#include "AppBase.h"
#include <assert.h>

#ifdef  _WIN32
#else
#include <android/asset_manager.h>
extern AAssetManager* g_assetManager;
#endif //  _WIN32


void VK_CHECK(VkResult ret)
{
    assert(ret == VK_SUCCESS);
}

//std::string AppBase::getPath(const std::string path)
//{
//#ifdef _WIN32
//	std::string android_path = "app/src/main/assets/" + path;
//	return android_path;
//#endif
//	return path;
//}
#ifdef _WIN32
std::vector<unsigned char> AppBase::readFileUnsignedCharWin32(const std::wstring path, bool example)
{
	std::vector<unsigned char> buffer;

	std::wstring enginePath = L"app/src/main/assets/" + path;
	if (example)
	{
		enginePath = L"example/src/main/assets/" + path;
	}
	std::ifstream file{ enginePath, std::ios::ate | std::ios::binary };

	if (!file.is_open())
	{
		throw std::runtime_error("failed to open file: ");
	}

	size_t fileSize = static_cast<size_t>(file.tellg());
	buffer.resize(fileSize);

	file.seekg(0);
	file.read((char*)buffer.data(), fileSize);
	file.close();


	return buffer;
}
#endif // _WIN32

std::vector<unsigned char> AppBase::readFileUnsignedChar(const std::string& path, bool example)
{
	std::vector<unsigned char> buffer;
#ifdef _WIN32
	std::string enginePath = "app/src/main/assets/" + path;
	if (example)
	{
		enginePath = "example/src/main/assets/" + path;
	}
	std::ifstream file{ enginePath, std::ios::ate | std::ios::binary };

	if (!file.is_open())
	{
		throw std::runtime_error("failed to open file: " + enginePath);
	}

	size_t fileSize = static_cast<size_t>(file.tellg());
	buffer.resize(fileSize);

	file.seekg(0);
	file.read((char*)buffer.data(), fileSize);
	file.close();
#else
	AAsset* asset = AAssetManager_open(g_assetManager, path.c_str(), AASSET_MODE_BUFFER);
	if (!asset) {
		logOut << "Failed to load file: " << path.c_str() << std::endl;
		return buffer;
	}

	size_t length = AAsset_getLength(asset);
	buffer.resize(length);
	AAsset_read(asset, (char*)buffer.data(), length);
	AAsset_close(asset);
#endif // _WIN32
	return buffer;
}

std::vector<char> AppBase::readFile(const std::string& path)
{
    std::vector<char> buffer;
#ifdef _WIN32
	std::string enginePath = "app/src/main/assets/" + path;
	std::ifstream file{ enginePath, std::ios::ate | std::ios::binary };

	if (!file.is_open())
	{
		throw std::runtime_error("failed to open file: " + enginePath);
	}

	size_t fileSize = static_cast<size_t>(file.tellg());
	buffer.resize(fileSize);

	file.seekg(0);
	file.read(buffer.data(), fileSize);
	file.close();
#else
	AAsset* asset = AAssetManager_open(g_assetManager, path.c_str(), AASSET_MODE_BUFFER);
	if (!asset) {
		logOut << "Failed to load file: " << path.c_str() << std::endl;
		return buffer;
	}

	size_t length = AAsset_getLength(asset);
    buffer.resize(length);
	AAsset_read(asset, buffer.data(), length);
	AAsset_close(asset);
#endif // _WIN32
	return buffer;
}

VkShaderModule AppBase::createShaderModule(VkDevice& device, 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;
}

bool AppBase::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;
}

void checkInstanceExtensions() {
    uint32_t extensionCount = 0;
    vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, nullptr);

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

    logOut << "Android Available instance extensions:" << std::endl;
    for (const auto& extension : extensions) {
        logOut << "ExtensionName:" << extension.extensionName << " Version:" << extension.specVersion << std::endl;
    }
}

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

	VkApplicationInfo appInfo{};
	appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
	appInfo.pApplicationName = "example";
	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;
#ifdef _WIN32
	// 获取 GLFW 所需的扩展
	uint32_t glfwExtensionCount = 0;
	const char** glfwExtensions;
	glfwExtensions = glfwGetRequiredInstanceExtensions(&glfwExtensionCount);

