#define GLFW_INCLUDE_NONE
#define GLFW_INCLUDE_VULKAN
#include <GLFW/glfw3.h>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <optional>
#include <set>
#include <span>
#include <stdexcept>

#include "src/util/types.h"

const uint32_t WIDTH  = 800;
const uint32_t HEIGHT = 600;

const std::array<const char*, 1> validationLayers = { "VK_LAYER_KHRONOS_validation" };

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

fn CreateDebugUtilsMessengerEXT(
  VkInstance                                instance,
  const VkDebugUtilsMessengerCreateInfoEXT* pCreateInfo,
  const VkAllocationCallbacks*              pAllocator,
  VkDebugUtilsMessengerEXT*                 pDebugMessenger
) -> VkResult {
  auto func = std::bit_cast<PFN_vkCreateDebugUtilsMessengerEXT>(
    vkGetInstanceProcAddr(instance, "vkCreateDebugUtilsMessengerEXT")
  );

  if (func != nullptr)
    return func(instance, pCreateInfo, pAllocator, pDebugMessenger);

  return VK_ERROR_EXTENSION_NOT_PRESENT;
}

fn DestroyDebugUtilsMessengerEXT(
  VkInstance                   instance,
  VkDebugUtilsMessengerEXT     debugMessenger,
  const VkAllocationCallbacks* pAllocator
) -> void {
  auto func = std::bit_cast<PFN_vkDestroyDebugUtilsMessengerEXT>(
    vkGetInstanceProcAddr(instance, "vkDestroyDebugUtilsMessengerEXT")
  );

  if (func != nullptr)
    func(instance, debugMessenger, pAllocator);
}

struct QueueFamilyIndices {
  std::optional<uint32_t> graphics_family;
  std::optional<uint32_t> present_family;

  fn isComplete() -> bool { return graphics_family.has_value() && present_family.has_value(); }
};

class Application {
 public:
  fn run() -> void {
    initWindow();
    initVulkan();
    mainLoop();
    cleanup();
  }

 private:
  GLFWwindow* mWindow;

  VkInstance               mInstance;
  VkDebugUtilsMessengerEXT mDebugMessenger;
  VkSurfaceKHR             mSurface;

  VkPhysicalDevice mPhysicalDevice = VK_NULL_HANDLE;
  VkDevice         mDevice;

  VkQueue mGraphicsQueue;
  VkQueue mPresentQueue;

  fn initWindow() -> void {
    glfwInit();

    glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
    glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);

    mWindow = glfwCreateWindow(WIDTH, HEIGHT, "Vulkan", nullptr, nullptr);
  }

  fn initVulkan() -> void {
    createInstance();
    setupDebugMessenger();
    createSurface();
    pickPhysicalDevice();
    createLogicalDevice();
  }

  fn mainLoop() -> void {
    while (!glfwWindowShouldClose(mWindow)) { glfwPollEvents(); }
  }

  fn cleanup() -> void {
    vkDestroyDevice(mDevice, nullptr);

    if (enableValidationLayers)
      DestroyDebugUtilsMessengerEXT(mInstance, mDebugMessenger, nullptr);

    vkDestroySurfaceKHR(mInstance, mSurface, nullptr);
    vkDestroyInstance(mInstance, nullptr);

    glfwDestroyWindow(mWindow);

    glfwTerminate();
  }

  fn createInstance() -> void {
    if (enableValidationLayers && !checkValidationLayerSupport())
      throw std::runtime_error("validation layers requested, but not available!");

    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;

    VkInstanceCreateInfo createInfo {};
    createInfo.sType            = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
    createInfo.pApplicationInfo = &appInfo;

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

    VkDebugUtilsMessengerCreateInfoEXT debugCreateInfo {};
    if (enableValidationLayers) {
      createInfo.enabledLayerCount   = static_cast<uint32_t>(validationLayers.size());
      createInfo.ppEnabledLayerNames = validationLayers.data();

      populateDebugMessengerCreateInfo(debugCreateInfo);
      createInfo.pNext = static_cast<VkDebugUtilsMessengerCreateInfoEXT*>(&debugCreateInfo);
    } else {
      createInfo.enabledLayerCount = 0;

      createInfo.pNext = nullptr;
    }

    extensions.emplace_back(VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME);

    createInfo.flags |= VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR;

    createInfo.enabledExtensionCount   = static_cast<u32>(extensions.size());
    createInfo.ppEnabledExtensionNames = extensions.data();

    for (const char* extension : extensions) std::cout << extension << std::endl;

