// Copyright 1998-2016 Epic Games, Inc. All Rights Reserved.

#include "Core.h"
#include "ModuleInterface.h"
#include "ModuleManager.h"
#include "TargetPlatform.h"
#include "TextureCompressorModule.h"
#include "PixelFormat.h"
#include "ImageCore.h"

DEFINE_LOG_CATEGORY_STATIC(LogTextureFormatUncompressed, Log, All);

/**
 * Macro trickery for supported format names.
 */
#define ENUM_SUPPORTED_FORMATS(op) \
	op(BGRA8) \
	op(G8) \
	op(VU8) \
	op(RGBA16F) \
	op(XGXR8) \
	op(RGBA8) \
	op(POTERROR)

#define DECL_FORMAT_NAME(FormatName) static FName GTextureFormatName##FormatName = FName(TEXT(#FormatName));
ENUM_SUPPORTED_FORMATS(DECL_FORMAT_NAME);
#undef DECL_FORMAT_NAME

#define DECL_FORMAT_NAME_ENTRY(FormatName) GTextureFormatName##FormatName ,
static FName GSupportedTextureFormatNames[] =
{
	ENUM_SUPPORTED_FORMATS(DECL_FORMAT_NAME_ENTRY)
};
#undef DECL_FORMAT_NAME_ENTRY

#undef ENUM_SUPPORTED_FORMATS

/**
 * Uncompressed texture format handler.
 */
class FTextureFormatUncompressed : public ITextureFormat
{
	virtual bool AllowParallelBuild() const override
	{
		return true;
	}

	virtual uint16 GetVersion(FName Format) const override
	{
		return 0;
	}

	virtual void GetSupportedFormats(TArray<FName>& OutFormats) const override
	{
		for (int32 i = 0; i < ARRAY_COUNT(GSupportedTextureFormatNames); ++i)
		{
			OutFormats.Add(GSupportedTextureFormatNames[i]);
		}
	}
	
	virtual FTextureFormatCompressorCaps GetFormatCapabilities() const override
	{
		return FTextureFormatCompressorCaps(); // Default capabilities.
	}

	virtual bool CompressImage(
		const FImage& InImage,
		const struct FTextureBuildSettings& BuildSettings,
		bool bImageHasAlphaChannel,
		FCompressedImage2D& OutCompressedImage
		) const override
	{
		if (BuildSettings.TextureFormatName == GTextureFormatNameG8)
		{
			FImage Image;
			InImage.CopyTo(Image, ERawImageFormat::G8, BuildSettings.GetGammaSpace());

			OutCompressedImage.SizeX = Image.SizeX;
			OutCompressedImage.SizeY = Image.SizeY;
			OutCompressedImage.PixelFormat = PF_G8;
			OutCompressedImage.RawData = Image.RawData;

			return true;
		}
		else if (BuildSettings.TextureFormatName == GTextureFormatNameVU8)
		{
			FImage Image;
			InImage.CopyTo(Image, ERawImageFormat::BGRA8, BuildSettings.GetGammaSpace());

			OutCompressedImage.SizeX = Image.SizeX;
			OutCompressedImage.SizeY = Image.SizeY;
			OutCompressedImage.PixelFormat = PF_V8U8;

			uint32 NumTexels = Image.SizeX * Image.SizeY * Image.NumSlices;
			OutCompressedImage.RawData.Empty(NumTexels * 2);
			OutCompressedImage.RawData.AddUninitialized(NumTexels * 2);
			const FColor* FirstColor = Image.AsBGRA8();
			const FColor* LastColor = FirstColor + NumTexels;
			int8* Dest = (int8*)OutCompressedImage.RawData.GetData();

			for (const FColor* Color = FirstColor; Color < LastColor; ++Color)
			{
				*Dest++ = (int32)Color->R - 128;
				*Dest++ = (int32)Color->G - 128;
			}

			return true;
		}
		else if (BuildSettings.TextureFormatName == GTextureFormatNameBGRA8)
		{
			FImage Image;
			InImage.CopyTo(Image, ERawImageFormat::BGRA8, BuildSettings.GetGammaSpace());

			OutCompressedImage.SizeX = Image.SizeX;
			OutCompressedImage.SizeY = Image.SizeY;
			OutCompressedImage.PixelFormat = PF_B8G8R8A8;
			OutCompressedImage.RawData = Image.RawData;

			return true;
		}
		else if (BuildSettings.TextureFormatName == GTextureFormatNameRGBA8)
		{
			FImage Image;
			InImage.CopyTo(Image, ERawImageFormat::BGRA8, BuildSettings.GetGammaSpace());

			OutCompressedImage.SizeX = Image.SizeX;
			OutCompressedImage.SizeY = Image.SizeY;
			OutCompressedImage.PixelFormat = PF_B8G8R8A8;

