imageFormat = surface_format.format,
        .imageColorSpace = surface_format.colorSpace,
        .imageExtent = present_extent,
        .imageArrayLayers = 1,
        .imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
        .imageSharingMode = VkSharingMode::VK_SHARING_MODE_EXCLUSIVE,
        .queueFamilyIndexCount = 0,
        .pQueueFamilyIndices = nullptr,
        .preTransform = surface_capabilities.currentTransform,
        .compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR,
        .presentMode = present_mode,
        .clipped = VK_TRUE,
        .oldSwapchain = VK_NULL_HANDLE,
    };

    auto swapchain = cruft::vk::make_owned<cruft::vk::swapchain> (ldevice, &swap_create_info, nullptr);

    std::vector<VkImage> swap_images = cruft::vk::error::try_values (
        vkGetSwapchainImagesKHR, ldevice, swapchain
    );

    using image_view_ptr = cruft::vk::owned_ptr<cruft::vk::image_view>;
    std::vector<image_view_ptr> swap_image_views;
    swap_image_views.reserve (std::size (swap_images));
    std::transform (
        std::cbegin (swap_images), std::cend (swap_images),
        std::back_inserter (swap_image_views),
        [&] (auto i) {
            VkImageViewCreateInfo create_info {};
            create_info.sType = cruft::vk::structure_type_v<VkImageViewCreateInfo>,
            create_info.pNext = nullptr,
            create_info.image = i,
            create_info.viewType = VK_IMAGE_VIEW_TYPE_2D,
            create_info.format = surface_format.format,
            create_info.components = VkComponentMapping {
                .r = VK_COMPONENT_SWIZZLE_IDENTITY,
                .g = VK_COMPONENT_SWIZZLE_IDENTITY,
                .b = VK_COMPONENT_SWIZZLE_IDENTITY,
                .a = VK_COMPONENT_SWIZZLE_IDENTITY,
            };
            create_info.subresourceRange = VkImageSubresourceRange {
                .aspectMask = VK_IMAGE_ASPECT_COLOR_BIT,
                .baseMipLevel = 0,
                .levelCount = 1,
                .baseArrayLayer = 0,
                .layerCount = 1
            };

            return cruft::vk::make_owned<cruft::vk::image_view> (ldevice, &create_info, nullptr);
    });

    auto graphics_queue = cruft::vk::make_owned<cruft::vk::queue> (ldevice, graphics_queue_id, 0);
    auto present_queue = cruft::vk::make_owned<cruft::vk::queue> (ldevice, present_queue_id, 0);


    //-------------------------------------------------------------------------
    auto vert_module = cruft::vk::make_owned<cruft::vk::shader_module> (ldevice, "./hello.vert.spv");
    auto frag_module = cruft::vk::make_owned<cruft::vk::shader_module> (ldevice, "./hello.frag.spv");


    //-------------------------------------------------------------------------
    VkBufferCreateInfo buffer_info {};
    buffer_info.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
    buffer_info.size = sizeof (VERTICES);
    buffer_info.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
    buffer_info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;

    auto vertex_buffer = cruft::vk::make_owned<cruft::vk::buffer> (ldevice, &buffer_info, nullptr);

    auto memory_requirements = cruft::vk::error::try_query (
        vkGetBufferMemoryRequirements, ldevice.native (), vertex_buffer
    );

    auto memory_properties = pdevice.memory_properties ();

    VkMemoryAllocateInfo allocate_info {};
    allocate_info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
    allocate_info.allocationSize = memory_requirements.size;
    allocate_info.memoryTypeIndex = [&] () {
        for (uint32_t i = 0; i < memory_properties.memoryTypeCount; ++i) {
            if ((memory_requirements.memoryTypeBits & (1u << i)) && memory_properties.memoryTypes[i].propertyFlags & (VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT))
                return i;
        }

        throw std::runtime_error ("no suitable memory type");
    } ();


    auto vertex_memory = cruft::vk::make_owned<cruft::vk::device_memory> (
        ldevice, &allocate_info, nullptr
    );

    cruft::vk::error::try_func (
        vkBindBufferMemory, ldevice, vertex_buffer, vertex_memory, 0
    );

    {
        auto data = map (vertex_memory, sizeof (VERTICES));
        memcpy (std::data (data), std::data (VERTICES), sizeof (VERTICES));
    }

    //-------------------------------------------------------------------------
    VkPipelineShaderStageCreateInfo vert_stage_info {};
    vert_stage_info.sType = cruft::vk::structure_type_v<VkPipelineShaderStageCreateInfo>;
    vert_stage_info.stage = VK_SHADER_STAGE_VERTEX_BIT;
    vert_stage_info.module = vert_module->native ();
    vert_stage_info.pName = "main";

