#include "renderer.h"

#include <set>
#include <vector>
#include <iostream>
#include <fstream>
#include <cstring>
#include <cmath>
#include <array>

#include "platform.h"
#include "mesh.h"

Renderer::Renderer() {
    createInstance();
#ifdef DEBUG
    if(enableDebug)
        createDebugMessenger();
#endif
    createLogicalDevice();
    createCommandPool();
    createPresentationRenderPass();
    createDescriptorPool();

    worldPass_ = new WorldPass(*this);
    postPass_ = new PostPass(*this);
}

Renderer::~Renderer() {
    vkDeviceWaitIdle(device_);

    delete postPass_;
    delete worldPass_;

    vkDestroyDescriptorPool(device_, descriptorPool_, nullptr);

    vkDestroyRenderPass(device_, presentationRenderPass_, nullptr);

    vkDestroyCommandPool(device_, commandPool_, nullptr);

#ifdef DEBUG
    destroyMessenger_(instance_, messenger_, nullptr);
#endif

    vkDestroyDevice(device_, nullptr);

    vkDestroyInstance(instance_, nullptr);
}

void Renderer::render(World& world, RenderTarget* target) {
    vkAcquireNextImageKHR(device_, target->swapchain, UINT64_MAX, target->imageAvailableSemaphore, nullptr, &target->currentImage);

    vkWaitForFences(device_, 1, &target->fences[target->currentImage], true, UINT64_MAX);
    vkResetFences(device_, 1, &target->fences[target->currentImage]);
    
    const VkCommandBuffer commandBuffer = target->commandBuffers[target->currentImage];

    VkCommandBufferBeginInfo beginInfo = {};
    beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;

    vkBeginCommandBuffer(commandBuffer, &beginInfo);

    VkViewport viewport = {};
    viewport.width = target->extent.width;
    viewport.height = target->extent.height;
    viewport.maxDepth = 1.0f;

    vkCmdSetViewport(commandBuffer, 0, 1, &viewport);

    VkRect2D scissor = {};
    scissor.extent = target->extent;

    vkCmdSetScissor(commandBuffer, 0, 1, &scissor);

    worldPass_->render(commandBuffer, world, target);

    VkClearValue clearColor = {};

    VkRenderPassBeginInfo renderPassBeginInfo = {};
    renderPassBeginInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
    renderPassBeginInfo.framebuffer = target->swapchainFramebuffers[target->currentImage];
    renderPassBeginInfo.renderPass = presentationRenderPass_;
    renderPassBeginInfo.renderArea.extent = target->extent;
    renderPassBeginInfo.clearValueCount = 1;
    renderPassBeginInfo.pClearValues = &clearColor;

    vkCmdBeginRenderPass(commandBuffer, &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);

    postPass_->render(commandBuffer, target);

    vkCmdEndRenderPass(commandBuffer);

    vkEndCommandBuffer(commandBuffer);

    const VkPipelineStageFlags waitStage = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;

    VkSubmitInfo submitInfo = {};
    submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submitInfo.waitSemaphoreCount = 1;
    submitInfo.pWaitSemaphores = &target->imageAvailableSemaphore;
    submitInfo.pWaitDstStageMask = &waitStage;
    submitInfo.commandBufferCount = 1;
    submitInfo.pCommandBuffers = &commandBuffer;
    submitInfo.signalSemaphoreCount = 1;
    submitInfo.pSignalSemaphores = &target->renderFinishedSemaphore;

    vkQueueSubmit(graphicsQueue_, 1, &submitInfo, target->fences[target->currentImage]);

    VkPresentInfoKHR presentInfo = {};
    presentInfo.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;
    presentInfo.waitSemaphoreCount = 1;
    presentInfo.pWaitSemaphores = &target->renderFinishedSemaphore;
    presentInfo.swapchainCount = 1;
    presentInfo.pSwapchains = &target->swapchain;
    presentInfo.pImageIndices = &target->currentImage;

    vkQueuePresentKHR(graphicsQueue_, &presentInfo);
}

RenderTarget* Renderer::createSurfaceRenderTarget(VkSurfaceKHR surface, RenderTarget* oldTarget) {
    vkDeviceWaitIdle(device_);

    RenderTarget* target = new RenderTarget();
    target->surface = surface;

