#include <cstdlib>
#include <fmt/format.h>
#include <iostream>
#include <span>
#include <vulkan/vulkan_core.h>

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

#include "util/magic_enum.hpp"
#include "util/types.h"

constexpr u32 WIDTH  = 800;
constexpr u32 HEIGHT = 600;

constexpr 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 VK_ERROR_EXTENSION_NOT_PRESENT;

  return func(instance, pCreateInfo, pAllocator, pDebugMessenger);
}

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);
}

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

 private:
  VkDebugUtilsMessengerEXT mDebugMessenger;
  VkInstance               mInstance;
  GLFWwindow*              mWindow;

  static fn checkValidationLayerSupport() -> bool {
    u32 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 fn getAvailableExtensions() -> std::vector<VkExtensionProperties> {
    u32 extensionCount = 0;
    vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, nullptr);

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

    return extensions;
  }

  static fn getRequiredExtensions() -> std::vector<const char*> {
    u32          glfwExtensionCount = 0;
    const char** 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 VKAPI_ATTR fn VKAPI_CALL debugCallback(
    // Severity - verbose, info, warning, error
    VkDebugUtilsMessageSeverityFlagBitsEXT /*messageSeverity*/,

    // Message Type - general, validation, performance
    VkDebugUtilsMessageTypeFlagsEXT /*messageType*/,

    // Callback Data - Contains details of the message
    // * pMessage    - The message as a null-terminated string
    // * pObjects    - Array of related objects
    // * objectCount - Number of related objects
    const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,

    // User Data - Any extra data the user may want to pass to the function
    void* /*pUserData*/
  ) -> VkBool32 /* If true, abort the call */ {
    std::cerr << "validation layer: " << pCallbackData->pMessage << std::endl;

    return VK_FALSE;
  }

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

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

    // Information used by vkCreateInstance
    VkInstanceCreateInfo createInfo {};
    createInfo.sType            = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
    createInfo.pApplicationInfo = &appInfo;

    VkDebugUtilsMessengerCreateInfoEXT debugCreateInfo {};

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

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

      createInfo.pNext = nullptr;
    }

    // Fixes macOS crashes
    std::vector<const char*> extensions = getRequiredExtensions();
    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();

    // Finally, create the instance (and throw an error if it fails)
    if (auto result = vkCreateInstance(&createInfo, nullptr, &mInstance); result != VK_SUCCESS)
      throw std::runtime_error(
        string("Failed to create instance! Error: ") + string(magic_enum::enum_name(result))
      );
  }

  fn initWindow() -> void {
    // Initialize GLFW
    glfwInit();

    // Don't create an OpenGL context
    glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);

    // Disable Resizing
    glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);

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

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

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

  fn cleanup() -> void {
    if (enableValidationLayers)
      DestroyDebugUtilsMessengerEXT(mInstance, mDebugMessenger, nullptr);

    vkDestroyInstance(mInstance, nullptr);
    glfwDestroyWindow(mWindow);
    glfwTerminate();
  }
};

fn main() -> int {
  Application app;

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

  return EXIT_SUCCESS;
}