/*
 *	tif2bsb.c - Convert a TIFF file into a BSB file, using a template
 *				containing all the geographic information.
 *
 *	Copyright (C) 2000  Stuart Cunningham <stuart_hc@users.sourceforge.net>
 *
 *	This library is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU Lesser General Public
 *	License as published by the Free Software Foundation; either
 *	version 2.1 of the License, or (at your option) any later version.
 *
 *	This library 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
 *	Lesser General Public License for more details.
 *
 *	You should have received a copy of the GNU Lesser General Public
 *	License along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *	$Id: tif2bsb.c,v 1.18 2004/11/30 17:52:04 stuart_hc Exp $
 *
 */


#include <stdio.h>
#include <stdlib.h>		/* for malloc() */
#include <string.h>		/* for strncmp() */

#include <tiffio.h>		/* libtiff - TIFF file I/O */
#include <bsb.h>

int read_8bpp_tiff_line(TIFF* tif, uint16_t bits_per_sample, int width, uint8_t *tiff_row, uint32_t row)
{
	int i, result;

	result = TIFFReadScanline(tif, tiff_row, row, 0);

	/* Copy the TIFF row expanding to 8 bits per pixel if necessary */
	switch (bits_per_sample)
	{
        case 8:		/* no modification needed */
        {
			break;
		}
        case 4:
		{
			/* Expand 4 bits-per-sample into 8 bits-per-sample		*/

			unsigned char	*p = tiff_row;
			uint8_t			a, b;

			if ((width % 2) != 0)			// Handle boundary condition
			{
				i = (width - 1) / 2;
				a = (p[i] >> 4) & 0xf;		// left nibble
				p[ width - 1 ] = a;
			}

			/* Start at the end of the compressed row and expand each pair */
			for (i = (width - 2) / 2; i >= 0; i--)
			{
				a = (p[i] >> 4) & 0xf;		// left nibble
				b = p[i] & 0xf;				// right nibble
				p[i*2] = a;
				p[i*2+1] = b;
			}
			break;
		}
	}
	return result;
}

/* Count unique colors in the TIFF color map.							*/
int count_tiff_colors(TIFF* tif, BSBImage *pImage, uint16_t bits_per_sample)
{
	int			i, j, max_colors = 0;
	uint64_t	histogram[256] = {0};
	uint8_t		*tiff_row;

	tiff_row = (uint8_t *)malloc(pImage->width);

	/* Scan through entire image computing a histogram of colormap indices	*/
	for (j = 0; j < pImage->height; j++)
	{
		uint8_t *p = tiff_row;

		read_8bpp_tiff_line(tif, bits_per_sample, pImage->width, tiff_row, j);

		for (i = 0; i < pImage->width; i++)
			histogram[*p++]++;
	}
	/* Count down from highest colormap index for the first non-zero value.	*/
	/* This will indicate the maximum number of colors.						*/
	for (i = 255; i >= 0; i--)
	{
		if (histogram[i] != 0)
		{
			max_colors = i + 1;		/* count of colors includes index 0 */
			break;
		}
	}
	free(tiff_row);

	return max_colors;
}

static int depth_for_colors[] = { 1, 2, 4, 8, 16, 32, 64, 128 };

/* Takes a .kap template and a tif file */
extern int main (int argc, char *argv[])
{
	BSBImage	image;
	int			i, j, arg_idx, depth = 0, num_colors = -1, *index;
	FILE		*tmpl_file, *out;
	TIFF*		tif;
	uint16_t	*red, *green, *blue;
	uint16_t	bits_per_sample, photometric, planar_config;
	uint8_t		*tiff_row, *scratch;
	char		line[1024];

	arg_idx = 1;
	if (argc > 2 && (argv[1][0] == '-' && argv[1][1] == 'c'))
	{
		num_colors = atol(argv[2]);
		arg_idx += 2;
	}

	if ((argc - arg_idx) != 3)
	{
		fprintf(stderr, "Usage:\n\ttif2bsb [-c colormap-size] template.kap input.tif output.kap\n");
		exit(1);
	}

	tif = TIFFOpen(argv[arg_idx+1], "rb");
	if (! tif)
	{
		fprintf(stderr, "Could not TIFFOpen \"%s\"\n", argv[arg_idx+1]);
		exit(1);
	}

	TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &image.width);
	TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &image.height);
	TIFFGetFieldDefaulted(tif, TIFFTAG_BITSPERSAMPLE, &bits_per_sample);
	TIFFGetFieldDefaulted(tif, TIFFTAG_PHOTOMETRIC, &photometric);
	TIFFGetFieldDefaulted(tif, TIFFTAG_PLANARCONFIG, &planar_config);

