#pragma comment(lib, "glfw3.lib")
#pragma comment(lib, "vulkan-1.lib")
#define GLFW_INCLUDE_VULKAN
#include <GLFW/glfw3.h>

#if _WIN32 || _WIN64
#include <algorithm>
#endif
#include <cstring>
#include <fstream>
#include <functional>
#include <iostream>
#include <limits>
#include <set>
#include <stdexcept>
#include <vector>

#include "main.h"

const int WIDTH = 1200;
const int HEIGHT = 900;

const std::vector<const char*> validationLayers = {
    "VK_LAYER_KHRONOS_validation"
};

const std::vector<const char*> deviceExtensions = {
	VK_KHR_SWAPCHAIN_EXTENSION_NAME
};

#ifdef NDEBUG
    const bool enableValidationLayers = false;
#else
    const bool enableValidationLayers = true;
#endif

class HelloTriangleApplication {
public:
	void run() {
		initWindow();
		initVulkan();
		mainLoop();
	}

	// our debug callback function, just prints the message from the Validation layer to stderr
	static VKAPI_ATTR VkBool32 VKAPI_CALL debugCallback( VkDebugReportFlagsEXT flags,
		VkDebugReportObjectTypeEXT objType, uint64_t obj, size_t location, int32_t code,
		const char* layerPrefix, const char* msg, void* userData) {
		std::cerr << "[Validation Layer]: " << msg << std::endl;

		return VK_FALSE;
	}

	static void onWindowResized(GLFWwindow* window, int width, int height) {
		if(width == 0 || height == 0) return;

		HelloTriangleApplication* app = reinterpret_cast<HelloTriangleApplication*>(glfwGetWindowUserPointer(window));
		app->recreateSwapChain();
	}

private:
	// Instance variables:
	GLFWwindow* window;
	VkInstance instance;
	VkDebugReportCallbackEXT callback;
	VkPhysicalDevice physicalDevice = VK_NULL_HANDLE;
	VkQueue graphicsQueue;
	VkDevice device;
	VkSurfaceKHR surface;
	VkQueue presentQueue;
	VkSwapchainKHR swapChain = VK_NULL_HANDLE;
	std::vector<VkImage> swapChainImages;
	VkFormat swapChainImageFormat;
	VkExtent2D swapChainExtent;
	std::vector<VkImageView> swapChainImageViews;
	VkRenderPass renderPass;
	VkPipelineLayout pipelineLayout;
	VkPipeline graphicsPipeline;
	std::vector<VkFramebuffer> swapChainFramebuffers;
	VkCommandPool commandPool;
	std::vector<VkCommandBuffer> commandBuffers;
	VkSemaphore imageAvailableSemaphore;
	VkSemaphore renderFinishedSemaphore;
	VkShaderModule vertShaderModule;
	VkShaderModule fragShaderModule;


	// Initialize our GLFW window.
	void initWindow() {
		glfwInit();

		glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);

		window = glfwCreateWindow(WIDTH, HEIGHT, "Vulkan", nullptr, nullptr);

		glfwSetWindowUserPointer(window, this);
		glfwSetWindowSizeCallback(window, HelloTriangleApplication::onWindowResized);
	}

	void initVulkan() {
		createInstance();
		setupDebugCallback();
		createSurface();
		pickPhysicalDevice();
		createLogicalDevice();
		createSwapChain();
		createImageViews();
		createRenderPass();
		createGraphicsPipeline();
		createFramebuffers();
		createCommandPool();
		createCommandBuffers();
		createSemaphores();
	}

	void recreateSwapChain() {
		vkDeviceWaitIdle(device);

		createSwapChain();
		createImageViews();
		createRenderPass();
		createGraphicsPipeline();
		createFramebuffers();
		createCommandBuffers();
	}

	// Figure out what extensions GLFW requires to make a Vulkan surface.
	// Also add the debug report extension, so we can add our debug report callback function.
	std::vector<const char*> getRequiredExtensions() {
		std::vector<const char*> extensions;

		unsigned int glfwExtensionCount = 0;
		const char** glfwExtensions;
		glfwExtensions = glfwGetRequiredInstanceExtensions(&glfwExtensionCount);

		for(unsigned int i = 0; i < glfwExtensionCount; i++) {
			extensions.push_back(glfwExtensions[i]);
		}

		if(enableValidationLayers) {
			extensions.push_back(VK_EXT_DEBUG_REPORT_EXTENSION_NAME);
		}

		return extensions;
	}

	// Create our VkInstance with the validation layers enabled and the extensions needed for
	// 	presentation on our surface GLFW will create.
	void createInstance() {
		if(enableValidationLayers && !checkValidationLayerSupport()) {
			throw std::runtime_error("validation layers requested, but not supported");
		}

