/*******************************************************************************
 * openexr.cpp
 *
 * This module contains the code to read and write files via the openexr library.
 *
 * ---------------------------------------------------------------------------
 * Persistence of Vision Ray Tracer ('POV-Ray') version 3.7.
 * Copyright 1991-2013 Persistence of Vision Raytracer Pty. Ltd.
 *
 * POV-Ray is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * POV-Ray is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * ---------------------------------------------------------------------------
 * POV-Ray is based on the popular DKB raytracer version 2.12.
 * DKBTrace was originally written by David K. Buck.
 * DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
 * ---------------------------------------------------------------------------
 * $File: //depot/public/povray/3.x/source/base/image/openexr.cpp $
 * $Revision: #1 $
 * $Change: 6069 $
 * $DateTime: 2013/11/06 11:59:40 $
 * $Author: chrisc $
 *******************************************************************************/

#include <boost/scoped_ptr.hpp>
#include <boost/scoped_array.hpp>

#include <string>

// configbase.h must always be the first POV file included within base *.cpp files
#include "base/configbase.h"
#include "base/image/image.h"
#include "base/fileinputoutput.h"
#include "base/image/openexr.h"
#include "base/types.h"


#ifndef OPENEXR_MISSING

#include <ImfRgbaFile.h>
#include <ImfStringAttribute.h>
#include <ImfMatrixAttribute.h>
#include <ImfArray.h>

#include "metadata.h"

// this must be the last file included
#include "base/povdebug.h"

namespace pov_base
{

namespace OpenEXR
{

using namespace Imf;
using namespace Imath;

/*****************************************************************************
* Local preprocessor defines
******************************************************************************/
#if (OPENEXR_VERSION_MAJOR < 3)
    #define OPENEXR_INT64 Int64
#else
    #define OPENEXR_INT64 uint64_t
#endif

/*****************************************************************************
* Local typedefs
******************************************************************************/
struct Messages
{
	vector<string> warnings;
	string error;
};

///////////////////////////////////////////
// class POV_EXR_OStream
///////////////////////////////////////////
class POV_EXR_OStream : public Imf::OStream
{
	public:
		POV_EXR_OStream(pov_base::OStream& pov_stream) : Imf::OStream(UCS2toASCIIString(pov_stream.Name()).c_str()), os(pov_stream) { }
		virtual ~POV_EXR_OStream() { }

		const char *fileName() const { return UCS2toASCIIString(os.Name()).c_str(); }

		void write(const char *c, int n)
		{
			if(!os.write(c, n))
				throw POV_EXCEPTION(kFileDataErr, "Error while writing EXR output");
		}

		OPENEXR_INT64 tellp()
		{
			POV_LONG pos = os.tellg();
			if(pos == (POV_LONG)-1)
				throw POV_EXCEPTION(kFileDataErr, "Error while writing EXR output");
			return(pos);
		}

		void seekp(OPENEXR_INT64 pos)
		{
			if(!os.seekg((POV_LONG)pos))
				throw POV_EXCEPTION(kFileDataErr, "Error when writing EXR output");
		}
	private:
		pov_base::OStream& os;
};

///////////////////////////////////////////
// class POV_EXR_IStream
///////////////////////////////////////////
class POV_EXR_IStream : public Imf::IStream
{
	public:
		POV_EXR_IStream(pov_base::IStream& pov_stream) : Imf::IStream(UCS2toASCIIString(pov_stream.Name()).c_str()), is(pov_stream)
		{
			is.seekg(0, IOBase::seek_end);
			fsize = is.tellg();
			is.seekg(0, IOBase::seek_set);
		}

		virtual ~POV_EXR_IStream() { }

		const char *fileName(void) const { return UCS2toASCIIString(is.Name()).c_str(); }
		void clear(void) { is.clearstate(); }

		bool read(char *c, int n)
		{
			if(!is.read(c, n))
				throw POV_EXCEPTION(kFileDataErr, "Error while reading EXR file");
			return (is.tellg() < fsize);
		}

		OPENEXR_INT64 tellg()
		{
			POV_LONG pos = is.tellg();
			if(pos == (POV_LONG)-1)
				throw POV_EXCEPTION(kFileDataErr, "Error while reading EXR file");
			return pos;
		}

		void seekg(OPENEXR_INT64 pos)
		{
			if(!is.seekg((POV_LONG)pos))
				throw POV_EXCEPTION(kFileDataErr, "Error while reading EXR file");
		}
	private:
		pov_base::IStream& is;
		POV_LONG fsize;
};

/*****************************************************************************
* Implementation
******************************************************************************/

Image *Read(IStream *file, const Image::ReadOptions& options)
{
	unsigned int width;
	unsigned int height;
	Image  *image = NULL;

