// Coding along: https://docs.vulkan.org/tutorial/

// comment and simplify and abstract away
// make pure/static as much as possible
// build with cmake for: linux/freebsd/mac/win/android/ios?
// raymarch game


#define GLFW_INCLUDE_VULKAN
#include <GLFW/glfw3.h>

#include <iostream>
#include <stdexcept>
#include <cstdlib>
#include <vector>
#include <cstring>
#include <optional>
#include <set>
#include <cstdint>
#include <limits>
#include <algorithm>
#include <fstream>
#include <functional>

class HelloTriangleApplication {

public:

    void run() {
        std::cout << "enableValidationLayers = " << enableValidationLayers << std::endl;
        initWindow();
        initVulkan();
        mainLoop();
        cleanup();
    }

private:

    static const int MAX_FRAMES_IN_FLIGHT = 2;
    static const uint32_t WIDTH = 800;
    static const uint32_t HEIGHT = 600;

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

    static const VkDebugUtilsMessageSeverityFlagBitsEXT minDebugMessageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT;

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

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

    // READ FILE - HELPER
    static std::vector<char> readFile(const std::string& filename) {
        std::ifstream file(filename, std::ios::ate | std::ios::binary);
        if (!file.is_open()) 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;
    }

    // JUST LIST AVILABLE EXTENSIONS
    static void listExt() {
        uint32_t extensionCount = 0;
        vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, nullptr);
        std::vector<VkExtensionProperties> extensionslist(extensionCount);
        vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, extensionslist.data());
        for (const auto& extension : extensionslist) {
            std::cout << "EXT: " << extension.extensionName << std::endl;
        }
    }

    // CHECK SUCCESS - HELPER
    static void checkSucc(const std::string &str, VkResult res){
        if(res!=VK_SUCCESS) throw std::runtime_error("failed to: " + str);
    }

    bool quit=false;
    GLFWwindow* window;
    VkInstance instance;
    VkDebugUtilsMessengerEXT debugMessenger;

    VkSurfaceKHR surface;

    VkPhysicalDevice physicalDevice = VK_NULL_HANDLE;
    VkDevice device;

    VkQueue graphicsQueue;
    VkQueue presentQueue;

    VkSwapchainKHR swapChain;
    std::vector<VkImage> swapChainImages;
    VkFormat swapChainImageFormat;
    VkExtent2D swapChainExtent;

    std::vector<VkImageView> swapChainImageViews;

    VkRenderPass renderPass;

    VkPipelineLayout pipelineLayout;
    VkPipeline graphicsPipeline;

    std::vector<VkFramebuffer> swapChainFramebuffers;

    VkCommandPool commandPool;
    VkCommandBuffer commandBuffer;

    VkSemaphore imageAvailableSemaphore;
    VkSemaphore renderFinishedSemaphore;
    VkFence inFlightFence;

    void initWindow() {
        glfwInit();
        glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API); // no OpenGL
        glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);   // no resizing
        window = glfwCreateWindow(WIDTH, HEIGHT, "Vulkan", nullptr, nullptr);
        glfwSetWindowUserPointer(window, this);
        glfwSetKeyCallback(window, key_callback);
        glfwSetWindowPos(window, 1000, 1000);
    }

    static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
    {
        if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
            std::cout << "ESC pressed -> quitting" << std::endl;
            static_cast<HelloTriangleApplication*>(glfwGetWindowUserPointer(window))->quit = true;
        }
    }

    void populateDebugMessengerCreateInfo(VkDebugUtilsMessengerCreateInfoEXT& createInfo) {
        createInfo = {};
        createInfo.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT;
        createInfo.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT;
        createInfo.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;
        createInfo.pfnUserCallback = debugCallback;
        createInfo.pUserData = nullptr; // Optional
    }

    static VKAPI_ATTR VkBool32 VKAPI_CALL debugCallback(
        VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity,
        VkDebugUtilsMessageTypeFlagsEXT messageType,
        const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
        void* pUserData) {

