#include <stdio.h>
#include <errno.h>
#include <sys/file.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>

int     Debug = 0;
char    *source_dir, *dest_dir;
time_t  now;

void
RenameJob(char *fname)
{
   char         buf[256];

   /* We first move the data file, this eases locking stuff */
   fname[0] = 'd';
   sprintf(buf, "%s/%s", dest_dir, fname);
   /* Does the dest file exist ? */
   if (access(buf, F_OK) == 0) {
      fprintf(stderr, "Destination %s already exists, skipping\n", fname);
      return;
   }
   if (Debug)
      fprintf(stderr, "Will rename %s to %s\n", fname, buf);
   rename(fname, buf);

   /* The we move the queue file, the lock will stay until released */
   fname[0] = 'q';
   sprintf(buf, "%s/%s", dest_dir, fname);
   if (access(buf, F_OK) == 0) {
      fprintf(stderr, "Destination %s already exists, skipping\n", fname);
      return;
   }
   if (Debug)
      fprintf(stderr, "Will rename %s to %s\n", fname, buf);
   rename(fname, buf);
}

void
CheckFile(char *fname, time_t delay)
{
   char         buf[256];
   FILE         *f;
   time_t       t;

   if ((f = fopen(fname, "r+")) == NULL) {
      fprintf(stderr, "Can't read %s: %s\n", fname, strerror(errno));
      return;
   }
   if (flock(fileno(f), LOCK_EX|LOCK_NB) == -1) {
      if (errno == EWOULDBLOCK) {
         if (Debug)
            fprintf(stderr, "%s already locked\n", fname);
      } else {
         fprintf(stderr, "Could not lock %s: %s\n", fname, strerror(errno));
      }
      fclose(f);
      return;
   }

   /* Get the job creation time */
   while (fgets(buf, sizeof buf, f) != NULL) {
      if (buf[0] == 'T') {
         t = atol(buf + 1);
         break;
      }
   }

   if (Debug)
      fprintf(stderr, "Age is : %ld (limit %ld)\n", now - t, delay);
   /* If the time is zero we did not find the T line, ignore the job */
   if (t > 0 && (t < (now - delay))) {
      RenameJob(fname);
   }
   fclose(f);
}

void
Usage(char *prog)
{
   fprintf(stderr, "Usage: %s source_dir dest_dir hours_age\n", prog);
   exit(1);
}

void main(int argn, char *argv[])
{
   DIR                  *dir;
   struct dirent        *d;
   struct stat          st;
   time_t               delay;

   /* Check the number of arguments */
   if (argn != 4) Usage(argv[0]);

   source_dir = argv[1];
   dest_dir   = argv[2];
   delay      = atol(argv[3]) * 3600;

   time(&now);

   /* Go to the source directory */
   if (chdir(source_dir) == -1) {
      fprintf(stderr, "Can't change directory to %s: %s\n", source_dir, strerror(errno));
      exit(1);
   }

   /* Are we authorized to write the destination directory ? */
   if (access(dest_dir, R_OK | W_OK | X_OK) == -1) {
      fprintf(stderr, "Can't access %s: %s\n", dest_dir, strerror(errno));
      exit(1);
   }

   /* Parse the source directory, we only work with the qf file */
   if ((dir = opendir(".")) == NULL) {
      fprintf(stderr, "Can't open %s: %s\n", dest_dir, strerror(errno));
      exit(1);
   }
   while ((d = readdir(dir)) != NULL) {
      if (d->d_reclen < 2 || d->d_name[0] != 'q' || d->d_name[1] != 'f')
         continue;
      if (Debug)
         fprintf(stderr, "Handling %s ", d->d_name);
      CheckFile(d->d_name, delay);
   }
   closedir(dir);
   exit(0);
}