		// Create VkApplicationInfo
		VkApplicationInfo appInfo = {};
		appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
		appInfo.pApplicationName = "Hello Triangle";
		appInfo.applicationVersion = VK_MAKE_VERSION(1, 0, 0);
		appInfo.pEngineName = "No Engine";
		appInfo.engineVersion = VK_MAKE_VERSION(1, 0, 0);
		appInfo.apiVersion = VK_API_VERSION_1_0;

		// Create VkInstanceCreateInfo and have it point to VkApplicationInfo
		VkInstanceCreateInfo createInfo = {};
		createInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
		createInfo.pApplicationInfo = &appInfo;

		// Enable the validation layers if they are requested
		if(enableValidationLayers) {
			createInfo.enabledLayerCount = validationLayers.size();
			createInfo.ppEnabledLayerNames = validationLayers.data();
		} else {
			createInfo.enabledLayerCount = 0;
		}
		
		auto reqExtensions = getRequiredExtensions();
		createInfo.enabledExtensionCount = reqExtensions.size();
		createInfo.ppEnabledExtensionNames = reqExtensions.data();

		if(vkCreateInstance(&createInfo, nullptr, &instance) != VK_SUCCESS) {
			throw std::runtime_error("failed to create Vulkan instance!");
		}

		uint32_t extensionCount = 0;

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

		std::cout << "available extensions:" << std::endl;

		for(const auto& extension : extensions) {
			std::cout << "\t" << extension.extensionName << std::endl;
		}
	}

	void destroyInstance() {
		vkDestroyInstance(instance, nullptr);
	}

	// Check if the validation layers are supported.
	bool checkValidationLayerSupport() {
		uint32_t layerCount;
		vkEnumerateInstanceLayerProperties(&layerCount, nullptr);

		std::vector<VkLayerProperties> availableLayers(layerCount);
		vkEnumerateInstanceLayerProperties(&layerCount, availableLayers.data());

		for(const char* layerName : validationLayers) {
			bool layerFound = false;

			for(const auto& layerProperties : availableLayers) {
				if(strcmp(layerName, layerProperties.layerName) == 0) {
					layerFound = true;
					break;
				}
			}

			if(!layerFound) {
				return false;
			}
		}

		return true;
	}

	// Set up our debug report callback to get information back from the validation layers.
	void setupDebugCallback() {
		if (!enableValidationLayers) return;
		
		VkDebugReportCallbackCreateInfoEXT createInfo = {};
		createInfo.sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT;
		createInfo.flags = VK_DEBUG_REPORT_ERROR_BIT_EXT | VK_DEBUG_REPORT_WARNING_BIT_EXT;
		createInfo.pfnCallback = debugCallback;

		if(CreateDebugReportCallbackEXT(instance, &createInfo, nullptr, &callback) != VK_SUCCESS) {
			throw std::runtime_error("failed to setup debug callback!");
		}
	}

	void cleanupDebugCallback() {
		if (!enableValidationLayers) return;

		DestroyDebugReportCallbackEXT(instance, callback, nullptr);
	}

	// Pick the first suitable physical device, using isDeviceSuitable(VkPhysicalDevice)
	void pickPhysicalDevice() {
		uint32_t deviceCount = 0;
		vkEnumeratePhysicalDevices(instance, &deviceCount, nullptr);

		if(deviceCount == 0) {
			throw std::runtime_error("Failed to find a device with Vulkan support!");
		}

		std::vector<VkPhysicalDevice> devices(deviceCount);
		vkEnumeratePhysicalDevices(instance, &deviceCount, devices.data());

		for(const auto& device : devices) {
			if(isDeviceSuitable(device)) {
				physicalDevice = device;
				break;
			}
		}

		if(physicalDevice == VK_NULL_HANDLE) {
			throw std::runtime_error("Failed to find a suitable device!");
		}
	}

	// Determine if the chosen physical device is suitable for our application.
	bool isDeviceSuitable(VkPhysicalDevice device) {
		/* example: device must be a discrete GPU and support geometry shaders
		VkPhysicalDeviceProperties deviceProperties;
		VkPhysicalDeviceFeatures deviceFeatures;
		vkGetPhysicalDeviceProperties(device, &deviceProperties);
		vkGetPhysicalDeviceFeatures(device, &deviceFeatures);

		return deviceProperties.deviceType == VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU && 
			deviceFeatures.geometryShader;
		*/