        if (messageSeverity >= minDebugMessageSeverity) {
                std::cerr << "validation layer: " << pCallbackData->pMessage << std::endl;
        }
        return VK_FALSE;
    }

    void initVulkan() {
        createInstance();           // 01 Setup -> Instance
        setupDebugMessenger();      // 02 Setup -> Validation Layers
        createSurface();            // 05 Presentation -> Window surface
        pickPhysicalDevice();       // 03 Setup -> Physical Device
        createLogicalDevice();      // 04 Setup -> Logical Device
        createSwapChain();          // 06 Presentation -> Swap Chain
        createImageViews();         // 07 Presentation -> Image Views
        createRenderPass();         // 11 Graphics Pipeline -> RenderPasses
        createGraphicsPipeline();   // 08 Graphics Pipeline -> Introduction
        createFramebuffers();       // 12 Drawing -> Framebuffers
        createCommandPool();        // 13 Drawing -> Commmand Buffers
        createCommandBuffer();      // --
        createSyncObjects ();       // 14 Drawing -> Rendering
    }

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

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

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

    void recordCommandBuffer(VkCommandBuffer commandBuffer, uint32_t imageIndex) {

        VkCommandBufferBeginInfo beginInfo{};
        beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
        beginInfo.flags = 0; // Optional
        beginInfo.pInheritanceInfo = nullptr; // Optional

        if (vkBeginCommandBuffer(commandBuffer, &beginInfo) != VK_SUCCESS) {
            throw std::runtime_error("failed to begin recording command buffer!");
        }

        VkRenderPassBeginInfo renderPassInfo{};
        renderPassInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
        renderPassInfo.renderPass = renderPass;
        renderPassInfo.framebuffer = swapChainFramebuffers[imageIndex];
        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(commandBuffer, &renderPassInfo, VK_SUBPASS_CONTENTS_INLINE);
        vkCmdBindPipeline(commandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, graphicsPipeline);

        VkViewport viewport{};
        viewport.x = 0.0f;
        viewport.y = 0.0f;
        viewport.width = static_cast<float>(swapChainExtent.width);
        viewport.height = static_cast<float>(swapChainExtent.height);
        viewport.minDepth = 0.0f;
        viewport.maxDepth = 1.0f;
        vkCmdSetViewport(commandBuffer, 0, 1, &viewport);

        VkRect2D scissor{};
        scissor.offset = {0, 0};
        scissor.extent = swapChainExtent;
        vkCmdSetScissor(commandBuffer, 0, 1, &scissor);

        // verex count, instance count, first vertex, first instance
        vkCmdDraw(commandBuffer, 6, 1, 0, 0);
        vkCmdEndRenderPass(commandBuffer);

        if (vkEndCommandBuffer(commandBuffer) != VK_SUCCESS) {
            throw std::runtime_error("failed to record command buffer!");
        }
    }

    void createCommandBuffer() {
        VkCommandBufferAllocateInfo allocInfo{};
        allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
        allocInfo.commandPool = commandPool;
        allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
        allocInfo.commandBufferCount = 1;

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

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

        VkCommandPoolCreateInfo poolInfo{};
        poolInfo.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
        poolInfo.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;
        poolInfo.queueFamilyIndex = queueFamilyIndices.graphicsFamily.value();

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

    void createFramebuffers() {
        swapChainFramebuffers.resize(swapChainImageViews.size());
        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 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;

        VkSubpassDependency dependency{};
        dependency.srcSubpass = VK_SUBPASS_EXTERNAL; // implicit subpass before OR after render pass (depends if defined on src or dst)
        dependency.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
        dependency.srcAccessMask = 0;
        dependency.dstSubpass = 0; // our one and only pass
        dependency.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
        dependency.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;

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

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

    void createGraphicsPipeline() {
         // 09 Graphics Pipeline -> Shader Modules
        auto vertShaderCode = readFile("shaders/vert.spv");
        auto fragShaderCode = readFile("shaders/frag.spv");
        std::cout << vertShaderCode.size() << std::endl;
        std::cout << fragShaderCode.size() << std::endl;
        VkShaderModule vertShaderModule = createShaderModule(vertShaderCode);
        VkShaderModule fragShaderModule = createShaderModule(fragShaderCode);

