/*!
 * \file raster/color_write.c
 * 
 * \brief Raster Library - Write color table of raster map
 *
 * (C) 1999-2009 by the GRASS Development Team
 *
 * This program is free software under the GNU General Public
 * License (>=v2). Read the file COPYING that comes with GRASS
 * for details.
 *
 * \author USACERL and many others
 */

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <grass/gis.h>
#include <grass/glocale.h>
#include <grass/raster.h>

static void write_rules(FILE *, struct _Color_Rule_ *, DCELL, DCELL);
static void write_new_colors(FILE *, struct Colors *);
static void write_old_colors(FILE *, struct Colors *);
static void forced_write_old_colors(FILE *, struct Colors *);
static void format_min(char *, double);
static void format_max(char *, double);

/*!
 * \brief Write map layer color table
 *
 * The color table is written for the raster map <i>name</i> in the
 * specified <i>mapset</i> from the <i>colors</i> structure.
 *
 * If there is an error, -1 is returned. No diagnostic is
 * printed. Otherwise, 1 is returned.
 *
 * The <i>colors</i> structure must be created properly, i.e.,
 * Rast_init_colors() to initialize the structure and Rast_add_c_color_rule()
 * to set the category colors. These routines are called by
 * higher level routines which read or create entire color tables,
 * such as Rast_read_colors() or Rast_make_ramp_colors().
 *
 * <b>Note:</b> The calling sequence for this function deserves
 * special attention. The <i>mapset</i> parameter seems to imply that
 * it is possible to overwrite the color table for a raster map which
 * is in another mapset. However, this is not what actually
 * happens. It is very useful for users to create their own color
 * tables for raster maps in other mapsets, but without overwriting
 * other users' color tables for the same raster map. If <i>mapset</i>
 * is the current mapset, then the color file for <i>name</i> will be
 * overwritten by the new color table. But if <i>mapset</i> is not the
 * current mapset, then the color table is actually written in the
 * current mapset under the <tt>colr2</tt> element as:
 * <tt>colr2/mapset/name</tt>.
 *
 * The rules are written out using floating-point format, removing
 * trailing zeros (possibly producing integers).  The flag marking the
 * colors as floating-point is <b>not</b> written.
 *
 * If the environment variable FORCE_GRASS3_COLORS is set (to anything at all)
 * then the output format is 3.0, even if the structure contains 4.0 rules.
 * This allows users to create 3.0 color files for export to sites which
 * don't yet have 4.0
 *
 * \param name map name
 * \param mapset mapset name
 * \param colors pointer to structure Colors which holds color info
 *
 * \return void
 */
void Rast_write_colors(const char *name, const char *mapset,
		      struct Colors *colors)
{
    char element[512];
    char xname[GNAME_MAX], xmapset[GMAPSET_MAX];
    FILE *fd;

    if (G_name_is_fully_qualified(name, xname, xmapset)) {
	if (strcmp(xmapset, mapset) != 0)
	    G_fatal_error(_("Qualified name <%s> doesn't match mapset <%s>"),
			  name, mapset);
	name = xname;
    }
    /*
     * if mapset is current mapset, remove colr2 file (created by pre 3.0 grass)
     *    and then write original color table
     * else write secondary color table
     */
    sprintf(element, "colr2/%s", mapset);
    if (strcmp(mapset, G_mapset()) == 0) {
	G_remove(element, name);	/* get rid of existing colr2, if any */
	strcpy(element, "colr");
    }
    if (!(fd = G_fopen_new(element, name)))
	G_fatal_error(_("Unable to create <%s> file for map <%s>"),
		      element, name);

    Rast__write_colors(fd, colors);
    fclose(fd);
}

/*!
 * \brief Write map layer color table
 *
 * \param fd file descriptor
 * \param colors pointer to Colors structure which holds color info
 */
void Rast__write_colors(FILE * fd, struct Colors *colors)
{
    if (getenv("FORCE_GRASS3_COLORS"))
	forced_write_old_colors(fd, colors);
    else if (colors->version < 0)
	write_old_colors(fd, colors);
    else
	write_new_colors(fd, colors);
}

static void write_new_colors(FILE * fd, struct Colors *colors)
{
    char str1[100], str2[100];

    format_min(str1, (double)colors->cmin);
    format_max(str2, (double)colors->cmax);
    fprintf(fd, "%% %s %s\n", str1, str2);

    if (colors->shift) {
	sprintf(str2, "%.17g", (double)colors->shift);
	G_trim_decimal(str2);
	fprintf(fd, "shift:%s\n", str2);
    }
    if (colors->invert)
	fprintf(fd, "invert\n");

    if (colors->null_set) {
	fprintf(fd, "nv:%d", colors->null_red);
	if (colors->null_red != colors->null_grn || colors->null_red
	    != colors->null_blu)
	    fprintf(fd, ":%d:%d", colors->null_grn, colors->null_blu);
	fprintf(fd, "\n");
    }
    if (colors->undef_set) {
	fprintf(fd, "*:%d", colors->undef_red);
	if (colors->undef_red != colors->undef_grn || colors->undef_red
	    != colors->undef_blu)
	    fprintf(fd, ":%d:%d", colors->undef_grn, colors->undef_blu);
	fprintf(fd, "\n");
    }
    if (colors->modular.rules) {
	fprintf(fd, "%s\n", "%%");
	write_rules(fd, colors->modular.rules, colors->cmin, colors->cmax);
	fprintf(fd, "%s\n", "%%");
    }
    if (colors->fixed.rules)
	write_rules(fd, colors->fixed.rules, colors->cmin, colors->cmax);
}