		QueueFamilyIndices indices = findQueueFamilies(device);

		bool extensionsSupported = checkDeviceExtensionSupport(device);

		bool swapChainAdequate = false;
		
		if(extensionsSupported) {
			SwapChainSupportDetails swapChainSupport = querySwapChainSupport(device);
			swapChainAdequate = !swapChainSupport.formats.empty() && !swapChainSupport.presentModes.empty();
		}

		return indices.isComplete() && extensionsSupported && swapChainAdequate;
	}

	// Check in the given physical device supports the extensions we require.
	bool checkDeviceExtensionSupport(VkPhysicalDevice device) {
		uint32_t extensionCount;
		vkEnumerateDeviceExtensionProperties(device, nullptr, &extensionCount, nullptr);

		std::vector<VkExtensionProperties> availableExtensions(extensionCount);
		vkEnumerateDeviceExtensionProperties(device, nullptr, &extensionCount, availableExtensions.data());

		std::set<std::string> requiredExtensions(deviceExtensions.begin(), deviceExtensions.end());
		
		for(const auto& extension : availableExtensions) {
			requiredExtensions.erase(extension.extensionName);
		}

		return requiredExtensions.empty();
	}

	// Find the queue families that support graphics and present. These could be
	// 	two different queue families, or the same one.
	QueueFamilyIndices findQueueFamilies(VkPhysicalDevice device) {
		QueueFamilyIndices indices;

		uint32_t queueFamilyCount;
		vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, nullptr);

		std::vector<VkQueueFamilyProperties> queueFamilies(queueFamilyCount);
		vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, queueFamilies.data());

		int i = 0;
		for(const auto& queueFamily : queueFamilies) {
			if(queueFamily.queueCount > 0 && (queueFamily.queueFlags & VK_QUEUE_GRAPHICS_BIT)) {
				indices.graphicsFamily = i;
			}
			VkBool32 presentSupport = false;
			vkGetPhysicalDeviceSurfaceSupportKHR(device, i, surface, &presentSupport);

			if(queueFamily.queueCount > 0 && presentSupport) {
				indices.presentFamily = i;
			}

			if(indices.isComplete()) {
				break;
			}

			i++;
		}

		return indices;
	}

	// Create the logical device with our required extensions, and the validation layers,
	// then create the graphics and present queues.
	void createLogicalDevice() {
		QueueFamilyIndices indices = findQueueFamilies(physicalDevice);

		std::vector<VkDeviceQueueCreateInfo> queueCreateInfos;
		std::set<int> uniqueQueueFamilies = {indices.graphicsFamily, indices.presentFamily};

		float queuePriority = 1.0f;
		for(int queueFamily : uniqueQueueFamilies) {
			VkDeviceQueueCreateInfo queueCreateInfo = {};
			queueCreateInfo.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
			queueCreateInfo.queueFamilyIndex = queueFamily;
			queueCreateInfo.queueCount = 1;
			queueCreateInfo.pQueuePriorities = &queuePriority;
			queueCreateInfos.push_back(queueCreateInfo);
		}

		VkPhysicalDeviceFeatures deviceFeatures = {};

		VkDeviceCreateInfo createInfo = {};
		createInfo.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
		createInfo.pQueueCreateInfos = queueCreateInfos.data();
		createInfo.queueCreateInfoCount = (uint32_t) queueCreateInfos.size();

		createInfo.pEnabledFeatures = &deviceFeatures;
		createInfo.enabledExtensionCount = deviceExtensions.size();
		createInfo.ppEnabledExtensionNames = deviceExtensions.data();

		if(enableValidationLayers) {
			createInfo.enabledLayerCount = validationLayers.size();
			createInfo.ppEnabledLayerNames= validationLayers.data();
		} else {
			createInfo.enabledLayerCount = 0;
		}

		if(vkCreateDevice(physicalDevice, &createInfo, nullptr, &device) != VK_SUCCESS) {
			throw std::runtime_error("failed to create logical device!");
		}
		
		vkGetDeviceQueue(device, indices.graphicsFamily, 0, &graphicsQueue);
		vkGetDeviceQueue(device, indices.presentFamily, 0, &presentQueue);
	}

	void destroyLogicalDevice() {
		vkDestroyDevice(device, nullptr);
	}

	// Have GLFW create a surface for us, this lets us not be concerned with the platform-specifics
	// involved in surfaces.
	void createSurface() {
		if(glfwCreateWindowSurface(instance, window, nullptr, &surface) != VK_SUCCESS) {
			throw std::runtime_error("failed to create window surface!");
		}
	}