	// 添加调试扩展
	for(int i = 0; i < glfwExtensionCount; i++) {
		extensions.push_back(glfwExtensions[i]);
	}
#else
    checkInstanceExtensions();
    // Android: 手动添加必要的扩展
    extensions.push_back(VK_KHR_SURFACE_EXTENSION_NAME);
    extensions.push_back(VK_KHR_ANDROID_SURFACE_EXTENSION_NAME);

    // 可选：添加这些扩展以获得更好的兼容性
    extensions.push_back(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME);
#endif

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

	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();
	}
	else {
		createInfo.enabledLayerCount = 0;
	}

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

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

	std::cerr << "validation layer: " << pCallbackData->pMessage << std::endl;

	return VK_FALSE;
}

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 AppBase::setupDebugMessenger() {
	if (!enableValidationLayers)
		return;

	VkDebugUtilsMessengerCreateInfoEXT 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

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


QueueFamilyIndices AppBase::findQueueFamilies(VkPhysicalDevice device, VkSurfaceKHR& surface) {
	QueueFamilyIndices indices;

	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) {
		if (queueFamily.queueFlags & VK_QUEUE_GRAPHICS_BIT) {
			indices.graphicsFamily = i;
		}
		VkBool32 presentSupport = false;
        VK_CHECK(vkGetPhysicalDeviceSurfaceSupportKHR(device, i, surface, &presentSupport));
		if (presentSupport) {
			indices.presentFamily = i;
		}
		if (indices.isComplete()) {
			break;
		}
		i++;
	}
	return indices;
}

bool AppBase::checkSwapChainSupport(VkPhysicalDevice device, VkSurfaceKHR& surface) {
	uint32_t formatCount;
	vkGetPhysicalDeviceSurfaceFormatsKHR(device, surface, &formatCount, nullptr);

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

	return formatCount > 0 && presentModeCount > 0;
}

bool AppBase::checkDeviceExtensionSupport(VkPhysicalDevice device) {
	// 获取设备支持的扩展数量
	uint32_t extensionCount;
	vkEnumerateDeviceExtensionProperties(device, nullptr, &extensionCount, nullptr);

	// 获取设备支持的扩展列表
	std::vector<VkExtensionProperties> availableExtensions(extensionCount);
	vkEnumerateDeviceExtensionProperties(device, nullptr, &extensionCount, availableExtensions.data());

	// 定义需要的扩展
	const std::vector<const char*> requiredExtensions = {
		VK_KHR_SWAPCHAIN_EXTENSION_NAME
	};

	// 检查所有需要的扩展是否都支持
	for (const char* requiredExtension : requiredExtensions) {
		bool extensionFound = false;
		for (const auto& extension : availableExtensions) {
			if (strcmp(requiredExtension, extension.extensionName) == 0) {
				extensionFound = true;
				break;
			}
		}

		if (!extensionFound) {
			return false; // 如果有一个扩展不支持，返回 false
		}
	}

	return true; // 所有扩展都支持
}


bool AppBase::isDeviceSuitable(VkPhysicalDevice device, VkSurfaceKHR& surface) {
	QueueFamilyIndices indices = findQueueFamilies(device, surface);
	bool extensionsSupported = checkDeviceExtensionSupport(device);
	bool swapChainAdequate = false;
	if (extensionsSupported) {
		swapChainAdequate = checkSwapChainSupport(device, surface);
	}
	return indices.isComplete() && extensionsSupported && swapChainAdequate;
}

void AppBase::pickPhysicalDevice(VkPhysicalDevice& physicalDevice, VkSurfaceKHR& surface) 
{
	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, surface)) {
			physicalDevice = device;
			break;
		}
	}

