/*
 *  spreadspace avr utils
 *
 *
 *  Copyright (C) 2013-2018 Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of spreadspace avr utils.
 *
 *  spreadspace avr utils is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  spreadspace avr utils is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <termios.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <time.h>
#include <stdio.h>
#include <sys/select.h>
#include <errno.h>
#include <string.h>

#define STATE_OFF 0
#define STATE_ON  1

void setDTRState (int fd, int state) {
  int flags;

  ioctl(fd, TIOCMGET, &flags);
  flags = (state == STATE_ON ? flags | TIOCM_DTR : flags & ~TIOCM_DTR);
  ioctl(fd, TIOCMSET, &flags);
}

int
main(int argc, char* argv[])
{
  char* device = argc < 2 ? "/dev/ttyUSB0" : argv[1];
  int fd = open(device, O_RDWR);
  if (fd < 0) {
    fprintf(stderr, "Could not open %s (%s)\n", device, strerror(errno));
    return EXIT_FAILURE;
  }

  printf("reseting arduino at %s\n", device);
  
  setDTRState(fd, STATE_ON);
  struct timeval sleeptime = {0, 100000}; // 100ms
  select(0, NULL, NULL, NULL, &sleeptime);
  setDTRState(fd, STATE_OFF);
  sleeptime.tv_sec = 0;
  sleeptime.tv_usec = 100000;
  select(0, NULL, NULL, NULL, &sleeptime);
  setDTRState(fd, STATE_ON);
  close(fd);

  return EXIT_SUCCESS;
}