    VkSurfaceCapabilitiesKHR surfaceCapabilities = {};
    vkGetPhysicalDeviceSurfaceCapabilitiesKHR(physicalDevice_, surface, &surfaceCapabilities);

    target->extent = surfaceCapabilities.currentExtent;

    uint32_t surfaceFormatCount = 0;
    vkGetPhysicalDeviceSurfaceFormatsKHR(physicalDevice_, surface, &surfaceFormatCount, nullptr);

    VkSurfaceFormatKHR* surfaceFormats = new VkSurfaceFormatKHR[surfaceFormatCount];
    vkGetPhysicalDeviceSurfaceFormatsKHR(physicalDevice_, surface, &surfaceFormatCount, surfaceFormats);

    uint32_t chosenFormat = 0;
    for(uint32_t i = 0; i < surfaceFormatCount; i++) {
        if(surfaceFormats[i].format == VK_FORMAT_B8G8R8A8_SRGB)
            chosenFormat = i;
    }

    VkBool32 supported = false;
    vkGetPhysicalDeviceSurfaceSupportKHR(physicalDevice_, queueIndices.presentation, surface, &supported);

    VkSwapchainCreateInfoKHR swapchainCreateInfo = {};
    swapchainCreateInfo.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR;
    swapchainCreateInfo.surface = surface;
    swapchainCreateInfo.minImageCount = surfaceCapabilities.minImageCount;
    swapchainCreateInfo.imageColorSpace = surfaceFormats[chosenFormat].colorSpace;
    swapchainCreateInfo.imageFormat = surfaceFormats[chosenFormat].format;
    swapchainCreateInfo.imageExtent = surfaceCapabilities.currentExtent;
    swapchainCreateInfo.imageArrayLayers = 1;
    swapchainCreateInfo.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
    swapchainCreateInfo.queueFamilyIndexCount = 1;
    swapchainCreateInfo.pQueueFamilyIndices = &queueIndices.presentation;
    swapchainCreateInfo.preTransform = surfaceCapabilities.currentTransform;
    swapchainCreateInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
    swapchainCreateInfo.presentMode = VK_PRESENT_MODE_FIFO_KHR;
    swapchainCreateInfo.clipped = true;

    if(oldTarget)
        swapchainCreateInfo.oldSwapchain = oldTarget->swapchain;

    vkCreateSwapchainKHR(device_, &swapchainCreateInfo, nullptr, &target->swapchain);

    if(oldTarget)
        destroyRenderTarget(oldTarget);

    delete[] surfaceFormats;

    uint32_t swapchainImageCount = 0;
    vkGetSwapchainImagesKHR(device_, target->swapchain, &swapchainImageCount, nullptr);

    target->numImages = swapchainImageCount;

    target->swapchainImages = new VkImage[swapchainImageCount];
    vkGetSwapchainImagesKHR(device_, target->swapchain, &swapchainImageCount, target->swapchainImages);

    // create frame resources
    target->swapchainImageViews = new VkImageView[swapchainImageCount];
    target->swapchainFramebuffers = new VkFramebuffer[swapchainImageCount];
    target->offscreenColorImages = new VkImage[swapchainImageCount];
    target->offscreenColorMemory = new VkDeviceMemory[swapchainImageCount];
    target->offscreenColorImageViews = new VkImageView[swapchainImageCount];
    target->offscreenDepthImages = new VkImage[swapchainImageCount];
    target->offscreenDepthMemory = new VkDeviceMemory[swapchainImageCount];
    target->offscreenDepthImageViews = new VkImageView[swapchainImageCount];
    target->offscreenFramebuffers = new VkFramebuffer[swapchainImageCount];
    for(uint32_t i = 0; i < swapchainImageCount; i++) {
        // swapchain image view
        {
            VkImageViewCreateInfo createInfo = {};
            createInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
            createInfo.image = target->swapchainImages[i];
            createInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
            createInfo.format = VK_FORMAT_B8G8R8A8_SRGB;
            createInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
            createInfo.subresourceRange.levelCount = 1;
            createInfo.subresourceRange.layerCount = 1;

            vkCreateImageView(device_, &createInfo, nullptr, &target->swapchainImageViews[i]);
        }

        // swapchain framebuffer
        {
            VkFramebufferCreateInfo framebufferInfo = {};
            framebufferInfo.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
            framebufferInfo.renderPass = presentationRenderPass_;
            framebufferInfo.attachmentCount = 1;
            framebufferInfo.pAttachments = &target->swapchainImageViews[i];
            framebufferInfo.width = target->extent.width;
            framebufferInfo.height = target->extent.height;
            framebufferInfo.layers = 1;

            vkCreateFramebuffer(device_, &framebufferInfo, nullptr, &target->swapchainFramebuffers[i]);
        }

