/*
 * safetitle sets the title of the terminal window to the given string,
 * unless the terminal type is blacklisted.
 */

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <termios.h>
#include <unistd.h>

#define WSCONS 0
#define SCREEN 1

#define WSCONS_DA (char[]){27,91,62,50,52,59,50,48,59,48,99,0}
#define SCREEN_DA (char[]){27,91,62,56,51,59,52,48,56,48,48,59,48,99,0}

int blacklisted(int);

int debug = 0;
int screen = 0;

int
main(int argc, char *argv[])
{
	char *ap;
	int ttyfd;
	struct termios term, restore;

        if(argc==2)
                ap = argv[1];
        else if(argc==3){
                ap = argv[2];
                if(strcmp(argv[1], "-d")==0)
			debug = 1;
                else
			goto usage;
        }else{
usage:		fprintf(stderr, "usage: %s [-d] title\n", argv[0]);
		return 1;
	}

	if((ttyfd = open("/dev/tty", O_RDWR))==-1)
		err(1, "open");

	tcgetattr(ttyfd, &restore);
	tcgetattr(ttyfd, &term);
	term.c_lflag &= ~(ICANON|ECHO);
	tcsetattr(ttyfd, TCSANOW, &term);

	if(blacklisted(ttyfd))
		goto end;

	/* set title */
	if(screen) dprintf(ttyfd, "\033P\033]2;%s\007\033\\", ap);
	else dprintf(ttyfd, "\033]2;%s\007", ap);

	tcsetattr(ttyfd, TCSANOW, &restore);
	return 0;
end:
	tcsetattr(ttyfd, TCSANOW, &restore);
	return 1;
}

int
blacklisted(int fd)
{
	char *buf, c;
	fd_set fds;
	int i, r;
	struct timeval timeout;

	if((buf = malloc(200*sizeof(char)))==NULL)
		err(1, "malloc");

	/* check if GNU screen */
	write(fd, "\033[>c", 4);
	i = 0;
	while(r = read(fd, &c, 1)){
		if(r==-1){
			warn("read");
			return 1;
		}
		buf[i++] = c;
		if(c=='c') break;
	}
	buf[i] = '\0';
	screen = strcmp(buf, SCREEN_DA)==0;

	/* ignore strange trailing nul before reading response */
	FD_ZERO(&fds);
	FD_SET(fd, &fds);
	timeout.tv_sec = 0;
	timeout.tv_usec = 0;
	while(select(fd+1, &fds, NULL, NULL, &timeout)>0)
		read(fd, &c, 1);

	/* check (real) terminal type(s) */
	if(screen) write(fd, "\033P\033[>c\033\\", 8);
	else write(fd, "\033[>c", 4);

	i = 0;
	while(r = read(fd, &c, 1)){
loop:
		if(r==-1){
			warn("read");
			return 1;
		}
		buf[i++] = c;
		if(c==99) break;
	}
	buf[i] = '\0';

	if(strcmp(buf, WSCONS_DA)==0){
		if(debug) fprintf(stderr, "blacklisted terminal type\n");
		return 1;
	}

	/* go back and check remaining responses (if any) */
check:
	FD_ZERO(&fds);
	FD_SET(fd, &fds);
	timeout.tv_sec = 0;
	timeout.tv_usec = 1; /* it takes a millisecond sometimes */
	if(screen && select(fd+1, &fds, NULL, NULL, &timeout)>0){
		/* ignore strange trailing nul before reading response */
		if(read(fd, &c, 1)==-1){
			warn("read");
			return 1;
		}
		i = 0;
		if(c==0) goto check;
		else goto loop;
	}

	return 0;
}