#include "Shader.h"

#include <vector>

namespace love {
	namespace graphics {
		namespace vulkan {
			static VkShaderStageFlagBits getStageBit(ShaderStageType type) {
				switch (type) {
				case SHADERSTAGE_VERTEX:
					return VK_SHADER_STAGE_VERTEX_BIT;
				case SHADERSTAGE_PIXEL:
					return VK_SHADER_STAGE_FRAGMENT_BIT;
				case SHADERSTAGE_COMPUTE:
					return VK_SHADER_STAGE_COMPUTE_BIT;
				}
				throw love::Exception("invalid type");
			}

			Shader::Shader(StrongRef<love::graphics::ShaderStage> stages[])
				: graphics::Shader(stages) {
				for (int i = 0; i < SHADERSTAGE_MAX_ENUM; i++) {
					if (!stages[i]) 
						continue;
					
					auto stage = dynamic_cast<ShaderStage*>(stages[i].get());

					VkPipelineShaderStageCreateInfo shaderStageInfo{};
					shaderStageInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
					shaderStageInfo.stage = getStageBit(stage->getStageType());
					shaderStageInfo.module = stage->getShaderModule();
					shaderStageInfo.pName = "main";

					shaderStages.push_back(shaderStageInfo);
				}
			}

			void Shader::attach() {
				if (Shader::current != this) {
					Graphics::flushBatchedDrawsGlobal();
					Shader::current = this;
					Vulkan::shaderSwitch();
				}
			}

			int Shader::getVertexAttributeIndex(const std::string& name) {
				return vertexAttributeIndices.at(name);
			}
		}
	}
}