#include <config.h>
#ifndef _plan9_
#include <aconfig.h>
#ifdef USE_PNG
#include <png.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#ifndef NO_MALLOC_H
#include <malloc.h>
#endif
#include <errno.h>
#else
#include <u.h>
#include <libc.h>
#include <stdio.h>
#endif
#include <filter.h>
#include <version.h>
#include <misc-f.h>
#include <xio.h>
#ifndef USE_PNG
CONST char *writepng(xio_constpath filename, CONST struct image *img)
{
    return
	"XaoS can not save images because it was incorrectly compiled. Please compile it with zlib and libpng";
}
#else

CONST char *writepng(xio_constpath filename, CONST struct image *image)
{
    png_structp png_ptr;
    png_infop info_ptr;
    png_color palette[256];
    volatile unsigned short a = 255;
    volatile unsigned char *b = (volatile unsigned char *) &a;
#ifdef _undefined_
    static char text[] =
	"XaoS" XaoS_VERSION " - a realtime interactive fractal zoomer";
    static png_text comments[] = {
	{
	 -1,
	 "Software",
	 text,
	 sizeof(text)}
    };
#endif
    FILE *file = fopen(filename, "wb");
    errno = -1;
    if (file == NULL) {
	return strerror(errno);
    }
    png_ptr =
	png_create_write_struct(PNG_LIBPNG_VER_STRING, (void *) NULL,
				(png_error_ptr) NULL,
				(png_error_ptr) NULL);
    if (!png_ptr)
	return "Unable to initialize pnglib";
    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr) {
	png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
	return "No memory to create png info structure";
    }
    if (setjmp(png_ptr->jmpbuf)) {
	png_destroy_write_struct(&png_ptr, &info_ptr);
	fclose(file);
	return strerror(errno);
    }
    png_init_io(png_ptr, file);
    png_set_filter(png_ptr, 0,
		   PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_PAETH |
		   PNG_FILTER_UP | PNG_FILTER_AVG);
    /* set the zlib compression level */
    /*png_set_compression_level(png_ptr, Z_BEST_COMPRESSION); */
    png_set_compression_level(png_ptr, Z_DEFAULT_COMPRESSION);

    /* set other zlib parameters */
    png_set_compression_mem_level(png_ptr, 8);
    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
    png_set_compression_window_bits(png_ptr, 15);
    png_set_compression_method(png_ptr, 8);

    info_ptr->width = image->width;
    info_ptr->height = image->height;
    /*info_ptr->gamma=1.0; */
    info_ptr->gamma = 0.5;
    info_ptr->valid |= PNG_INFO_gAMA | PNG_INFO_pHYs;
    info_ptr->x_pixels_per_unit = (png_uint_32) (100 / image->pixelwidth);
    info_ptr->y_pixels_per_unit = (png_uint_32) (100 / image->pixelheight);


    switch (image->palette->type) {
    case C256:
	{
	    int i;
	    info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
	    info_ptr->bit_depth = image->bytesperpixel * 8;
	    info_ptr->palette = palette;
	    info_ptr->valid |= PNG_INFO_PLTE;
	    for (i = 0; i < image->palette->end; i++)
		info_ptr->palette[i].red = image->palette->rgb[i][0],
		    info_ptr->palette[i].green = image->palette->rgb[i][1],
		    info_ptr->palette[i].blue = image->palette->rgb[i][2],
		    info_ptr->num_palette = image->palette->end;
	}
	break;
    case SMALLITER:
    case LARGEITER:
    case GRAYSCALE:
	info_ptr->color_type = PNG_COLOR_TYPE_GRAY;
	info_ptr->bit_depth = image->bytesperpixel * 8;
	break;
    case TRUECOLOR:
    case TRUECOLOR24:
    case TRUECOLOR16:
	info_ptr->color_type = PNG_COLOR_TYPE_RGB;
	info_ptr->bit_depth = 8;
	info_ptr->sig_bit.red = 8 - image->palette->info.truec.rprec;
	info_ptr->sig_bit.green = 8 - image->palette->info.truec.gprec;
	info_ptr->sig_bit.blue = 8 - image->palette->info.truec.bprec;
	break;
    }
    info_ptr->interlace_type = 0;
#ifdef _undefined_
    png_set_text(png_ptr, info_ptr, comments,
		 sizeof(comments) / sizeof(png_text));
#endif

    png_write_info(png_ptr, info_ptr);
    /*png_set_filler(png_ptr,0,PNG_FILLER_AFTER); */
    png_set_packing(png_ptr);
    if (image->palette->type & (TRUECOLOR | TRUECOLOR24 | TRUECOLOR16))
	png_set_shift(png_ptr, &(info_ptr->sig_bit));
    if (*b == 255)
	png_set_swap(png_ptr);
    png_set_bgr(png_ptr);
    switch (image->palette->type) {
    case C256:
    case GRAYSCALE:
    case SMALLITER:
    case LARGEITER:
#ifdef STRUECOLOR24
    case TRUECOLOR24:
	png_write_image(png_ptr, (png_bytepp) image->currlines);
	break;
#endif
    case TRUECOLOR:
	{
	    int i, y;
	    unsigned char *r = (unsigned char *) malloc(image->width * 3);
	    for (i = 0; i < image->height; i++) {
		for (y = 0; y < image->width; y++)
		    r[y * 3 + 2] =
			(((pixel32_t **) (image->
					  currlines))[i][y] &
			 image->palette->info.truec.rmask) >> image->
			palette->info.truec.rshift, r[y * 3 + 1] =
			(((pixel32_t **) (image->
					  currlines))[i][y] &
			 image->palette->info.truec.gmask) >> image->
			palette->info.truec.gshift, r[y * 3] =
			(((pixel32_t **) (image->
					  currlines))[i][y] &
			 image->palette->info.truec.bmask) >> image->
			palette->info.truec.bshift;
		png_write_rows(png_ptr, (png_bytepp) & r, 1);
	    }
	}
	break;
#ifdef SUPPORT16
    case TRUECOLOR16:
	{
	    int i, y;
	    unsigned char *r = (unsigned char *) malloc(image->width * 3);
	    for (i = 0; i < image->height; i++) {
		for (y = 0; y < image->width; y++)
		    r[y * 3 + 2] =
			(((pixel16_t **) (image->
					  currlines))[i][y] &
			 image->palette->info.truec.rmask) >> image->
			palette->info.truec.rshift, r[y * 3 + 1] =
			(((pixel16_t **) (image->
					  currlines))[i][y] &
			 image->palette->info.truec.gmask) >> image->
			palette->info.truec.gshift, r[y * 3] =
			(((pixel16_t **) (image->
					  currlines))[i][y] &
			 image->palette->info.truec.bmask) >> image->
			palette->info.truec.bshift;
		png_write_rows(png_ptr, (png_bytepp) & r, 1);
	    }
	}
	break;
#endif
    }
    png_write_end(png_ptr, info_ptr);
    png_destroy_write_struct(&png_ptr, &info_ptr);
    fclose(file);
    return NULL;
}
#endif