/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include "VulkanShader.hpp"
#include "../Context.hpp"
#include "../Device.hpp"
#include "../../Scene/Vertex.hpp"

namespace openVulkanoCpp::Vulkan
{
	namespace
	{
		constexpr vk::PrimitiveTopology ToVkTopology(Scene::Topology topology)
		{
			switch (topology)
			{
				case Scene::Topology::PointList: return vk::PrimitiveTopology::ePointList;
				case Scene::Topology::LineList: return vk::PrimitiveTopology::eLineList;
				case Scene::Topology::LineStripe: return vk::PrimitiveTopology::eLineStrip;
				case Scene::Topology::TriangleList: return vk::PrimitiveTopology::eTriangleList;
				case Scene::Topology::TriangleStripe: return vk::PrimitiveTopology::eTriangleStrip;
				default: throw std::runtime_error("Unknown topology!");
			}
		}
	}

	void VulkanShader::Init(Context* context, Scene::Shader* shader, IShaderOwner* owner)
	{
		this->device = context->device->device;
		this->shader = shader;
		this->owner = owner;
		this->context = context;
		shaderModuleVertex = context->device->CreateShaderModule(shader->vertexShaderName + ".vert.spv");
		shaderModuleFragment = context->device->CreateShaderModule(shader->fragmentShaderName + ".frag.spv");
		BuildPipeline();
	}

	void VulkanShader::BuildPipeline()
	{
		std::vector<vk::PipelineShaderStageCreateInfo> shaderStageCreateInfos(2);
		shaderStageCreateInfos[0] = { {}, vk::ShaderStageFlagBits::eVertex, shaderModuleVertex, "main" };
		shaderStageCreateInfos[1] = { {}, vk::ShaderStageFlagBits::eFragment, shaderModuleFragment, "main" };

		auto vertexBindDesc = vk::VertexInputBindingDescription(0, sizeof(Vertex), vk::VertexInputRate::eVertex);
		std::vector<vk::VertexInputAttributeDescription> attributeDescriptions;
		attributeDescriptions.emplace_back(0, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, position));
		attributeDescriptions.emplace_back(1, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, normal));
		attributeDescriptions.emplace_back(2, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, tangent));
		attributeDescriptions.emplace_back(3, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, biTangent));
		attributeDescriptions.emplace_back(4, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, textureCoordinates));
		attributeDescriptions.emplace_back(5, 0, vk::Format::eR32G32B32A32Sfloat, offsetof(Vertex, color));

		vk::PipelineViewportStateCreateInfo viewportStateCreateInfo = { {}, 1, &context->swapChain.GetFullscreenViewport(), 1, &context->swapChain.GetFullscreenScissor() };
		vk::PipelineVertexInputStateCreateInfo pipelineVertexInputStateCreateInfo = { {}, 1, &vertexBindDesc,
																					  static_cast<uint32_t>(attributeDescriptions.size()), attributeDescriptions.data() };
		vk::PipelineInputAssemblyStateCreateInfo inputAssembly = { {}, ToVkTopology(shader->topology), 0 };
		vk::PipelineRasterizationStateCreateInfo rasterizer = {};
		rasterizer.cullMode = vk::CullModeFlagBits::eBack;
		vk::PipelineMultisampleStateCreateInfo msaa = {};
		vk::PipelineDepthStencilStateCreateInfo depth = { {}, 1, 1, vk::CompareOp::eLess };
		depth.maxDepthBounds = 1;
		vk::PipelineColorBlendAttachmentState colorBlendAttachment = {};
		colorBlendAttachment.colorWriteMask = vk::ColorComponentFlagBits::eA | vk::ColorComponentFlagBits::eB | vk::ColorComponentFlagBits::eG | vk::ColorComponentFlagBits::eR;
		vk::PipelineColorBlendStateCreateInfo colorInfo = {};
		colorInfo.attachmentCount = 1;
		colorInfo.pAttachments = &colorBlendAttachment;



		vk::GraphicsPipelineCreateInfo pipelineCreateInfo = { {}, static_cast<uint32_t>(shaderStageCreateInfos.size()), shaderStageCreateInfos.data(), &pipelineVertexInputStateCreateInfo, &inputAssembly,
															  nullptr, &viewportStateCreateInfo, &rasterizer, &msaa, &depth, &colorInfo, nullptr, context->pipeline.pipelineLayout, context->swapChainRenderPass.renderPass };
		pipeline = this->device.createGraphicsPipeline({}, pipelineCreateInfo).value;
	}

	void VulkanShader::Resize()
	{
		device.destroyPipeline(pipeline);
		BuildPipeline();
	}

	void VulkanShader::Record(vk::CommandBuffer& cmdBuffer, uint32_t bufferId)
	{
		cmdBuffer.bindPipeline(vk::PipelineBindPoint::eGraphics, pipeline);
	}

	void VulkanShader::Close()
	{
		owner->RemoveShader(this);
		shader = nullptr;
		device.destroyPipeline(pipeline);
		device.destroyShaderModule(shaderModuleVertex);
		device.destroyShaderModule(shaderModuleFragment);
	}
}