// 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 "CImageWriterPNG.h"

#ifdef _IRR_COMPILE_WITH_PNG_WRITER_

#include "IImage.h"
#include "CColorConverter.h"
#include "IWriteFile.h"
#include "os.h" // for logging

#ifdef _IRR_COMPILE_WITH_LIBPNG_
#ifndef _IRR_USE_NON_SYSTEM_LIB_PNG_
	#include <png.h> // use system lib png
#else // _IRR_USE_NON_SYSTEM_LIB_PNG_
	#include "libpng/png.h" // use irrlicht included lib png
#endif // _IRR_USE_NON_SYSTEM_LIB_PNG_
#endif // _IRR_COMPILE_WITH_LIBPNG_

namespace irr
{
namespace video
{

IImageWriter* createImageWriterPNG()
{
	return new CImageWriterPNG;
}

#ifdef _IRR_COMPILE_WITH_LIBPNG_
// PNG function for error handling
static void png_cpexcept_error(png_structp png_ptr, png_const_charp msg)
{
	os::Printer::log("PNG fatal error", msg, ELL_ERROR);
	longjmp(png_jmpbuf(png_ptr), 1);
}

// PNG function for warning handling
static void png_cpexcept_warning(png_structp png_ptr, png_const_charp msg)
{
	os::Printer::log("PNG warning", msg, ELL_WARNING);
}

// PNG function for file writing
void PNGAPI user_write_data_fcn(png_structp png_ptr, png_bytep data, png_size_t length)
{
	png_size_t check;

	io::IWriteFile* file=(io::IWriteFile*)png_get_io_ptr(png_ptr);
	check=(png_size_t) file->write((const void*)data,(u32)length);

	if (check != length)
		png_error(png_ptr, "Write Error");
}
#endif // _IRR_COMPILE_WITH_LIBPNG_

CImageWriterPNG::CImageWriterPNG()
{
#ifdef _DEBUG
	setDebugName("CImageWriterPNG");
#endif
}

bool CImageWriterPNG::isAWriteableFileExtension(const io::path& filename) const
{
#ifdef _IRR_COMPILE_WITH_LIBPNG_
	return core::hasFileExtension ( filename, "png" );
#else
	return false;
#endif
}

bool CImageWriterPNG::writeImage(io::IWriteFile* file, IImage* image,u32 param) const
{
#ifdef _IRR_COMPILE_WITH_LIBPNG_
	if (!file || !image)
		return false;

	// Allocate the png write struct
	png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
		NULL, (png_error_ptr)png_cpexcept_error, (png_error_ptr)png_cpexcept_warning);
	if (!png_ptr)
	{
		os::Printer::log("PNGWriter: Internal PNG create write struct failure", file->getFileName(), ELL_ERROR);
		return false;
	}

	// Set compression level 
	// Sadly Irrlicht used param=0 as default and an u32 type
	// So to avoid breaking downward compatibility we keep 0 as default (which is -1 in zlib) and subtract 1 from param to everything into zlib range
	if (param <= 10)	// Z_BEST_COMPRESSION is 9 - values above have so far no meaning
		png_set_compression_level(png_ptr, (int)param-1);

	// Allocate the png info struct
	png_infop info_ptr = png_create_info_struct(png_ptr);
	if (!info_ptr)
	{
		os::Printer::log("PNGWriter: Internal PNG create info struct failure", file->getFileName(), ELL_ERROR);
		png_destroy_write_struct(&png_ptr, NULL);
		return false;
	}

	// for proper error handling
	if (setjmp(png_jmpbuf(png_ptr)))
	{
		png_destroy_write_struct(&png_ptr, &info_ptr);
		return false;
	}

	png_set_write_fn(png_ptr, file, user_write_data_fcn, NULL);

	// Set info
	switch(image->getColorFormat())
	{
		case ECF_A8R8G8B8:
		case ECF_A1R5G5B5:
			png_set_IHDR(png_ptr, info_ptr,
				image->getDimension().Width, image->getDimension().Height,
				8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
				PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
		break;
		default:
			png_set_IHDR(png_ptr, info_ptr,
				image->getDimension().Width, image->getDimension().Height,
				8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
				PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
	}

	s32 lineWidth = image->getDimension().Width;
	switch(image->getColorFormat())
	{
	case ECF_R8G8B8:
	case ECF_R5G6B5:
		lineWidth*=3;
		break;
	case ECF_A8R8G8B8:
	case ECF_A1R5G5B5:
		lineWidth*=4;
		break;
	// TODO: Error handling in case of unsupported color format
	default:
		break;
	}
	u8* tmpImage = new u8[image->getDimension().Height*lineWidth];
	if (!tmpImage)
	{
		os::Printer::log("PNGWriter: Internal PNG create image failure", file->getFileName(), ELL_ERROR);
		png_destroy_write_struct(&png_ptr, &info_ptr);
		return false;
	}

	u8* data = (u8*)image->getData();
	switch(image->getColorFormat())
	{
	case ECF_R8G8B8:
		CColorConverter::convert_R8G8B8toR8G8B8(data,image->getDimension().Height*image->getDimension().Width,tmpImage);
		break;
	case ECF_A8R8G8B8:
		CColorConverter::convert_A8R8G8B8toA8R8G8B8(data,image->getDimension().Height*image->getDimension().Width,tmpImage);
		break;
	case ECF_R5G6B5:
		CColorConverter::convert_R5G6B5toR8G8B8(data,image->getDimension().Height*image->getDimension().Width,tmpImage);
		break;
	case ECF_A1R5G5B5:
		CColorConverter::convert_A1R5G5B5toA8R8G8B8(data,image->getDimension().Height*image->getDimension().Width,tmpImage);
		break;
		// TODO: Error handling in case of unsupported color format
	default:
		os::Printer::log("CImageWriterPNG does not support image format", ColorFormatNames[image->getColorFormat()], ELL_WARNING);
		png_destroy_write_struct(&png_ptr, &info_ptr);
		delete [] tmpImage;
		return false;
	}

	// Create array of pointers to rows in image data

	//Used to point to image rows
	u8** RowPointers = new png_bytep[image->getDimension().Height];
	if (!RowPointers)
	{
		os::Printer::log("PNGWriter: Internal PNG create row pointers failure", file->getFileName(), ELL_ERROR);
		png_destroy_write_struct(&png_ptr, &info_ptr);
		delete [] tmpImage;
		return false;
	}

	data=tmpImage;
	// Fill array of pointers to rows in image data
	for (u32 i=0; i<image->getDimension().Height; ++i)
	{
		RowPointers[i]=data;
		data += lineWidth;
	}
	// for proper error handling
	if (setjmp(png_jmpbuf(png_ptr)))
	{
		png_destroy_write_struct(&png_ptr, &info_ptr);
		delete [] RowPointers;
		delete [] tmpImage;
		return false;
	}

	png_set_rows(png_ptr, info_ptr, RowPointers);

	if (image->getColorFormat()==ECF_A8R8G8B8 || image->getColorFormat()==ECF_A1R5G5B5)
		png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_BGR, NULL);
	else
	{
		png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
	}

	delete [] RowPointers;
	delete [] tmpImage;
	png_destroy_write_struct(&png_ptr, &info_ptr);
	return true;
#else
	return false;
#endif
}

} // namespace video
} // namespace irr

#endif