			// swizzle each texel
			uint32 NumTexels = Image.SizeX * Image.SizeY * Image.NumSlices;
			OutCompressedImage.RawData.Empty(NumTexels * 4);
			OutCompressedImage.RawData.AddUninitialized(NumTexels * 4);
			const FColor* FirstColor = Image.AsBGRA8();
			const FColor* LastColor = FirstColor + NumTexels;
			int8* Dest = (int8*)OutCompressedImage.RawData.GetData();

			for (const FColor* Color = FirstColor; Color < LastColor; ++Color)
			{
				*Dest++ = (int32)Color->R;
				*Dest++ = (int32)Color->G;
				*Dest++ = (int32)Color->B;
				*Dest++ = (int32)Color->A;
			}

			return true;
		}
		else if (BuildSettings.TextureFormatName == GTextureFormatNameXGXR8)
		{
			FImage Image;
			InImage.CopyTo(Image, ERawImageFormat::BGRA8, BuildSettings.GetGammaSpace());

			OutCompressedImage.SizeX = Image.SizeX;
			OutCompressedImage.SizeY = Image.SizeY;
			OutCompressedImage.PixelFormat = PF_B8G8R8A8;

			// swizzle each texel
			uint32 NumTexels = Image.SizeX * Image.SizeY * Image.NumSlices;
			OutCompressedImage.RawData.Empty(NumTexels * 4);
			OutCompressedImage.RawData.AddUninitialized(NumTexels * 4);
			const FColor* FirstColor = Image.AsBGRA8();
			const FColor* LastColor = FirstColor + NumTexels;
			int8* Dest = (int8*)OutCompressedImage.RawData.GetData();

			for (const FColor* Color = FirstColor; Color < LastColor; ++Color)
			{
				*Dest++ = (int32)Color->B;
				*Dest++ = (int32)Color->G;
				*Dest++ = (int32)Color->A;
				*Dest++ = (int32)Color->R;
			}

			return true;
		}
		else if (BuildSettings.TextureFormatName == GTextureFormatNameRGBA16F)
		{
			FImage Image;
			InImage.CopyTo(Image, ERawImageFormat::RGBA16F, EGammaSpace::Linear);

			OutCompressedImage.SizeX = Image.SizeX;
			OutCompressedImage.SizeY = Image.SizeY;
			OutCompressedImage.PixelFormat = PF_FloatRGBA;
			OutCompressedImage.RawData = Image.RawData;

			return true;
		}
		else if (BuildSettings.TextureFormatName == GTextureFormatNamePOTERROR)
		{
			// load the error image data we will just repeat into the texture
			TArray<uint8> ErrorData;
			FFileHelper::LoadFileToArray(ErrorData, TEXT("../../../Engine/Content/MobileResources/PowerOfTwoError64x64.raw"));

			// set output
			OutCompressedImage.SizeX = InImage.SizeX;
			OutCompressedImage.SizeY = InImage.SizeY;
			OutCompressedImage.PixelFormat = PF_B8G8R8A8;

			// allocate output memory
			check(InImage.NumSlices == 1);
			uint32 NumTexels = InImage.SizeX * InImage.SizeY;
			OutCompressedImage.RawData.Empty(NumTexels * 4);
			OutCompressedImage.RawData.AddUninitialized(NumTexels * 4);

			// write out texels
			uint8* Src = ErrorData.GetData();
			uint8* Dest = (uint8*)OutCompressedImage.RawData.GetData();
			for (int32 Y = 0; Y < InImage.SizeY; Y++)
			{
				for (int32 X = 0; X < InImage.SizeX * 4; X++)
				{
					int32 SrcX = X & (64 * 4 - 1);
					int32 SrcY = Y & 63;
					Dest[Y * InImage.SizeX * 4 + X] = Src[SrcY * 64 * 4 + SrcX];
				}
			}

			
			return true;
		}
		
		UE_LOG(LogTextureFormatUncompressed, Warning,
			TEXT("Cannot convert uncompressed image to format '%s'."),
			*BuildSettings.TextureFormatName.ToString()
			);

		return false;
	}
};

/**
 * Module for uncompressed texture formats.
 */
static ITextureFormat* Singleton = NULL;

class FTextureFormatUncompressedModule : public ITextureFormatModule
{
public:
	virtual ~FTextureFormatUncompressedModule()
	{
		delete Singleton;
		Singleton = NULL;
	}
	virtual ITextureFormat* GetTextureFormat()
	{
		if (!Singleton)
		{
			Singleton = new FTextureFormatUncompressed();
		}
		return Singleton;
	}
};

IMPLEMENT_MODULE(FTextureFormatUncompressedModule, TextureFormatUncompressed);