// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CColorConverter.h"
#include "SColor.h"
#include "os.h"
#include "irrString.h"

// Warning: The naming of Irrlicht color formats
// is not consistent regarding actual component order in memory.
// E.g. in CImage, ECF_R8G8B8 is handled per-byte and stored as [R][G][B] in memory
// while ECF_A8R8G8B8 is handled as an u32 0xAARRGGBB so [B][G][R][A] (little endian) in memory.
// The conversions suffer from the same inconsistencies, e.g.
// convert_R8G8B8toA8R8G8B8 converts [R][G][B] into 0xFFRRGGBB = [B][G][R][FF] (little endian);
// convert_A1R5G5B5toR8G8B8 converts 0bARRRRRGGGGGBBBBB into [R][G][B].
// This also means many conversions may be broken on big endian.

namespace irr
{
namespace video
{

//! converts a 8 bit palettized or non palettized image (A8) into R8G8B8
void CColorConverter::convert8BitTo24Bit(const u8 *in, u8 *out, s32 width, s32 height, const u8 *palette, s32 linepad, bool flip)
{
	if (!in || !out)
		return;

	const s32 lineWidth = 3 * width;
	if (flip)
		out += lineWidth * height;

	for (s32 y = 0; y < height; ++y) {
		if (flip)
			out -= lineWidth; // one line back
		for (s32 x = 0; x < lineWidth; x += 3) {
			if (palette) {
#ifdef __BIG_ENDIAN__
				out[x + 0] = palette[(in[0] << 2) + 0];
				out[x + 1] = palette[(in[0] << 2) + 1];
				out[x + 2] = palette[(in[0] << 2) + 2];
#else
				out[x + 0] = palette[(in[0] << 2) + 2];
				out[x + 1] = palette[(in[0] << 2) + 1];
				out[x + 2] = palette[(in[0] << 2) + 0];
#endif
			} else {
				out[x + 0] = in[0];
				out[x + 1] = in[0];
				out[x + 2] = in[0];
			}
			++in;
		}
		if (!flip)
			out += lineWidth;
		in += linepad;
	}
}

//! converts a 8 bit palettized or non palettized image (A8) into R8G8B8
void CColorConverter::convert8BitTo32Bit(const u8 *in, u8 *out, s32 width, s32 height, const u8 *palette, s32 linepad, bool flip)
{
	if (!in || !out)
		return;

	const u32 lineWidth = 4 * width;
	if (flip)
		out += lineWidth * height;

	u32 x;
	u32 c;
	for (u32 y = 0; y < (u32)height; ++y) {
		if (flip)
			out -= lineWidth; // one line back

		if (palette) {
			for (x = 0; x < (u32)width; x += 1) {
				c = in[x];
				((u32 *)out)[x] = ((u32 *)palette)[c];
			}
		} else {
			for (x = 0; x < (u32)width; x += 1) {
				c = in[x];
#ifdef __BIG_ENDIAN__
				((u32 *)out)[x] = c << 24 | c << 16 | c << 8 | 0x000000FF;
#else
				((u32 *)out)[x] = 0xFF000000 | c << 16 | c << 8 | c;
#endif
			}
		}

		if (!flip)
			out += lineWidth;
		in += width + linepad;
	}
}

//! converts 16bit data to 16bit data
void CColorConverter::convert16BitTo16Bit(const s16 *in, s16 *out, s32 width, s32 height, s32 linepad, bool flip)
{
	if (!in || !out)
		return;

	if (flip)
		out += width * height;

	for (s32 y = 0; y < height; ++y) {
		if (flip)
			out -= width;
#ifdef __BIG_ENDIAN__
		for (s32 x = 0; x < width; ++x)
			out[x] = os::Byteswap::byteswap(in[x]);
#else
		memcpy(out, in, width * sizeof(s16));
#endif
		if (!flip)
			out += width;
		in += width;
		in += linepad;
	}
}

//! copies R8G8B8 24bit data to 24bit data
void CColorConverter::convert24BitTo24Bit(const u8 *in, u8 *out, s32 width, s32 height, s32 linepad, bool flip, bool bgr)
{
	if (!in || !out)
		return;

	const s32 lineWidth = 3 * width;
	if (flip)
		out += lineWidth * height;

	for (s32 y = 0; y < height; ++y) {
		if (flip)
			out -= lineWidth;
		if (bgr) {
			for (s32 x = 0; x < lineWidth; x += 3) {
				out[x + 0] = in[x + 2];
				out[x + 1] = in[x + 1];
				out[x + 2] = in[x + 0];
			}
		} else {
			memcpy(out, in, lineWidth);
		}
		if (!flip)
			out += lineWidth;
		in += lineWidth;
		in += linepad;
	}
}

