/* This program copyright 2003 Perry Harrington (pedward at dainst dot com)
 *
 * This program is covered under the GPL license.  For information on the GPL
 * license, see http://www.gnu.org/licenses/licenses.html#GPL
 *
 * Serial initialization code was taken from public domain examples.
 *
 * The program expects 2 arguments, the serial port to access and the baud rate.
 * The user must have permissions to access the port.
 *
 * Compile with: gcc -Wall -o terminal terminal.c
 *
 */

#include <stdio.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>

#define ESCAPE 	'~'
#define QUIT	'q'
#define CRLF	'c'
#define DELBS	'b'

/* baudrate settings are defined in <asm/termbits.h>, which is
included by <termios.h> */
#define BAUDRATE B57600
/* change this definition for the correct port */
/*#define MODEMDEVICE "/dev/ttyS0"*/
#define _POSIX_SOURCE 1 /* POSIX compliant source */

#define FALSE 0
#define TRUE 1

int parseBaud(char *baudrate)
{
	int	i;

	sscanf(baudrate, "%d",&i);

	switch (i) {
		case 460800:
			return B460800;
		case 230400:
			return B230400;
		case 115200:
			return B115200;
		case 57600:
			return B57600;
		case 38400:
			return B38400;
		case 19200:
			return B19200;
		case 9600:
			return B9600;
		case 4800:
			return B4800;
		case 2400:
			return B2400;
		case 1800:
			return B1800;
		case 1200:
			return B1200;
		case 600:
			return B600;
		case 300:
			return B300;
		case 200:
			return B200;
		case 150:
			return B150;
		case 134:
			return B134;
		case 110:
			return B110;
		case 75:
			return B75;
		case 50:
			return B50;
		default:
			return B0;
	}
}

void usage(void)
{
	printf("terminal port baud\n");
	printf("Ex: terminal /dev/ttyS0 57600\n");
}

int main(int argc, char *argv[])
{
	unsigned char	buf[1024];
	unsigned int	baudrate;
	int fd, res;
	int crlf_conv = TRUE;
	int del_bs = TRUE;
	char	last,prev;
	struct termios oldtio,newtio;
	struct termios coldtio,cnewtio;
	fd_set	fds;
	int STOP=FALSE; 


	if (argc != 3) {
		fprintf(stderr, "You must supply a port name and baudrate!\n");
		usage();
		exit(1);
	}

	baudrate = parseBaud(argv[2]);

	if (baudrate == B0) {
		fprintf(stderr, "Invalid baudrate: %s\n", argv[2]);
		usage();
		exit(1);
	}

	/* 
	  Open modem device for reading and writing and not as controlling tty
	  because we don't want to get killed if linenoise sends CTRL-C.
	*/
	fd = open(argv[1], O_RDWR | O_NOCTTY ); 
	if (fd <0) {perror(argv[1]); exit(-1); }

	tcgetattr(fd,&oldtio); /* save current serial port settings */
	tcgetattr(0,&coldtio); /* save current serial port settings */
	memset(&newtio, 0, sizeof(newtio)); /* clear struct for new port settings */
	memcpy(&cnewtio, &coldtio, sizeof(cnewtio));

	/* 
	  BAUDRATE: Set bps rate. You could also use cfsetispeed and cfsetospeed.
	  CRTSCTS : output hardware flow control (only used if the cable has
		    all necessary lines. See sect. 7 of Serial-HOWTO)
	  CS8     : 8n1 (8bit,no parity,1 stopbit)
	  CLOCAL  : local connection, no modem contol
	  CREAD   : enable receiving characters
	*/
	newtio.c_cflag = baudrate | CS8 | CLOCAL | CREAD;
	 
	/*
	  IGNPAR  : ignore bytes with parity errors
	  ICRNL   : map CR to NL (otherwise a CR input on the other computer
		    will not terminate input)
	  otherwise make device raw (no other input processing)
	*/
	 //newtio.c_iflag = IGNPAR | IGNBRK;
	newtio.c_iflag = 0;