    VkPipelineShaderStageCreateInfo frag_stage_info = vert_stage_info;
    frag_stage_info.stage = VK_SHADER_STAGE_FRAGMENT_BIT;
    frag_stage_info.module = frag_module->native ();

    VkPipelineShaderStageCreateInfo stages[] = {
        vert_stage_info, frag_stage_info
    };


    //-------------------------------------------------------------------------
    VkVertexInputBindingDescription vertex_binding {};
    vertex_binding.binding = 0;
    vertex_binding.stride = sizeof (vertex_t);
    vertex_binding.inputRate = VK_VERTEX_INPUT_RATE_VERTEX;

    std::array<VkVertexInputAttributeDescription,2> vertex_attribute {};
    vertex_attribute[0].binding = 0;
    vertex_attribute[0].location = 0;
    vertex_attribute[0].format = to_format_v<decltype(VERTICES[0].position)>;
    vertex_attribute[0].offset = offsetof(vertex_t, position);

    vertex_attribute[1].binding = 0;
    vertex_attribute[1].location = 1;
    vertex_attribute[1].format = to_format_v<decltype(VERTICES[0].colour)>;
    vertex_attribute[1].offset = offsetof (vertex_t, colour);


    //-------------------------------------------------------------------------
    VkPipelineVertexInputStateCreateInfo vertex_input {};
    vertex_input.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
    vertex_input.vertexBindingDescriptionCount = 1;
    vertex_input.pVertexBindingDescriptions = &vertex_binding;
    vertex_input.vertexAttributeDescriptionCount = 2;
    vertex_input.pVertexAttributeDescriptions = std::data (vertex_attribute);

    VkPipelineInputAssemblyStateCreateInfo assembly_info {};
    assembly_info.sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO;
    assembly_info.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
    assembly_info.primitiveRestartEnable = VK_FALSE;


    //-------------------------------------------------------------------------
    VkViewport viewport {
        .x = 0.f,
        .y = 0.f,
        .width  = float (present_extent.width),
        .height = float (present_extent.height),
        .minDepth = 0.f,
        .maxDepth = 1.f,
    };

    VkRect2D scissor {
        .offset = {},
        .extent = present_extent
    };


    //-------------------------------------------------------------------------
    VkPipelineLayoutCreateInfo pipeline_layout_info {};
    pipeline_layout_info.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
    pipeline_layout_info.setLayoutCount = 0;
    pipeline_layout_info.pSetLayouts = nullptr;
    pipeline_layout_info.pushConstantRangeCount = 0;
    pipeline_layout_info.pPushConstantRanges = 0;

    auto pipeline_layout = cruft::vk::make_owned<cruft::vk::pipeline_layout> (
        ldevice, &pipeline_layout_info, nullptr
    );


    //-------------------------------------------------------------------------
    VkAttachmentDescription color_attachment {};
    color_attachment.format         = surface_format.format;
    color_attachment.samples        = VK_SAMPLE_COUNT_1_BIT;
    color_attachment.loadOp         = VK_ATTACHMENT_LOAD_OP_CLEAR;
    color_attachment.storeOp        = VK_ATTACHMENT_STORE_OP_STORE;
    color_attachment.stencilLoadOp  = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
    color_attachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
    color_attachment.initialLayout  = VK_IMAGE_LAYOUT_UNDEFINED;
    color_attachment.finalLayout    = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;

    VkAttachmentReference colour_attachment_ref {};
    colour_attachment_ref.attachment = 0;
    colour_attachment_ref.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

    VkSubpassDescription subpass {};
    subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
    subpass.colorAttachmentCount = 1;
    subpass.pColorAttachments = &colour_attachment_ref;

    VkRenderPassCreateInfo render_pass_info {};
    render_pass_info.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
    render_pass_info.attachmentCount = 1;
    render_pass_info.pAttachments = &color_attachment;
    render_pass_info.subpassCount = 1;
    render_pass_info.pSubpasses = &subpass;

    auto render_pass = cruft::vk::make_owned<cruft::vk::render_pass> (
        ldevice, &render_pass_info, nullptr
    );


    //-------------------------------------------------------------------------
    VkPipelineViewportStateCreateInfo viewport_create_info {};
    viewport_create_info.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
    viewport_create_info.viewportCount = 1;
    viewport_create_info.pViewports = &viewport;
    viewport_create_info.scissorCount = 1;
    viewport_create_info.pScissors = &scissor;

