#include "Graphics.h"
#include "Buffer.h"
#include "SDL_vulkan.h"
#include "window/Window.h"
#include "common/Exception.h"
#include "Shader.h"
#include "graphics/Texture.h"
#include "Vulkan.h"
#include "common/version.h"
#include "common/pixelformat.h"

#include <algorithm>
#include <vector>
#include <cstring>
#include <set>
#include <fstream>
#include <iostream>
#include <array>


namespace love {
namespace graphics {
namespace vulkan {
static VkIndexType getVulkanIndexBufferType(IndexDataType type) {
	switch (type) {
	case INDEX_UINT16: return VK_INDEX_TYPE_UINT16;
	case INDEX_UINT32: return VK_INDEX_TYPE_UINT32;
	default:
		throw love::Exception("unknown Index Data type");
	}
}

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

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

	// https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VK_KHR_push_descriptor.html
	VK_KHR_PUSH_DESCRIPTOR_EXTENSION_NAME
};

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

constexpr int MAX_FRAMES_IN_FLIGHT = 2;

constexpr uint32_t vulkanApiVersion = VK_API_VERSION_1_3;

const char* Graphics::getName() const {
	return "love.graphics.vulkan";
}

const VkDevice Graphics::getDevice() const {
	return device;
}

const VkPhysicalDevice Graphics::getPhysicalDevice() const {
	return physicalDevice;
}

const VmaAllocator Graphics::getVmaAllocator() const {
	return vmaAllocator;
}

Graphics::~Graphics() {
	// We already cleaned those up by clearing out batchedDrawBuffers. 
	// We set them to nullptr here so the base class doesn't crash
	// when it tries to free this.
	batchedDrawState.vb[0] = nullptr;
	batchedDrawState.vb[1] = nullptr;
	batchedDrawState.indexBuffer = nullptr;
}

// START OVERRIDEN FUNCTIONS

love::graphics::Texture* Graphics::newTexture(const love::graphics::Texture::Settings& settings, const love::graphics::Texture::Slices* data) {
	return new Texture(this, settings, data);
}

love::graphics::Buffer* Graphics::newBuffer(const love::graphics::Buffer::Settings& settings, const std::vector<love::graphics::Buffer::DataDeclaration>& format, const void* data, size_t size, size_t arraylength) {
	return new Buffer(this, settings, format, data, size, arraylength);
}

// FIXME: clear stencil and depth missing.
void Graphics::clear(OptionalColorD color, OptionalInt stencil, OptionalDouble depth) {
	VkClearAttachment attachment{};

	if (color.hasValue) {
		attachment.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		attachment.clearValue.color.float32[0] = static_cast<float>(color.value.r);
		attachment.clearValue.color.float32[1] = static_cast<float>(color.value.g);
		attachment.clearValue.color.float32[2] = static_cast<float>(color.value.b);
		attachment.clearValue.color.float32[3] = static_cast<float>(color.value.a);
	}

	VkClearRect rect{};
	rect.layerCount = 1;
	rect.rect.extent.width = static_cast<uint32_t>(currentViewportWidth);
	rect.rect.extent.height = static_cast<uint32_t>(currentViewportHeight);

	vkCmdClearAttachments(commandBuffers[imageIndex], 1, &attachment, 1, &rect);
}

void Graphics::clear(const std::vector<OptionalColorD>& colors, OptionalInt stencil, OptionalDouble depth) {
	std::vector<VkClearAttachment> attachments;
	for (const auto& color : colors) {
		VkClearAttachment attachment{};
		if (color.hasValue) {
			attachment.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			attachment.clearValue.color.float32[0] = static_cast<float>(color.value.r);
			attachment.clearValue.color.float32[1] = static_cast<float>(color.value.g);
			attachment.clearValue.color.float32[2] = static_cast<float>(color.value.b);
			attachment.clearValue.color.float32[3] = static_cast<float>(color.value.a);
		}
		attachments.push_back(attachment);
	}

	VkClearRect rect{};
	rect.layerCount = 1;
	rect.rect.extent.width = static_cast<uint32_t>(currentViewportWidth);
	rect.rect.extent.height = static_cast<uint32_t>(currentViewportHeight);

	vkCmdClearAttachments(commandBuffers[imageIndex], static_cast<uint32_t>(attachments.size()), attachments.data(), 1, &rect);
}

void Graphics::present(void* screenshotCallbackdata) {
	if (!isActive()) {
		return;
	}

	flushBatchedDraws();

	endRecordingGraphicsCommands();

	if (imagesInFlight[imageIndex] != VK_NULL_HANDLE) {
		vkWaitForFences(device, 1, &imagesInFlight.at(imageIndex), VK_TRUE, UINT64_MAX);
	}
	imagesInFlight[imageIndex] = inFlightFences[currentFrame];

	// all data transfers should happen before any draw calls.
	std::vector<VkCommandBuffer> submitCommandbuffers = { dataTransferCommandBuffers.at(currentFrame), commandBuffers.at(imageIndex) };

	VkSubmitInfo submitInfo{};
	submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;

	VkSemaphore waitSemaphores[] = { imageAvailableSemaphores.at(currentFrame) };
	VkPipelineStageFlags waitStages[] = { VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT };
	submitInfo.waitSemaphoreCount = 1;
	submitInfo.pWaitSemaphores = waitSemaphores;
	submitInfo.pWaitDstStageMask = waitStages;

	submitInfo.commandBufferCount = static_cast<uint32_t>(submitCommandbuffers.size());
	submitInfo.pCommandBuffers = submitCommandbuffers.data();

	VkSemaphore signalSemaphores[] = { renderFinishedSemaphores.at(currentFrame) };
	submitInfo.signalSemaphoreCount = 1;
	submitInfo.pSignalSemaphores = signalSemaphores;

	vkResetFences(device, 1, &inFlightFences[currentFrame]);

	if (vkQueueSubmit(graphicsQueue, 1, &submitInfo, inFlightFences.at(currentFrame)) != VK_SUCCESS) {
		throw love::Exception("failed to submit draw command buffer");
	}

	VkPresentInfoKHR presentInfo{};
	presentInfo.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;

	presentInfo.waitSemaphoreCount = 1;
	presentInfo.pWaitSemaphores = signalSemaphores;

	VkSwapchainKHR swapChains[] = { swapChain };
	presentInfo.swapchainCount = 1;
	presentInfo.pSwapchains = swapChains;

	presentInfo.pImageIndices = &imageIndex;

