/**
 *
 * ***** BEGIN GPL/BL DUAL LICENSE BLOCK *****
 *
 * 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. The Blender
 * Foundation also sells licenses for use in proprietary software under
 * the Blender License.  See http://www.blender.org/BL/ for information
 * about this.
 *
 * 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.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL/BL DUAL LICENSE BLOCK *****
 * $Id: png.c,v 1.1 2003/12/04 18:18:05 sirdude Exp $
 */


#include "png.h"

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef WIN32
#include "BLI_winstuff.h"
#endif
#include "BLI_blenlib.h"

#include "imbuf.h"
#include "imbuf_patch.h"

#include "IMB_imbuf_types.h"
#include "IMB_imbuf.h"

#include "IMB_allocimbuf.h"
#include "IMB_cmap.h"
#include "IMB_png.h"

typedef struct PNGReadStruct {
        unsigned char *data;
        unsigned int size;
        unsigned int seek;
}PNGReadStruct;

static void ReadData( png_structp png_ptr, png_bytep data, png_size_t length);
static void WriteData( png_structp png_ptr, png_bytep data, png_size_t length);
static void Flush( png_structp png_ptr);

int imb_is_a_png(void *mem)
{
        int ret_val = 0;

        if (mem) {
                ret_val = !png_sig_cmp(mem, 0, 8);
        }

        return(ret_val);
}

static void Flush(png_structp png_ptr) 
{ 
}

static void WriteData( png_structp png_ptr, png_bytep data, png_size_t length)
{
	ImBuf *ibuf = (ImBuf *) png_get_io_ptr(png_ptr);

	// if buffer is to small increase it.
	while (ibuf->encodedsize + length > ibuf->encodedbuffersize) {
		imb_enlargeencodedbufferImBuf(ibuf);
	}

	memcpy(ibuf->encodedbuffer + ibuf->encodedsize, data, length);
	ibuf->encodedsize += length;
}

static void ReadData( png_structp png_ptr, png_bytep data, png_size_t length)
{
	PNGReadStruct *rs= (PNGReadStruct *) png_get_io_ptr(png_ptr);

	if (rs) {
		if (length <= rs->size - rs->seek) {
			memcpy(data, rs->data + rs->seek, length);
			rs->seek += length;
			return;
		}
	}

	printf("Reached EOF while decoding PNG\n");
	longjmp(png_jmpbuf(png_ptr), 1);
}

short imb_savepng(struct ImBuf *ibuf, int file, int flags)
{
	png_structp png_ptr;
	png_infop info_ptr;
	unsigned char *pixels = 0;
	unsigned char *from, *to;
	png_bytepp row_pointers = 0;
	int i, bytesperpixel, color_type = PNG_COLOR_TYPE_GRAY;
	FILE *fp = 0;

	bytesperpixel = (ibuf->depth + 7) >> 3;
	if ((bytesperpixel > 4) || (bytesperpixel == 2)) {
		printf("imb_savepng: unsupported bytes per pixel: %d\n", bytesperpixel);
		return (0);
	}

	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
		NULL, NULL, NULL);
	if (png_ptr == NULL) {
		printf("Cannot png_create_write_struct\n");
		return 0;
	}

	info_ptr = png_create_info_struct(png_ptr);
	if (info_ptr == NULL) {
		png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
		printf("Cannot png_create_info_struct\n");
		return 0;
	}

	if (setjmp(png_jmpbuf(png_ptr))) {
		png_destroy_write_struct(&png_ptr, &info_ptr);
		if (pixels) MEM_freeN(pixels);
		if (row_pointers) MEM_freeN(row_pointers);
		// printf("Aborting\n");
		if (fp) {
			fflush(fp);
			fclose(fp);
		}
		return 0;
	}

