#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <grass/gis.h>
#include "local_proto.h"
/**************************************************************
 * clean_temp
 *
 *   looks for all files in mapset temp directory
 *   of the form pid.n and removes those which have
 *   been abandoned their processes (pid).
 *
 *   also removes any other file found which is "old"
 *   with an modification time greater then 4 days
 *
 *   2006: Rewritten for GRASS 6 by Roberto Flor, ITC-irst
 *
 **************************************************************/

#include <limits.h>
#include <string.h>
#include <errno.h>
#ifdef PATH_MAX
#define BUF_MAX PATH_MAX
#else
#define BUF_MAX 4096
#endif

extern int errno;

#define SLEEP 30	/* 30 minutes */

/* Recursively scan the directory pathname, removing directory and files */

void clean_dir(const char *pathname,uid_t uid,pid_t pid,time_t now,int max_age)
{
    char buf[BUF_MAX];
    DIR *curdir;
    struct dirent *cur_entry;
    struct stat info;
    int n,pathlen;

    curdir = opendir(pathname);
    if (curdir == NULL ) {
	G_warning("Can't open directory %s: %s,skipping\n",pathname,strerror(errno));
	return;
    }
    /* loop over current dir */
    while ((cur_entry = readdir(curdir)))
    {
	if ((G_strcasecmp(cur_entry->d_name,".") == 0 )|| (G_strcasecmp(cur_entry->d_name,"..")==0)) 
		continue; /* Skip dir and parent dir entries */
		
	if ( (pathlen=G_snprintf(buf,BUF_MAX,"%s/%s",pathname,cur_entry->d_name)) >= BUF_MAX) 
		G_fatal_error("clean_temp: exceeded maximum pathname length %d, got %d, should'nt happen",BUF_MAX,pathlen);

	if (stat(buf, &info) != 0) {
		G_warning("Can't stat file %s: %s,skipping\n",buf,strerror(errno));
		continue;
	}
	if ( S_ISDIR(info.st_mode)) { /* It's a dir, recurring */
		clean_dir(buf,uid,pid,now,max_age);
		/* Return here means we have completed the subdir recursion */
		/* Trying to remove the now empty dir */
		if ( info.st_uid != uid ) /* Not owners of dir */
			continue;	
#ifndef DEBUG_CLEAN
		if (rmdir(buf) != 0 ) {
			if ( errno != ENOTEMPTY ) {
			  	G_warning("Can't remove empty directory %s: %s,skipping\n",buf,strerror(errno));
			}
		}
#else
		G_warning("Removing directory %s\n",buf);
#endif
	} else { /* It's a file check it */
		if ( info.st_uid == uid ) { /* Remove only files owned by current user */
			if (sscanf (cur_entry->d_name, "%d.%d", &pid, &n) == 2 ) {
				if (!find_process (pid)) 
#ifndef DEBUG_CLEAN
					if ( unlink (buf) != 0 )
			  			G_warning("Can't remove file %s: %s,skipping\n",buf,strerror(errno));
#else
			  			G_warning("Removing file %s\n",buf);
#endif
			} else {
				if ((now - info.st_mtime) > max_age) /* Not modified in 4 days: TODO configurable param */
#ifndef DEBUG_CLEAN
					if ( unlink (buf) != 0 )
			  			G_warning("Can't remove file %s: %s,skipping\n",buf,strerror(errno));
#else
			  			G_warning("Removing file %s\n",buf);
#endif
			}
		}
	}
    }
    closedir(curdir);
    return;
}

int 
main (int argc, char *argv[])
{
    char *mapset;
    char element[GNAME_MAX];
    char tmppath[BUF_MAX];
    pid_t ppid;
    pid_t pid;
    uid_t uid;
    time_t now;
    long max_age;

    G_gisinit(argv[0]) ;
    pid = 0;
    ppid = 0;
    if (argc > 1)
	sscanf(argv[1],"%d", &ppid);

/* Get the mapset temp directory */
    G__temp_element(element);
    G__file_name (tmppath, element, "", mapset = G_mapset());

/* get user id and current time in seconds */
#ifdef __MINGW32__
    /* TODO */
    uid = -1;
#else
    uid = getuid () ;
#endif

    now = time(NULL) ;

/* set maximum age in seconds (4 days) */
    max_age = 4 * 24 * 60 * 60 ;

/*
* Scan the temp directory and subdirectory for 
* files owned by the user and of the form pid.n
* to be removed if the process is not running
* all "old" files are removed as well
*/

    while(1)
    {
	if (ppid > 0 && !find_process(ppid))
	    break;
    	clean_dir(tmppath,uid,pid,now,max_age);
	if (ppid <= 0)
	    break;
	G_sleep(SLEEP);
    }
    exit(0);
}

int 
find_process (int pid)
{
#ifdef __MINGW32__
    /* TODO */
    return -1;
#else
    return (kill (pid, 0) == 0 || errno != ESRCH) ;
#endif
}