        // offscreen image
        {
            VkImageCreateInfo imageCreateInfo = {};
            imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
            imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
            imageCreateInfo.format = VK_FORMAT_R32G32B32A32_SFLOAT;
            imageCreateInfo.extent.width = target->extent.width;
            imageCreateInfo.extent.height = target->extent.height;
            imageCreateInfo.extent.depth = 1;
            imageCreateInfo.mipLevels = 1;
            imageCreateInfo.arrayLayers = 1;
            imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
            imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
            imageCreateInfo.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;

            vkCreateImage(device_, &imageCreateInfo, nullptr, &target->offscreenColorImages[i]);

            VkMemoryRequirements memoryRequirements = {};
            vkGetImageMemoryRequirements(device_, target->offscreenColorImages[i], &memoryRequirements);

            VkMemoryAllocateInfo allocateInfo = {};
            allocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
            allocateInfo.allocationSize = memoryRequirements.size;
            allocateInfo.memoryTypeIndex = findMemoryType(memoryRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);

            vkAllocateMemory(device_, &allocateInfo, nullptr, &target->offscreenColorMemory[i]);
            vkBindImageMemory(device_, target->offscreenColorImages[i], target->offscreenColorMemory[i], 0);
        }

        // offscreen image view
        {
            VkImageViewCreateInfo createInfo = {};
            createInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
            createInfo.image = target->offscreenColorImages[i];
            createInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
            createInfo.format = VK_FORMAT_R32G32B32A32_SFLOAT;
            createInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
            createInfo.subresourceRange.levelCount = 1;
            createInfo.subresourceRange.layerCount = 1;

            vkCreateImageView(device_, &createInfo, nullptr, &target->offscreenColorImageViews[i]);
        }
        
        // offscreen depth image
        {
            VkImageCreateInfo imageCreateInfo = {};
            imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
            imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
            imageCreateInfo.format = VK_FORMAT_D32_SFLOAT;
            imageCreateInfo.extent.width = target->extent.width;
            imageCreateInfo.extent.height = target->extent.height;
            imageCreateInfo.extent.depth = 1;
            imageCreateInfo.mipLevels = 1;
            imageCreateInfo.arrayLayers = 1;
            imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
            imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
            imageCreateInfo.usage = VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
            
            vkCreateImage(device_, &imageCreateInfo, nullptr, &target->offscreenDepthImages[i]);
            
            VkMemoryRequirements memoryRequirements = {};
            vkGetImageMemoryRequirements(device_, target->offscreenDepthImages[i], &memoryRequirements);
            
            VkMemoryAllocateInfo allocateInfo = {};
            allocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
            allocateInfo.allocationSize = memoryRequirements.size;
            allocateInfo.memoryTypeIndex = findMemoryType(memoryRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
            
            vkAllocateMemory(device_, &allocateInfo, nullptr, &target->offscreenDepthMemory[i]);
            vkBindImageMemory(device_, target->offscreenDepthImages[i], target->offscreenDepthMemory[i], 0);
        }
        
        // offscreen depth image view
        {
            VkImageViewCreateInfo createInfo = {};
            createInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
            createInfo.image = target->offscreenDepthImages[i];
            createInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
            createInfo.format = VK_FORMAT_D32_SFLOAT;
            createInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT;
            createInfo.subresourceRange.levelCount = 1;
            createInfo.subresourceRange.layerCount = 1;
            
            vkCreateImageView(device_, &createInfo, nullptr, &target->offscreenDepthImageViews[i]);
        }

        // offscreen framebuffer
        {
            const std::array<VkImageView, 2> attachments = {
                target->offscreenColorImageViews[i],
                target->offscreenDepthImageViews[i]
            };
            
            VkFramebufferCreateInfo framebufferInfo = {};
            framebufferInfo.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
            framebufferInfo.renderPass = worldPass_->getRenderPass();
            framebufferInfo.attachmentCount = attachments.size();
            framebufferInfo.pAttachments = attachments.data();
            framebufferInfo.width = target->extent.width;
            framebufferInfo.height = target->extent.height;
            framebufferInfo.layers = 1;

            vkCreateFramebuffer(device_, &framebufferInfo, nullptr, &target->offscreenFramebuffers[i]);
        }
    }

    postPass_->createDescriptorSet(target);

