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

#define VULKAN_HPP_NO_CONSTRUCTORS
#include <vulkan/vulkan.hpp>

#include "fmt/base.h"
#include "util/types.h"

constexpr int WIDTH  = 800;
constexpr int HEIGHT = 600;

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

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

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

 private:
  GLFWwindow* mWindow;

  vk::UniqueInstance mInstance;

  vk::UniqueHandle<vk::DebugUtilsMessengerEXT, vk::DispatchLoaderDynamic> mDebugMessenger;
  vk::DispatchLoaderDynamic                                               mLoader;

  void initWindow() {
    glfwInit();

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

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

  void initVulkan() {
    createInstance();
    setupDebugMessenger();
  }

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

    vk::DebugUtilsMessengerCreateInfoEXT messengerCreateInfo {
      .messageSeverity = vk::DebugUtilsMessageSeverityFlagBitsEXT::eVerbose |
                         vk::DebugUtilsMessageSeverityFlagBitsEXT::eWarning |
                         vk::DebugUtilsMessageSeverityFlagBitsEXT::eError,
      .messageType = vk::DebugUtilsMessageTypeFlagBitsEXT::eGeneral |
                     vk::DebugUtilsMessageTypeFlagBitsEXT::eValidation |
                     vk::DebugUtilsMessageTypeFlagBitsEXT::ePerformance,
      .pfnUserCallback = debugCallback,
    };

    mDebugMessenger = mInstance->createDebugUtilsMessengerEXTUnique(messengerCreateInfo, nullptr, mLoader);
  }

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

  void cleanup() {
    // NOTE: instance destruction is handled by UniqueInstance

    glfwDestroyWindow(mWindow);

    glfwTerminate();
  }

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

    vk::ApplicationInfo appInfo { .pApplicationName   = "Hello Triangle",
                                  .applicationVersion = 1,
                                  .pEngineName        = "No Engine",
                                  .engineVersion      = 1,
                                  .apiVersion         = VK_API_VERSION_1_0 };

    vk::InstanceCreateInfo createInfo { .pApplicationInfo = &appInfo };

    // Retrieve extensions using custom function
    std::vector<const char*> extensions = getRequiredExtensions();

    vk::DebugUtilsMessengerCreateInfoEXT debugCreateInfo {};
    if (enableValidationLayers) {
      createInfo.setEnabledLayerCount(static_cast<uint32_t>(validationLayers.size()))
        .setPpEnabledLayerNames(validationLayers.data());

      createInfo.setPNext(&debugCreateInfo);
    } else {
      createInfo.setEnabledLayerCount(0).setPNext(nullptr);
    }

    // Enable the portability extension and set flags
    extensions.push_back(VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME);
    createInfo.setEnabledExtensionCount(static_cast<uint32_t>(extensions.size()))
      .setPpEnabledExtensionNames(extensions.data())
      .setFlags(vk::InstanceCreateFlagBits::eEnumeratePortabilityKHR);

    fmt::println("Available extensions:");

    for (const char* extension : extensions) fmt::println("\t{}", extension);

    try {
      mInstance = vk::createInstanceUnique(createInfo);
      mLoader   = vk::DispatchLoaderDynamic(mInstance.get(), vkGetInstanceProcAddr);
    } catch (const vk::SystemError& err) {
      throw std::runtime_error("Failed to create instance: " + std::string(err.what()));
    }
  }

  static fn checkValidationLayerSupport() -> bool {
    std::vector<vk::LayerProperties> availableLayers = vk::enumerateInstanceLayerProperties();

    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;
  }

  static fn getRequiredExtensions() -> std::vector<const char*> {
    u32          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 VKAPI_ATTR fn VKAPI_CALL debugCallback(
    VkDebugUtilsMessageSeverityFlagBitsEXT /*messageSeverity*/,
    VkDebugUtilsMessageTypeFlagsEXT /*messageType*/,
    const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
    void* /*pUserData*/
  ) -> VkBool32 {
    fmt::println("Validation layer: {}", pCallbackData->pMessage);

    return VK_FALSE;
  }
};

fn main() -> i32 {
  HelloTriangleApplication app;

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

  return EXIT_SUCCESS;
}