	void destroySurface() {
		vkDestroySurfaceKHR(instance, surface, nullptr);
	}

	// Find out what formats and present modes the physical device supports.
	SwapChainSupportDetails querySwapChainSupport(VkPhysicalDevice device) {
		SwapChainSupportDetails details;

		vkGetPhysicalDeviceSurfaceCapabilitiesKHR(device, surface, &details.capabilities);

		uint32_t formatCount;
		vkGetPhysicalDeviceSurfaceFormatsKHR(device, surface, &formatCount, nullptr);

		if(formatCount != 0) {
			details.formats.resize(formatCount);
			vkGetPhysicalDeviceSurfaceFormatsKHR(device, surface, &formatCount, details.formats.data());
		}

		uint32_t presentModeCount;
		vkGetPhysicalDeviceSurfacePresentModesKHR(device, surface, &presentModeCount, nullptr);

		if(presentModeCount != 0) {
			details.presentModes.resize(presentModeCount);
			vkGetPhysicalDeviceSurfacePresentModesKHR(device, surface, &presentModeCount, details.presentModes.data());
		}

		return details;
	}

	VkSurfaceFormatKHR chooseSwapSurfaceFormat(const std::vector<VkSurfaceFormatKHR>& availableFormats) {
		// If the surface has no preference of format, use 24-bit BGR and the SRGB color space
		if(availableFormats.size() == 1 && availableFormats[0].format == VK_FORMAT_UNDEFINED) {
			return {VK_FORMAT_B8G8R8_UNORM, VK_COLOR_SPACE_SRGB_NONLINEAR_KHR};
		}

		// See if this same 24-bit BGR and SRGB combo is available
		for(const auto& availableFormat : availableFormats) {
			if(availableFormat.format == VK_FORMAT_B8G8R8_UNORM && availableFormat.colorSpace == VK_COLOR_SPACE_SRGB_NONLINEAR_KHR) {
				return availableFormat;
			}
		}

		// As a last resort, pick the surface's first preferred format
		return availableFormats[0];
	}

	VkPresentModeKHR chooseSwapPresentMode(const std::vector<VkPresentModeKHR> availablePresentModes) {
		// Look if the the surface supports the "mailbox" present mode (similar to triple buffering)
		for(const auto& availablePresentMode : availablePresentModes) {
			if(availablePresentMode == VK_PRESENT_MODE_MAILBOX_KHR) {
				return availablePresentMode;
			}
		}

		// If not, use the first in first out present mode (similar to basic double buffered vsync)
		return VK_PRESENT_MODE_FIFO_KHR;
	}

	VkExtent2D chooseSwapExtent(const VkSurfaceCapabilitiesKHR& capabilities) {
		// Swap extent is resolution of the swap chain images we will be drawing to

		// Attempt to use the current extent, if it is valid.
		if(capabilities.currentExtent.width != std::numeric_limits<uint32_t>::max()) {
			return capabilities.currentExtent;
		} else {
			VkExtent2D actualExtent = {WIDTH, HEIGHT};

			// Get the size of extent we can use. 
			actualExtent.width = std::max(capabilities.minImageExtent.width, std::min(capabilities.maxImageExtent.width, actualExtent.width));
			actualExtent.height = std::max(capabilities.minImageExtent.height, std::min(capabilities.maxImageExtent.height, actualExtent.height));

			return actualExtent;
		}
	}

	// Create the swap chain that will be used to submit completed frames to
	void createSwapChain() {
		SwapChainSupportDetails swapChainSupport = querySwapChainSupport(physicalDevice);

		VkSurfaceFormatKHR surfaceFormat = chooseSwapSurfaceFormat(swapChainSupport.formats);
		VkPresentModeKHR presentMode = chooseSwapPresentMode(swapChainSupport.presentModes);
		VkExtent2D extent = chooseSwapExtent(swapChainSupport.capabilities);

		// Attempt to use 1 + minimum image count for this device's swap chain support
		uint32_t imageCount = swapChainSupport.capabilities.minImageCount + 1;
		// If this is too many, clamp to the maximum image count.
		if(swapChainSupport.capabilities.maxImageCount > 0 && imageCount > swapChainSupport.capabilities.maxImageCount) {
			imageCount = swapChainSupport.capabilities.maxImageCount;
		}