    VkCommandBufferAllocateInfo allocateInfo = {};
    allocateInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    allocateInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
    allocateInfo.commandPool = commandPool_;
    allocateInfo.commandBufferCount = swapchainImageCount;

    target->commandBuffers = new VkCommandBuffer[swapchainImageCount];

    vkAllocateCommandBuffers(device_, &allocateInfo, target->commandBuffers);

    VkSemaphoreCreateInfo semaphoreCreateInfo = {};
    semaphoreCreateInfo.sType = VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO;

    vkCreateSemaphore(device_, &semaphoreCreateInfo, nullptr, &target->imageAvailableSemaphore);
    vkCreateSemaphore(device_, &semaphoreCreateInfo, nullptr, &target->renderFinishedSemaphore);

    VkFenceCreateInfo fenceCreateInfo = {};
    fenceCreateInfo.sType = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO;
    fenceCreateInfo.flags = VK_FENCE_CREATE_SIGNALED_BIT;

    target->fences = new VkFence[swapchainImageCount];

    for(uint32_t i = 0; i < swapchainImageCount; i++)
        vkCreateFence(device_, &fenceCreateInfo, nullptr, &target->fences[i]);

    return target;
}

void Renderer::destroyRenderTarget(RenderTarget* target) {
    vkDeviceWaitIdle(device_);

    for(uint32_t i = 0; i < target->numImages; i++)
        vkDestroyFence(device_, target->fences[i], nullptr);

    delete[] target->fences;

    vkDestroySemaphore(device_, target->renderFinishedSemaphore, nullptr);
    vkDestroySemaphore(device_, target->imageAvailableSemaphore, nullptr);

    vkFreeCommandBuffers(device_, commandPool_, target->numImages, target->commandBuffers);

    delete[] target->commandBuffers;

    vkFreeDescriptorSets(device_, descriptorPool_, target->numImages, target->postSets);

    for(uint32_t i = 0; i < target->numImages; i++) {
        vkDestroyFramebuffer(device_, target->offscreenFramebuffers[i], nullptr);
        
        vkDestroyImageView(device_, target->offscreenDepthImageViews[i], nullptr);
        vkFreeMemory(device_, target->offscreenDepthMemory[i], nullptr);
        vkDestroyImage(device_, target->offscreenDepthImages[i], nullptr);
        
        vkDestroyImageView(device_, target->offscreenColorImageViews[i], nullptr);
        vkFreeMemory(device_, target->offscreenColorMemory[i], nullptr);
        vkDestroyImage(device_, target->offscreenColorImages[i], nullptr);

        vkDestroyFramebuffer(device_, target->swapchainFramebuffers[i], nullptr);
        vkDestroyImageView(device_, target->swapchainImageViews[i], nullptr);
    }
    
    delete[] target->offscreenFramebuffers;
    delete[] target->offscreenDepthImageViews;
    delete[] target->offscreenDepthMemory;
    delete[] target->offscreenDepthImages;
    delete[] target->offscreenColorImageViews;
    delete[] target->offscreenColorMemory;
    delete[] target->offscreenColorImages;

    delete[] target->swapchainFramebuffers;
    delete[] target->swapchainImageViews;
    delete[] target->swapchainImages;
    
    delete[] target->postSets;

    vkDestroySwapchainKHR(device_, target->swapchain, nullptr);

    delete target;
}

void Renderer::takeScreenshot(RenderTarget* target) {
    VkImageCreateInfo imageCreateInfo = {};
    imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
    imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
    imageCreateInfo.format = VK_FORMAT_R8G8B8A8_UNORM;
    imageCreateInfo.extent.width = target->extent.width;
    imageCreateInfo.extent.height = target->extent.height;
    imageCreateInfo.extent.depth = 1;
    imageCreateInfo.mipLevels = 1;
    imageCreateInfo.arrayLayers = 1;
    imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
    imageCreateInfo.tiling = VK_IMAGE_TILING_LINEAR;
    imageCreateInfo.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT;
    
    VkImage image = nullptr;
    vkCreateImage(device_, &imageCreateInfo, nullptr, &image);
    
    VkMemoryRequirements memoryRequirements = {};
    vkGetImageMemoryRequirements(device_, image, &memoryRequirements);
    
    VkMemoryAllocateInfo allocateInfo = {};
    allocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
    allocateInfo.allocationSize = memoryRequirements.size;
    allocateInfo.memoryTypeIndex = findMemoryType(memoryRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT);
    