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

  static fn populateDebugMessengerCreateInfo(VkDebugUtilsMessengerCreateInfoEXT& createInfo) -> void {
    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;
  }

  fn setupDebugMessenger() -> void {
    if (!enableValidationLayers)
      return;

    VkDebugUtilsMessengerCreateInfoEXT createInfo;
    populateDebugMessengerCreateInfo(createInfo);

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

  fn createSurface() -> void {
    if (glfwCreateWindowSurface(mInstance, mWindow, nullptr, &mSurface) != VK_SUCCESS)
      throw std::runtime_error("failed to create window surface!");
  }

  fn pickPhysicalDevice() -> void {
    uint32_t deviceCount = 0;
    vkEnumeratePhysicalDevices(mInstance, &deviceCount, nullptr);

    if (deviceCount == 0)
      throw std::runtime_error("failed to find GPUs with Vulkan support!");

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

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

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

  fn createLogicalDevice() -> void {
    QueueFamilyIndices indices = findQueueFamilies(mPhysicalDevice);

    std::vector<VkDeviceQueueCreateInfo> queueCreateInfos;
    std::set<uint32_t>                   uniqueQueueFamilies = { indices.graphics_family.value(),
                                                                 indices.present_family.value() };

    float queuePriority = 1.0F;
    for (uint32_t 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.queueCreateInfoCount = static_cast<uint32_t>(queueCreateInfos.size());
    createInfo.pQueueCreateInfos    = queueCreateInfos.data();

    createInfo.pEnabledFeatures = &deviceFeatures;

    createInfo.enabledExtensionCount = 0;

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

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

    vkGetDeviceQueue(mDevice, indices.graphics_family.value(), 0, &mGraphicsQueue);
    vkGetDeviceQueue(mDevice, indices.present_family.value(), 0, &mPresentQueue);
  }

  fn isDeviceSuitable(VkPhysicalDevice device) -> bool {
    QueueFamilyIndices indices = findQueueFamilies(device);

    return indices.isComplete();
  }

  fn findQueueFamilies(VkPhysicalDevice device) -> QueueFamilyIndices {
    QueueFamilyIndices indices;

    uint32_t queueFamilyCount = 0;
    vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, nullptr);

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

    u32 idx = 0;

    for (const auto& queueFamily : queueFamilies) {
      if (queueFamily.queueFlags & VK_QUEUE_GRAPHICS_BIT)
        indices.graphics_family = idx;

      VkBool32 presentSupport = false;
      vkGetPhysicalDeviceSurfaceSupportKHR(device, idx, mSurface, &presentSupport);

      if (presentSupport)
        indices.present_family = idx;

      if (indices.isComplete())
        break;

      idx++;
    }

    return indices;
  }

  static fn getRequiredExtensions() -> std::vector<const char*> {
    uint32_t     glfwExtensionCount = 0;
    const char** glfwExtensions     = nullptr;
    glfwExtensions                  = glfwGetRequiredInstanceExtensions(&glfwExtensionCount);

    std::vector<const char*> extensions;
    if (glfwExtensions) {
      std::span<const char*> extSpan(glfwExtensions, glfwExtensionCount);
      extensions.assign(extSpan.begin(), extSpan.end());
    }

    if (enableValidationLayers)
      extensions.push_back(VK_EXT_DEBUG_UTILS_EXTENSION_NAME);

    return extensions;
  }

  static fn checkValidationLayerSupport() -> bool {
    uint32_t layerCount = 0;
    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(
              static_cast<const char*>(layerName), static_cast<const char*>(layerProperties.layerName)
            ) == 0) {
          layerFound = true;
          break;
        }
      }

      if (!layerFound)
        return false;
    }

    return true;
  }

  static VKAPI_ATTR fn VKAPI_CALL debugCallback(
    VkDebugUtilsMessageSeverityFlagBitsEXT /*messageSeverity*/,
    VkDebugUtilsMessageTypeFlagsEXT /*messageType*/,
    const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
    void* /*pUserData*/
  ) -> VkBool32 {
    std::cerr << "validation layer: " << pCallbackData->pMessage << std::endl;

    return VK_FALSE;
  }
};

auto main() -> int {
  Application app;

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

  return EXIT_SUCCESS;
}