        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};

        // 10 Graphics Pipeline -> Fixed Functions
        std::vector<VkDynamicState> dynamicStates = {
            VK_DYNAMIC_STATE_VIEWPORT,
            VK_DYNAMIC_STATE_SCISSOR
        };

        VkPipelineDynamicStateCreateInfo dynamicState{};
        dynamicState.sType = VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO;
        dynamicState.dynamicStateCount = static_cast<uint32_t>(dynamicStates.size());
        dynamicState.pDynamicStates = dynamicStates.data();

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

        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;
*/

//      DYN STATE
        VkPipelineViewportStateCreateInfo viewportState{};
        viewportState.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
        viewportState.viewportCount = 1;
        viewportState.scissorCount = 1;

//        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; // Optional
        rasterizer.depthBiasClamp = 0.0f; // Optional
        rasterizer.depthBiasSlopeFactor = 0.0f; // Optional

        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; // Optional
        multisampling.pSampleMask = nullptr; // Optional
        multisampling.alphaToCoverageEnable = VK_FALSE; // Optional
        multisampling.alphaToOneEnable = VK_FALSE; // Optional

        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_FALSE;
        colorBlendAttachment.srcColorBlendFactor = VK_BLEND_FACTOR_ONE; // Optional
        colorBlendAttachment.dstColorBlendFactor = VK_BLEND_FACTOR_ZERO; // Optional
        colorBlendAttachment.colorBlendOp = VK_BLEND_OP_ADD; // Optional
        colorBlendAttachment.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE; // Optional
        colorBlendAttachment.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO; // Optional
        colorBlendAttachment.alphaBlendOp = VK_BLEND_OP_ADD; // Optional

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

        VkPipelineLayoutCreateInfo pipelineLayoutInfo{};
        pipelineLayoutInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
        pipelineLayoutInfo.setLayoutCount = 0; // Optional
        pipelineLayoutInfo.pSetLayouts = nullptr; // Optional
        pipelineLayoutInfo.pushConstantRangeCount = 0; // Optional
        pipelineLayoutInfo.pPushConstantRanges = nullptr; // Optional

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

        // 12 Graphics Pipeline -> Conclusion
        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; // Optional
        pipelineInfo.pColorBlendState = &colorBlending;
        pipelineInfo.pDynamicState = &dynamicState;
        pipelineInfo.layout = pipelineLayout;
        pipelineInfo.renderPass = renderPass;
        pipelineInfo.subpass = 0;
        pipelineInfo.basePipelineHandle = VK_NULL_HANDLE; // Optional
        pipelineInfo.basePipelineIndex = -1; // Optional

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

        vkDestroyShaderModule(device, fragShaderModule, nullptr);
        vkDestroyShaderModule(device, vertShaderModule, nullptr);
    }

    VkShaderModule createShaderModule(const std::vector<char>& code) {
        VkShaderModuleCreateInfo createInfo{};
        createInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
        createInfo.codeSize = code.size();
        createInfo.pCode = reinterpret_cast<const uint32_t*>(code.data());
        VkShaderModule shaderModule;
        if (vkCreateShaderModule(device, &createInfo, nullptr, &shaderModule) != VK_SUCCESS) {
            throw std::runtime_error("failed to create shader module!");
        }
        return shaderModule;
    }

    void createImageViews() {
        swapChainImageViews.resize(swapChainImages.size());
        for (size_t i = 0; i < swapChainImages.size(); i++) {
            std::cout  << "Swap Chain Image: " << i << std::endl;
            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;
            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 createSwapChain() {
        SwapChainSupportDetails swapChainSupport = querySwapChainSupport(physicalDevice);

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

        uint32_t imageCount = swapChainSupport.capabilities.minImageCount + 1;
        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;
        createInfo.imageArrayLayers = 1;
        createInfo.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;