    VkDeviceMemory imageMemory = nullptr;
    vkAllocateMemory(device_, &allocateInfo, nullptr, &imageMemory);
    vkBindImageMemory(device_, image, imageMemory, 0);
    
    VkCommandBufferAllocateInfo bufferAllocateInfo = {};
    bufferAllocateInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    bufferAllocateInfo.commandPool = commandPool_;
    bufferAllocateInfo.commandBufferCount = 1;
    
    VkCommandBuffer commandBuffer = nullptr;
    vkAllocateCommandBuffers(device_, &bufferAllocateInfo, &commandBuffer);
    
    VkCommandBufferBeginInfo beginInfo = {};
    beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
    
    vkBeginCommandBuffer(commandBuffer, &beginInfo);
    
    // change screenshot image to transfer dst layout
    {
        VkImageMemoryBarrier imageMemoryBarrier = {};
        imageMemoryBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
        imageMemoryBarrier.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
        imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
        imageMemoryBarrier.image = image;
        imageMemoryBarrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        imageMemoryBarrier.subresourceRange.layerCount = 1;
        imageMemoryBarrier.subresourceRange.levelCount = 1;
        
        vkCmdPipelineBarrier(
            commandBuffer,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            0,
            0, nullptr,
            0, nullptr,
            1, &imageMemoryBarrier);
    }
    
    const VkImage srcImage = target->swapchainImages[0]; // FIXME: use previous image
    
    // change offscreen image to transfer src layout
    {
        VkImageMemoryBarrier imageMemoryBarrier = {};
        imageMemoryBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
        imageMemoryBarrier.srcAccessMask = VK_ACCESS_MEMORY_READ_BIT;
        imageMemoryBarrier.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
        imageMemoryBarrier.oldLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
        imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
        imageMemoryBarrier.image = srcImage;
        imageMemoryBarrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        imageMemoryBarrier.subresourceRange.layerCount = 1;
        imageMemoryBarrier.subresourceRange.levelCount = 1;
        
        vkCmdPipelineBarrier(
            commandBuffer,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            0,
            0, nullptr,
            0, nullptr,
            1, &imageMemoryBarrier);
    }
        
    VkImageCopy imageCopy = {};
    imageCopy.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    imageCopy.srcSubresource.layerCount = 1;
    imageCopy.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    imageCopy.dstSubresource.layerCount = 1;
    imageCopy.extent.width = target->extent.width;
    imageCopy.extent.height = target->extent.height;
    imageCopy.extent.depth = 1;
    
    // Issue the copy command
    vkCmdCopyImage(
        commandBuffer,
        srcImage,
        VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
        image,
        VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
        1,
        &imageCopy);
    
    // change screenshot image from transfer dst to general (for mapping memory)
    {
        VkImageMemoryBarrier imageMemoryBarrier = {};
        imageMemoryBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
        imageMemoryBarrier.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
        imageMemoryBarrier.dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
        imageMemoryBarrier.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
        imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_GENERAL;
        imageMemoryBarrier.image = image;
        imageMemoryBarrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        imageMemoryBarrier.subresourceRange.layerCount = 1;
        imageMemoryBarrier.subresourceRange.levelCount = 1;
        
        vkCmdPipelineBarrier(
            commandBuffer,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            0,
            0, nullptr,
            0, nullptr,
            1, &imageMemoryBarrier);
    }
 
    // change offscreen image layout back to normal
    {
        VkImageMemoryBarrier imageMemoryBarrier = {};
        imageMemoryBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
        imageMemoryBarrier.srcAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
        imageMemoryBarrier.dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
        imageMemoryBarrier.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
        imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
        imageMemoryBarrier.image = srcImage;
        imageMemoryBarrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        imageMemoryBarrier.subresourceRange.layerCount = 1;
        imageMemoryBarrier.subresourceRange.levelCount = 1;
        
        vkCmdPipelineBarrier(
            commandBuffer,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            VK_PIPELINE_STAGE_TRANSFER_BIT,
            0,
            0, nullptr,
            0, nullptr,
            1, &imageMemoryBarrier);
    }
    
    vkEndCommandBuffer(commandBuffer);
    
    VkSubmitInfo submitInfo = {};
    submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submitInfo.commandBufferCount = 1;
    submitInfo.pCommandBuffers = &commandBuffer;
    
    VkFenceCreateInfo fenceCreateInfo = {};
    fenceCreateInfo.sType = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO;
    