		VkSwapchainCreateInfoKHR createInfo = {};
		createInfo.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR;
		createInfo.surface = surface;
		createInfo.minImageCount = imageCount;
		createInfo.imageFormat = surfaceFormat.format;
		createInfo.imageColorSpace = surfaceFormat.colorSpace;
		createInfo.imageExtent = extent;
		// Number of layers each image in swap chain consists of (stereoscopic app might use 2 layers)
		createInfo.imageArrayLayers = 1;
		// Tell Vulkan we will be rendering directly to the images in this swap chain.
		createInfo.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;

		QueueFamilyIndices indices = findQueueFamilies(physicalDevice);
		// Array of queue family indices we will use. Only used if they are different queue families.
		uint32_t queueFamilyIndices[] = {(uint32_t) indices.graphicsFamily, (uint32_t) indices.presentFamily};

		// If graphics queue and present queue are on different queue families, we must tell Vulkan both queue
		// 	families will be concurrently sharing this swap chain. 
		if(indices.graphicsFamily != indices.presentFamily) {
			createInfo.imageSharingMode = VK_SHARING_MODE_CONCURRENT;
			createInfo.queueFamilyIndexCount = 2;
			createInfo.pQueueFamilyIndices = queueFamilyIndices;
		} else {
			// Graphics queue and present queue are on same queue family,
			// 	so the swap chain does not need to be shared.
			createInfo.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
			createInfo.queueFamilyIndexCount = 0;
			createInfo.pQueueFamilyIndices = nullptr;
		}

		// We do not want the swap chain images to be transformed, so use the current transform.
		createInfo.preTransform = swapChainSupport.capabilities.currentTransform;
		// Ignore alpha for blending with other windows.
		createInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;

		createInfo.presentMode = presentMode;
		createInfo.clipped = VK_TRUE; // Clip pixels that are obscured for improved perf.

		// We have no old swap chain for now. Could be used if the window is resized or something
		// 	and we want to create a new swap chain to match the new window size.
		createInfo.oldSwapchain = VK_NULL_HANDLE;

		VkSwapchainKHR oldSwapChain = swapChain;
		createInfo.oldSwapchain = oldSwapChain;

		VkSwapchainKHR newSwapChain;
		if(vkCreateSwapchainKHR(device, &createInfo, nullptr, &newSwapChain) != VK_SUCCESS) {
			throw std::runtime_error("failed to create swap chain!");
		}

		swapChain = newSwapChain;

		// Get the swapchain images.
		vkGetSwapchainImagesKHR(device, swapChain, &imageCount, nullptr);
		swapChainImages.resize(imageCount);
		vkGetSwapchainImagesKHR(device, swapChain, &imageCount, swapChainImages.data());

		// Store image format and extent of the swap chain images.
		swapChainImageFormat = surfaceFormat.format;
		swapChainExtent = extent;
	}

	void destroySwapChain() {
		vkDestroySwapchainKHR(device, swapChain, nullptr);
	}

	void createImageViews() {
		swapChainImageViews.resize(swapChainImages.size(), VkImageView{});

		// For each image in the swap chain create a VkImageView
		for(uint32_t i = 0; i < swapChainImages.size(); i++) {
			VkImageViewCreateInfo createInfo = {};
			createInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
			createInfo.image = swapChainImages[i];

			createInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
			createInfo.format = swapChainImageFormat;

			// all our components should only be "swizzled" with the identity matrix.
			createInfo.components.r = VK_COMPONENT_SWIZZLE_IDENTITY;
			createInfo.components.g = VK_COMPONENT_SWIZZLE_IDENTITY;
			createInfo.components.b = VK_COMPONENT_SWIZZLE_IDENTITY;
			createInfo.components.a = VK_COMPONENT_SWIZZLE_IDENTITY;

			createInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			createInfo.subresourceRange.baseMipLevel = 0;
			createInfo.subresourceRange.levelCount = 1;
			createInfo.subresourceRange.baseArrayLayer = 0;
			createInfo.subresourceRange.layerCount = 1;

			if(vkCreateImageView(device, &createInfo, nullptr, &swapChainImageViews[i]) != VK_SUCCESS) {
				throw std::runtime_error("failed to create image views!");
			}

		}
	}

	void destroyImageViews() {
		for (uint32_t i = 0; i < swapChainImages.size(); i++) {
			vkDestroyImageView(device, swapChainImageViews[i], nullptr);
		}
	}

	void createGraphicsPipeline() {
		std::cerr << "Loading vertex shader." << std::endl;
		auto vertShaderCode = readFile("shaders/vert.spv");
		std::cerr << "Loading fragment shader." << std::endl;
		auto fragShaderCode = readFile("shaders/frag.spv");

		createShaderModule(vertShaderCode, &vertShaderModule);
		createShaderModule(fragShaderCode, &fragShaderModule);