        QueueFamilyIndices indices = findQueueFamilies(physicalDevice);
        uint32_t queueFamilyIndices[] = {indices.graphicsFamily.value(), indices.presentFamily.value()};

        if (indices.graphicsFamily != indices.presentFamily) {
            // handle swap chain across different queues
            createInfo.imageSharingMode = VK_SHARING_MODE_CONCURRENT;
            createInfo.queueFamilyIndexCount = 2;
            createInfo.pQueueFamilyIndices = queueFamilyIndices;
        } else {
            createInfo.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
            createInfo.queueFamilyIndexCount = 0; // Optional
            createInfo.pQueueFamilyIndices = nullptr; // Optional
        }

        createInfo.preTransform = swapChainSupport.capabilities.currentTransform;
        createInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
        createInfo.presentMode = presentMode;
        createInfo.clipped = VK_TRUE; // don't care about pixels obscured by other windows (we do not need to read them back)
        createInfo.oldSwapchain = VK_NULL_HANDLE;

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

        vkGetSwapchainImagesKHR(device, swapChain, &imageCount, nullptr);
        swapChainImages.resize(imageCount);
        vkGetSwapchainImagesKHR(device, swapChain, &imageCount, swapChainImages.data());
        swapChainImageFormat = surfaceFormat.format;
        swapChainExtent = extent;
    }

    void createSurface() {
        if (glfwCreateWindowSurface(instance, window, nullptr, &surface) != VK_SUCCESS) {
            throw std::runtime_error("failed to create window surface!");
        }
    }

    void createLogicalDevice() {

        QueueFamilyIndices indices = findQueueFamilies(physicalDevice);
        std::set<uint32_t> uniqueQueueFamilies = {indices.graphicsFamily.value(), indices.presentFamily.value()};

        VkPhysicalDeviceFeatures deviceFeatures{};

        VkDeviceCreateInfo createInfo{};
        createInfo.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
        createInfo.pEnabledFeatures = &deviceFeatures;
        createInfo.enabledExtensionCount = static_cast<uint32_t>(deviceExtensions.size());
        createInfo.ppEnabledExtensionNames = deviceExtensions.data();

        // for backward compat.
        if (enableValidationLayers) {
            createInfo.enabledLayerCount = static_cast<uint32_t>(validationLayers.size());
            createInfo.ppEnabledLayerNames = validationLayers.data();
        } else {
            createInfo.enabledLayerCount = 0;
        }

        std::vector<VkDeviceQueueCreateInfo> queueCreateInfos;
        for (uint32_t queueFamily : uniqueQueueFamilies) {
            float queuePriority = 1.0f;
            VkDeviceQueueCreateInfo queueCreateInfo{};
            queueCreateInfo.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
            queueCreateInfo.queueFamilyIndex = queueFamily;
            queueCreateInfo.queueCount = 1;
            queueCreateInfo.pQueuePriorities = &queuePriority;
            queueCreateInfos.push_back(queueCreateInfo);
        }

        createInfo.queueCreateInfoCount = static_cast<uint32_t>(queueCreateInfos.size());
        createInfo.pQueueCreateInfos = queueCreateInfos.data();

        if (vkCreateDevice(physicalDevice, &createInfo, nullptr, &device) != VK_SUCCESS) {
           throw std::runtime_error("failed to create logical device!");
        }

        vkGetDeviceQueue(device, indices.graphicsFamily.value(), 0, &graphicsQueue);
        vkGetDeviceQueue(device, indices.presentFamily.value(), 0, &presentQueue);
    }

    void pickPhysicalDevice() {

        // we could rate and sort and pick best, but let's keep simple for now.

        uint32_t deviceCount = 0;
        vkEnumeratePhysicalDevices(instance, &deviceCount, nullptr);
        if (deviceCount == 0) {
            throw std::runtime_error("failed to find GPUs with Vulkan support!");
        }
        std::vector<VkPhysicalDevice> devices(deviceCount);
        vkEnumeratePhysicalDevices(instance, &deviceCount, devices.data());