    VkFence fence = nullptr;
    vkCreateFence(device_, &fenceCreateInfo, nullptr, &fence);
    
    vkQueueSubmit(graphicsQueue_, 1, &submitInfo, fence);
    
    vkWaitForFences(device_, 1, &fence, true, -1);
    vkDestroyFence(device_, fence, nullptr);
    
    vkFreeCommandBuffers(device_, commandPool_, 1, &commandBuffer);
    
    VkImageSubresource subResource = {};
    subResource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    
    VkSubresourceLayout subResourceLayout = {};
    vkGetImageSubresourceLayout(device_, image, &subResource, &subResourceLayout);
    
    const char* data = nullptr;
    vkMapMemory(device_, imageMemory, 0, VK_WHOLE_SIZE, 0, (void**)&data);
    data += subResourceLayout.offset;
    
    std::ofstream file("screenshot.ppm", std::ios::out | std::ios::binary);
    file << "P6\n" << target->extent.width << "\n" << target->extent.height << "\n" << 255 << "\n";
  
    for(uint32_t y = 0; y < target->extent.height; y++) {
        const unsigned int* row = reinterpret_cast<const unsigned int*>(data);
        for(uint32_t x = 0; x < target->extent.width; x++) {
            file.write(reinterpret_cast<const char*>(row), 3);
            row++;
        }
        
        data += subResourceLayout.rowPitch;
    }
    
    file.close();
    
    vkUnmapMemory(device_, imageMemory);
    
    vkFreeMemory(device_, imageMemory, nullptr);
    vkDestroyImage(device_, image, nullptr);
}

VkShaderModule Renderer::createShader(const char* path) {
    std::ifstream file(path, std::ios::ate | std::ios::binary);

    size_t fileSize = (size_t) file.tellg();
    std::vector<char> buffer(fileSize);
    file.seekg(0);
    file.read(buffer.data(), fileSize);
    file.close();

    VkShaderModuleCreateInfo createInfo = {};
    createInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
    createInfo.codeSize = buffer.size();
    createInfo.pCode = reinterpret_cast<const uint32_t*>(buffer.data());

    VkShaderModule shaderModule;
    vkCreateShaderModule(device_, &createInfo, nullptr, &shaderModule);

    return shaderModule;
}

uint32_t Renderer::findMemoryType(const uint32_t typeFilter, const VkMemoryPropertyFlags properties) {
    for (uint32_t i = 0; i < deviceMemoryProperties_.memoryTypeCount; i++) {
        if ((typeFilter & (1 << i)) && (deviceMemoryProperties_.memoryTypes[i].propertyFlags & properties) == properties) {
            return i;
        }
    }

    return 0;
}

void Renderer::fillMeshBuffers(Mesh* mesh) {
    // vertex
    {
        VkBufferCreateInfo bufferInfo = {};
        bufferInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
        bufferInfo.size = sizeof(Vertex) * mesh->vertices.size();
        bufferInfo.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
        bufferInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;

        vkCreateBuffer(device_, &bufferInfo, nullptr, &mesh->vertexBuffer);

        VkMemoryRequirements memRequirements;
        vkGetBufferMemoryRequirements(device_, mesh->vertexBuffer, &memRequirements);

        VkMemoryAllocateInfo allocInfo = {};
        allocInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        allocInfo.allocationSize = memRequirements.size;
        allocInfo.memoryTypeIndex = findMemoryType(memRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);

        vkAllocateMemory(device_, &allocInfo, nullptr, &mesh->vertexMemory);
        vkBindBufferMemory(device_, mesh->vertexBuffer, mesh->vertexMemory, 0);

        void* data;
        vkMapMemory(device_, mesh->vertexMemory, 0, bufferInfo.size, 0, &data);
            memcpy(data, mesh->vertices.data(), bufferInfo.size);
        vkUnmapMemory(device_, mesh->vertexMemory);
    }

    // index
    {
        VkBufferCreateInfo bufferInfo = {};
        bufferInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
        bufferInfo.size = sizeof(uint32_t) * mesh->indices.size();
        bufferInfo.usage = VK_BUFFER_USAGE_INDEX_BUFFER_BIT;
        bufferInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;

        vkCreateBuffer(device_, &bufferInfo, nullptr, &mesh->indexBuffer);

        VkMemoryRequirements memRequirements;
        vkGetBufferMemoryRequirements(device_, mesh->indexBuffer, &memRequirements);