	VkResult result = vkQueuePresentKHR(presentQueue, &presentInfo);

	if (result == VK_ERROR_OUT_OF_DATE_KHR || result == VK_SUBOPTIMAL_KHR || framebufferResized) {
		framebufferResized = false;
		recreateSwapChain();
	}
	else if (result != VK_SUCCESS) {
		throw love::Exception("failed to present swap chain image");
	}
	
	currentFrame = (currentFrame + 1) % MAX_FRAMES_IN_FLIGHT;

	updatedBatchedDrawBuffers();
	startRecordingGraphicsCommands();
}

void Graphics::setViewportSize(int width, int height, int pixelwidth, int pixelheight) {
	this->width = width;
	this->height = height;
	this->pixelWidth = pixelwidth;
	this->pixelHeight = pixelheight;

	resetProjection();
}

bool Graphics::setMode(void* context, int width, int height, int pixelwidth, int pixelheight, bool windowhasstencil, int msaa) {
	cleanUpFunctions.clear();
	cleanUpFunctions.resize(MAX_FRAMES_IN_FLIGHT);

	createVulkanInstance();
	createSurface();
	pickPhysicalDevice();
	createLogicalDevice();
	initVMA();
	initCapabilities();
	createSwapChain();
	createImageViews();
	createSyncObjects();
	createCommandPool();
	createCommandBuffers();
	startRecordingGraphicsCommands();
	createQuadIndexBuffer();
	createDefaultTexture();
	createDefaultShaders();
	currentFrame = 0;

	created = true;

	float whiteColor[] = { 1.0f, 1.0f, 1.0f, 1.0f };

	batchedDrawBuffers.clear();
	batchedDrawBuffers.reserve(MAX_FRAMES_IN_FLIGHT);
	for (int i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {
		batchedDrawBuffers.emplace_back();
		// Initial sizes that should be good enough for most cases. It will
		// resize to fit if needed, later.
		batchedDrawBuffers[i].vertexBuffer1 = new StreamBuffer(this, BUFFERUSAGE_VERTEX, 1024 * 1024 * 1);
		batchedDrawBuffers[i].vertexBuffer2 = new StreamBuffer(this, BUFFERUSAGE_VERTEX, 256 * 1024 * 1);
		batchedDrawBuffers[i].indexBuffer = new StreamBuffer(this, BUFFERUSAGE_INDEX, sizeof(uint16) * LOVE_UINT16_MAX);

		// sometimes the VertexColor is not set, so we manually adjust it to white color
		batchedDrawBuffers[i].constantColorBuffer = new StreamBuffer(this, BUFFERUSAGE_VERTEX, sizeof(whiteColor));
		auto mapInfo = batchedDrawBuffers[i].constantColorBuffer->map(sizeof(whiteColor));
		memcpy(mapInfo.data, whiteColor, sizeof(whiteColor));
		batchedDrawBuffers[i].constantColorBuffer->unmap(sizeof(whiteColor));
		batchedDrawBuffers[i].constantColorBuffer->markUsed(sizeof(whiteColor));
	}

	updatedBatchedDrawBuffers();

	Shader::current = Shader::standardShaders[graphics::Shader::StandardShader::STANDARD_DEFAULT];
	restoreState(states.back());
	
	setViewportSize(width, height, pixelwidth, pixelheight);
	renderTargetTexture = nullptr;
	currentViewportWidth = 0.0f;
	currentViewportHeight = 0.0f;

	Vulkan::resetShaderSwitches();

	return true;
}

void Graphics::initCapabilities() {
	// todo
	capabilities.features[FEATURE_MULTI_RENDER_TARGET_FORMATS] = false;
	capabilities.features[FEATURE_CLAMP_ZERO] = false;
	capabilities.features[FEATURE_CLAMP_ONE] = false;
	capabilities.features[FEATURE_BLEND_MINMAX] = false;
	capabilities.features[FEATURE_LIGHTEN] = false;
	capabilities.features[FEATURE_FULL_NPOT] = false;
	capabilities.features[FEATURE_PIXEL_SHADER_HIGHP] = true;
	capabilities.features[FEATURE_SHADER_DERIVATIVES] = false;
	capabilities.features[FEATURE_GLSL3] = true;
	capabilities.features[FEATURE_GLSL4] = true;
	capabilities.features[FEATURE_INSTANCING] = false;
	capabilities.features[FEATURE_TEXEL_BUFFER] = false;
	capabilities.features[FEATURE_INDEX_BUFFER_32BIT] = true;
	capabilities.features[FEATURE_COPY_BUFFER] = false;
	capabilities.features[FEATURE_COPY_BUFFER_TO_TEXTURE] = false;
	capabilities.features[FEATURE_COPY_TEXTURE_TO_BUFFER] = false;
	capabilities.features[FEATURE_COPY_RENDER_TARGET_TO_BUFFER] = false;
	static_assert(FEATURE_MAX_ENUM == 17, "Graphics::initCapabilities must be updated when adding a new graphics feature!");

	VkPhysicalDeviceProperties properties;
	vkGetPhysicalDeviceProperties(physicalDevice, &properties);

	capabilities.limits[LIMIT_POINT_SIZE] = properties.limits.pointSizeRange[1];
	capabilities.limits[LIMIT_TEXTURE_SIZE] = properties.limits.maxImageDimension2D;
	capabilities.limits[LIMIT_TEXTURE_LAYERS] = properties.limits.maxImageArrayLayers;
	capabilities.limits[LIMIT_VOLUME_TEXTURE_SIZE] = properties.limits.maxImageDimension3D;
	capabilities.limits[LIMIT_CUBE_TEXTURE_SIZE] = properties.limits.maxImageDimensionCube;
	capabilities.limits[LIMIT_TEXEL_BUFFER_SIZE] = properties.limits.maxTexelBufferElements;	// ?
	capabilities.limits[LIMIT_SHADER_STORAGE_BUFFER_SIZE] = properties.limits.maxStorageBufferRange;	// ?
	capabilities.limits[LIMIT_THREADGROUPS_X] = 0;  // todo
	capabilities.limits[LIMIT_THREADGROUPS_Y] = 0;  // todo
	capabilities.limits[LIMIT_THREADGROUPS_Z] = 0;  // todo
	capabilities.limits[LIMIT_RENDER_TARGETS] = 1;	// todo
	capabilities.limits[LIMIT_TEXTURE_MSAA] = 1;	// todo
	capabilities.limits[LIMIT_ANISOTROPY] = 1.0f;	// todo
	static_assert(LIMIT_MAX_ENUM == 13, "Graphics::initCapabilities must be updated when adding a new system limit!");

	capabilities.textureTypes[TEXTURE_2D] = true;
	capabilities.textureTypes[TEXTURE_2D_ARRAY] = true;
	capabilities.textureTypes[TEXTURE_VOLUME] = false;
	capabilities.textureTypes[TEXTURE_CUBE] = false;
}

void Graphics::getAPIStats(int& shaderswitches) const {
	shaderswitches = Vulkan::getNumShaderSwitches();
}

void Graphics::unSetMode() {
	created = false;
	vkDeviceWaitIdle(device);
	Volatile::unloadAll();
	cleanup();
}

void Graphics::setActive(bool enable) {
	flushBatchedDraws();
	active = enable;
}

void Graphics::setFrontFaceWinding(Winding winding) {
	const auto& currentState = states.back();

	if (currentState.winding == winding) {
		return;
	}

	flushBatchedDraws();

	states.back().winding = winding;
}

void Graphics::setColorMask(ColorChannelMask mask) {
	flushBatchedDraws();

	states.back().colorMask = mask;
}

void Graphics::setBlendState(const BlendState& blend) {
	flushBatchedDraws();

	states.back().blend = blend;
}

void Graphics::setPointSize(float size) {
	if (size != states.back().pointSize)
		flushBatchedDraws();

	states.back().pointSize = size;
}

bool Graphics::usesGLSLES() const {
	return false;
}

Graphics::RendererInfo Graphics::getRendererInfo() const {
	VkPhysicalDeviceProperties deviceProperties;
	vkGetPhysicalDeviceProperties(physicalDevice, &deviceProperties);