		VkPipelineShaderStageCreateInfo vertShaderStageInfo = {};
		vertShaderStageInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
		vertShaderStageInfo.stage = VK_SHADER_STAGE_VERTEX_BIT;
		vertShaderStageInfo.module = vertShaderModule;
		vertShaderStageInfo.pName = "main";

		VkPipelineShaderStageCreateInfo fragShaderStageInfo = {};
		fragShaderStageInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
		fragShaderStageInfo.stage = VK_SHADER_STAGE_FRAGMENT_BIT;
		fragShaderStageInfo.module = fragShaderModule;
		fragShaderStageInfo.pName = "main";

		VkPipelineShaderStageCreateInfo shaderStages[] = {vertShaderStageInfo, fragShaderStageInfo};

		VkPipelineVertexInputStateCreateInfo vertexInputInfo = {};
		vertexInputInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
		vertexInputInfo.vertexBindingDescriptionCount = 0;
		vertexInputInfo.pVertexBindingDescriptions = nullptr;
		vertexInputInfo.vertexAttributeDescriptionCount = 0;
		vertexInputInfo.pVertexAttributeDescriptions = nullptr;

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

		VkViewport viewport = {};
		viewport.x = 0.0f;
		viewport.y = 0.0f;
		viewport.width = (float) swapChainExtent.width;
		viewport.height = (float) swapChainExtent.height;
		viewport.minDepth = 0.0f;
		viewport.maxDepth = 1.0f;

		VkRect2D scissor = {};
		scissor.offset = {0, 0};
		scissor.extent = swapChainExtent;

		VkPipelineViewportStateCreateInfo viewportState = {};
		viewportState.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
		viewportState.viewportCount = 1;
		viewportState.pViewports = &viewport;
		viewportState.scissorCount = 1;
		viewportState.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 = 1.0f;

		rasterizer.cullMode = VK_CULL_MODE_BACK_BIT;
		rasterizer.frontFace = VK_FRONT_FACE_CLOCKWISE;

		rasterizer.depthBiasEnable = VK_FALSE;
		rasterizer.depthBiasConstantFactor = 0.0f;
		rasterizer.depthBiasClamp = 0.0f;
		rasterizer.depthBiasSlopeFactor = 0.0f;

		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 colorBlendAttachment = {};
		colorBlendAttachment.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT |
			VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
		colorBlendAttachment.blendEnable = VK_TRUE;
		colorBlendAttachment.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA;
		colorBlendAttachment.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
		colorBlendAttachment.colorBlendOp = VK_BLEND_OP_ADD;
		colorBlendAttachment.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE;
		colorBlendAttachment.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
		colorBlendAttachment.alphaBlendOp = VK_BLEND_OP_ADD;

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

		VkPipelineLayoutCreateInfo pipelineLayoutInfo = {};
		pipelineLayoutInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
		pipelineLayoutInfo.setLayoutCount = 0;
		pipelineLayoutInfo.pSetLayouts = nullptr;

		if(vkCreatePipelineLayout(device, &pipelineLayoutInfo, nullptr, &pipelineLayout) != VK_SUCCESS) {
			throw std::runtime_error("failed to create pipeline layout!");
		}

		VkGraphicsPipelineCreateInfo pipelineInfo = {};
		pipelineInfo.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
		pipelineInfo.stageCount = 2;
		pipelineInfo.pStages = shaderStages;
		
		pipelineInfo.pVertexInputState = &vertexInputInfo;
		pipelineInfo.pInputAssemblyState = &inputAssembly;
		pipelineInfo.pViewportState = &viewportState;
		pipelineInfo.pRasterizationState = &rasterizer;
		pipelineInfo.pMultisampleState = &multisampling;
		pipelineInfo.pDepthStencilState = nullptr;
		pipelineInfo.pColorBlendState = &colorBlending;
		pipelineInfo.pDynamicState = nullptr;

		pipelineInfo.layout = pipelineLayout;

		pipelineInfo.renderPass = renderPass;
		pipelineInfo.subpass = 0;

		pipelineInfo.basePipelineHandle = VK_NULL_HANDLE;
		pipelineInfo.basePipelineIndex = -1;

		if(vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &pipelineInfo, nullptr, &graphicsPipeline) != VK_SUCCESS) {
			throw std::runtime_error("failed to create graphics pipeline!");
		}
	}

	void destroyGraphicsPipeline() {
		vkDestroyShaderModule(device, fragShaderModule, nullptr);
		vkDestroyShaderModule(device, vertShaderModule, nullptr);
		vkDestroyPipeline(device, graphicsPipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
	}

	static std::vector<char> readFile(const std::string& filename) {
		// Start reading at end of the file, as binary.
		std::ifstream file(filename, std::ios::ate | std::ios::binary);	

		if(!file.is_open()) {
			std::cerr << "Error code: " << strerror(errno) << std::endl;
			throw std::runtime_error("failed to open file!");
		}

