// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef sw_Blitter_hpp
#define sw_Blitter_hpp

#include "Memset.hpp"
#include "RoutineCache.hpp"
#include "Reactor/Reactor.hpp"
#include "Vulkan/VkFormat.h"

#include <mutex>
#include <cstring>

namespace vk
{
	class Image;
	class Buffer;
}

namespace sw
{
	class Blitter
	{
		struct Options
		{
			explicit Options() = default;
			explicit Options(bool filter, bool allowSRGBConversion)
				: writeMask(0xF), clearOperation(false), filter(filter), allowSRGBConversion(allowSRGBConversion), clampToEdge(false) {}
			explicit Options(unsigned int writeMask)
				: writeMask(writeMask), clearOperation(true), filter(false), allowSRGBConversion(true), clampToEdge(false) {}

			union
			{
				struct
				{
					bool writeRed : 1;
					bool writeGreen : 1;
					bool writeBlue : 1;
					bool writeAlpha : 1;
				};

				unsigned char writeMask;
			};

			bool clearOperation : 1;
			bool filter : 1;
			bool allowSRGBConversion : 1;
			bool clampToEdge : 1;
		};

		struct State : Memset<State>, Options
		{
			State() : Memset(this, 0) {}
			State(const Options &options) : Memset(this, 0), Options(options) {}
			State(vk::Format sourceFormat, vk::Format destFormat, int srcSamples, int destSamples, const Options &options) :
				Memset(this, 0), Options(options), sourceFormat(sourceFormat), destFormat(destFormat), srcSamples(srcSamples), destSamples(destSamples) {}

			bool operator==(const State &state) const
			{
				static_assert(is_memcmparable<State>::value, "Cannot memcmp State");
				return memcmp(this, &state, sizeof(State)) == 0;
			}

			vk::Format sourceFormat;
			vk::Format destFormat;
			int srcSamples = 0;
			int destSamples = 0;
		};

		struct BlitData
		{
			void *source;
			void *dest;
			int sPitchB;
			int dPitchB;
			int sSliceB;
			int dSliceB;

			float x0;
			float y0;
			float w;
			float h;

			int y0d;
			int y1d;
			int x0d;
			int x1d;

			int sWidth;
			int sHeight;
		};

		struct CubeBorderData
		{
			void *layers;
			int pitchB;
			uint32_t layerSize;
			uint32_t dim;
		};

	public:
		Blitter();
		virtual ~Blitter();

		void clear(void *pixel, vk::Format format, vk::Image *dest, const vk::Format& viewFormat, const VkImageSubresourceRange& subresourceRange, const VkRect2D* renderArea = nullptr);

		void blit(const vk::Image *src, vk::Image *dst, VkImageBlit region, VkFilter filter);
		void blitToBuffer(const vk::Image *src, VkImageSubresourceLayers subresource, VkOffset3D offset, VkExtent3D extent, uint8_t *dst, int bufferRowPitch, int bufferSlicePitch);
		void blitFromBuffer(const vk::Image *dst, VkImageSubresourceLayers subresource, VkOffset3D offset, VkExtent3D extent, uint8_t *src, int bufferRowPitch, int bufferSlicePitch);

		void updateBorders(vk::Image* image, const VkImageSubresourceLayers& subresourceLayers);

	private:
		enum Edge { TOP, BOTTOM, RIGHT, LEFT };

		bool fastClear(void *pixel, vk::Format format, vk::Image *dest, const vk::Format& viewFormat, const VkImageSubresourceRange& subresourceRange, const VkRect2D* renderArea);

		Float4 readFloat4(Pointer<Byte> element, const State &state);
		void write(Float4 &color, Pointer<Byte> element, const State &state);
		Int4 readInt4(Pointer<Byte> element, const State &state);
		void write(Int4 &color, Pointer<Byte> element, const State &state);
		static void ApplyScaleAndClamp(Float4 &value, const State &state, bool preScaled = false);
		static Int ComputeOffset(Int &x, Int &y, Int &pitchB, int bytes, bool quadLayout);
		static Float4 LinearToSRGB(Float4 &color);
		static Float4 sRGBtoLinear(Float4 &color);

		using BlitFunction = FunctionT<void(const BlitData*)>;
		using BlitRoutineType = BlitFunction::RoutineType;
		BlitRoutineType getBlitRoutine(const State &state);
		BlitRoutineType generate(const State &state);

		using CornerUpdateFunction = FunctionT<void(const CubeBorderData*)>;
		using CornerUpdateRoutineType = CornerUpdateFunction::RoutineType;
		CornerUpdateRoutineType getCornerUpdateRoutine(const State &state);
		CornerUpdateRoutineType generateCornerUpdate(const State& state);
		void computeCubeCorner(Pointer<Byte>& layer, Int& x0, Int& x1, Int& y0, Int& y1, Int& pitchB, const State& state);

		void copyCubeEdge(vk::Image* image,
	                      const VkImageSubresourceLayers& dstSubresourceLayers, Edge dstEdge,
	                      const VkImageSubresourceLayers& srcSubresourceLayers, Edge srcEdge);

		std::mutex blitMutex;
		RoutineCacheT<State, BlitFunction::CFunctionType> blitCache; // guarded by blitMutex
		std::mutex cornerUpdateMutex;
		RoutineCacheT<State, CornerUpdateFunction::CFunctionType> cornerUpdateCache; // guarded by cornerUpdateMutex
	};
}

#endif   // sw_Blitter_hpp