        VkMemoryAllocateInfo allocInfo = {};
        allocInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        allocInfo.allocationSize = memRequirements.size;
        allocInfo.memoryTypeIndex = findMemoryType(memRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);

        vkAllocateMemory(device_, &allocInfo, nullptr, &mesh->indexMemory);
        vkBindBufferMemory(device_, mesh->indexBuffer, mesh->indexMemory, 0);

        void* data;
        vkMapMemory(device_, mesh->indexMemory, 0, bufferInfo.size, 0, &data);
        memcpy(data, mesh->indices.data(), bufferInfo.size);
        vkUnmapMemory(device_, mesh->indexMemory);
    }
}

void Renderer::destroyMeshBuffers(Mesh* mesh) {
    vkDeviceWaitIdle(device_);

    vkFreeMemory(device_, mesh->indexMemory, nullptr);
    vkDestroyBuffer(device_, mesh->indexBuffer, nullptr);

    vkFreeMemory(device_, mesh->vertexMemory, nullptr);
    vkDestroyBuffer(device_, mesh->vertexBuffer, nullptr);
}

void Renderer::createInstance() {
    uint32_t layerCount = 0;
    vkEnumerateInstanceLayerProperties(&layerCount, nullptr);

    VkLayerProperties* availableLayers = new VkLayerProperties[layerCount];
    vkEnumerateInstanceLayerProperties(&layerCount, availableLayers);

    std::vector<const char*> enabledLayers;
#ifdef DEBUG
    for(uint32_t i = 0; i < layerCount; i++) {
        if(!strcmp(availableLayers[i].layerName, "VK_LAYER_LUNARG_standard_validation"))
            enabledLayers.push_back("VK_LAYER_LUNARG_standard_validation");
    }
#endif

    delete[] availableLayers;

    uint32_t extensionCount = 0;
    vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, nullptr);

    VkExtensionProperties* availableExtensions = new VkExtensionProperties[extensionCount];
    vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, availableExtensions);

    std::vector<const char*> enabledExtensions;
#ifdef DEBUG
    for(uint32_t i = 0; i < extensionCount; i++) {
        if(!strcmp(availableExtensions[i].extensionName, "VK_EXT_debug_utils")) {
            enabledExtensions.push_back("VK_EXT_debug_utils");
            enableDebug = true;
        }
    }
#endif

    delete[] availableExtensions;

    auto requiredExtensions = platform::getRequiredExtensions();
    enabledExtensions.insert(enabledExtensions.end(), requiredExtensions.begin(), requiredExtensions.end());

    VkInstanceCreateInfo instanceCreateInfo = {};
    instanceCreateInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
    instanceCreateInfo.enabledLayerCount = enabledLayers.size();
    instanceCreateInfo.ppEnabledLayerNames = enabledLayers.data();
    instanceCreateInfo.enabledExtensionCount = enabledExtensions.size();
    instanceCreateInfo.ppEnabledExtensionNames = enabledExtensions.data();

    vkCreateInstance(&instanceCreateInfo, nullptr, &instance_);
}

#ifdef DEBUG
void Renderer::createDebugMessenger() {
    createMessenger_ = (PFN_vkCreateDebugUtilsMessengerEXT)vkGetInstanceProcAddr(instance_, "vkCreateDebugUtilsMessengerEXT");
    destroyMessenger_ = (PFN_vkDestroyDebugUtilsMessengerEXT)vkGetInstanceProcAddr(instance_, "vkDestroyDebugUtilsMessengerEXT");

    VkDebugUtilsMessengerCreateInfoEXT messengerCreateInfo = {};
    messengerCreateInfo.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT;
    messengerCreateInfo.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT;
    messengerCreateInfo.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;
    messengerCreateInfo.pfnUserCallback = [](VkDebugUtilsMessageSeverityFlagBitsEXT, unsigned int, const VkDebugUtilsMessengerCallbackDataEXT* callback, void*) -> unsigned int {
        std::cout << callback->pMessage << std::endl;

        return VK_SUCCESS;
    };

    createMessenger_(instance_, &messengerCreateInfo, nullptr, &messenger_);
}
#endif

void Renderer::createLogicalDevice() {
    uint32_t physicalDeviceCount = 0;
    vkEnumeratePhysicalDevices(instance_, &physicalDeviceCount, nullptr);

