Written by Dana Kirsch and Solomon Assefa

#include <stdio.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <termios.h>
#include <sys/uio.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>
#include <malloc.h>

/* declarations */
void hash(int);
char msg[256];

int OpenPort() {
  struct termios t;
  int fd= open("/dev/cua1", O_RDWR);

  if (fd < 0) {
    perror("opening com1 port");
  } else {
    tcgetattr(fd, &t);
    cfsetispeed(&t, B2400);
    cfsetospeed(&t, B2400);
    cfmakeraw(&t);
    tcsetattr(fd, TCSANOW, &t);
  } return(fd);
}

void main() {
  int port; 

  int last=0;
  int sum;
// time_t time;

  char firstbyte, secondbyte, fourthbyte;
  char thirdbyte;

  port = OpenPort();
  
  while (1) {


/* firstbyte is the floor, secondbyte is the room number, thirdbyte is the
 * ASCII representation of the room letter designation, fourthbyte is
 * the message for the hash table. 
 */
    
  getid(port, &firstbyte, &secondbyte, &thirdbyte, &fourthbyte);

/* NEED A BETTER ERROR CHECKING MEATHOD !!!!!!!!!!! */
    sum = (firstbyte + secondbyte + thirdbyte + fourthbyte);

/* if the signal changes, room number or message, then write (to the 
 * history file) the date, time, place, and message. 
 */
    if (sum != last)  {
       // printf("%s\n", ctime(time(NULL)) ); 
	hash(fourthbyte);
	printf("Room: %d%d%c - %s \n", firstbyte, secondbyte, thirdbyte, msg);
    } 
    last = sum;
    fflush(stdout);
  }
}

int getid(int port, char *fst, char *snd, char *thd, char *fth) {
 char buffer[4];
 char i;

 read(port, buffer, 4);

 *fst = buffer[0];
 *snd = buffer[1];
 *thd = buffer[2];
 *fth = buffer[3];
 return 0;

}
 
void hash(int num) {
  switch (num) {
  case 0:
    sprintf(msg, "Want to leave a message?");
    break;
  case 2:
    sprintf(msg, "I have a demo in the afternoon -- Thad");
    break;
  case 3:
    sprintf(msg, "You had a call.  Call her back when  you get in");
    break;
  case 4:
    sprintf(msg, "Come to my office, please -- Prof. Sandy");
    break;
  case 5: 
    sprintf(msg,"Gone for the day. -- Thad");
    break;
  case 6: 
    sprintf(msg,"Solo has gone for some cocoa");
    break;
  case 7: 
    sprintf(msg,"Please make sure the lights are off when you leave!");
    break;
  case 8:
    sprintf(msg, "I have a meeting now.  I will be back in an hour");
    break;
  case 9:
    sprintf(msg, "Please do not disturb. Door is locked from inside.");
    break;
  default:
    sprintf(msg,"No messages"); 
    break; 
  }
}