/* overall min and max data values in color table */
static void write_rules(FILE * fd, struct _Color_Rule_ *crules, DCELL dmin,
			DCELL dmax)
{
    struct _Color_Rule_ *rule;
    char str[100];

    /* find the end of the rules list */
    rule = crules;
    while (rule->next)
	rule = rule->next;

    /* write out the rules in reverse order */
    for (; rule; rule = rule->prev) {
	if (rule->low.value == dmin)
	    format_min(str, (double)rule->low.value);
	else {
	    sprintf(str, "%.17g", (double)rule->low.value);
	    G_trim_decimal(str);
	}
	fprintf(fd, "%s:%d", str, (int)rule->low.red);
	if (rule->low.red != rule->low.grn || rule->low.red != rule->low.blu)
	    fprintf(fd, ":%d:%d", rule->low.grn, rule->low.blu);
	/* even if low==high, write second end when the high is dmax */
	if (rule->high.value == dmax || rule->low.value != rule->high.value) {
	    if (rule->high.value == dmax)
		format_max(str, (double)rule->high.value);
	    else {
		sprintf(str, "%.17g", (double)rule->high.value);
		G_trim_decimal(str);
	    }
	    fprintf(fd, " %s:%d", str, (int)rule->high.red);
	    if (rule->high.red != rule->high.grn ||
		rule->high.red != rule->high.blu)
		fprintf(fd, ":%d:%d", rule->high.grn, rule->high.blu);
	}
	fprintf(fd, "\n");
    }
}

static void write_old_colors(FILE * fd, struct Colors *colors)
{
    int i, n;

    fprintf(fd, "#%ld first color\n", (long)colors->fixed.min);
    if (colors->null_set) {
	fprintf(fd, "%d %d %d\n",
		(int)colors->null_red,
		(int)colors->null_grn, (int)colors->null_blu);
    }
    else
	fprintf(fd, "255 255 255\n");	/* white */

    n = colors->fixed.max - colors->fixed.min + 1;

    for (i = 0; i < n; i++) {
	fprintf(fd, "%d", (int)colors->fixed.lookup.red[i]);
	if (colors->fixed.lookup.red[i] != colors->fixed.lookup.grn[i]
	    || colors->fixed.lookup.red[i] != colors->fixed.lookup.blu[i])
	    fprintf(fd, " %d %d",
		    (int)colors->fixed.lookup.grn[i],
		    (int)colors->fixed.lookup.blu[i]);
	fprintf(fd, "\n");
    }
}

static void forced_write_old_colors(FILE * fd, struct Colors *colors)
{
    int red, grn, blu;
    CELL cat;

    fprintf(fd, "#%ld first color\n", (long)colors->cmin);
    cat = 0;
    Rast_get_c_color(&cat, &red, &grn, &blu, colors);
    fprintf(fd, "%d %d %d\n", red, grn, blu);

    for (cat = colors->cmin; cat <= colors->cmax; cat++) {
	Rast_get_c_color(&cat, &red, &grn, &blu, colors);
	fprintf(fd, "%d", red);
	if (red != grn || red != blu)
	    fprintf(fd, " %d %d", grn, blu);
	fprintf(fd, "\n");
    }
}


static void format_min(char *str, double dval)
{
    double dtmp;

    sprintf(str, "%.17g", dval);
    /* Note that G_trim_decimal() does not trim e.g. 1.0000000e-20 */
    G_trim_decimal(str);
    sscanf(str, "%lf", &dtmp);
    if (dtmp != dval) {  /* if no zeros after decimal point were trimmed */
	/* lower dval by GRASS_EPSILON fraction */
	if (dval > 0)
	    sprintf(str, "%.17g", dval * (1 - GRASS_EPSILON));
	else
	    sprintf(str, "%.17g", dval * (1 + GRASS_EPSILON));
    }
}


static void format_max(char *str, double dval)
{
    double dtmp;

    sprintf(str, "%.17g", dval);
    /* Note that G_trim_decimal() does not trim e.g. 1.0000000e-20 */
    G_trim_decimal(str);
    sscanf(str, "%lf", &dtmp);
    if (dtmp != dval) {  /* if  no zeros after decimal point were trimmed */
	/* increase dval by by GRASS_EPSILON fraction */
	if (dval > 0)
	    sprintf(str, "%.17g", dval * (1 + GRASS_EPSILON));
	else
	    sprintf(str, "%.17g", dval * (1 - GRASS_EPSILON));
    }
}