//! Resizes the surface to a new size and converts it at the same time
//! to an A8R8G8B8 format, returning the pointer to the new buffer.
void CColorConverter::convert16bitToA8R8G8B8andResize(const s16 *in, s32 *out, s32 newWidth, s32 newHeight, s32 currentWidth, s32 currentHeight)
{
	if (!newWidth || !newHeight)
		return;

	// note: this is very very slow. (i didn't want to write a fast version.
	// but hopefully, nobody wants to convert surfaces every frame.

	f32 sourceXStep = (f32)currentWidth / (f32)newWidth;
	f32 sourceYStep = (f32)currentHeight / (f32)newHeight;
	f32 sy;
	s32 t;

	for (s32 x = 0; x < newWidth; ++x) {
		sy = 0.0f;

		for (s32 y = 0; y < newHeight; ++y) {
			t = in[(s32)(((s32)sy) * currentWidth + x * sourceXStep)];
			t = (((t >> 15) & 0x1) << 31) | (((t >> 10) & 0x1F) << 19) |
				(((t >> 5) & 0x1F) << 11) | (t & 0x1F) << 3;
			out[(s32)(y * newWidth + x)] = t;

			sy += sourceYStep;
		}
	}
}

//! copies X8R8G8B8 32 bit data
void CColorConverter::convert32BitTo32Bit(const s32 *in, s32 *out, s32 width, s32 height, s32 linepad, bool flip)
{
	if (!in || !out)
		return;

	if (flip)
		out += width * height;

	for (s32 y = 0; y < height; ++y) {
		if (flip)
			out -= width;
#ifdef __BIG_ENDIAN__
		for (s32 x = 0; x < width; ++x)
			out[x] = os::Byteswap::byteswap(in[x]);
#else
		memcpy(out, in, width * sizeof(s32));
#endif
		if (!flip)
			out += width;
		in += width;
		in += linepad;
	}
}

void CColorConverter::convert_A1R5G5B5toR8G8B8(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		dB[2] = (*sB & 0x7c00) >> 7;
		dB[1] = (*sB & 0x03e0) >> 2;
		dB[0] = (*sB & 0x1f) << 3;

		sB += 1;
		dB += 3;
	}
}

void CColorConverter::convert_A1R5G5B5toB8G8R8(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		dB[0] = (*sB & 0x7c00) >> 7;
		dB[1] = (*sB & 0x03e0) >> 2;
		dB[2] = (*sB & 0x1f) << 3;

		sB += 1;
		dB += 3;
	}
}

void CColorConverter::convert_A1R5G5B5toR5G5B5A1(const void *sP, s32 sN, void *dP)
{
	const u16 *sB = (const u16 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		*dB = (*sB << 1) | (*sB >> 15);
		++sB;
		++dB;
	}
}

void CColorConverter::convert_A1R5G5B5toA8R8G8B8(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u32 *dB = (u32 *)dP;

	for (s32 x = 0; x < sN; ++x)
		*dB++ = A1R5G5B5toA8R8G8B8(*sB++);
}

void CColorConverter::convert_A1R5G5B5toA1R5G5B5(const void *sP, s32 sN, void *dP)
{
	memcpy(dP, sP, sN * 2);
}

void CColorConverter::convert_A1R5G5B5toR5G6B5(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x)
		*dB++ = A1R5G5B5toR5G6B5(*sB++);
}

void CColorConverter::convert_A8R8G8B8toR8G8B8(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		// sB[3] is alpha
		dB[0] = sB[2];
		dB[1] = sB[1];
		dB[2] = sB[0];

		sB += 4;
		dB += 3;
	}
}

void CColorConverter::convert_A8R8G8B8toB8G8R8(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		// sB[3] is alpha
		dB[0] = sB[0];
		dB[1] = sB[1];
		dB[2] = sB[2];

		sB += 4;
		dB += 3;
	}
}

void CColorConverter::convert_A8R8G8B8toA8R8G8B8(const void *sP, s32 sN, void *dP)
{
	memcpy(dP, sP, sN * 4);
}