	Graphics::RendererInfo info;
	info.device = deviceProperties.deviceName;
	info.vendor = Vulkan::getVendorName(deviceProperties.vendorID);
	info.version = Vulkan::getVulkanApiVersion(deviceProperties.apiVersion);
	info.name = "Vulkan";

	return info;
}

void Graphics::draw(const DrawCommand& cmd) {
	prepareDraw(*cmd.attributes, *cmd.buffers, cmd.texture, cmd.primitiveType, cmd.cullMode);

	vkCmdDraw(commandBuffers.at(imageIndex), static_cast<uint32_t>(cmd.vertexCount), static_cast<uint32_t>(cmd.instanceCount), static_cast<uint32_t>(cmd.vertexStart), 0);
}

void Graphics::draw(const DrawIndexedCommand& cmd) {
	prepareDraw(*cmd.attributes, *cmd.buffers, cmd.texture, cmd.primitiveType, cmd.cullMode);

	vkCmdBindIndexBuffer(commandBuffers.at(imageIndex), (VkBuffer)cmd.indexBuffer->getHandle(), static_cast<VkDeviceSize>(cmd.indexBufferOffset), getVulkanIndexBufferType(cmd.indexType));
	vkCmdDrawIndexed(commandBuffers.at(imageIndex), static_cast<uint32_t>(cmd.indexCount), static_cast<uint32_t>(cmd.instanceCount), 0, 0, 0);
}

void Graphics::drawQuads(int start, int count, const VertexAttributes& attributes, const BufferBindings& buffers, graphics::Texture* texture) {
	const int MAX_VERTICES_PER_DRAW = LOVE_UINT16_MAX;
	const int MAX_QUADS_PER_DRAW = MAX_VERTICES_PER_DRAW / 4;

	prepareDraw(attributes, buffers, texture, PRIMITIVE_TRIANGLES, CULL_BACK);

	vkCmdBindIndexBuffer(commandBuffers.at(imageIndex), (VkBuffer)quadIndexBuffer->getHandle(), 0, getVulkanIndexBufferType(INDEX_UINT16));

	int baseVertex = start * 4;

	for (int quadindex = 0; quadindex < count; quadindex += MAX_QUADS_PER_DRAW) {
		int quadcount = std::min(MAX_QUADS_PER_DRAW, count - quadindex);

		vkCmdDrawIndexed(commandBuffers.at(imageIndex), static_cast<uint32_t>(quadcount * 6), 1, 0, baseVertex, 0);
		baseVertex += quadcount * 4;
	}
}

void Graphics::setColor(Colorf c) {
	c.r = std::min(std::max(c.r, 0.0f), 1.0f);
	c.g = std::min(std::max(c.g, 0.0f), 1.0f);
	c.b = std::min(std::max(c.b, 0.0f), 1.0f);
	c.a = std::min(std::max(c.a, 0.0f), 1.0f);

	states.back().color = c;
}

void Graphics::setScissor(const Rect& rect) {
	flushBatchedDraws();
	
	states.back().scissor = true;
	states.back().scissorRect = rect;
}

void Graphics::setScissor() {
	flushBatchedDraws();

	states.back().scissor = false;
}

void Graphics::setWireframe(bool enable) {
	flushBatchedDraws();

	states.back().wireframe = enable;
}

PixelFormat Graphics::getSizedFormat(PixelFormat format, bool rendertarget, bool readable) const { 
	switch (format) {
	case PIXELFORMAT_NORMAL:
		if (isGammaCorrect()) {
			return PIXELFORMAT_RGBA8_UNORM_sRGB;
		}
		else {
			return PIXELFORMAT_RGBA8_UNORM;
		}
	case PIXELFORMAT_HDR:
		return PIXELFORMAT_RGBA16_FLOAT;
	default:
		return format;
	}
}

bool Graphics::isPixelFormatSupported(PixelFormat format, uint32 usage, bool sRGB) { 
	return true;
}

Renderer Graphics::getRenderer() const {
	return RENDERER_VULKAN;
}

graphics::StreamBuffer* Graphics::newStreamBuffer(BufferUsage type, size_t size) {
	return new StreamBuffer(this, type, size);
}

Matrix4 Graphics::computeDeviceProjection(const Matrix4& projection, bool rendertotexture) const { 
	uint32 flags = DEVICE_PROJECTION_DEFAULT;
	return calculateDeviceProjection(projection, flags);
}

void Graphics::setRenderTargetsInternal(const RenderTargets& rts, int pixelw, int pixelh, bool hasSRGBtexture) {
	endRenderPass();

	if (rts.colors.size() == 0) {
		startRenderPass(nullptr, swapChainExtent.width, swapChainExtent.height);
	} else {
		// fixme: multi canvas render.
		auto& firstRenderTarget = rts.getFirstTarget();
		startRenderPass(static_cast<Texture*>(firstRenderTarget.texture), pixelw, pixelh);
	}
}

// END IMPLEMENTATION OVERRIDDEN FUNCTIONS

void Graphics::startRecordingGraphicsCommands() {
	vkWaitForFences(device, 1, &inFlightFences[currentFrame], VK_TRUE, UINT64_MAX);

	while (true) {
		VkResult result = vkAcquireNextImageKHR(device, swapChain, UINT64_MAX, imageAvailableSemaphores[currentFrame], VK_NULL_HANDLE, &imageIndex);
		if (result == VK_ERROR_OUT_OF_DATE_KHR) {
			recreateSwapChain();
			continue;
		}
		else if (result != VK_SUCCESS && result != VK_SUBOPTIMAL_KHR) {
			throw love::Exception("failed to acquire swap chain image");
		}

		break;
	}

	for (auto& cleanUpFn : cleanUpFunctions.at(currentFrame)) {
		cleanUpFn();
	}
	cleanUpFunctions.at(currentFrame).clear();

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

	if (vkBeginCommandBuffer(commandBuffers.at(imageIndex), &beginInfo) != VK_SUCCESS) {
		throw love::Exception("failed to begin recording command buffer");
	}
	if (vkBeginCommandBuffer(dataTransferCommandBuffers.at(currentFrame), &beginInfo) != VK_SUCCESS) {
		throw love::Exception("failed to begin recording data transfer command buffer");
	}

	Vulkan::cmdTransitionImageLayout(commandBuffers.at(imageIndex), swapChainImages[imageIndex], VK_IMAGE_LAYOUT_UNDEFINED, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);

	startRenderPass(nullptr, swapChainExtent.width, swapChainExtent.height);

