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#define SERVER_PATH "/var/run/chrony.ttyS0.sock"
//#define SERVER_PATH "/tmp/server.sock"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <ros/ros.h>
#include "sensor_msgs/TimeReference.h"
#include <errno.h>
#include <sys/uio.h>
#include <time.h>

extern "C"
{
#include <sys/time.h>
}

struct sock_sample
{
  struct timeval tv;
  double offset;
  int pulse;
  int leap;
  int _pad;
  int magic;
};

int client_socket, rc, len;
struct sockaddr_un remote;
char buf[40];

void callback(const sensor_msgs::TimeReference::ConstPtr &msg)
{
  struct sock_sample sample;
  int currentTime;
  currentTime = time(NULL);
  sample.magic = 0x534f434;
  sample.pulse = 0;
  sample.leap = 0;
  sample._pad = 0;
  double secs = msg->header.stamp.toSec();
  sample.tv.tv_sec = (int)secs;
  sample.tv.tv_usec = ((int)((secs - sample.tv.tv_sec) * 1000000));
  double x = abs(currentTime - secs);
  sample.offset = x;

  rc = sendto(client_socket, (struct sock_sample *)&sample, sizeof(sample), 0, (struct sockaddr *)&remote, sizeof(remote));
  if (rc == -1)
  {
    printf("SENDTO ERROR = %s\n", strerror(errno));
    close(client_socket);
    exit(1);
  }
  else
  {
    //printf("Data sent!\n");
  }

  printf("[%d]\n", sample.tv.tv_sec);
  printf("%d\n", currentTime);
  printf("%f\n", sample.offset);

  exit;
}

int main(int argc, char *argv[])
{
  system("sudo chmod u=rwx,g=rwx,o=rwx /var/run/chrony.ttyS0.sock");
  memset(&remote, 0, sizeof(struct sockaddr_un));
  /****************************************/
  /* Create a UNIX domain datagram socket */
  /****************************************/
  client_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
  if (client_socket == -1)
  {
    printf("SOCKET ERROR");
    exit(1);
  }

  /***************************************/
  /* Set up the UNIX sockaddr structure  */
  /* by using AF_UNIX for the family and */
  /* giving it a filepath to send to.    */
  /***************************************/
  remote.sun_family = AF_UNIX;
  strcpy(remote.sun_path, SERVER_PATH);

  // This must be called before anything else ROS-related
  ros::init(argc, argv, "timing");

  // Create a ROS node handle
  ros::NodeHandle nh;

  ros::Subscriber sub = nh.subscribe("/imu/time_ref", 1000, callback);

  // Don't exit the program.
  ros::spin();

  // /* Close socket. */
  // close(sockfd);
  // unlink(server_addr.sun_path);
  // unlink(client_addr.sun_path);

  /******************************/
  /* Close the sockets and exit */
  /******************************/
  rc = close(client_socket);

  return 1;
}

# Welcome to the chrony configuration file. See chrony.conf(5) for more
# information about usuable directives.

# This will use (up to):
# - 4 sources from ntp.ubuntu.com which some are ipv6 enabled
# - 2 sources from 2.ubuntu.pool.ntp.org which is ipv6 enabled as well
# - 1 source from [01].ubuntu.pool.ntp.org each (ipv4 only atm)
# This means by default, up to 6 dual-stack and up to 2 additional IPv4-only
# sources will be used.
# At the same time it retains some protection against one of the entries being
# down (compare to just using one of the lines). See (LP: #1754358) for the
# discussion.
#
# About using servers from the NTP Pool Project in general see (LP: #104525).
# Approved by Ubuntu Technical Board on 2011-02-08.
# See http://www.pool.ntp.org/join.html for more information.
#pool ntp.ubuntu.com        iburst maxsources 4
#pool 0.ubuntu.pool.ntp.org iburst maxsources 1
#pool 1.ubuntu.pool.ntp.org iburst maxsources 1
#pool 2.ubuntu.pool.ntp.org iburst maxsources 2
#refclock SHM 0:perm=0606 noselect
refclock SOCK /var/run/chrony.ttyS0.sock

# This directive specify the location of the file containing ID/key pairs for
# NTP authentication.
keyfile /etc/chrony/chrony.keys

# This directive specify the file into which chronyd will store the rate
# information.
driftfile /var/lib/chrony/chrony.drift

# Uncomment the following line to turn logging on.
#log tracking measurements statistics

# Log files location.
logdir /var/log/chrony

# Stop bad estimates upsetting machine clock.
maxupdateskew 100.0

# This directive enables kernel synchronisation (every 11 minutes) of the
# real-time clock. Note that it can’t be used along with the 'rtcfile' directive.
rtcsync

# Step the system clock instead of slewing it if the adjustment is larger than
# one second, but only in the first three clock updates.
makestep 1 3