    VkPipelineRasterizationStateCreateInfo rasterizer {};
    rasterizer.sType = VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO;
    rasterizer.depthClampEnable = VK_FALSE;
    rasterizer.rasterizerDiscardEnable = VK_FALSE;
    rasterizer.polygonMode = VK_POLYGON_MODE_FILL;
    rasterizer.lineWidth = 1.f;
    rasterizer.cullMode = VK_CULL_MODE_BACK_BIT;
    rasterizer.frontFace = VK_FRONT_FACE_CLOCKWISE;
    rasterizer.depthBiasEnable = VK_FALSE;
    rasterizer.depthBiasConstantFactor = 0.f;
    rasterizer.depthBiasClamp = 0.f;
    rasterizer.depthBiasSlopeFactor = 0.f;

    VkPipelineMultisampleStateCreateInfo multisampling {};
    multisampling.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
    multisampling.sampleShadingEnable = VK_FALSE;
    multisampling.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
    multisampling.minSampleShading = 1.0f;
    multisampling.pSampleMask = nullptr;
    multisampling.alphaToCoverageEnable = VK_FALSE;
    multisampling.alphaToOneEnable = VK_FALSE;

    VkPipelineColorBlendAttachmentState blend_attachment = {};
    blend_attachment.colorWriteMask =
        VK_COLOR_COMPONENT_R_BIT |
        VK_COLOR_COMPONENT_G_BIT |
        VK_COLOR_COMPONENT_B_BIT |
        VK_COLOR_COMPONENT_A_BIT;
    blend_attachment.blendEnable = VK_FALSE;
    blend_attachment.srcColorBlendFactor = VK_BLEND_FACTOR_ONE;
    blend_attachment.dstColorBlendFactor = VK_BLEND_FACTOR_ZERO;
    blend_attachment.colorBlendOp        = VK_BLEND_OP_ADD;
    blend_attachment.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE;
    blend_attachment.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
    blend_attachment.alphaBlendOp        = VK_BLEND_OP_ADD;

    VkPipelineColorBlendStateCreateInfo colour_blend = {};
    colour_blend.sType = VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO;
    colour_blend.logicOpEnable = VK_FALSE;
    colour_blend.logicOp = VK_LOGIC_OP_COPY;
    colour_blend.attachmentCount = 1;
    colour_blend.pAttachments = &blend_attachment;
    colour_blend.blendConstants[0] = 0.0f;
    colour_blend.blendConstants[1] = 0.0f;
    colour_blend.blendConstants[2] = 0.0f;
    colour_blend.blendConstants[3] = 0.0f;

    VkGraphicsPipelineCreateInfo pipeline_info {};
    pipeline_info.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
    pipeline_info.stageCount = 2;
    pipeline_info.pStages = stages;
    pipeline_info.pVertexInputState = &vertex_input;
    pipeline_info.pInputAssemblyState = &assembly_info;
    pipeline_info.pViewportState = &viewport_create_info;
    pipeline_info.pRasterizationState = &rasterizer;
    pipeline_info.pMultisampleState = &multisampling;
    pipeline_info.pDepthStencilState = nullptr;
    pipeline_info.pColorBlendState = &colour_blend;
    pipeline_info.layout = pipeline_layout->native ();
    pipeline_info.renderPass = render_pass->native ();
    pipeline_info.subpass = 0;
    pipeline_info.basePipelineHandle = VK_NULL_HANDLE;
    pipeline_info.basePipelineIndex = -1;

    auto graphics_pipeline = cruft::vk::make_owned<
        cruft::vk::pipeline<cruft::vk::bindpoint::GRAPHICS>
    > (
        ldevice, VK_NULL_HANDLE, 1, &pipeline_info, nullptr
    );

    //-------------------------------------------------------------------------
    using framebuffer_ptr = cruft::vk::owned_ptr<cruft::vk::framebuffer>;
    std::vector<framebuffer_ptr> swapchain_framebuffers;

    std::transform (std::cbegin (swap_image_views),
                    std::cend   (swap_image_views),
                    std::back_inserter (swapchain_framebuffers),
                    [&] (const auto &i) {
        VkImageView attachments[] = {
            i->native ()
        };

        VkFramebufferCreateInfo framebuffer_info {};
        framebuffer_info.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
        framebuffer_info.renderPass = render_pass->native ();
        framebuffer_info.attachmentCount = 1;
        framebuffer_info.pAttachments = attachments;
        framebuffer_info.width = present_extent.width;
        framebuffer_info.height = present_extent.height;
        framebuffer_info.layers = 1;

        return cruft::vk::make_owned<cruft::vk::framebuffer> (ldevice, &framebuffer_info, nullptr);
    });


