/* 
 * lightingcontrol
 *
 * Copyright (C) 2012 Jonathan McCrohan
 *
 * This program 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
 * (at your option) any later version.

 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

// gcc lightingcontrol.c -o lightingcontrol -lm `pkg-config --libs --cflags libconfig`

#ifndef VERSION_STRING
#define VERSION_STRING "[undefined version]"
#endif

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <sys/select.h>
#include <signal.h>
#include <fcntl.h>

#include <libconfig.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <string.h>

#include <syslog.h>

#include <termios.h>
#include <fcntl.h>

// handle SIGALRM by resetting it
void
minute_check (int signum)
{
  syslog (LOG_DEBUG, "SIGALRM");
  alarm (60);
}

int
main (int argc, char *argv[])
{

  int SYSLOG_CONSOLE_OUTPUT = 0;
  int k;

  // check the argv array for strings matching -d
  for (k = 1; k < argc; k++)
    {
      if (strcmp (argv[k], "-d") == 0)
	{
	  SYSLOG_CONSOLE_OUTPUT = LOG_PERROR;
	}
    }

  openlog ("lightingcontrol", SYSLOG_CONSOLE_OUTPUT | LOG_PID | LOG_CONS,
	   LOG_USER);

  syslog (LOG_INFO, "");
  syslog (LOG_INFO, "lightingcontrol [%s] starting", VERSION_STRING);
  syslog (LOG_INFO, "");

  const char *configfile = "lightingcontrol.cfg";
  config_t cfg;

  const char *serial_device_address;
  int serial_baud_rate;
  int serial_data_bits;
  const char *serial_parity;
  int serial_stop_bits;
  char *p;

  config_init (&cfg);

  // attempt to read config
  // loads entire file to memory and destroys file descriptor
  if (!config_read_file (&cfg, configfile))
    {
      fprintf (stderr, "%s:%d - %s\n", config_error_file (&cfg),
	       config_error_line (&cfg), config_error_text (&cfg));
      config_destroy (&cfg);
      syslog (LOG_ERR, "Unable to find configfile");
      return -1;
    }
  else
    {
      syslog (LOG_INFO, "configfile found successfully");
    }

  // die if core config file options aren't there
  if (!(config_lookup_string (&cfg, "serial.device", &serial_device_address)
	&& config_lookup_int (&cfg, "serial.baud", &serial_baud_rate)
	&& config_lookup_int (&cfg, "serial.data_bits", &serial_data_bits)
	&& config_lookup_string (&cfg, "serial.parity", &serial_parity)
	&& config_lookup_int (&cfg, "serial.stop_bits", &serial_stop_bits)))
    {
      syslog (LOG_ERR,
	      "Incomplete serial configuration. Check configuration file");
      closelog ();
      return -1;
    }

  syslog (LOG_INFO, "Serial Port=[%s]", serial_device_address);
  syslog (LOG_INFO, "Serial Port Parameters=[%d %d %c %d]", serial_baud_rate,
	  serial_data_bits, serial_parity[0], serial_stop_bits);

  // SIGALRM used to wake for loop up every 60 secs
  // sleep puts whole thread to sleep which isn't what we want
  // other methods involve CPU spinlocks which are inefficient
  signal (SIGALRM, minute_check);
  alarm (1);

  for (;;)
    {
      // block until SIGARLM
      select (0, NULL, NULL, NULL, NULL);

      time_t t = time (NULL);
      struct tm unixtime_min_time_t = *localtime (&t);

      config_setting_t *schedules;

      schedules = config_lookup (&cfg, "schedule");

      // find number of schedules
      unsigned int num_schedules = config_setting_length (schedules);

      syslog (LOG_DEBUG, "num_schedules=[%d]", num_schedules);

      int i;
      // cycle through each schedule and pull info from config file
      for (i = 0; i < num_schedules; ++i)
	{
	  config_setting_t *scene_element =
	    config_setting_get_elem (schedules, i);
	  int sceneid;
	  config_setting_lookup_int (scene_element, "sceneid", &sceneid);
	  syslog (LOG_DEBUG, "sceneid=[%d]", sceneid);
	  const char *scene_day;
	  char scene_day_lower[20];
	  config_setting_lookup_string (scene_element, "day", &scene_day);
	  strcpy (scene_day_lower, scene_day);
	  p = scene_day_lower;
	  // convert strings to lower case
	  for (; *p; ++p)
	    *p = tolower (*p);
	  syslog (LOG_DEBUG, "scene_day=[%s]", scene_day_lower);