	// OpenEXR files store linear color values by default, so never convert unless the user overrides
	// (e.g. to handle a non-compliant file).
	GammaCurvePtr gamma;
	if (options.gammacorrect)
	{
		if (options.gammaOverride)
			gamma = TranscodingGammaCurve::Get(options.workingGamma, options.defaultGamma);
		else
			gamma = TranscodingGammaCurve::Get(options.workingGamma, NeutralGammaCurve::Get());
	}

	// OpenEXR officially uses premultiplied alpha, so that's the preferred mode to use for the image container unless the user overrides
	// (e.g. to handle a non-compliant file).
	bool premul = true;
	if (options.premultiplyOverride)
		premul = options.premultiply;

	// TODO: code this to observe the request for alpha in the input file type.
	POV_EXR_IStream is(*file);
	try
	{
		RgbaInputFile rif(is);
		Array2D<Rgba> pixels;
		Box2i dw = rif.dataWindow();
		Image::ImageDataType imagetype = options.itype;

		width = dw.max.x - dw.min.x + 1;
		height = dw.max.y - dw.min.y + 1;
		pixels.resizeErase(height, width);
		rif.setFrameBuffer(&pixels[0][0] - dw.min.x - dw.min.y * width, 1, width);
		rif.readPixels(dw.min.y, dw.max.y);

		if(imagetype == Image::Undefined)
			imagetype = Image::RGBFT_Float;

		image = Image::Create(width, height, imagetype);
		image->SetPremultiplied(premul); // set desired storage mode regarding alpha premultiplication

		for(int row = 0; row < height; row++)
		{
			for(int col = 0; col < width; col++)
			{
				struct Rgba &rgba = pixels [row][col];
				SetEncodedRGBAValue(image, col, row, gamma, (float)rgba.r, (float)rgba.g, (float)rgba.b, (float)rgba.a, premul);
			}
		}
	}
	catch(const std::exception& e)
	{
		throw POV_EXCEPTION(kFileDataErr, e.what());
	}

	return image;
}

void Write(OStream *file, const Image *image, const Image::WriteOptions& options)
{
	int width = image->GetWidth();
	int height = image->GetHeight();
	bool use_alpha = image->HasTransparency() && options.alphachannel;
	float pixelAspect = 1.0;
	Header hdr(width, height, pixelAspect, Imath::V2f(0, 0), 1.0, INCREASING_Y, ZIP_COMPRESSION);
	boost::scoped_array<Rgba> pixels(new Rgba[width * height]);
	Rgba *p = pixels.get();
	GammaCurvePtr gamma = TranscodingGammaCurve::Get(options.workingGamma, NeutralGammaCurve::Get());

	// OpenEXR officially uses premultiplied alpha, so that's the way we do it unless the user overrides
	// (e.g. to handle a non-compliant file).
	bool premul = true;
	if (options.premultiplyOverride)
		premul = options.premultiply;

	for(int row = 0; row < height; row++)
	{
		for(int col = 0; col < width; col++)
		{
			float r, g, b, a;
			GetEncodedRGBAValue(image, col, row, gamma, r, g, b, a, premul);
			*p++ = Rgba(r, g, b, use_alpha ? a : 1.0f);
		}
	}

	POV_EXR_OStream os(*file);
	try
	{
		Imf::RgbaChannels channels;
		if (options.grayscale)
			if (use_alpha)
				channels = WRITE_YA; // only write luminance & alpha
			else
				channels = WRITE_Y; // only write luminance
		else
			if (use_alpha)
				channels = WRITE_RGBA; // write RGB & alpha
			else
				channels = WRITE_RGB; // write RGB

		Metadata meta;
		string comments;
		if (!meta.getComment1().empty())
			comments += meta.getComment1() + "\n";
		if (!meta.getComment2().empty())
			comments += meta.getComment2() + "\n";
		if (!meta.getComment3().empty())
			comments += meta.getComment3() + "\n";
		if (!meta.getComment4().empty())
			comments += meta.getComment4() + "\n";

		if (!comments.empty())
			hdr.insert("comments",StringAttribute(comments.c_str()));

		string software= meta.getSoftware();
		string datetime= meta.getDateTime();
		hdr.insert("software",StringAttribute(software.c_str()));
		hdr.insert("creation",StringAttribute(datetime.c_str()));

		RgbaOutputFile rof(os, hdr, channels);
		rof.setFrameBuffer(pixels.get(), 1, width);
		rof.writePixels(height);
	}
	catch(const std::exception& e)
	{
		throw POV_EXCEPTION(kFileDataErr, e.what());
	}
}

} // end of namespace OpenEXR

} // end of namespace pov_base

#endif  // OPENEXR_MISSING