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

        if (physicalDevice == VK_NULL_HANDLE) throw std::runtime_error("failed to find a suitable GPU!");
    }

    bool isDeviceSuitable(VkPhysicalDevice device) {

        VkPhysicalDeviceProperties deviceProperties;
        VkPhysicalDeviceFeatures deviceFeatures;

        vkGetPhysicalDeviceProperties(device, &deviceProperties);
        vkGetPhysicalDeviceFeatures(device, &deviceFeatures);

        bool discrete = deviceProperties.deviceType == VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU;
        std::cout << "PHYSICAL DEVICE: " << deviceProperties.deviceName << " discrete:" << discrete << std::endl;
        printQueueFamilies(device);
        // 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;
    }

    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) {
            // std::cout << "Available Device Extension: " << extension.extensionName << std::endl;
            requiredExtensions.erase(extension.extensionName);
        }

        return requiredExtensions.empty();
    }

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

        VkDebugUtilsMessengerCreateInfoEXT createInfo;
        populateDebugMessengerCreateInfo(createInfo);

        if (CreateDebugUtilsMessengerEXT(instance, &createInfo, nullptr, &debugMessenger) != VK_SUCCESS) {
            throw std::runtime_error("failed to set up debug messenger!");
        }
    }



    void drawFrame() {

        vkWaitForFences(device, 1, &inFlightFence, VK_TRUE, UINT64_MAX);
        vkResetFences(device, 1, &inFlightFence);

        uint32_t imageIndex;
        vkAcquireNextImageKHR(device, swapChain, UINT64_MAX, imageAvailableSemaphore, VK_NULL_HANDLE, &imageIndex);
        vkResetCommandBuffer(commandBuffer, 0);
        recordCommandBuffer(commandBuffer, imageIndex);

        VkSubmitInfo submitInfo{};
        submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
        VkSemaphore waitSemaphores[] = {imageAvailableSemaphore};
        VkSemaphore signalSemaphores[] = {renderFinishedSemaphore};
        VkPipelineStageFlags waitStages[] = {VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT};
        submitInfo.waitSemaphoreCount = 1;
        submitInfo.pWaitSemaphores = waitSemaphores;
        submitInfo.pWaitDstStageMask = waitStages;
        submitInfo.signalSemaphoreCount = 1;
        submitInfo.pSignalSemaphores = signalSemaphores;
        submitInfo.commandBufferCount = 1;
        submitInfo.pCommandBuffers = &commandBuffer;

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

        VkPresentInfoKHR presentInfo{};
        VkSwapchainKHR swapChains[] = {swapChain};
        presentInfo.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;
        presentInfo.waitSemaphoreCount = 1;
        presentInfo.pWaitSemaphores = signalSemaphores;
        presentInfo.swapchainCount = 1;
        presentInfo.pSwapchains = swapChains;
        presentInfo.pImageIndices = &imageIndex;
        presentInfo.pResults = nullptr; // Optional

        vkQueuePresentKHR(presentQueue, &presentInfo);
    }

    void createInstance() {

        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;

        auto extensions = getRequiredExtensions();

        if (enableValidationLayers && !checkValidationLayerSupport()) {
            throw std::runtime_error("validation layers requested, but not available!");
        }

        VkDebugUtilsMessengerCreateInfoEXT debugCreateInfo{};
        populateDebugMessengerCreateInfo(debugCreateInfo);

        VkInstanceCreateInfo createInfo{};
        createInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
        createInfo.pApplicationInfo = &appInfo;
        createInfo.enabledExtensionCount = static_cast<uint32_t>(extensions.size());
        createInfo.ppEnabledExtensionNames = extensions.data();

        if (enableValidationLayers) {
            createInfo.enabledLayerCount = static_cast<uint32_t>(validationLayers.size());
            createInfo.ppEnabledLayerNames = validationLayers.data();
            createInfo.pNext = (VkDebugUtilsMessengerCreateInfoEXT*) &debugCreateInfo; // for debugging of: vkCreateInstance & vkDestroyInstance
        } else {
            createInfo.enabledLayerCount = 0;
            createInfo.pNext = nullptr;
        }