	Vulkan::resetShaderSwitches();
}

void Graphics::endRecordingGraphicsCommands() {
	endRenderPass();

	Vulkan::cmdTransitionImageLayout(commandBuffers.at(imageIndex), swapChainImages[imageIndex], VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL, VK_IMAGE_LAYOUT_PRESENT_SRC_KHR);

	if (vkEndCommandBuffer(commandBuffers.at(imageIndex)) != VK_SUCCESS) {
		throw love::Exception("failed to record command buffer");
	}
	if (vkEndCommandBuffer(dataTransferCommandBuffers.at(currentFrame)) != VK_SUCCESS) {
		throw love::Exception("failed to record data transfer command buffer");
	}
}

void Graphics::updatedBatchedDrawBuffers() {
	batchedDrawState.vb[0] = batchedDrawBuffers[currentFrame].vertexBuffer1;
	batchedDrawState.vb[0]->nextFrame();
	batchedDrawState.vb[1] = batchedDrawBuffers[currentFrame].vertexBuffer2; 
	batchedDrawState.vb[1]->nextFrame();
	batchedDrawState.indexBuffer = batchedDrawBuffers[currentFrame].indexBuffer;
	batchedDrawState.indexBuffer->nextFrame();
}

uint32_t Graphics::getNumImagesInFlight() const {
	return MAX_FRAMES_IN_FLIGHT;
}

const VkDeviceSize Graphics::getMinUniformBufferOffsetAlignment() const {
	return minUniformBufferOffsetAlignment;
}

graphics::Texture* Graphics::getDefaultTexture() const {
	return dynamic_cast<graphics::Texture*>(standardTexture.get());
}

const PFN_vkCmdPushDescriptorSetKHR Graphics::getVkCmdPushDescriptorSetKHRFunctionPointer() const {
	return vkCmdPushDescriptorSet;
}

VkCommandBuffer Graphics::getDataTransferCommandBuffer() {
	return dataTransferCommandBuffers.at(currentFrame);
}

void Graphics::queueCleanUp(std::function<void()> cleanUp) {
	cleanUpFunctions.at(currentFrame).push_back(std::move(cleanUp));
}

VkCommandBuffer Graphics::beginSingleTimeCommands() {
	VkCommandBufferAllocateInfo allocInfo{};
	allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
	allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
	allocInfo.commandPool = commandPool;
	allocInfo.commandBufferCount = 1;

	VkCommandBuffer commandBuffer;
	vkAllocateCommandBuffers(device, &allocInfo, &commandBuffer);

	VkCommandBufferBeginInfo beginInfo{};
	beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
	beginInfo.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;

	vkBeginCommandBuffer(commandBuffer, &beginInfo);

	return commandBuffer;
}

void Graphics::endSingleTimeCommands(VkCommandBuffer commandBuffer) {
	vkEndCommandBuffer(commandBuffer);

	VkSubmitInfo submitInfo{};
	submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
	submitInfo.commandBufferCount = 1;
	submitInfo.pCommandBuffers = &commandBuffer;

	vkQueueSubmit(graphicsQueue, 1, &submitInfo, VK_NULL_HANDLE);
	vkQueueWaitIdle(graphicsQueue);
	vkFreeCommandBuffers(device, commandPool, 1, &commandBuffer);
}

graphics::Shader::BuiltinUniformData Graphics::getCurrentBuiltinUniformData() {
	love::graphics::Shader::BuiltinUniformData data;

	data.transformMatrix = getTransform();
	data.projectionMatrix = getDeviceProjection();

	// The normal matrix is the transpose of the inverse of the rotation portion
	// (top-left 3x3) of the transform matrix.
	{
		Matrix3 normalmatrix = Matrix3(data.transformMatrix).transposedInverse();
		const float* e = normalmatrix.getElements();
		for (int i = 0; i < 3; i++)
		{
			data.normalMatrix[i].x = e[i * 3 + 0];
			data.normalMatrix[i].y = e[i * 3 + 1];
			data.normalMatrix[i].z = e[i * 3 + 2];
			data.normalMatrix[i].w = 0.0f;
		}
	}

	// Store DPI scale in an unused component of another vector.
	data.normalMatrix[0].w = (float)getCurrentDPIScale();

	// Same with point size.
	data.normalMatrix[1].w = getPointSize();

	data.screenSizeParams.x = static_cast<float>(swapChainExtent.width);
	data.screenSizeParams.y = static_cast<float>(swapChainExtent.height);

	data.screenSizeParams.z = 1.0f;
	data.screenSizeParams.w = 0.0f;

	data.constantColor = getColor();
	gammaCorrectColor(data.constantColor);

	return data;
}

void Graphics::createVulkanInstance() {
	if (enableValidationLayers && !checkValidationSupport()) {
		throw love::Exception("validation layers requested, but not available");
	}

	VkApplicationInfo appInfo{};
	appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
	appInfo.pApplicationName = "LOVE";
	appInfo.applicationVersion = VK_MAKE_VERSION(1, 0, 0);	//todo, get this version from somewhere else?
	appInfo.pEngineName = "LOVE Engine";
	appInfo.engineVersion = VK_MAKE_VERSION(VERSION_MAJOR, VERSION_MINOR, VERSION_REV);
	appInfo.apiVersion = vulkanApiVersion;

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

	auto window = Module::getInstance<love::window::Window>(M_WINDOW);
	const void* handle = window->getHandle();

	unsigned int count;
	if (SDL_Vulkan_GetInstanceExtensions((SDL_Window*)handle, &count, nullptr) != SDL_TRUE) {
		throw love::Exception("couldn't retrieve sdl vulkan extensions");
	}

	std::vector<const char*> extensions = {};	// can add more here
	size_t addition_extension_count = extensions.size();
	extensions.resize(addition_extension_count + count);

	if (SDL_Vulkan_GetInstanceExtensions((SDL_Window*)handle, &count, extensions.data() + addition_extension_count) != SDL_TRUE) {
		throw love::Exception("couldn't retrieve sdl vulkan extensions");
	}

	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;
		createInfo.ppEnabledLayerNames = nullptr;
	}

	if (vkCreateInstance(
		&createInfo, 
		nullptr, 
		&instance) != VK_SUCCESS) {
		throw love::Exception("couldn't create vulkan instance");
	}
}

bool Graphics::checkValidationSupport() {
	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 Graphics::pickPhysicalDevice() {
	uint32_t deviceCount = 0;
	vkEnumeratePhysicalDevices(instance, &deviceCount, nullptr);

	if (deviceCount == 0) {
		throw love::Exception("failed to find GPUs with Vulkan support");
	}

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

	std::multimap<int, VkPhysicalDevice> candidates;

	for (const auto& device : devices) {
		int score = rateDeviceSuitability(device);
		candidates.insert(std::make_pair(score, device));
	}

	if (candidates.rbegin()->first > 0) {
		physicalDevice = candidates.rbegin()->second;
	}
	else {
		throw love::Exception("failed to find a suitable gpu");
	}