    //-------------------------------------------------------------------------
    VkCommandPoolCreateInfo pool_info {};
    pool_info.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
    pool_info.queueFamilyIndex = device_queues[0].queueFamilyIndex;

    auto command_pool = cruft::vk::make_owned<cruft::vk::command_pool> (
        ldevice, &pool_info, nullptr
    );

    std::vector<VkCommandBuffer> command_buffers (swapchain_framebuffers.size ());
    VkCommandBufferAllocateInfo alloc_info = {};
    alloc_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    alloc_info.commandPool = command_pool->native ();
    alloc_info.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
    alloc_info.commandBufferCount = util::cast::lossless<uint32_t> (command_buffers.size());
    cruft::vk::error::try_code (
        vkAllocateCommandBuffers (ldevice.native (), &alloc_info, command_buffers.data ())
    );

    for (size_t i = 0; i < command_buffers.size (); ++i) {
        VkCommandBufferBeginInfo command_begin {};
        command_begin.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
        command_begin.flags = VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT;

        cruft::vk::error::try_code (
            vkBeginCommandBuffer (command_buffers[i], &command_begin)
        );

        VkRenderPassBeginInfo render_begin {};
        render_begin.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
        render_begin.renderPass = render_pass->native ();
        render_begin.framebuffer = swapchain_framebuffers[i]->native ();
        render_begin.renderArea.extent = present_extent;

        VkClearValue clear_color { 0.f, 0.f, 0.f, 1.f };
        render_begin.clearValueCount = 1;
        render_begin.pClearValues = &clear_color;

        vkCmdBeginRenderPass (command_buffers[i], &render_begin, VK_SUBPASS_CONTENTS_INLINE);

        vkCmdBindPipeline (
            command_buffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, graphics_pipeline->native ()
        );

        VkBuffer buffers[] = {vertex_buffer->native ()};
        VkDeviceSize offsets[] = {0};
        vkCmdBindVertexBuffers (command_buffers[i], 0, 1, buffers, offsets);

        vkCmdDraw (command_buffers[i], 3, 1, 0, 0);

        vkCmdEndRenderPass (command_buffers[i]);

        cruft::vk::error::try_func (&vkEndCommandBuffer, command_buffers[i]);
    };

    VkSemaphoreCreateInfo semaphore_info {};
    semaphore_info.sType = VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO;

    auto image_semaphore  = cruft::vk::make_owned<cruft::vk::semaphore> (
        ldevice, &semaphore_info, nullptr
    );

    auto render_semaphore = cruft::vk::make_owned<cruft::vk::semaphore> (
        ldevice, &semaphore_info, nullptr
    );

    uint32_t image_index;
    cruft::vk::error::try_code (
        vkAcquireNextImageKHR (
            ldevice.native (), swapchain->native (),
            std::numeric_limits<uint64_t>::max (),
            image_semaphore->native (), VK_NULL_HANDLE,
            &image_index
        )
    );

    VkSubmitInfo submit_info {};
    submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    VkSemaphore wait_semaphores[] = { image_semaphore->native () };
    VkPipelineStageFlags wait_stages[] = { VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT };
    submit_info.waitSemaphoreCount = 1;
    submit_info.pWaitSemaphores = wait_semaphores;
    submit_info.pWaitDstStageMask = wait_stages;
    submit_info.commandBufferCount = 1;
    submit_info.pCommandBuffers = &command_buffers[image_index];

    VkSemaphore signal_semaphores[] = { render_semaphore->native () };
    submit_info.signalSemaphoreCount = 1;
    submit_info.pSignalSemaphores = signal_semaphores;

    cruft::vk::error::try_func (
        vkQueueSubmit, graphics_queue, 1, &submit_info, VK_NULL_HANDLE
    );

    VkSubpassDependency dependency {};
    dependency.srcSubpass = VK_SUBPASS_EXTERNAL;
    dependency.dstSubpass = 0;
    dependency.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
    dependency.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
    dependency.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
    render_pass_info.dependencyCount = 1;
    render_pass_info.pDependencies = &dependency;

    VkPresentInfoKHR present_info {};
    present_info.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;
    present_info.waitSemaphoreCount = 1;
    present_info.pWaitSemaphores = signal_semaphores;

    VkSwapchainKHR swapchains[] = { swapchain->native () };
    present_info.swapchainCount = 1;
    present_info.pSwapchains = swapchains;
    present_info.pImageIndices = &image_index;
    present_info.pResults = nullptr;

    cruft::vk::error::try_func (vkQueuePresentKHR, present_queue, &present_info);

    LOG_INFO ("entering runloop");
    while (!window.should_close ()) {
        glfw_instance.poll_events ();
    }

    cruft::vk::error::try_func (vkDeviceWaitIdle, ldevice.native ());
    LOG_INFO ("terminating");
}