/* make_mask.c

Program defines a coordinate system and then
call read_srtm_mask (double lat, double lon)
to build a bitmask for the 1 -r 2-minute formats
	0 = water
	1 = land
but I think this really means 0 = ocean, 1 = not ocean.

Writes binary bitmask to stdout.
*/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
/* #include <float.h>
#include <limits.h>  */

#include "blockstat.h"	/* Used for coordinate system definition */


int	main (int argc, char **argv) {

	struct BM_CSYS coords;
	
	double	x, y;
	
	int	coord_choice = -1;
	int	i, j, k;
	int	nerrs = 0;
	int	nbytes, val;
	
	unsigned char *bitmask;
	
	static unsigned char maskset[8] = {128, 64, 32, 16, 8, 4, 2, 1};

	
	for (k = 1; k < argc; k++) {
		if (argv[k][0] == '-') {
			switch (argv[k][1]) {
			
				case 'C':
					nerrs += ((sscanf(&argv[k][2], "%d", &coord_choice)) != 1);
					break;

				default:
					nerrs++;
					break;
			}
		}
		else {
			nerrs++;
		}
	}

	if (init_coords (&coords, coord_choice)) {	
		fprintf (stderr, "You must set a coordinate system choice.\n");
		nerrs++;
	}

	if (nerrs || (argc == 1) ) {
	
		fprintf (stderr, "usage:  make_mask -C<#>  > landsea.bits\n\n");
		if (argc == 1) exit (EXIT_SUCCESS);
		fprintf (stderr, "\tUse -C<#> to set the block coordinate system, where <#> is one of:\n");
		fprintf (stderr, "\t-C%d to select the SRTM30 (lon/lat, 30 arc sec, to +/- 90, pixel) system.\n", GTOPO30);
		fprintf (stderr, "\t-C%d to select the IMG1M72 (mercator, 1 arc min, to +/- 72.005977, pixel) system.\n", IMG1M72);
		fprintf (stderr, "\t-C%d to select the IMG1M81 (mercator, 1 arc min, to +/- 80.738009, pixel) system.\n", IMG1M81);
		fprintf (stderr, "\t-C%d to select the IMG2M72 (mercator, 2 arc min, to +/- 72.005977, pixel) system.\n", IMG2M72);
		fprintf (stderr, "\t-C%d to select the IMG2M81 (mercator, 2 arc min, to +/- 80.738009, pixel) system.\n\n", IMG2M81);
		exit (EXIT_FAILURE);
	}
	
	nbytes = coords.ntot / 8;	/* All our coordinate systems have ntot divisible by 8  */
        /*printf("%d \n",nbytes);*/
	
	if ( (bitmask = calloc ((size_t)nbytes, (size_t)1)) == NULL) {
		fprintf (stderr, "make_mask:  Error.  Failed to calloc %d bytes for the mask.\n", nbytes);
		exit (EXIT_FAILURE);
	}

	for (i = 0, k = 0; i < nbytes; i++) {
		for (j = 0; j < 8; j++, k++) {
			lonlat_from_k (k, &x, &y, &coords);
			if (x > 180.0) x -= 360.0;
			val = (int) read_srtm_mask (&x, &y);	/* This fn returns a type NV_INT32 */
			if (val < 0 || val > 1) {
				fprintf (stderr, "make_mask:  read_srtm_mask returns %d at k = %d, x = %.8lg, y = %.8lg\n",
					val, k, x, y);
				exit (EXIT_FAILURE);
			}
			if (val) bitmask[i] |= maskset[j];
                        /*if(i > 4200000) printf("%d %f %f %d \n",i,x,y,val);*/
		}
	}
	
	fwrite ((void *)bitmask, (size_t)1, (size_t)nbytes, stdout);
	
	free ((void *)bitmask);
	
	exit (EXIT_SUCCESS);
}