void CColorConverter::convert_A8R8G8B8toA1R5G5B5(const void *sP, s32 sN, void *dP)
{
	u32 *sB = (u32 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x)
		*dB++ = A8R8G8B8toA1R5G5B5(*sB++);
}

void CColorConverter::convert_A8R8G8B8toA1B5G5R5(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		s32 r = sB[0] >> 3;
		s32 g = sB[1] >> 3;
		s32 b = sB[2] >> 3;
		s32 a = sB[3] >> 3;

		dB[0] = (a << 15) | (r << 10) | (g << 5) | (b);

		sB += 4;
		dB += 1;
	}
}

void CColorConverter::convert_A8R8G8B8toR5G6B5(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		s32 r = sB[2] >> 3;
		s32 g = sB[1] >> 2;
		s32 b = sB[0] >> 3;

		dB[0] = (r << 11) | (g << 5) | (b);

		sB += 4;
		dB += 1;
	}
}

void CColorConverter::convert_A8R8G8B8toR3G3B2(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		u8 r = sB[2] & 0xe0;
		u8 g = (sB[1] & 0xe0) >> 3;
		u8 b = (sB[0] & 0xc0) >> 6;

		dB[0] = (r | g | b);

		sB += 4;
		dB += 1;
	}
}

void CColorConverter::convert_R8G8B8toR8G8B8(const void *sP, s32 sN, void *dP)
{
	memcpy(dP, sP, sN * 3);
}

void CColorConverter::convert_R8G8B8toA8R8G8B8(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u32 *dB = (u32 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		*dB = 0xff000000 | (sB[0] << 16) | (sB[1] << 8) | sB[2];

		sB += 3;
		++dB;
	}
}

void CColorConverter::convert_R8G8B8toA1R5G5B5(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		s32 r = sB[0] >> 3;
		s32 g = sB[1] >> 3;
		s32 b = sB[2] >> 3;

		dB[0] = (0x8000) | (r << 10) | (g << 5) | (b);

		sB += 3;
		dB += 1;
	}
}

void CColorConverter::convert_A8R8G8B8toR8G8B8A8(const void *sP, s32 sN, void *dP)
{
	const u32 *sB = (const u32 *)sP;
	u32 *dB = (u32 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		*dB++ = (*sB << 8) | (*sB >> 24);
		++sB;
	}
}

void CColorConverter::convert_A8R8G8B8toA8B8G8R8(const void *sP, s32 sN, void *dP)
{
	const u32 *sB = (const u32 *)sP;
	u32 *dB = (u32 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		*dB++ = (*sB & 0xff00ff00) | ((*sB & 0x00ff0000) >> 16) | ((*sB & 0x000000ff) << 16);
		++sB;
	}
}

void CColorConverter::convert_R8G8B8toB8G8R8(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		dB[2] = sB[0];
		dB[1] = sB[1];
		dB[0] = sB[2];

		sB += 3;
		dB += 3;
	}
}

void CColorConverter::convert_R8G8B8toR5G6B5(const void *sP, s32 sN, void *dP)
{
	u8 *sB = (u8 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		s32 r = sB[0] >> 3;
		s32 g = sB[1] >> 2;
		s32 b = sB[2] >> 3;

		dB[0] = (r << 11) | (g << 5) | (b);

		sB += 3;
		dB += 1;
	}
}

void CColorConverter::convert_R5G6B5toR5G6B5(const void *sP, s32 sN, void *dP)
{
	memcpy(dP, sP, sN * 2);
}

void CColorConverter::convert_R5G6B5toR8G8B8(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		dB[0] = (*sB & 0xf800) >> 8;
		dB[1] = (*sB & 0x07e0) >> 3;
		dB[2] = (*sB & 0x001f) << 3;

		sB += 1;
		dB += 3;
	}
}

void CColorConverter::convert_R5G6B5toB8G8R8(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u8 *dB = (u8 *)dP;

	for (s32 x = 0; x < sN; ++x) {
		dB[2] = (*sB & 0xf800) >> 8;
		dB[1] = (*sB & 0x07e0) >> 3;
		dB[0] = (*sB & 0x001f) << 3;

		sB += 1;
		dB += 3;
	}
}

void CColorConverter::convert_R5G6B5toA8R8G8B8(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u32 *dB = (u32 *)dP;

