// Blaze.cpp : This file contains the 'main' function. Program execution begins and ends there.
//


#include <array>
#include <cassert>
#include <span>

#include <volk.h>

#define SDL_MAIN_USE_CALLBACKS 1
#include <memory>
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>
#include <SDL3/SDL_filesystem.h>
#include <SDL3/SDL_vulkan.h>

#include "AppState.h"
#include "Frame.h"
#include "GlobalMemory.h"
#include "MacroUtils.h"
#include "MathUtil.h"
#include "RenderDevice.h"
#include "MiscData.h"

constexpr uint32_t WIDTH = 1280;
constexpr uint32_t HEIGHT = 720;
constexpr uint32_t NUM_FRAMES = 3;

using Byte = uint8_t;

constexpr size_t operator ""_KiB(size_t const value)
{
	return value * 1024;
}

constexpr size_t operator ""_MiB(size_t const value)
{
	return value * 1024_KiB;
}

constexpr size_t operator ""_GiB(size_t const value)
{
	return value * 1024_MiB;
}

namespace Blaze::Global
{
	GlobalMemory g_Memory;
}

SDL_AppResult SDL_AppInit(void** pAppState, int, char**)
{
	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);

	Blaze::Global::g_Memory.init(128_MiB);

	*pAppState = CreateAppState(&Blaze::Global::g_Memory, WIDTH, HEIGHT);
	if (!*pAppState)
		return SDL_APP_FAILURE;

	AppState& appState = *static_cast<AppState*>(*pAppState);

	if (!appState.isInit())
	{
		return SDL_APP_FAILURE;
	}

	return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppIterate(void* appstate)
{
	AppState& appState = *static_cast<AppState*>(appstate);
	RenderDevice& renderDevice = *appState.renderDevice;
	MiscData& misc = *appState.miscData;
	Frame& currentFrame = renderDevice.frames[renderDevice.frameIndex];

	VK_CHECK(vkWaitForFences(renderDevice.device, 1, &currentFrame.frameReadyToReuse, VK_TRUE, std::numeric_limits<uint32_t>::max()));
	// All resources of frame 'frameIndex' are free.

	uint32_t currentImageIndex;
	VK_CHECK(vkAcquireNextImageKHR(renderDevice.device, renderDevice.swapchain, std::numeric_limits<uint32_t>::max(), currentFrame.imageAcquiredSemaphore, nullptr, &currentImageIndex));

	VK_CHECK(vkResetFences(renderDevice.device, 1, &currentFrame.frameReadyToReuse));
	VK_CHECK(vkResetCommandPool(renderDevice.device, currentFrame.commandPool, 0));

	misc.acquireToRenderBarrier.image = renderDevice.swapchainImages[currentImageIndex];
	misc.renderToPresentBarrier.image = renderDevice.swapchainImages[currentImageIndex];

	VkCommandBuffer cmd = currentFrame.commandBuffer;

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

	VkClearColorValue constexpr static BLACK_CLEAR = {
		.float32 = { 0.0f, 0.0f, 0.0f, 1.0f },
	};

	VK_CHECK(vkBeginCommandBuffer(cmd, &beginInfo));
	{
		VkRenderingAttachmentInfo const attachmentInfo = {
			.sType = VK_STRUCTURE_TYPE_RENDERING_ATTACHMENT_INFO,
			.pNext = nullptr,
			.imageView = renderDevice.swapchainViews[currentImageIndex],
			.imageLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
			.resolveMode = VK_RESOLVE_MODE_NONE,
			.resolveImageView = nullptr,
			.resolveImageLayout = VK_IMAGE_LAYOUT_UNDEFINED,
			.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR,
			.storeOp = VK_ATTACHMENT_STORE_OP_STORE,
			.clearValue = {.color = BLACK_CLEAR},
		};

		VkRenderingInfo renderingInfo = {
			.sType = VK_STRUCTURE_TYPE_RENDERING_INFO,
			.pNext = nullptr,
			.flags = 0,
			.renderArea = {.offset = {0,0}, .extent = renderDevice.swapchainExtent},
			.layerCount = 1,
			.viewMask = 0,
			.colorAttachmentCount = 1,
			.pColorAttachments = &attachmentInfo,
			.pDepthAttachment = nullptr,
			.pStencilAttachment = nullptr,
		};

		vkCmdPipelineBarrier2(cmd, &misc.acquireToRenderDependency);
		vkCmdBeginRendering(cmd, &renderingInfo);
		{
			VkViewport viewport = {
				.x = 0,
				.y = static_cast<float>(renderDevice.swapchainExtent.height),
				.width = static_cast<float>(renderDevice.swapchainExtent.width),
				.height = -static_cast<float>(renderDevice.swapchainExtent.height),
				.minDepth = 0.0f,
				.maxDepth = 1.0f,
			};
			vkCmdSetViewport(cmd, 0, 1, &viewport);
			VkRect2D scissor = {
				.offset = {0, 0},
				.extent = renderDevice.swapchainExtent,
			};
			vkCmdSetScissor(cmd, 0, 1, &scissor);

			// Render Something?
			vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, misc.trianglePipeline);
			vkCmdDraw(cmd, 3, 1, 0, 0);

		}
		vkCmdEndRendering(cmd);
		vkCmdPipelineBarrier2(cmd, &misc.renderToPresentDependency);
	}
	VK_CHECK(vkEndCommandBuffer(cmd));

	VkPipelineStageFlags stageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
	VkSubmitInfo const submitInfo = {
		.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO,
		.pNext = nullptr,
		.waitSemaphoreCount = 1,
		.pWaitSemaphores = &currentFrame.imageAcquiredSemaphore,
		.pWaitDstStageMask = &stageMask,
		.commandBufferCount = 1,
		.pCommandBuffers = &cmd,
		.signalSemaphoreCount = 1,
		.pSignalSemaphores = &currentFrame.renderFinishedSemaphore,
	};
	VK_CHECK(vkQueueSubmit(renderDevice.directQueue, 1, &submitInfo, currentFrame.frameReadyToReuse));

	VkPresentInfoKHR const presentInfo = {
		.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR,
		.pNext = nullptr,
		.waitSemaphoreCount = 1,
		.pWaitSemaphores = &currentFrame.renderFinishedSemaphore,
		.swapchainCount = 1,
		.pSwapchains = &renderDevice.swapchain,
		.pImageIndices = &currentImageIndex,
		.pResults = nullptr,
	};

	VK_CHECK(vkQueuePresentKHR(renderDevice.directQueue, &presentInfo));

	renderDevice.frameIndex = (renderDevice.frameIndex + 1) % NUM_FRAMES;

	return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppEvent(void*, SDL_Event* event)
{
	if (event->type == SDL_EVENT_QUIT)
	{
		return SDL_APP_SUCCESS;
	}

	return SDL_APP_CONTINUE;
}

void SDL_AppQuit(void* appstate, SDL_AppResult)
{
	AppState* appState = static_cast<AppState*> (appstate);

	appState->cleanup();

	Blaze::Global::g_Memory.destroy();
}