	VkPhysicalDeviceProperties properties;
	vkGetPhysicalDeviceProperties(physicalDevice, &properties);
	minUniformBufferOffsetAlignment = properties.limits.minUniformBufferOffsetAlignment;
}

bool Graphics::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) {
		requiredExtensions.erase(extension.extensionName);
	}

	return requiredExtensions.empty();
}

// if the score is nonzero then the device is suitable.
// A higher rating means generally better performance
// if the score is 0 the device is unsuitable
int Graphics::rateDeviceSuitability(VkPhysicalDevice device) {
	VkPhysicalDeviceProperties deviceProperties;
	VkPhysicalDeviceFeatures deviceFeatures;
	vkGetPhysicalDeviceProperties(device, &deviceProperties);
	vkGetPhysicalDeviceFeatures(device, &deviceFeatures);

	int score = 1;

	// optional 

	if (deviceProperties.deviceType == VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU) {
		score += 1000;
	}
	if (deviceProperties.deviceType == VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU) {
		score += 100;
	}
	if (deviceProperties.deviceType == VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU) {
		score += 10;
	}

	// definitely needed

	QueueFamilyIndices indices = findQueueFamilies(device);
	if (!indices.isComplete()) {
		score = 0;
	}

	bool extensionsSupported = checkDeviceExtensionSupport(device);
	if (!extensionsSupported) {
		score = 0;
	}

	if (extensionsSupported) {
		auto swapChainSupport = querySwapChainSupport(device);
		bool swapChainAdequate = !swapChainSupport.formats.empty() && !swapChainSupport.presentModes.empty();
		if (!swapChainAdequate) {
			score = 0;
		}
	}

	if (!deviceFeatures.samplerAnisotropy) {
		score = 0;
	}

	if (!deviceFeatures.fillModeNonSolid) {
		score = 0;
	}

	return score;
}

QueueFamilyIndices Graphics::findQueueFamilies(VkPhysicalDevice device) {
	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;
		vkGetPhysicalDeviceSurfaceSupportKHR(device, i, surface, &presentSupport);

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

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

		i++;
	}

	return indices;
}

void Graphics::createLogicalDevice() {
	QueueFamilyIndices indices = findQueueFamilies(physicalDevice);

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

	VkPhysicalDeviceDynamicRenderingFeatures dynamicRenderingFeature{};
	dynamicRenderingFeature.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DYNAMIC_RENDERING_FEATURES;
	dynamicRenderingFeature.dynamicRendering = VK_TRUE;

	VkPhysicalDeviceFeatures deviceFeatures{};
	deviceFeatures.samplerAnisotropy = VK_TRUE;
	deviceFeatures.fillModeNonSolid = VK_TRUE;

	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.pNext = &dynamicRenderingFeature;

	createInfo.enabledExtensionCount = static_cast<uint32_t>(deviceExtensions.size());
	createInfo.ppEnabledExtensionNames = deviceExtensions.data();

	// can this be removed?
	if (enableValidationLayers) {
		createInfo.enabledLayerCount = static_cast<uint32_t>(validationLayers.size());
		createInfo.ppEnabledLayerNames = validationLayers.data();
	}
	else {
		createInfo.enabledLayerCount = 0;
	}

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

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

	vkCmdPushDescriptorSet = (PFN_vkCmdPushDescriptorSetKHR) vkGetDeviceProcAddr(device, "vkCmdPushDescriptorSetKHR");
	if (!vkCmdPushDescriptorSet) {
		// fixme: how widely adopted is this extension?
		throw love::Exception("could not get a valid function pointer for vkCmdPushDescriptorSetKHR");
	}
}

void Graphics::initVMA() {
	VmaVulkanFunctions vulkanFunctions = {};
	vulkanFunctions.vkGetInstanceProcAddr = &vkGetInstanceProcAddr;
	vulkanFunctions.vkGetDeviceProcAddr = &vkGetDeviceProcAddr;

	VmaAllocatorCreateInfo allocatorCreateInfo = {};
	allocatorCreateInfo.vulkanApiVersion = vulkanApiVersion;
	allocatorCreateInfo.physicalDevice = physicalDevice;
	allocatorCreateInfo.device = device;
	allocatorCreateInfo.instance = instance;
	allocatorCreateInfo.pVulkanFunctions = &vulkanFunctions;

	if (vmaCreateAllocator(&allocatorCreateInfo, &vmaAllocator) != VK_SUCCESS) {
		throw love::Exception("failed to create vma allocator");
	}
}

void Graphics::createSurface() {
	auto window = Module::getInstance<love::window::Window>(M_WINDOW);
	const void* handle = window->getHandle();
	if (SDL_Vulkan_CreateSurface((SDL_Window*)handle, instance, &surface) != SDL_TRUE) {
		throw love::Exception("failed to create window surface");
	}
}

SwapChainSupportDetails Graphics::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;
}

void Graphics::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) {
		createInfo.imageSharingMode = VK_SHARING_MODE_CONCURRENT;
		createInfo.queueFamilyIndexCount = 2;
		createInfo.pQueueFamilyIndices = queueFamilyIndices;
	}
	else {
		createInfo.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
		createInfo.queueFamilyIndexCount = 0;
		createInfo.pQueueFamilyIndices = nullptr;
	}

	createInfo.preTransform = swapChainSupport.capabilities.currentTransform;
	createInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
	createInfo.presentMode = presentMode;
	createInfo.clipped = VK_TRUE;
	createInfo.oldSwapchain = VK_NULL_HANDLE;

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

	vkGetSwapchainImagesKHR(device, swapChain, &imageCount, nullptr);
	swapChainImages.resize(imageCount);
	vkGetSwapchainImagesKHR(device, swapChain, &imageCount, swapChainImages.data());

	swapChainImageFormat = surfaceFormat.format;
	swapChainExtent = extent;
}

VkSurfaceFormatKHR Graphics::chooseSwapSurfaceFormat(const std::vector<VkSurfaceFormatKHR>& availableFormats) {
	for (const auto& availableFormat : availableFormats) {
		// fixme: what if this format and colorspace is not available?
		if (availableFormat.format == VK_FORMAT_B8G8R8A8_UNORM && availableFormat.colorSpace == VK_COLOR_SPACE_SRGB_NONLINEAR_KHR) {
			return availableFormat;
		}
	}

	return availableFormats[0];
}

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

	return VK_PRESENT_MODE_FIFO_KHR;
}

VkExtent2D Graphics::chooseSwapExtent(const VkSurfaceCapabilitiesKHR& capabilities) {
	if (capabilities.currentExtent.width != UINT32_MAX) {
		return capabilities.currentExtent;
	}
	else {
		auto window = Module::getInstance<love::window::Window>(M_WINDOW);
		const void* handle = window->getHandle();

		int width, height;
		// is this the equivalent of glfwGetFramebufferSize ?
		SDL_Vulkan_GetDrawableSize((SDL_Window*)handle, &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 Graphics::createImageViews() {
	swapChainImageViews.resize(swapChainImages.size());