        // Create Instance
        checkSucc("CREATE INSTANCE", vkCreateInstance(&createInfo, nullptr, &instance));
    }

    // instance validation layers apply to all Vulkan calls (enble on device level for compat)
    const 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) {
                std::cout << "LAYER AVAILABLE: " << layerProperties.layerName << std::endl;
                if (strcmp(layerName, layerProperties.layerName) == 0) layerFound=true;
            }
            if (!layerFound) return false;
        }
        return true;
    }

    static std::vector<const char*> getRequiredExtensions() {
        uint32_t glfwExtensionCount = 0;
        const char** glfwExtensions;
        glfwExtensions = glfwGetRequiredInstanceExtensions(&glfwExtensionCount); //e.g VK_KHR_surface

        std::vector<const char*> extensions(glfwExtensions, glfwExtensions + glfwExtensionCount); // pointer range

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

        for (const auto s:extensions){
            std:: cout << "REQUIRED EXTENSION: " << s << std::endl;
        }

        return extensions;
    }

    VkResult CreateDebugUtilsMessengerEXT(VkInstance instance, const VkDebugUtilsMessengerCreateInfoEXT* pCreateInfo, const VkAllocationCallbacks* pAllocator, VkDebugUtilsMessengerEXT* pDebugMessenger) {
        auto func = (PFN_vkCreateDebugUtilsMessengerEXT) vkGetInstanceProcAddr(instance, "vkCreateDebugUtilsMessengerEXT");
        if (func != nullptr) {
            return func(instance, pCreateInfo, pAllocator, pDebugMessenger);
        } else {
            return VK_ERROR_EXTENSION_NOT_PRESENT;
        }
    }

    void DestroyDebugUtilsMessengerEXT(VkInstance instance, VkDebugUtilsMessengerEXT debugMessenger, const VkAllocationCallbacks* pAllocator) {
        auto func = (PFN_vkDestroyDebugUtilsMessengerEXT) vkGetInstanceProcAddr(instance, "vkDestroyDebugUtilsMessengerEXT");
        if (func != nullptr) {
            func(instance, debugMessenger, pAllocator);
        }
    }

    struct SwapChainSupportDetails {
        VkSurfaceCapabilitiesKHR capabilities;
        std::vector<VkSurfaceFormatKHR> formats;
        std::vector<VkPresentModeKHR> presentModes;
    };

    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;
    }

    struct QueueFamilyIndices {
        std::optional<uint32_t> graphicsFamily;
        std::optional<uint32_t> presentFamily;
        bool isComplete() {
            return graphicsFamily.has_value() && presentFamily.has_value();
        }
    };

    static void printQueueFamilies(VkPhysicalDevice device) {
        uint32_t queueFamilyCount = 0;
        vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, nullptr);
        std::vector<VkQueueFamilyProperties> queueFamilies(queueFamilyCount);
        vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, queueFamilies.data());

        int i = 0;
        for (const auto& queueFamily : queueFamilies) {
            bool gfx = queueFamily.queueFlags & VK_QUEUE_GRAPHICS_BIT;
            bool cmp = queueFamily.queueFlags & VK_QUEUE_COMPUTE_BIT;
            bool trf = queueFamily.queueFlags & VK_QUEUE_TRANSFER_BIT;
            std::cout << "QUEUE FAMILY " << i << " : x " << queueFamily.queueCount << " gfx=" << gfx << " cmp=" << cmp << " trf=" << trf << std::endl;
            i++;
        }
    }

    QueueFamilyIndices findQueueFamilies(VkPhysicalDevice device) {

        uint32_t queueFamilyCount = 0;
        vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, nullptr);
        std::vector<VkQueueFamilyProperties> queueFamilies(queueFamilyCount);
        vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, queueFamilies.data());