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


// 计算面的法线
void AppBase::calculateFaceNormal(const TextureLoadingVertexStructure& v0,
	const TextureLoadingVertexStructure& v1,
	const TextureLoadingVertexStructure& v2,
	float* outNormal)
{
	// 计算两个边向量
	float edge1[3] = { v1.pos[0] - v0.pos[0], v1.pos[1] - v0.pos[1], v1.pos[2] - v0.pos[2] };
	float edge2[3] = { v2.pos[0] - v0.pos[0], v2.pos[1] - v0.pos[1], v2.pos[2] - v0.pos[2] };

	// 叉积计算法线
	outNormal[0] = edge1[1] * edge2[2] - edge1[2] * edge2[1];
	outNormal[1] = edge1[2] * edge2[0] - edge1[0] * edge2[2];
	outNormal[2] = edge1[0] * edge2[1] - edge1[1] * edge2[0];

	// 归一化
	float length = std::sqrt(outNormal[0] * outNormal[0] +
		outNormal[1] * outNormal[1] +
		outNormal[2] * outNormal[2]);

	if (length > 0.0f) {
		outNormal[0] /= length;
		outNormal[1] /= length;
		outNormal[2] /= length;
	}
}

// 计算所有顶点的法线
void AppBase::calculateVertexNormals(std::vector<TextureLoadingVertexStructure>& obj_vertices,
	const std::vector<uint32_t>& obj_indices)
{
	// 验证索引数量是3的倍数
	if (obj_indices.size() % 3 != 0) {
		return; // 或者抛出异常
	}

	// 为每个顶点创建法线累加器和计数
	std::vector<std::array<float, 3>> normalSums(obj_vertices.size(), { 0.0f, 0.0f, 0.0f });
	std::vector<int> normalCounts(obj_vertices.size(), 0);

	// 遍历所有三角形
	for (size_t i = 0; i < obj_indices.size(); i += 3) {
		uint32_t idx0 = obj_indices[i];
		uint32_t idx1 = obj_indices[i + 1];
		uint32_t idx2 = obj_indices[i + 2];

		// 验证索引有效性
		if (idx0 >= obj_vertices.size() || idx1 >= obj_vertices.size() || idx2 >= obj_vertices.size()) {
			continue;
		}

		// 获取三角形的三个顶点
		const auto& v0 = obj_vertices[idx0];
		const auto& v1 = obj_vertices[idx1];
		const auto& v2 = obj_vertices[idx2];

		// 计算面的法线
		float faceNormal[3];
		calculateFaceNormal(v0, v1, v2, faceNormal);

		// 将面法线累加到每个顶点
		for (int j = 0; j < 3; j++) {
			normalSums[idx0][j] += faceNormal[j];
			normalSums[idx1][j] += faceNormal[j];
			normalSums[idx2][j] += faceNormal[j];
		}

		normalCounts[idx0]++;
		normalCounts[idx1]++;
		normalCounts[idx2]++;
	}

	// 计算每个顶点的平均法线并归一化
	for (size_t i = 0; i < obj_vertices.size(); i++) {
		if (normalCounts[i] > 0) {
			// 计算平均值
			float avgNormal[3] = {
				normalSums[i][0] / normalCounts[i],
				normalSums[i][1] / normalCounts[i],
				normalSums[i][2] / normalCounts[i]
			};

			// 归一化
			float length = std::sqrt(avgNormal[0] * avgNormal[0] +
				avgNormal[1] * avgNormal[1] +
				avgNormal[2] * avgNormal[2]);

			if (length > 0.0f) {
				obj_vertices[i].normal[0] = avgNormal[0] / length;
				obj_vertices[i].normal[1] = avgNormal[1] / length;
				obj_vertices[i].normal[2] = avgNormal[2] / length;
			}
			else {
				// 如果法线长度为0，设置为默认值
				obj_vertices[i].normal[0] = 0.0f;
				obj_vertices[i].normal[1] = 1.0f;
				obj_vertices[i].normal[2] = 0.0f;
			}
		}
		else {
			// 如果没有面使用这个顶点，设置默认法线
			obj_vertices[i].normal[0] = 0.0f;
			obj_vertices[i].normal[1] = 1.0f;
			obj_vertices[i].normal[2] = 0.0f;
		}
	}
}