	for (size_t i = 0; i < swapChainImages.size(); i++) {
		VkImageViewCreateInfo createInfo{};
		createInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
		createInfo.image = swapChainImages.at(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.at(i)) != VK_SUCCESS) {
			throw love::Exception("failed to create image views");
		}
	}
}

void Graphics::createDefaultShaders() {
	for (int i = 0; i < Shader::STANDARD_MAX_ENUM; i++) {
		auto stype = (Shader::StandardShader)i;

		if (!Shader::standardShaders[i]) {
			std::vector<std::string> stages;
			stages.push_back(Shader::getDefaultCode(stype, SHADERSTAGE_VERTEX));
			stages.push_back(Shader::getDefaultCode(stype, SHADERSTAGE_PIXEL));
			Shader::standardShaders[i] = newShader(stages, {});
		}
	}
}

bool Graphics::usesConstantVertexColor(const VertexAttributes& vertexAttributes) {
	return !!(vertexAttributes.enableBits & (1u << ATTRIB_COLOR));
}

void Graphics::createVulkanVertexFormat(
	VertexAttributes vertexAttributes, 
	std::vector<VkVertexInputBindingDescription> &bindingDescriptions, 
	std::vector<VkVertexInputAttributeDescription> &attributeDescriptions) {
	std::set<uint32_t> usedBuffers;

	auto allBits = vertexAttributes.enableBits;

	bool usesColor = false;

	uint8_t highestBufferBinding = 0;
	
	for (uint32_t i = 0; i < VertexAttributes::MAX; i++) {	// change to loop like in opengl implementation ?
		uint32 bit = 1u << i;
		if (allBits & bit) {
			if (i == ATTRIB_COLOR) {
				usesColor = true;
			}

			auto attrib = vertexAttributes.attribs[i];
			auto bufferBinding = attrib.bufferIndex;
			if (usedBuffers.find(bufferBinding) == usedBuffers.end()) {	// use .contains() when c++20 is enabled
				usedBuffers.insert(bufferBinding);

				VkVertexInputBindingDescription bindingDescription{};
				bindingDescription.binding = bufferBinding;
				if (vertexAttributes.instanceBits & (1u << bufferBinding)) {
					bindingDescription.inputRate = VK_VERTEX_INPUT_RATE_INSTANCE;
				}
				else {
					bindingDescription.inputRate = VK_VERTEX_INPUT_RATE_VERTEX;
				}
				bindingDescription.stride = vertexAttributes.bufferLayouts[bufferBinding].stride;
				bindingDescriptions.push_back(bindingDescription);

				highestBufferBinding = std::max(highestBufferBinding, bufferBinding);
			}

			VkVertexInputAttributeDescription attributeDescription{};
			attributeDescription.location = i;
			attributeDescription.binding = bufferBinding;
			attributeDescription.offset = attrib.offsetFromVertex;
			attributeDescription.format = Vulkan::getVulkanVertexFormat(attrib.format);

			attributeDescriptions.push_back(attributeDescription);
		}
	}

	// do we need to use a constant VertexColor?
	if (!usesColor) {
		// FIXME: is there a case where gaps happen between buffer bindings?
		// then this doesn't work. We might need to enable null buffers again.
		const auto constantColorBufferBinding = highestBufferBinding + 1;

		VkVertexInputBindingDescription bindingDescription{};
		bindingDescription.binding = constantColorBufferBinding;
		bindingDescription.inputRate = VK_VERTEX_INPUT_RATE_VERTEX;
		bindingDescription.stride = 0;	// no stride, will always read the same color multiple times.
		bindingDescriptions.push_back(bindingDescription);

		VkVertexInputAttributeDescription attributeDescription{};
		attributeDescription.binding = constantColorBufferBinding;
		attributeDescription.location = ATTRIB_COLOR;
		attributeDescription.offset = 0;
		attributeDescription.format = VK_FORMAT_R32G32B32A32_SFLOAT;
		attributeDescriptions.push_back(attributeDescription);
	}
}

void Graphics::prepareDraw(const VertexAttributes& attributes, const BufferBindings& buffers, graphics::Texture* texture, PrimitiveType primitiveType, CullMode cullmode) {
	GraphicsPipelineConfiguration configuration;
	configuration.vertexAttributes = attributes;
	configuration.shader = (Shader*)Shader::current;
	configuration.primitiveType = primitiveType;
	configuration.wireFrame = states.back().wireframe;
	configuration.blendState = states.back().blend;
	configuration.colorChannelMask = states.back().colorMask;
	configuration.winding = states.back().winding;
	configuration.cullmode = cullmode;
	configuration.framebufferFormat = currentFramebufferOutputFormat;
	configuration.viewportWidth = currentViewportWidth;
	configuration.viewportHeight = currentViewportHeight;
	if (states.back().scissor) {
		configuration.scissorRect = states.back().scissorRect;
	}
	else {
		configuration.scissorRect = std::nullopt;
	}
	std::vector<VkBuffer> bufferVector;
	std::vector<VkDeviceSize> offsets;

	for (uint32_t i = 0; i < VertexAttributes::MAX; i++) {
		if (buffers.useBits & (1u << i)) {
			bufferVector.push_back((VkBuffer)buffers.info[i].buffer->getHandle());
			offsets.push_back((VkDeviceSize)buffers.info[i].offset);
		}
	}

	if (usesConstantVertexColor(attributes)) {
		bufferVector.push_back((VkBuffer)batchedDrawBuffers[currentFrame].constantColorBuffer->getHandle());
		offsets.push_back((VkDeviceSize)0);
	}

	auto currentUniformData = getCurrentBuiltinUniformData();
	configuration.shader->setUniformData(currentUniformData);
	if (texture == nullptr) {
		configuration.shader->setMainTex(standardTexture.get());
	}
	else {
		configuration.shader->setMainTex(texture);
	}

	ensureGraphicsPipelineConfiguration(configuration);

	configuration.shader->cmdPushDescriptorSets(commandBuffers.at(imageIndex), static_cast<uint32_t>(currentFrame));
	vkCmdBindVertexBuffers(commandBuffers.at(imageIndex), 0, static_cast<uint32_t>(bufferVector.size()), bufferVector.data(), offsets.data());
}

void Graphics::startRenderPass(Texture* texture, uint32_t w, uint32_t h) {
	VkRenderingAttachmentInfo colorAttachmentInfo{};
	colorAttachmentInfo.sType = VK_STRUCTURE_TYPE_RENDERING_ATTACHMENT_INFO;
	colorAttachmentInfo.imageLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
	colorAttachmentInfo.loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
	if (texture) {
		colorAttachmentInfo.imageView = (VkImageView)texture->getRenderTargetHandle();
		auto vulkanFormat = Vulkan::getTextureFormat(texture->getPixelFormat());
		currentFramebufferOutputFormat = vulkanFormat.internalFormat;

		renderTargetTexture = texture;
	} else {
		colorAttachmentInfo.imageView = swapChainImageViews[imageIndex];
		currentFramebufferOutputFormat = swapChainImageFormat;

		renderTargetTexture = nullptr;
	}
	colorAttachmentInfo.storeOp = VK_ATTACHMENT_STORE_OP_STORE;