	for (s32 x = 0; x < sN; ++x)
		*dB++ = R5G6B5toA8R8G8B8(*sB++);
}

void CColorConverter::convert_R5G6B5toA1R5G5B5(const void *sP, s32 sN, void *dP)
{
	u16 *sB = (u16 *)sP;
	u16 *dB = (u16 *)dP;

	for (s32 x = 0; x < sN; ++x)
		*dB++ = R5G6B5toA1R5G5B5(*sB++);
}

bool CColorConverter::canConvertFormat(ECOLOR_FORMAT sourceFormat, ECOLOR_FORMAT destFormat)
{
	switch (sourceFormat) {
	case ECF_A1R5G5B5:
		switch (destFormat) {
		case ECF_A1R5G5B5:
		case ECF_R5G6B5:
		case ECF_A8R8G8B8:
		case ECF_R8G8B8:
			return true;
		default:
			break;
		}
		break;
	case ECF_R5G6B5:
		switch (destFormat) {
		case ECF_A1R5G5B5:
		case ECF_R5G6B5:
		case ECF_A8R8G8B8:
		case ECF_R8G8B8:
			return true;
		default:
			break;
		}
		break;
	case ECF_A8R8G8B8:
		switch (destFormat) {
		case ECF_A1R5G5B5:
		case ECF_R5G6B5:
		case ECF_A8R8G8B8:
		case ECF_R8G8B8:
			return true;
		default:
			break;
		}
		break;
	case ECF_R8G8B8:
		switch (destFormat) {
		case ECF_A1R5G5B5:
		case ECF_R5G6B5:
		case ECF_A8R8G8B8:
		case ECF_R8G8B8:
			return true;
		default:
			break;
		}
		break;
	default:
		break;
	}
	return false;
}

void CColorConverter::convert_viaFormat(const void *sP, ECOLOR_FORMAT sF, s32 sN,
		void *dP, ECOLOR_FORMAT dF)
{
	// please also update can_convert_viaFormat when adding new conversions
	switch (sF) {
	case ECF_A1R5G5B5:
		switch (dF) {
		case ECF_A1R5G5B5:
			convert_A1R5G5B5toA1R5G5B5(sP, sN, dP);
			break;
		case ECF_R5G6B5:
			convert_A1R5G5B5toR5G6B5(sP, sN, dP);
			break;
		case ECF_A8R8G8B8:
			convert_A1R5G5B5toA8R8G8B8(sP, sN, dP);
			break;
		case ECF_R8G8B8:
			convert_A1R5G5B5toR8G8B8(sP, sN, dP);
			break;

		default:
			break;
		}
		break;
	case ECF_R5G6B5:
		switch (dF) {
		case ECF_A1R5G5B5:
			convert_R5G6B5toA1R5G5B5(sP, sN, dP);
			break;
		case ECF_R5G6B5:
			convert_R5G6B5toR5G6B5(sP, sN, dP);
			break;
		case ECF_A8R8G8B8:
			convert_R5G6B5toA8R8G8B8(sP, sN, dP);
			break;
		case ECF_R8G8B8:
			convert_R5G6B5toR8G8B8(sP, sN, dP);
			break;

		default:
			break;
		}
		break;
	case ECF_A8R8G8B8:
		switch (dF) {
		case ECF_A1R5G5B5:
			convert_A8R8G8B8toA1R5G5B5(sP, sN, dP);
			break;
		case ECF_R5G6B5:
			convert_A8R8G8B8toR5G6B5(sP, sN, dP);
			break;
		case ECF_A8R8G8B8:
			convert_A8R8G8B8toA8R8G8B8(sP, sN, dP);
			break;
		case ECF_R8G8B8:
			convert_A8R8G8B8toR8G8B8(sP, sN, dP);
			break;

		default:
			break;
		}
		break;
	case ECF_R8G8B8:
		switch (dF) {
		case ECF_A1R5G5B5:
			convert_R8G8B8toA1R5G5B5(sP, sN, dP);
			break;
		case ECF_R5G6B5:
			convert_R8G8B8toR5G6B5(sP, sN, dP);
			break;
		case ECF_A8R8G8B8:
			convert_R8G8B8toA8R8G8B8(sP, sN, dP);
			break;
		case ECF_R8G8B8:
			convert_R8G8B8toR8G8B8(sP, sN, dP);
			break;

		default:
			break;
		}
		break;

	default:
		break;
	}
}

} // end namespace video
} // end namespace irr