	/*
	 Raw output.
	*/
	newtio.c_oflag = 0;
	 
	/*
	  ICANON  : enable canonical input
	  disable all echo functionality, and don't send signals to calling program
	*/
	 //newtio.c_lflag = ICANON;
	newtio.c_lflag = 0;

	cfmakeraw(&newtio);
	 
	/* 
	  initialize all control characters 
	  default values can be found in /usr/include/termios.h, and are given
	  in the comments, but we don't need them here
	*/
	newtio.c_cc[VINTR]    = 0;     /* Ctrl-c */ 
	newtio.c_cc[VQUIT]    = 0;     /* Ctrl-\ */
	newtio.c_cc[VERASE]   = 0;     /* del */
	newtio.c_cc[VKILL]    = 0;     /* @ */
	newtio.c_cc[VEOF]     = 0;     /* Ctrl-d */
	newtio.c_cc[VTIME]    = 0;     /* inter-character timer unused */
	newtio.c_cc[VMIN]     = 1;     /* blocking read until 1 character arrives */
	newtio.c_cc[VSWTC]    = 0;     /* '\0' */
	newtio.c_cc[VSTART]   = 0;     /* Ctrl-q */ 
	newtio.c_cc[VSTOP]    = 0;     /* Ctrl-s */
	newtio.c_cc[VSUSP]    = 0;     /* Ctrl-z */
	newtio.c_cc[VEOL]     = 0;     /* '\0' */
	newtio.c_cc[VREPRINT] = 0;     /* Ctrl-r */
	newtio.c_cc[VDISCARD] = 0;     /* Ctrl-u */
	newtio.c_cc[VWERASE]  = 0;     /* Ctrl-w */
	newtio.c_cc[VLNEXT]   = 0;     /* Ctrl-v */
	newtio.c_cc[VEOL2]    = 0;     /* '\0' */

	/* 
	  now clean the modem line and activate the settings for the port
	*/
	tcflush(fd, TCIFLUSH);
	tcsetattr(fd,TCSANOW,&newtio);
	
	cnewtio.c_lflag &= ~(ECHO|ICANON);

	tcflush(0, TCIFLUSH);
	tcsetattr(0,TCSANOW,&cnewtio);

	last = prev = '\0';

	printf("Escape keys, type at beginning of line:\n\t%c%c quits\n\t%c%c toggles CRLF conversion\n\t%c%c toggles DEL to BS conversion\n\n", ESCAPE, QUIT, ESCAPE, CRLF, ESCAPE, DELBS);
	while (STOP==FALSE) {     /* loop until we have a terminating condition */
		FD_ZERO(&fds);
		FD_SET(fd,&fds);
		FD_SET(0,&fds);
		res = select(fd+1,&fds,NULL,NULL,NULL);

		if (res < 0) {
			perror("select");
		} else if (res > 0) {
			if (FD_ISSET(fd, &fds)) {
				res = read(fd,buf,sizeof(buf));
				write(1,buf,res);
			}
			if (FD_ISSET(0, &fds)) {
				res = read(0,buf,sizeof(buf));
				if ((prev == '\n' || prev == '\r') && last == ESCAPE) {
					switch(buf[0]) {
						case QUIT:
							STOP = TRUE;
							continue;
						case CRLF:
							crlf_conv = !crlf_conv;
							break;
						case DELBS:
							del_bs = !del_bs;
						default:
							break;
					}
				}
				if (del_bs == TRUE && (buf[0] == 0x7F)) {
					write(fd,"\b",1);
				} else if (crlf_conv == TRUE && ((buf[0] == '\r' && buf[1] == '\n') || buf[0] == '\n' )) {
					write(fd,"\r",1);
				} else {
					write(fd,buf,res);
				}
				prev = last;
				last = buf[0];
			}
		}
	}

	/* restore the old port settings */
	tcsetattr(fd,TCSANOW,&oldtio);
	tcsetattr(0,TCSANOW,&coldtio);

	close(fd);
	printf("exit...\n");
	return 0;
}