/* AbiWord
 * Copyright (C) 1998 AbiSource, Inc.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  
 * 02111-1307, USA.
 */

#include <stdlib.h>
#include <png.h>

#include "gr_UnixImage.h"
#include "ut_assert.h"
#include "ut_bytebuf.h"

GR_UnixImage::GR_UnixImage(const char* szName)
{
	m_image = NULL;
	
	if (szName)
	{
		strcpy(m_szName, szName);
	}
	else
	{
		strcpy(m_szName, "UnixImage");
	}
}

struct _bb
{
	const UT_ByteBuf* pBB;
	UT_uint32 iCurPos;
};

static void _png_read(png_structp png_ptr, png_bytep data, png_size_t length)
{
	struct _bb* p = (struct _bb*) png_get_io_ptr(png_ptr);
	const UT_Byte* pBytes = p->pBB->getPointer(0);

	memcpy(data, pBytes + p->iCurPos, length);
	p->iCurPos += length;
}

static void _png_write(png_structp png_ptr, png_bytep data, png_size_t length)
{
	UT_ByteBuf* pBB = (UT_ByteBuf*) png_get_io_ptr(png_ptr);

	pBB->ins(pBB->getLength(), data, length);
}

static void _png_flush(png_structp /* png_ptr */)
{
}

GR_UnixImage::~GR_UnixImage()
{
	if (m_image)
	{
		if (m_image->data)
		{
			free(m_image->data);
			m_image->data = NULL;
		}

		delete m_image;
		m_image = NULL;
	}
}

UT_sint32	GR_UnixImage::getDisplayWidth(void) const
{
   return m_image->width;
}

UT_sint32	GR_UnixImage::getDisplayHeight(void) const
{
   return m_image->height;
}

UT_Bool		GR_UnixImage::convertToBuffer(UT_ByteBuf** ppBB) const
{
	/*
	 The purpose of this routine is to convert our internal 24-bit
	 Fatmap into a PNG image, storing it in a ByteBuf and returning it
	 to the caller.
	 */
	
	// Create our bytebuf
	UT_ByteBuf* pBB = new UT_ByteBuf();
	
	png_structp png_ptr;
	png_infop info_ptr;
	
	// initialize some libpng stuff
	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
									  (png_error_ptr)NULL, (png_error_ptr)NULL);
	
	info_ptr = png_create_info_struct(png_ptr);

	// libpng will longjmp back to here if a fatal error occurs
	if (setjmp(png_ptr->jmpbuf))
	{
		/* If we get here, we had a problem reading the file */
		png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
		*ppBB = NULL;
		
		return UT_FALSE;
	}

	// We want libpng to write to our ByteBuf, not stdio
	png_set_write_fn(png_ptr, (void *)pBB, _png_write, _png_flush);

	UT_uint32 iWidth = m_image->width;
	UT_uint32 iHeight = m_image->height;

	png_set_IHDR(png_ptr,
				 info_ptr,
				 iWidth,
				 iHeight,
				 8,							// 8 bits per channel (24 bits for all 3 channels)
				 PNG_COLOR_TYPE_RGB,
				 PNG_INTERLACE_NONE,
				 PNG_COMPRESSION_TYPE_BASE,
				 PNG_FILTER_TYPE_BASE);

	/* Write the file header information.  REQUIRED */
	png_write_info(png_ptr, info_ptr);

	UT_Byte * pBits = ((unsigned char*) m_image->data);
	
	UT_Byte* pData = (UT_Byte*) malloc(iWidth * iHeight * 3);
	UT_ASSERT(pData); // TODO outofmem
		
	UT_uint32 	iRow;
	UT_uint32 	iCol;
	UT_Byte* 	pRow;
	UT_uint32 	iBytesInRow;

	// We only handle 24-bit data, as that's all we'll ever be passing to
	// gdk_draw_rgb_image(), and all we'll ever hold internally.
	