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

		return buffer;
	}

	void createShaderModule(const std::vector<char>& code, VkShaderModule* shaderModule) {
		VkShaderModuleCreateInfo createInfo = {};
		createInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
		createInfo.codeSize = code.size();
		createInfo.pCode = (uint32_t*) code.data();

		if(vkCreateShaderModule(device, &createInfo, nullptr, shaderModule) != VK_SUCCESS) {
			throw std::runtime_error("failed to create shader module!");
		}
	}

	void createRenderPass() {
		VkAttachmentDescription colorAttachment = {};
		colorAttachment.format = swapChainImageFormat;
		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.attachment = 0;
		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;

		VkSubpassDependency dependency = {};
		dependency.srcSubpass = VK_SUBPASS_EXTERNAL;
		dependency.dstSubpass = 0;
		dependency.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependency.srcAccessMask = 0;
		dependency.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependency.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;

		renderPassInfo.dependencyCount = 1;
		renderPassInfo.pDependencies = &dependency;

		if(vkCreateRenderPass(device, &renderPassInfo, nullptr, &renderPass) != VK_SUCCESS) {
			throw std::runtime_error("failed to create render pass!");
		}
	}
	
	void destroyRenderPass() {
		vkDestroyRenderPass(device, renderPass, nullptr);
	}

	void createFramebuffers() {
		swapChainFramebuffers.resize(swapChainImageViews.size(), VkFramebuffer{});

		for(size_t i = 0; i < swapChainImageViews.size(); i++) {
			VkImageView attachments[] = { swapChainImageViews[i] };

			VkFramebufferCreateInfo framebufferInfo = {};
			framebufferInfo.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
			framebufferInfo.renderPass = renderPass;
			framebufferInfo.attachmentCount = 1;
			framebufferInfo.pAttachments = attachments;
			framebufferInfo.width = swapChainExtent.width;
			framebufferInfo.height = swapChainExtent.height;
			framebufferInfo.layers = 1;

			if(vkCreateFramebuffer(device, &framebufferInfo, nullptr, &swapChainFramebuffers[i]) != VK_SUCCESS) {
				throw std::runtime_error("failed to create framebuffer!");
			}

		}
	}

	void destroyFramebuffers() {
		for (size_t i = 0; i < swapChainImageViews.size(); i++) {
			vkDestroyFramebuffer(device, swapChainFramebuffers[i], nullptr);
		}
	}

	void createCommandPool() {
		QueueFamilyIndices queueFamilyIndices = findQueueFamilies(physicalDevice);

		VkCommandPoolCreateInfo poolInfo = {};
		poolInfo.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
		poolInfo.queueFamilyIndex = queueFamilyIndices.graphicsFamily;
		poolInfo.flags = 0;

		if(vkCreateCommandPool(device, &poolInfo, nullptr, &commandPool) != VK_SUCCESS) {
			throw std::runtime_error("failed to create command pool!");
		}
	}

	void destroyCommandPool() {
		vkDestroyCommandPool(device, commandPool, nullptr);
	}

	void createCommandBuffers() {
		if(commandBuffers.size() > 0) {
			vkFreeCommandBuffers(device, commandPool, commandBuffers.size(), commandBuffers.data());
		}

		commandBuffers.resize(swapChainFramebuffers.size());

		VkCommandBufferAllocateInfo allocInfo = {};
		allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
		allocInfo.commandPool = commandPool;
		allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
		allocInfo.commandBufferCount = (uint32_t) commandBuffers.size();

		if(vkAllocateCommandBuffers(device, &allocInfo, commandBuffers.data()) != VK_SUCCESS) {
			throw std::runtime_error("failed to allocate command buffers!");
		}

		for(size_t i = 0; i < commandBuffers.size(); i++) {
			VkCommandBufferBeginInfo beginInfo = {};
			beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
			beginInfo.flags = VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT;
			beginInfo.pInheritanceInfo = nullptr;

			vkBeginCommandBuffer(commandBuffers[i], &beginInfo);