    VkPhysicalDevice* physicalDevices = new VkPhysicalDevice[physicalDeviceCount];
    vkEnumeratePhysicalDevices(instance_, &physicalDeviceCount, physicalDevices);

    for(uint32_t i = 0; i < physicalDeviceCount; i++) {
        VkPhysicalDeviceProperties properties = {};
        vkGetPhysicalDeviceProperties(physicalDevices[i], &properties);

        physicalDevice_ = physicalDevices[i];
    }

    delete[] physicalDevices;

    vkGetPhysicalDeviceMemoryProperties(physicalDevice_, &deviceMemoryProperties_);

    uint32_t queueFamilyPropertiesCount = 0;
    vkGetPhysicalDeviceQueueFamilyProperties(physicalDevice_, &queueFamilyPropertiesCount, nullptr);

    VkQueueFamilyProperties* queueFamilyProperties = new VkQueueFamilyProperties[queueFamilyPropertiesCount];
    vkGetPhysicalDeviceQueueFamilyProperties(physicalDevice_, &queueFamilyPropertiesCount, queueFamilyProperties);

    for(uint32_t i = 0; i < queueFamilyPropertiesCount; i++) {
        if(queueFamilyProperties[i].queueFlags & VK_QUEUE_GRAPHICS_BIT)
            queueIndices.graphics = i;
    }

    delete[] queueFamilyProperties;

    queueIndices.presentation = queueIndices.graphics; //FIXME: this may not always be true!!

    const std::set<uint32_t> queueFamilyIndices = {queueIndices.graphics};
    std::vector<VkDeviceQueueCreateInfo> deviceQueueCreateInfos;
    for(auto queueFamilyIndex : queueFamilyIndices) {
        const float priority = 1.0f;

        VkDeviceQueueCreateInfo queueCreateInfo = {};
        queueCreateInfo.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
        queueCreateInfo.queueFamilyIndex = queueFamilyIndex;
        queueCreateInfo.queueCount = 1;
        queueCreateInfo.pQueuePriorities = &priority;

        deviceQueueCreateInfos.push_back(queueCreateInfo);
    }

    const std::vector<const char*> enabledExtensions = {"VK_KHR_swapchain"};

    VkDeviceCreateInfo deviceCreateInfo = {};
    deviceCreateInfo.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
    deviceCreateInfo.queueCreateInfoCount = deviceQueueCreateInfos.size();
    deviceCreateInfo.pQueueCreateInfos = deviceQueueCreateInfos.data();
    deviceCreateInfo.enabledExtensionCount = enabledExtensions.size();
    deviceCreateInfo.ppEnabledExtensionNames = enabledExtensions.data();

    vkCreateDevice(physicalDevice_, &deviceCreateInfo, nullptr, &device_);

    vkGetDeviceQueue(device_, queueIndices.graphics, 0, &graphicsQueue_);
}

void Renderer::createCommandPool() {
    VkCommandPoolCreateInfo poolCreateInfo = {};
    poolCreateInfo.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
    poolCreateInfo.queueFamilyIndex = queueIndices.graphics;
    poolCreateInfo.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;

    vkCreateCommandPool(device_, &poolCreateInfo, nullptr, &commandPool_);
}

void Renderer::createPresentationRenderPass() {
    VkAttachmentDescription colorAttachment = {};
    colorAttachment.format = VK_FORMAT_B8G8R8A8_SRGB;
    colorAttachment.samples = VK_SAMPLE_COUNT_1_BIT;
    colorAttachment.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
    colorAttachment.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
    colorAttachment.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
    colorAttachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
    colorAttachment.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
    colorAttachment.finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;

    VkAttachmentReference colorAttachmentRef = {};
    colorAttachmentRef.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

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

    VkRenderPassCreateInfo renderPassInfo = {};
    renderPassInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
    renderPassInfo.attachmentCount = 1;
    renderPassInfo.pAttachments = &colorAttachment;
    renderPassInfo.subpassCount = 1;
    renderPassInfo.pSubpasses = &subpass;

    vkCreateRenderPass(device_, &renderPassInfo, nullptr, &presentationRenderPass_);
}

void Renderer::createDescriptorPool() {
    const std::array<VkDescriptorPoolSize, 2> poolSizes = {
        VkDescriptorPoolSize{VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 15},
        VkDescriptorPoolSize{VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 15}
    };

    VkDescriptorPoolCreateInfo poolInfo = {};
    poolInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
    poolInfo.flags = VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT;
    poolInfo.poolSizeCount = poolSizes.size();
    poolInfo.pPoolSizes = poolSizes.data();
    poolInfo.maxSets = 15;

    vkCreateDescriptorPool(device_, &poolInfo, nullptr, &descriptorPool_);
}