	VkRenderingInfo renderingInfo{};
	renderingInfo.sType = VK_STRUCTURE_TYPE_RENDERING_INFO;
	renderingInfo.renderArea.extent.width = w;
	renderingInfo.renderArea.extent.height = h;
	renderingInfo.layerCount = 1;
	renderingInfo.colorAttachmentCount = 1;
	renderingInfo.pColorAttachments = &colorAttachmentInfo;

	currentViewportWidth = (float)w;
	currentViewportHeight = (float)h;

	if (renderTargetTexture) {
		Vulkan::cmdTransitionImageLayout(commandBuffers.at(imageIndex), (VkImage)texture->getHandle(), VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
	}

	vkCmdBeginRendering(commandBuffers.at(imageIndex), &renderingInfo);

	currentGraphicsPipeline = VK_NULL_HANDLE;
}

void Graphics::endRenderPass() {
	vkCmdEndRendering(commandBuffers.at(imageIndex));

	if (renderTargetTexture) {
		Vulkan::cmdTransitionImageLayout(commandBuffers.at(imageIndex), (VkImage)renderTargetTexture->getHandle(), VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
		renderTargetTexture = nullptr;
	}
}

VkSampler Graphics::createSampler(const SamplerState& samplerState) {
	VkPhysicalDeviceProperties properties{};
	vkGetPhysicalDeviceProperties(physicalDevice, &properties);

	VkSamplerCreateInfo samplerInfo{};
	samplerInfo.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
	samplerInfo.magFilter = Vulkan::getFilter(samplerState.magFilter);
	samplerInfo.minFilter = Vulkan::getFilter(samplerState.minFilter);
	samplerInfo.addressModeU = Vulkan::getWrapMode(samplerState.wrapU);
	samplerInfo.addressModeV = Vulkan::getWrapMode(samplerState.wrapV);
	samplerInfo.addressModeW = Vulkan::getWrapMode(samplerState.wrapW);
	samplerInfo.anisotropyEnable = VK_TRUE;
	samplerInfo.maxAnisotropy = properties.limits.maxSamplerAnisotropy;	// fixme: samplerState.maxAnisotropy
	samplerInfo.borderColor = VK_BORDER_COLOR_INT_OPAQUE_BLACK;
	samplerInfo.unnormalizedCoordinates = VK_FALSE;
	if (samplerState.depthSampleMode.hasValue) {
		samplerInfo.compareEnable = VK_TRUE;
		samplerInfo.compareOp = Vulkan::getCompareOp(samplerState.depthSampleMode.value);
	} else {
		samplerInfo.compareEnable = VK_FALSE;
		samplerInfo.compareOp = VK_COMPARE_OP_ALWAYS;
	}
	samplerInfo.mipmapMode = Vulkan::getMipMapMode(samplerState.mipmapFilter);
	samplerInfo.mipLodBias = samplerState.lodBias;
	samplerInfo.minLod = 0.0f;	// fixme: samplerState.minLod
	samplerInfo.maxLod = 0.0f;	// fixme: samplerState.maxLod

	VkSampler sampler;
	if (vkCreateSampler(device, &samplerInfo, nullptr, &sampler) != VK_SUCCESS) {
		throw love::Exception("failed to create sampler");
	}

	return sampler;
}

VkSampler Graphics::getCachedSampler(const SamplerState& samplerState) {
	auto it = samplers.find(samplerState);
	if (it != samplers.end()) {
		return it->second;
	} else {
		VkSampler sampler = createSampler(samplerState);
		samplers.insert({samplerState, sampler});
		return sampler;
	}
}

VkPipeline Graphics::createGraphicsPipeline(GraphicsPipelineConfiguration configuration) {
	auto &shaderStages = configuration.shader->getShaderStages();

	std::vector<VkVertexInputBindingDescription> bindingDescriptions;
	std::vector<VkVertexInputAttributeDescription> attributeDescriptions;
	
	createVulkanVertexFormat(configuration.vertexAttributes, bindingDescriptions, attributeDescriptions);

	VkPipelineVertexInputStateCreateInfo vertexInputInfo{};
	vertexInputInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
	vertexInputInfo.vertexBindingDescriptionCount = static_cast<uint32_t>(bindingDescriptions.size());
	vertexInputInfo.pVertexBindingDescriptions = bindingDescriptions.data();
	vertexInputInfo.vertexAttributeDescriptionCount = static_cast<uint32_t>(attributeDescriptions.size());
	vertexInputInfo.pVertexAttributeDescriptions = attributeDescriptions.data();

	VkPipelineInputAssemblyStateCreateInfo inputAssembly{};
	inputAssembly.sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO;
	inputAssembly.topology = Vulkan::getPrimitiveTypeTopology(configuration.primitiveType);
	inputAssembly.primitiveRestartEnable = VK_FALSE;
	
	VkViewport viewport{};
	viewport.x = 0.0f;
	viewport.y = 0.0f;
	viewport.width = configuration.viewportWidth;
	viewport.height = configuration.viewportHeight;
	viewport.minDepth = 0.0f;
	viewport.maxDepth = 1.0f;

	VkRect2D scissor{};
	if (configuration.scissorRect.has_value()) {
		scissor.offset.x = configuration.scissorRect.value().x;
		scissor.offset.y = configuration.scissorRect.value().y;
		scissor.extent.width = static_cast<uint32_t>(configuration.scissorRect.value().w);
		scissor.extent.height = static_cast<uint32_t>(configuration.scissorRect.value().h);
	}
	else {
		scissor.offset = { 0, 0 };
		scissor.extent = swapChainExtent;
	}

	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 = Vulkan::getPolygonMode(configuration.wireFrame);
	rasterizer.lineWidth = 1.0f;
	rasterizer.cullMode = Vulkan::getCullMode(configuration.cullmode);
	rasterizer.frontFace = Vulkan::getFrontFace(configuration.winding);
	rasterizer.depthBiasEnable = VK_FALSE;
	rasterizer.depthBiasConstantFactor = 0.0f;
	rasterizer.depthBiasClamp = 0.0f;
	rasterizer.depthBiasSlopeFactor = 0.0f;

	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 = Vulkan::getColorMask(configuration.colorChannelMask);
	colorBlendAttachment.blendEnable = Vulkan::getBool(configuration.blendState.enable);
	colorBlendAttachment.srcColorBlendFactor = Vulkan::getBlendFactor(configuration.blendState.srcFactorRGB);
	colorBlendAttachment.dstColorBlendFactor = Vulkan::getBlendFactor(configuration.blendState.dstFactorRGB);
	colorBlendAttachment.colorBlendOp = Vulkan::getBlendOp(configuration.blendState.operationRGB);
	colorBlendAttachment.srcAlphaBlendFactor = Vulkan::getBlendFactor(configuration.blendState.srcFactorA);
	colorBlendAttachment.dstAlphaBlendFactor = Vulkan::getBlendFactor(configuration.blendState.dstFactorA);
	colorBlendAttachment.alphaBlendOp = Vulkan::getBlendOp(configuration.blendState.operationA);