	/* Check for supported TIFF files */
	if (image.width == 0 || image.height == 0)
	{
		fprintf(stderr, "Invalid TIFF file (width=%d,height=%d)\n", image.width, image.height);
		exit(1);
	}
	if (photometric != PHOTOMETRIC_PALETTE)
	{
		fprintf(stderr, "No support for TIFF files with PHOTOMETRIC=%d (only images containing color maps supported)\n", photometric);
		exit(1);
	}
	if (bits_per_sample != 8 && bits_per_sample != 4)
	{
		fprintf(stderr, "No support for TIFF files with BITSPERSAMPLE=%d (only 4 or 8 bits per sample supported)\n", bits_per_sample);
		exit(1);
	}
	if (planar_config != PLANARCONFIG_CONTIG)
	{
		fprintf(stderr, "No support for TIFF files with PLANARCONFIG=%d (only single plane images supported)\n", planar_config);
		exit(1);
	}

	/* TIFFGetField allocates memory for color fields - TIFFClose frees it. */
	TIFFGetField(tif, TIFFTAG_COLORMAP, &red, &green, &blue);

	tiff_row = (uint8_t *)malloc(image.width);
	if (! tiff_row)
	{
		fprintf(stderr,"Cannot allocate %d bytes for image row\n", image.width);
		exit(1);
	}

	if (num_colors == -1)
		num_colors = count_tiff_colors(tif, &image, bits_per_sample);

	if (num_colors <= 0)
	{
		fprintf(stderr, "Error - no colors found in image\n");
		exit(1);
	}

	/* The BSB format cannot cope with more than 128 colors */
	if (num_colors > 128)
	{
		fprintf(stderr, "Too many colors for BSB format (%d > 128 max.)\n", num_colors);
		fprintf(stderr, "Try reducing the colors.\n\tE.g. Using ImageMagick\n\tconvert -colors 128 ...\n\n");
		fprintf(stderr, "Or use -c max-colors to restrict the colormap to max-colors\n");
		exit(1);
	}

	/* Given num_colors in input image, compute required "depth"	*/
	/* E.g. num_colors=35, depth=6  (2^6 = 64)						*/
	for (i = 0; i < (int)sizeof(depth_for_colors); i++)
	{
		if (num_colors < depth_for_colors[i])
			break;
		depth = i + 1;
	}
	image.depth = depth;

	out = fopen(argv[arg_idx+2], "wb");
	if (! out)
	{
		perror(argv[arg_idx+2]);
		exit(1);
	}

	/* Copy in all text lines from template excluding RGB and IFM tags */
	tmpl_file = fopen(argv[arg_idx], "rb");
	while (fgets(line, sizeof(line), tmpl_file) != NULL)
	{
		if (strncmp("RGB/", line, 4) == 0)
			continue;
		if (strncmp("IFM/", line, 4) == 0)
			continue;
		if (line[0] == 0x1a)
			break;
		fputs(line, out);
	}
	fclose(tmpl_file);

	/* Write IFM tag */
	fprintf(out, "IFM/%d\r\n", depth);
	/* Write RGB tags for colormap */
	for (i = 0; i < num_colors; i++)
	{
		fprintf(out, "RGB/%d,%d,%d,%d\r\n",
					i+1,
					red[i] >> 8,
					green[i] >> 8,
					blue[i] >> 8
					);
	}
	fputc(0x1a, out);
	fputc('\0', out);
	fputc(depth, out);

	index = (int *)malloc((image.height + 1) * sizeof(int));

	scratch = (uint8_t *)malloc(image.width + 8);	/* max space encoded line can take */

	/* Read rows from tif, write to bsb */
	for (j = 0; j < image.height; j++)
	{
		int		len;

		/* Record start-of-row file position for index table */
		index[j] = ftell(out);

		read_8bpp_tiff_line(tif, bits_per_sample, image.width, tiff_row, j);

		/* Compress raster and write to BSB file */
		len = bsb_compress_row(&image, j, tiff_row, scratch);
		fwrite(scratch, len, 1, out);
	}
	free(scratch);
	free(tiff_row);
	TIFFClose(tif);

	/* record start-of-index-table file position in the index table */
	index[image.height] = ftell(out);

	bsb_write_index(out, image.height, index);
	free(index);

	fclose(out);

	return 0;
}