	// copy image data

	pixels = MEM_mallocN(ibuf->x * ibuf->y * bytesperpixel * sizeof(unsigned char), "pixels");
	if (pixels == NULL) {
		printf("Cannot allocate pixels array\n");
		return 0;
	}

	from = (unsigned char *) ibuf->rect;
	to = pixels;

	switch (bytesperpixel) {
	case 4:
		color_type = PNG_COLOR_TYPE_RGBA;
		for (i = ibuf->x * ibuf->y; i > 0; i--) {
			to[0] = from[0];
			to[1] = from[1];
			to[2] = from[2];
			to[3] = from[3];
			to += 4; from += 4;
		}
		break;
	case 3:
		color_type = PNG_COLOR_TYPE_RGB;
		for (i = ibuf->x * ibuf->y; i > 0; i--) {
			to[0] = from[0];
			to[1] = from[1];
			to[2] = from[2];
			to += 3; from += 4;
		}
		break;
	case 1:
		color_type = PNG_COLOR_TYPE_GRAY;
		for (i = ibuf->x * ibuf->y; i > 0; i--) {
			to[0] = from[0];
			to++; from += 4;
		}
		break;
	}

	if (flags & IB_mem) {
		// create image in memory
		imb_addencodedbufferImBuf(ibuf);
		ibuf->encodedsize = 0;

		png_set_write_fn(png_ptr,
			 (png_voidp) ibuf,
			 WriteData,
			 Flush);
	} else {
		fp = fdopen(file, "wb");
		png_init_io(png_ptr, fp);
	}

	/*
	png_set_filter(png_ptr, 0,
		PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
		PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
		PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
		PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
		PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
		PNG_ALL_FILTERS);

	png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
	*/

	// png image settings
	png_set_IHDR(png_ptr,
		 info_ptr,
		 ibuf->x,
		 ibuf->y,
		 8,
		 color_type,
		 PNG_INTERLACE_NONE,
		 PNG_COMPRESSION_TYPE_DEFAULT,
		 PNG_FILTER_TYPE_DEFAULT);

	// write the file header information
	png_write_info(png_ptr, info_ptr);

	// allocate memory for an array of row-pointers
	row_pointers = (png_bytepp) MEM_mallocN(ibuf->y * sizeof(png_bytep), "row_pointers");
	if (row_pointers == NULL) {
			printf("Cannot allocate row-pointers array\n");
			return 0;
	}

	// set the individual row-pointers to point at the correct offsets
	for (i = 0; i < ibuf->y; i++) {
		row_pointers[ibuf->y-1-i] = (png_bytep)
			((unsigned char *)pixels + (i * ibuf->x) * bytesperpixel * sizeof(unsigned char));
	}

	// write out the entire image data in one call
	png_write_image(png_ptr, row_pointers);

	// write the additional chunks to the PNG file (not really needed)
	png_write_end(png_ptr, info_ptr);

	// clean up
	MEM_freeN(pixels);
	MEM_freeN(row_pointers);
	png_destroy_write_struct(&png_ptr, &info_ptr);

	if (fp) {
		fflush(fp);
		fclose(fp);
	}

	return(1);
}

struct ImBuf *imb_loadpng(unsigned char *mem, int size, int flags)
{
	struct ImBuf *ibuf = 0;
	png_structp png_ptr;
	png_infop info_ptr;
	unsigned char *pixels = 0;
	png_bytepp row_pointers = 0;
	png_uint_32 width, height;
	int bit_depth, color_type;
	PNGReadStruct ps;

	unsigned char *from, *to;
	int i, bytesperpixel;

	if (imb_is_a_png(mem) == 0) return(0);

	png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
		NULL, NULL, NULL);
	if (png_ptr == NULL) {
		printf("Cannot png_create_read_struct\n");
		return 0;
	}

	info_ptr = png_create_info_struct(png_ptr);
	if (info_ptr == NULL) {
		png_destroy_read_struct(&png_ptr, (png_infopp)NULL, 
			(png_infopp)NULL);
		printf("Cannot png_create_info_struct\n");
		return 0;
	}

	ps.size = size;
	ps.data = mem;
	ps.seek = 0;

	png_set_read_fn(png_ptr, (void *) &ps, ReadData);

	if (setjmp(png_jmpbuf(png_ptr))) {
		png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
		if (pixels) MEM_freeN(pixels);
		if (row_pointers) MEM_freeN(row_pointers);
		if (ibuf) IMB_freeImBuf(ibuf);
		return 0;
	}