	iBytesInRow = iWidth * 3;

	for (iRow = 0; iRow<iHeight; iRow++)
	{
		pRow = pBits + iRow * iBytesInRow;
			
		for (iCol=0; iCol<iWidth; iCol++)
		{
			pData[(iRow*iWidth + iCol)*3 + 0] = pRow[iCol*3 + 0];
			pData[(iRow*iWidth + iCol)*3 + 1] = pRow[iCol*3 + 1];
			pData[(iRow*iWidth + iCol)*3 + 2] = pRow[iCol*3 + 2];
		}
	}
	
	/*
	  Now that we have converted the image to a normalized 24-bit
	  representation, we can save it out to the PNG file.
	*/
	for (UT_uint32 i=0; i<iHeight; i++)
	{
		UT_Byte *pThisRow = pData + i * iWidth * 3;
		
		png_write_rows(png_ptr, &pThisRow, 1);
	}

	/*
	  We then free our 24-bit buffer.
	*/
	free(pData);

	/*
	  Wrap things up with libpng
	*/
	png_write_end(png_ptr, info_ptr);

	/* clean up after the write, and free any memory allocated */
	png_destroy_write_struct(&png_ptr, (png_infopp)NULL);

	// And pass the ByteBuf back to our caller
	*ppBB = pBB;

	return UT_TRUE;
}

UT_Bool	GR_UnixImage::convertFromBuffer(const UT_ByteBuf* pBB, UT_sint32 iDisplayWidth, UT_sint32 iDisplayHeight)
{
      png_structp png_ptr;
      png_infop info_ptr;
      png_uint_32 width, height;
      int bit_depth, color_type, interlace_type;
      
      png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (void*) NULL,
				       NULL, NULL);
      
      if (png_ptr == NULL)
	{
	   return UT_FALSE;
	}
      
      /* Allocate/initialize the memory for image information.  REQUIRED. */
      info_ptr = png_create_info_struct(png_ptr);
      if (info_ptr == NULL)
	{
	   png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
	   return UT_FALSE;
	}
      
      /* Set error handling if you are using the setjmp/longjmp method (this is
       * the normal method of doing things with libpng).  REQUIRED unless you
       * set up your own error handlers in the png_create_read_struct() earlier.
       */
      if (setjmp(png_ptr->jmpbuf))
	{
	   /* Free all of the memory associated with the png_ptr and info_ptr */
	   png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
	   
	   /* If we get here, we had a problem reading the file */
	   return UT_FALSE;
	}
      
      struct _bb myBB;
      myBB.pBB = pBB;
      myBB.iCurPos = 0;
      
      png_set_read_fn(png_ptr, (void *)&myBB, _png_read);
      
      /* The call to png_read_info() gives us all of the information from the
       * PNG file before the first IDAT (image data chunk).  REQUIRED
       */
      png_read_info(png_ptr, info_ptr);
      
      png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
		   &interlace_type, NULL, NULL);
      
      /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
       * byte into separate bytes (useful for paletted and grayscale images).
       */
      png_set_packing(png_ptr);
      
      /* Expand paletted colors into true RGB triplets */
      png_set_expand(png_ptr);
      
      /*  If we've got images with 16 bits per channel, we don't need that
       much precision.  We'll do fine with 8 bits per channel */
      png_set_strip_16(png_ptr);
      
      /*  For simplicity, treat grayscale as RGB */
      png_set_gray_to_rgb(png_ptr);
      
      /*  For simplicity, we'll ignore alpha */
      png_set_strip_alpha(png_ptr);
      
      /*  We want libpng to deinterlace the image for us */
      UT_uint32 iInterlacePasses = png_set_interlace_handling(png_ptr);
      
      UT_uint32 iBytesInRow = width * 3;
      
      Fatmap* pFM = new Fatmap;
      pFM->width = width;
      pFM->height = height;
      
      // allocate for 3 bytes each pixel (one for R, G, and B)
      pFM->data = (guchar *) calloc(pFM->width * pFM->height * 3, sizeof(guchar));
      
      if (!pFM->data)
	{
	   png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
	   return UT_FALSE;
	}
      
      UT_Byte * pBits = (UT_Byte *) pFM->data;
      
