#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

const char* progname;
const char* progversion = "1.0";

static void usage(FILE* f)
{
  fprintf(f, "\n");
  fprintf(f, "Usage: %s [options] <usecs>\n", progname);
  fprintf(f, "\n");
  fprintf(f, "       options:\n");
  fprintf(f, "                -h or --help : Print help.\n");
  fprintf(f, "             -v or --version : Display version.\n");
  fprintf(f, "\n");
}

static const char* basename(const char* fullpath)
{
  const char* rv = NULL;
  assert(fullpath);
  rv = strrchr(fullpath, '/');
  return rv ? ++rv : fullpath;
}

int main(int argc, char* argv[])
{
  int rv = -1;
  int i = 0;

  progname = basename(argv[0]);

  if( argc == 1 ) {
    usage(stdout);
    rv = 1;
  }

  /*
   * Check command-line parameters.
   */
  for( i = 1 ; i < argc ; ++i ) {
    if( (strcmp(argv[i], "-h") == 0) || (strcmp(argv[i], "--help") == 0) ) {
      usage(stdout);
      rv = 0;
      break;
    }
    if( (strcmp(argv[i], "-v") == 0) || (strcmp(argv[i], "--version") == 0) ) {
      printf("%s: v%s\n", progname, progversion);
      rv = 0;
      break;
    }
    if( argv[i][0] == '-' ) {
      fprintf(stderr, "\n");
      fprintf(stderr, "%s: Error: Unknown option \"%s\"\n", progname, argv[i]);
      usage(stderr);
      rv = 1;
      break;
    }
    /* Leave i pointing to the first non-option parameter. */
    break;
  }

  /*
   * i should be pointing to the last parameter on the command line.
   */
  if( i < argc - 1 ) {
    int j = 0;
    fprintf(stderr, "\n");
    fprintf(stderr, "%s: Error: Too many arguments: \"", progname);
    for( j = i + 1 ; j < argc ; ++j ) {
      fprintf(stderr, "%s%s", argv[j], (j == argc - 1) ? "" : " ");
    }
    fprintf(stderr, "\"\n");
    usage(stderr);
    rv = 1;
  }

  /* 
   * Check to see if the value for <usecs> is valid.
   */
  if( rv == -1 ) {
    char* endptr = NULL;
    long usecs = 0;
    usecs = strtol(argv[i], &endptr, 0);
    if( *endptr != '\0' ) {
      fprintf(stderr, "\n");
      fprintf(stderr,
              "%s: Error: Unable to convert \"%s\" to a long integer\n",
              progname,
              argv[i]);
      usage(stderr);
      rv = 1;

    /*
     * usleep
     */
    } else {
      usleep(usecs);
      rv = 0;
    }
  }

  return (rv == -1) ? 0 : rv;
}