	// png_set_sig_bytes(png_ptr, 8);

	png_read_info(png_ptr, info_ptr);
	png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, 
		&color_type, NULL, NULL, NULL);

	if (bit_depth == 16) {
		png_set_strip_16(png_ptr);
		bit_depth = 8;
	}

	bytesperpixel = png_get_channels(png_ptr, info_ptr);

	switch(color_type) {
	case PNG_COLOR_TYPE_RGB:
	case PNG_COLOR_TYPE_RGB_ALPHA:
		break;
	case PNG_COLOR_TYPE_PALETTE:
		png_set_palette_to_rgb(png_ptr);
		if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
			bytesperpixel = 4;
		} else {
			bytesperpixel = 3;
		}
		break;
	case PNG_COLOR_TYPE_GRAY:
	case PNG_COLOR_TYPE_GRAY_ALPHA:
		if (bit_depth < 8) {
			png_set_expand(png_ptr);
			bit_depth = 8;
		}
		break;
	default:
		printf("PNG format not supported\n");
		longjmp(png_jmpbuf(png_ptr), 1);
	}
	
	ibuf = IMB_allocImBuf(width, height, 8 * bytesperpixel, 0, 0);

	if (ibuf) {
		ibuf->ftype = PNG;
	} else {
		printf("Couldn't allocate memory for PNG image\n");
	}

	if (ibuf && ((flags & IB_test) == 0)) {
		imb_addrectImBuf(ibuf);

		pixels = MEM_mallocN(ibuf->x * ibuf->y * bytesperpixel * sizeof(unsigned char), "pixels");
		if (pixels == NULL) {
			printf("Cannot allocate pixels array\n");
			longjmp(png_jmpbuf(png_ptr), 1);
		}

		// allocate memory for an array of row-pointers
		row_pointers = (png_bytepp) MEM_mallocN(ibuf->y * sizeof(png_bytep), "row_pointers");
		if (row_pointers == NULL) {
			printf("Cannot allocate row-pointers array\n");
			longjmp(png_jmpbuf(png_ptr), 1);
		}

		// set the individual row-pointers to point at the correct offsets
		for (i = 0; i < ibuf->y; i++) {
			row_pointers[ibuf->y-1-i] = (png_bytep)
			((unsigned char *)pixels + (i * ibuf->x) * bytesperpixel * sizeof(unsigned char));
		}

		png_read_image(png_ptr, row_pointers);

		// copy image data

		to = (unsigned char *) ibuf->rect;
		from = pixels;

		switch (bytesperpixel) {
		case 4:
			for (i = ibuf->x * ibuf->y; i > 0; i--) {
				to[0] = from[0];
				to[1] = from[1];
				to[2] = from[2];
				to[3] = from[3];
				to += 4; from += 4;
			}
			break;
		case 3:
			for (i = ibuf->x * ibuf->y; i > 0; i--) {
				to[0] = from[0];
				to[1] = from[1];
				to[2] = from[2];
				to[3] = 0xff;
				to += 4; from += 3;
			}
			break;
		case 2:
			for (i = ibuf->x * ibuf->y; i > 0; i--) {
				to[0] = to[1] = to[2] = from[0];
				to[3] = from[1];
				to += 4; from += 2;
			}
			break;
		case 1:
			for (i = ibuf->x * ibuf->y; i > 0; i--) {
				to[0] = to[1] = to[2] = from[0];
				to[3] = 0xff;
				to += 4; from++;
			}
			break;
		}

		png_read_end(png_ptr, info_ptr);
	}

	// clean up
	MEM_freeN(pixels);
	MEM_freeN(row_pointers);
	png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);

	return(ibuf);
}