      UT_Byte ** pRowStarts = (UT_Byte **) calloc(height, sizeof(UT_Byte *));
      
      // fill a list of the starts of rows, so png_read_rows() can walk
      // the pointer it gets (&pRowStarts) up each element to get a new
      // place (row) to throw data.
      for (UT_uint32 iRow = 0; iRow < height; iRow++)
	pRowStarts[iRow] = ((UT_Byte *) pBits + (iRow * iBytesInRow));
      
      for (; iInterlacePasses; iInterlacePasses--)
	png_read_rows(png_ptr, pRowStarts, NULL, height);
      
      free(pRowStarts);
      
      /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
      png_read_end(png_ptr, info_ptr);
      
      /* clean up after the read, and free any memory allocated - REQUIRED */
      png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
      
      if (
	  (((UT_sint32) width) != iDisplayWidth)
	  || (((UT_sint32) height) != iDisplayHeight)
	  )
	{
	   Fatmap* pDisplayFM = new Fatmap;
	   Fatmap* pOtherFM = pFM;
	   
	   pDisplayFM->width = iDisplayWidth;
	   pDisplayFM->height = iDisplayHeight;
	   
	   // allocate for 3 bytes each pixel (one for R, G, and B)
	   pDisplayFM->data = (guchar *) calloc(pDisplayFM->width * pDisplayFM->height * 3, sizeof(guchar));
	   
	   if (!pDisplayFM->data)
	     {
		delete pDisplayFM;
		free(pOtherFM->data);
		delete pOtherFM;
		return UT_FALSE;
	     }
	   
	   // stretch the pixels from pOtherFM into pDisplayFM
	   
	   /*
	    TODO this code came from imlib.  It's not exactly
	    a match for our coding standards, so it needs a
	    certain amount of cleanup.  However, it seems
	    to be working nicely.
	    */
	   
	     {
		int                 x, y, *xarray;
		unsigned char     **yarray, *ptr, *ptr2, *ptr22;
		int                 pos, inc, w3;
		
		xarray = (int*) malloc(sizeof(int) * iDisplayWidth);
		
		if (!xarray)
		  {
		     // TODO outofmem
		     return UT_FALSE;
		  }
		yarray = (unsigned char**) malloc(sizeof(unsigned char *) * iDisplayHeight);
		
		if (!yarray)
		  {
		     // TODO outofmem
		     return UT_FALSE;
		  }
		
		ptr22 = pOtherFM->data;
		w3 = pOtherFM->width * 3;
		
		// set up xarray
		inc = ((pOtherFM->width) << 16) / iDisplayWidth;
		pos = 0;
		for (x = 0; x < iDisplayWidth; x++)
		  {
		     xarray[x] = (pos >> 16) + (pos >> 16) + (pos >> 16);
		     pos += inc;
		  }
		
		// set up yarray
		inc = ((pOtherFM->height) << 16) / iDisplayHeight;
		pos = 0;
		for (x = 0; x < iDisplayHeight; x++)
		  {
		     yarray[x] = ptr22 + ((pos >> 16) * w3);
		     pos += inc;
		  }
		
		// crunch the data
		ptr = pDisplayFM->data;
		for (y = 0; y < iDisplayHeight; y++)
		  {
		     for (x = 0; x < iDisplayWidth; x++)
		       {
			  ptr2 = yarray[y] + xarray[x];
			  *ptr++ = (int)*ptr2++;
			  *ptr++ = (int)*ptr2++;
			  *ptr++ = (int)*ptr2;
		       }
		  }
	     }
	   
	   pFM = pDisplayFM;
	   
	   free(pOtherFM->data);
	   delete pOtherFM;
	}
      
      // should NOT already be set
      UT_ASSERT(!m_image);
      
      if (m_image)
	{
	   // free the data in it too
	   if (m_image->data)
	     {
		free(m_image->data);
		m_image->data = NULL;
	     }
	   
	   delete m_image;
	   m_image = NULL;
	}
      
      m_image = pFM;
      return UT_TRUE;

}