/************************************************************************
 * usage: i.find location mapset element file [element2 file2]...
 *
 * produces a file containing the names of files of type
 * element (cell, dig, etc) in the search path for the mapset in location
 *
 * the output file is in the format used by i.ask, which does a popup menu
 * of the files, and lets the user select one using the mouse
 *
 * at present this routine requires that both the current location/mapset
 * and the specified location/mapset be valid for the user.
 * I hope to remove this requirement some time.
 *
 * note: the list is created in other file, and when complete it is moved
 *       to the one specified on the command line. This allows programs
 *       to run this command in background and check for completion by
 *       looking for the file.
 *
 *       if there are no files, the list file is not created
 *
 ***********************************************************************/

#include <dirent.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <grass/gis.h>
#include <grass/glocale.h>


/* function prototypes */
static int find (FILE *fd, char *element);


int 
main (int argc, char *argv[])
{
    char *tempfile;
    int n;

    if (argc < 5 || argc%2 == 0)
	G_fatal_error(_("usage: %s location mapset element file."), argv[0]);

    G_gisinit (argv[0]);

    /*
     * this code assumes that the SEARCH PATH is not read
     * until we call G__mapset_name() in find()
     */
    tempfile = G_tempfile();

    G__setenv ("LOCATION_NAME", argv[1]);
    G__setenv ("MAPSET", argv[2]);

    for (n = 3; n < argc; n += 2)
    {
        FILE *fd;
        int ok;

        /* get this list into a temp file first */
	fd = fopen (tempfile, "w");
	if (fd == NULL)
            G_fatal_error(_("Unable to open temp file."));

        remove(argv[n+1]);
	ok = find (fd, argv[n]);
	fclose (fd);

        /* move the temp file to the real file
         * this allows programs to run i.find in the background
         * and check for completion by looking for the file
         */
	if (ok)
            rename(tempfile, argv[n+1]);

        remove(tempfile);
    }
    G_free(tempfile);

    return 0;
}


static int find (FILE *fd, char *element)
{
    int len1 = 0, len2 = 0;
    char *mapset;
    int n;

    fseek (fd, 0L, SEEK_SET);
    fwrite (&len1, sizeof(len1), 1L, fd);
    fwrite (&len2, sizeof(len2), 1L, fd);

    for (n=0; ((mapset = G__mapset_name(n)) != NULL); n++)
    {
        int len;
        char dir[1024];
        struct dirent *dp;
        DIR *dfd;

	G__file_name (dir, element, "", mapset);
        if ((dfd = opendir(dir)) == NULL)
            continue;

	len = strlen (mapset);
	if (len > len2)
	    len2 = len;

        while ((dp = readdir(dfd)) != NULL)
        {
	    if(dp->d_name[0] != '.')
	    {       	
		fprintf(fd, "%s %s\n", dp->d_name, mapset);
		len = strlen(dp->d_name);
		if (len > len1)
		    len1 = len;
	    }	   
        }

        closedir(dfd);
    }

    if (len1 == 0 || len2 == 0)
	return 0;

    fflush (fd);
    fseek (fd, 0L, SEEK_SET);
    fwrite (&len1, sizeof(len1), 1L, fd);
    fwrite (&len2, sizeof(len2), 1L, fd);

    return 1;
}