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

	VkFormat framebufferOutputFormat = configuration.framebufferFormat;

	VkPipelineRenderingCreateInfo pipelineRenderingCreateInfo{};
	pipelineRenderingCreateInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_RENDERING_CREATE_INFO;
	pipelineRenderingCreateInfo.colorAttachmentCount = 1;
	pipelineRenderingCreateInfo.pColorAttachmentFormats = &framebufferOutputFormat;

	VkGraphicsPipelineCreateInfo pipelineInfo{};
	pipelineInfo.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
	pipelineInfo.stageCount = static_cast<uint32_t>(shaderStages.size());
	pipelineInfo.pStages = shaderStages.data();
	pipelineInfo.pVertexInputState = &vertexInputInfo;
	pipelineInfo.pInputAssemblyState = &inputAssembly;
	pipelineInfo.pViewportState = &viewportState;
	pipelineInfo.pRasterizationState = &rasterizer;
	pipelineInfo.pMultisampleState = &multisampling;
	pipelineInfo.pDepthStencilState = nullptr;
	pipelineInfo.pColorBlendState = &colorBlending;
	pipelineInfo.pDynamicState = nullptr;
	pipelineInfo.layout = configuration.shader->getGraphicsPipelineLayout();
	pipelineInfo.subpass = 0;
	pipelineInfo.basePipelineHandle = VK_NULL_HANDLE;
	pipelineInfo.basePipelineIndex = -1;
	pipelineInfo.pNext = &pipelineRenderingCreateInfo;

	VkPipeline graphicsPipeline;
	if (vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &pipelineInfo, nullptr, &graphicsPipeline) != VK_SUCCESS) {
		throw love::Exception("failed to create graphics pipeline");
	}
	return graphicsPipeline;
}

void Graphics::ensureGraphicsPipelineConfiguration(GraphicsPipelineConfiguration configuration) {
	auto it = graphicsPipelines.find(configuration);
	if (it != graphicsPipelines.end()) {
		if (it->second != currentGraphicsPipeline) {
			vkCmdBindPipeline(commandBuffers.at(imageIndex), VK_PIPELINE_BIND_POINT_GRAPHICS, it->second);
			currentGraphicsPipeline = it->second;
		}
	} else {
		VkPipeline pipeline = createGraphicsPipeline(configuration);
		graphicsPipelines.insert({configuration, pipeline});
		vkCmdBindPipeline(commandBuffers.at(imageIndex), VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
		currentGraphicsPipeline = pipeline;
	}
}

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

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

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

void Graphics::createCommandBuffers() {
	commandBuffers.resize(swapChainImages.size());
	dataTransferCommandBuffers.resize(MAX_FRAMES_IN_FLIGHT);

	VkCommandBufferAllocateInfo allocInfo{};
	allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
	allocInfo.commandPool = commandPool;
	allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
	allocInfo.commandBufferCount = (uint32_t)commandBuffers.size();

	if (vkAllocateCommandBuffers(device, &allocInfo, commandBuffers.data()) != VK_SUCCESS) {
		throw love::Exception("failed to allocate command buffers");
	}

	VkCommandBufferAllocateInfo dataTransferAllocInfo{};
	dataTransferAllocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
	dataTransferAllocInfo.commandPool = commandPool;
	dataTransferAllocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
	dataTransferAllocInfo.commandBufferCount = (uint32_t)MAX_FRAMES_IN_FLIGHT;

	if (vkAllocateCommandBuffers(device, &dataTransferAllocInfo, dataTransferCommandBuffers.data()) != VK_SUCCESS) {
		throw love::Exception("failed to allocate data transfer command buffers");
	}
}

void Graphics::createSyncObjects() {
	imageAvailableSemaphores.resize(MAX_FRAMES_IN_FLIGHT);
	renderFinishedSemaphores.resize(MAX_FRAMES_IN_FLIGHT);
	inFlightFences.resize(MAX_FRAMES_IN_FLIGHT);
	imagesInFlight.resize(swapChainImages.size(), VK_NULL_HANDLE);

	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;

	for (size_t i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {
		if (vkCreateSemaphore(device, &semaphoreInfo, nullptr, &imageAvailableSemaphores.at(i)) != VK_SUCCESS ||
			vkCreateSemaphore(device, &semaphoreInfo, nullptr, &renderFinishedSemaphores.at(i)) != VK_SUCCESS ||
			vkCreateFence(device, &fenceInfo, nullptr, &inFlightFences.at(i)) != VK_SUCCESS) {
			throw love::Exception("failed to create synchronization objects for a frame!");
		}
	}
}

void Graphics::createDefaultTexture() {
	Texture::Settings settings;
	standardTexture.reset((Texture*)newTexture(settings));
}

void Graphics::cleanup() {
	delete quadIndexBuffer;
	quadIndexBuffer = nullptr;

	cleanupSwapChain();

	for (auto &cleanUpFns : cleanUpFunctions) {
		for (auto &cleanUpFn : cleanUpFns) {
			cleanUpFn();
		}
	}
	cleanUpFunctions.clear();

	vmaDestroyAllocator(vmaAllocator);
	batchedDrawBuffers.clear();
	for (size_t i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {
		vkDestroySemaphore(device, renderFinishedSemaphores[i], nullptr);
		vkDestroySemaphore(device, imageAvailableSemaphores[i], nullptr);
		vkDestroyFence(device, inFlightFences[i], nullptr);
	}

	vkFreeCommandBuffers(device, commandPool, static_cast<uint32_t>(commandBuffers.size()), commandBuffers.data());
	vkFreeCommandBuffers(device, commandPool, MAX_FRAMES_IN_FLIGHT, dataTransferCommandBuffers.data());

	for (auto const& p : samplers) {
		vkDestroySampler(device, p.second, nullptr);
	}
	samplers.clear();

	// fixme: maybe we should clean up some pipelines if they haven't been used in a while.
	for (auto const& p : graphicsPipelines) {
		vkDestroyPipeline(device, p.second, nullptr);
	}
	graphicsPipelines.clear();

	vkDestroyCommandPool(device, commandPool, nullptr);
	vkDestroyDevice(device, nullptr);
	vkDestroySurfaceKHR(instance, surface, nullptr);
	vkDestroyInstance(instance, nullptr);
}

void Graphics::cleanupSwapChain() {
	for (size_t i = 0; i < swapChainImageViews.size(); i++) {
		vkDestroyImageView(device, swapChainImageViews[i], nullptr);
	}
	vkDestroySwapchainKHR(device, swapChain, nullptr);
}

void Graphics::recreateSwapChain() {
	vkDeviceWaitIdle(device);

	cleanupSwapChain();

	createSwapChain();
	createImageViews();
}

love::graphics::Graphics* createInstance() {
	love::graphics::Graphics* instance = nullptr;

	try {
		instance = new Graphics();
	}
	catch (love::Exception& e) {
		printf("Cannot create Vulkan renderer: %s\n", e.what());
	}

	return instance;
}
} // vulkan
} // graphics
} // love