			VkRenderPassBeginInfo renderPassInfo = {};
			renderPassInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
			renderPassInfo.renderPass = renderPass;
			renderPassInfo.framebuffer = swapChainFramebuffers[i];
			renderPassInfo.renderArea.offset = {0, 0};
			renderPassInfo.renderArea.extent = swapChainExtent;

			VkClearValue clearColor = {0.0f, 0.0f, 0.0f, 1.0f};
			renderPassInfo.clearValueCount = 1;
			renderPassInfo.pClearValues = &clearColor;

			vkCmdBeginRenderPass(commandBuffers[i], &renderPassInfo, VK_SUBPASS_CONTENTS_INLINE);

			vkCmdBindPipeline(commandBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, graphicsPipeline);

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

			vkCmdEndRenderPass(commandBuffers[i]);

			if(vkEndCommandBuffer(commandBuffers[i]) != VK_SUCCESS) {
				throw std::runtime_error("failed to record command buffer!");
			}
		}
	}
	
	void destroyCommandBuffers() {
		if (commandBuffers.size() > 0) {
			vkFreeCommandBuffers(device, commandPool, commandBuffers.size(), commandBuffers.data());
		}
	}

	void createSemaphores() {
		VkSemaphoreCreateInfo semaphoreInfo = {};
		semaphoreInfo.sType = VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO;

		if(vkCreateSemaphore(device, &semaphoreInfo, nullptr, &imageAvailableSemaphore) != VK_SUCCESS ||
				vkCreateSemaphore(device, &semaphoreInfo, nullptr, &renderFinishedSemaphore) != VK_SUCCESS) {
			throw std::runtime_error("failed to create semaphores!");
		}
	}

	void destroySemaphores() {
		vkDestroySemaphore(device, imageAvailableSemaphore, nullptr);
		vkDestroySemaphore(device, renderFinishedSemaphore, nullptr);
	}

	void mainLoop() {
		// While we shouldn't close, have glfw poll for events
		while(!glfwWindowShouldClose(window)) {
			glfwPollEvents();
			drawFrame();
		}

		vkDeviceWaitIdle(device);
		cleanup();
	}

	void cleanup() {
		destroySemaphores();
		destroyCommandBuffers();
		destroyCommandPool();
		destroyFramebuffers();
		destroyGraphicsPipeline();
		destroyRenderPass();
		destroyImageViews();
		destroySwapChain();
		destroyLogicalDevice();
		destroySurface();
		cleanupDebugCallback();
		destroyInstance();
	}

	void drawFrame() {
		uint32_t imageIndex;
		vkAcquireNextImageKHR(device, swapChain, std::numeric_limits<uint64_t>::max(), imageAvailableSemaphore, VK_NULL_HANDLE, &imageIndex);

		VkSubmitInfo submitInfo = {};
		submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;

		VkSemaphore waitSemaphores[] = {imageAvailableSemaphore};
		VkPipelineStageFlags waitStages[] = {VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT};
		submitInfo.waitSemaphoreCount = 1;
		submitInfo.pWaitSemaphores = waitSemaphores;
		submitInfo.pWaitDstStageMask = waitStages;
		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &commandBuffers[imageIndex];

		VkSemaphore signalSemaphores[] = {renderFinishedSemaphore};
		submitInfo.signalSemaphoreCount = 1;
		submitInfo.pSignalSemaphores = signalSemaphores;

		if(vkQueueSubmit(graphicsQueue, 1, &submitInfo, VK_NULL_HANDLE) != VK_SUCCESS) {
			throw std::runtime_error("failed to submit draw command buffer!");
		}

		VkPresentInfoKHR presentInfo = {};
		presentInfo.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;

		presentInfo.waitSemaphoreCount = 1;
		presentInfo.pWaitSemaphores = signalSemaphores;

		VkSwapchainKHR swapChains[] = {swapChain};
		presentInfo.swapchainCount = 1;
		presentInfo.pSwapchains = swapChains;
		presentInfo.pImageIndices = &imageIndex;
		presentInfo.pResults = nullptr;

		vkQueuePresentKHR(presentQueue, &presentInfo);
	}
};

int main() {
	HelloTriangleApplication app;

	try {
		app.run();
	} catch (const std::runtime_error& e) {
		std::cerr << e.what() << std::endl;
		return EXIT_FAILURE;
	}

	return EXIT_SUCCESS;
}