#include <string.h>
#include <grass/gis.h>

static char *append(char *, char *);
static int do_text(char *,long,long);
static int reclass_text(char *,struct Reclass *,int);

char *
maskinfo (void)
{
    struct Reclass reclass;
    char *results;
    char text[100];
    int next;
    int first;
    char *append();

    results = NULL;
    if (G_find_cell ("MASK", G_mapset()) == NULL)
	return "none" ;
    if (G_get_reclass ("MASK", G_mapset(), &reclass) <= 0)
    {
	sprintf (text, "MASK in %s", G_mapset());
	return append(results, text);
    }

    sprintf (text, "%s in %s", reclass.name, reclass.mapset);
    results = append (results, text);
    next = 0;
    first = 1;
    do
    {
	next = reclass_text (text, &reclass, next);
	if (*text == 0) break;
	if (first)
	{
	    first = 0;
	    results = append (results, ", categories");
	}
	results = append (results, " ");
	results = append (results, text);
    }
    while (next >= 0);
    G_free_reclass (&reclass);
    return results;
}

static int reclass_text (char *text,struct Reclass *reclass, int next)
{
    int i;
    int n;
    int first;

    *text = 0;

    n = reclass->num ;

    first = -1;
    for (i = next; i < n; i++)
    {
	if (reclass->table[i])
	{
	    if (first < 0)
		first = i;
	}
	else if (first >= 0)
	{
	    do_text (text, (long)(first+reclass->min),(long)(i-1+reclass->min));
	    first = -1;
	    if (strlen (text) > 60)
		return i;
	}
    }
    if (first >= 0)
	do_text (text, (long)(first+reclass->min), (long)(i-1+reclass->min));
    return -1;
}

static int do_text(char *text,long first,long last)
{
    char work[40];

    if (*text)
	strcat (text, " ");

    if (first == last)
	sprintf (work, "%ld", first);
    else
	sprintf (work, "%ld-%ld", first, last);

    strcat (text, work);

    return 0;
}

static char *append ( char *results, char *text)
{
    if (results == NULL)
	return G_store (text);
    results = G_realloc (results, strlen(results)+strlen(text)+1);
    strcat (results, text);
    return results;
}