        QueueFamilyIndices indices;


        int i = 0;
        for (const auto& queueFamily : queueFamilies) {
            if (queueFamily.queueFlags & VK_QUEUE_GRAPHICS_BIT) {
                indices.graphicsFamily = i;
            }

            VkBool32 presentSupport = false;
            vkGetPhysicalDeviceSurfaceSupportKHR(device, i, surface, &presentSupport);

            if (presentSupport) {
                indices.presentFamily = i;
            }

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

        return indices;
    }

    VkSurfaceFormatKHR chooseSwapSurfaceFormat(const std::vector<VkSurfaceFormatKHR>& availableFormats) {
        for (const auto& availableFormat : availableFormats) {
            if (availableFormat.format == VK_FORMAT_B8G8R8A8_SRGB && availableFormat.colorSpace == VK_COLOR_SPACE_SRGB_NONLINEAR_KHR) {
                return availableFormat;
            }
        }
        return availableFormats[0];
    }

    VkPresentModeKHR chooseSwapPresentMode(const std::vector<VkPresentModeKHR>& availablePresentModes) {
        for (const auto& availablePresentMode : availablePresentModes) {
            if (availablePresentMode == VK_PRESENT_MODE_MAILBOX_KHR) {
                return availablePresentMode;
            }
        }

        return VK_PRESENT_MODE_FIFO_KHR;
    }

    VkExtent2D chooseSwapExtent(const VkSurfaceCapabilitiesKHR& capabilities) {
        if (capabilities.currentExtent.width != std::numeric_limits<uint32_t>::max()) {
            return capabilities.currentExtent;
        } else {
            int width, height;
            glfwGetFramebufferSize(window, &width, &height);

            VkExtent2D actualExtent = {
                static_cast<uint32_t>(width),
                static_cast<uint32_t>(height)
            };

            actualExtent.width = std::clamp(actualExtent.width, capabilities.minImageExtent.width, capabilities.maxImageExtent.width);
            actualExtent.height = std::clamp(actualExtent.height, capabilities.minImageExtent.height, capabilities.maxImageExtent.height);

            return actualExtent;
        }
    }

    void mainLoop() {
        std::cout << "Enter Main Loop" << std::endl;
        while (!glfwWindowShouldClose(window) && !quit) {
            glfwPollEvents();
            drawFrame();  // 14 Drawing -> Rendering
        }
        vkDeviceWaitIdle(device);
        std::cout << "Exit Main Loop" << std::endl;
    }

    void cleanup() {
        vkDestroySemaphore(device, imageAvailableSemaphore, nullptr);
        vkDestroySemaphore(device, renderFinishedSemaphore, nullptr);
        vkDestroyFence(device, inFlightFence, nullptr);
        vkDestroyCommandPool(device, commandPool, nullptr);
        for (auto framebuffer : swapChainFramebuffers) {
            vkDestroyFramebuffer(device, framebuffer, nullptr);
        }
        vkDestroyPipeline(device, graphicsPipeline, nullptr);
        vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
        vkDestroyRenderPass(device, renderPass, nullptr);
        for (auto imageView : swapChainImageViews) {
           vkDestroyImageView(device, imageView, nullptr);
        }
        vkDestroySwapchainKHR(device, swapChain, nullptr);
        vkDestroyDevice(device, nullptr);

        if (enableValidationLayers) {
           DestroyDebugUtilsMessengerEXT(instance, debugMessenger, nullptr);
        }
        vkDestroySurfaceKHR(instance, surface, nullptr);
        vkDestroyInstance(instance, nullptr);
        glfwDestroyWindow(window);
        glfwTerminate();
    }

};

int main() {
    HelloTriangleApplication app;
    std::cout << "Miguel's Vulkan" << std::endl;
    try {
        app.run();
    } catch (const std::exception& e) {
        std::cout << "Exception" << std::endl;
        std::cerr << e.what() << std::endl;
        return EXIT_FAILURE;
    }
    std::cout << "Finito" << std::endl;
    return EXIT_SUCCESS;
}