	  const char *scene_time;
	  config_setting_lookup_string (scene_element, "time", &scene_time);
	  syslog (LOG_DEBUG, "scene_time=[%s]", scene_time);

	  char daystring[20];
	  char timestring[20];

	  strftime (daystring, 20, "%A", &unixtime_min_time_t);
	  strftime (timestring, 20, "%H:%M", &unixtime_min_time_t);
	  p = daystring;
	  // convert strings to lower case
	  for (; *p; ++p)
	    *p = tolower (*p);

	  syslog (LOG_DEBUG, "current_day=[%s]", daystring);
	  syslog (LOG_DEBUG, "current_time=[%s]", timestring);
	  if ((strcmp (scene_day_lower, daystring) == 0)
	      && (strcmp (scene_time, timestring) == 0))

	    {

	      // attempt to create new serial connection
	      struct termios term;
	      int serialport = open (serial_device_address,
				     O_RDWR | O_NOCTTY | O_NONBLOCK);
	      if (serialport < 0)
		{
		  syslog (LOG_ERR, "Unable to create serial object");
		}

	      syslog (LOG_INFO, "serialport=[%d]", serialport);

	      if (serial_baud_rate == 115200)
		{
		  term.c_cflag = B115200;
		}
	      else if (serial_baud_rate == 57600)
		{
		  term.c_cflag = B57600;
		}
	      else if (serial_baud_rate == 38400)
		{
		  term.c_cflag = B38400;
		}
	      else if (serial_baud_rate == 19200)
		{
		  term.c_cflag = B19200;
		}
	      else if (serial_baud_rate == 9600)
		{
		  term.c_cflag = B9600;
		}
	      else if (serial_baud_rate == 4800)
		{
		  term.c_cflag = B4800;
		}
	      else if (serial_baud_rate == 2400)
		{
		  term.c_cflag = B2400;
		}
	      else if (serial_baud_rate == 1800)
		{
		  term.c_cflag = B1800;
		}
	      else if (serial_baud_rate == 1200)
		{
		  term.c_cflag = B1200;
		}


	      if (serial_data_bits == 5)
		{
		  term.c_cflag |= CS5;
		}
	      else if (serial_data_bits == 6)
		{
		  term.c_cflag |= CS6;
		}
	      else if (serial_data_bits == 7)
		{
		  term.c_cflag |= CS7;
		}
	      else
		{
		  term.c_cflag |= CS8;
		}

	      if (serial_parity == "E")
		{
		  term.c_cflag |= PARENB;
		}
	      else if (serial_parity == "O")
		{
		  term.c_cflag |= PARENB | PARODD;
		}

	      if (serial_stop_bits == 2)
		{
		  term.c_cflag |= CSTOPB;
		}
	      term.c_iflag = 0;
	      term.c_oflag = 0;
	      term.c_lflag = 0;

	      tcflush (serialport, TCIFLUSH);
	      tcsetattr (serialport, TCSANOW, &term);

	      config_setting_t *messagearray;
	      messagearray =
		config_setting_get_member (scene_element, "message");

	      int j, k;
	      // eight byte messages
	      unsigned char serialmsg[8];
	      int nummessages;

	      // count number of messages to send
	      nummessages = config_setting_length (messagearray);

	      for (j = 0; j < nummessages; j++)
		{
		  config_setting_t *message;
		  // iterate over each message
		  message = config_setting_get_elem (messagearray, j);
		  // ensure checksum byte is zero'd before calculation
		  serialmsg[7] = 0;
		  for (k = 0; k < 7; k++)
		    {
		      serialmsg[k] = config_setting_get_int_elem (message, k);
		      serialmsg[7] += serialmsg[k];
		    }
		  // checksum calculation
		  serialmsg[7] = (~serialmsg[7] & 0xff) + 1;

		  // write message out over serial port
		  write (serialport, serialmsg, sizeof (serialmsg));
		  syslog (LOG_INFO, "MESSAGE SENT");
		  syslog (LOG_INFO,
			  "[%02x][%02x][%02x][%02x][%02x][%02x][%02x][%02x]",
			  serialmsg[0], serialmsg[1], serialmsg[2],
			  serialmsg[3], serialmsg[4], serialmsg[5],
			  serialmsg[6], serialmsg[7]);
		  syslog (LOG_INFO, "SCENEID=[%d] SENT", sceneid);
		  syslog (LOG_INFO, "current_day=[%s]", daystring);
		  syslog (LOG_INFO, "current_time=[%s]", timestring);
		  syslog (LOG_INFO, "nummessages=[%d]", nummessages);
		  usleep (100);
		}


	      close (serialport);

	      sleep (1);

	    }
	}
    }
}