/*
 *  xtitle.c
 * 
 *  Reads and writes xterm titles.  Something of a hack.
 *
 *  $Id: xtitle.c,v 1.14 2005/10/19 15:59:26 tjd Exp $
 * 
 * 
 *  Copyright (C) 2003 Tim Deegan (tjd@phlegethon.org)
 *
 *  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 2 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 *  02111-1307, USA.
 */
 
#undef HAVE_GNU_GETOPT  /* Turn this on if you have GNU getopt() */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <errno.h>
#include <termios.h>
#include <signal.h>

#ifdef HAVE_GNU_GETOPT
#define _GNU_SOURCE
#include <getopt.h>
const struct option longopts[] = {
	{"help",       0, NULL, 'h'},
	{"read-icon",  0, NULL, 'i'},
	{"read",       0, NULL, 'r'},
	{"force",      0, NULL, 'f'},
	{NULL,         0, NULL, 0}
    };
#endif

/*
 * Globals
 */
static const char * me;
static struct termios saved_tios;

/*
 * How to belch forth a usage message
 */
static void usage ()
{
    fprintf(stderr, 
	    "%s: usage: %s [-hrf] [title]\n"
	    "  -h%s    Print this message\n"
	    "  -r%s    Return the current title\n"
	    "  -i%s    Return the current icon label\n"
            "  -f%s    Don't perform any sanity checks\n",
	    me, me,
#ifdef HAVE_GNU_GETOPT
	    ", --help     ", ", --read     ", ", --read-icon", ", --force    "
#else 
	    "", "", "", ""
#endif
	);
    exit(2);
}


/*
 * How to handle timeouts
 */
static void timeout (int sig)
{
    tcsetattr(0, TCSANOW, &saved_tios);
    fprintf(stderr, "%s: timed out - are you sure this is an xterm?\n", me);
    exit(3);
}


/*
 * How to handle unexpected responses
 */
static void garbage (void)
{
    tcsetattr(0, TCSANOW, &saved_tios);
    fprintf(stderr, "%s: garbled reply - are you sure this is an xterm?\n", 
	    me);
    fprintf(stderr, "%s\n", strerror(errno));
    exit(3);
}

static void stdin_write_error (void)
{
    write(0, "\007", 1);
    fprintf(stderr, "%s: cannot write to stdin: %s\n", me, strerror(errno));
    exit(1);
}

/*
 * The heart of it all
 */
int main (int argc, char **argv)
{
    int force = 0, reading = 0, icon = 0, i, len, rv;
    const char *term;
    struct termios tios;
    struct sigaction sa;
    char b;
    

    /*
     * Prettified name for error messages 
     */
    if ((me = strrchr(argv[0], '/') + 1) == (char *)1) me = argv[0]; 

    /* 
     * Arguments
     */
    while (
#ifdef HAVE_GNU_GETOPT
	   (i = getopt_long(argc, argv, "hirf?", longopts, NULL))
#else 
	   (i = getopt(argc, argv, "hirf?"))
#endif
	   != -1) {
	switch (i) {
	default:
	case 'h':
	case '?':
	    usage();
	    break;
	case 'r':
	    reading = 1; 
	    icon = 0;
	    break;
	case 'i':
	    reading = 1; 
	    icon = 1; 
	    break;
	case 'f':
	    force = 1;
	}
    }

    /* 
     * Sanity checks
     */
    if (!force) {
	if (!isatty(0)) {
	    fprintf(stderr, "%s: stdin is not a TTY.\n", me);
	    exit(1);
	}
	if ((term = getenv("TERM")) == NULL) {
	    fprintf(stderr, "%s: TERM is not set.\n", me);
	    exit(1);
	}
	if (strncmp(term, "xterm", 5) 
	    && strncmp(term, "rxvt", 4)
	    && strncmp(term, "dtterm", 6)) {
	    fprintf(stderr, "%s: TERM (%s) doesn't look like an xterm.\n", 
		    me, term);
	    exit(1);
	}
    }

    /*
     * Operations
     */
    if (reading) { /* Grab the current title before changing it */ 

	/* Get the current TTY settings */
	rv = tcgetattr(0, &saved_tios);

	/* 
	 * Set a timer in case xterm doesn't respond
	 */
	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = &timeout;  
	sigaction(SIGALRM, &sa, NULL);
	alarm(3);
	
	/* Turn off line-buffer and echo on stdin */
	tios = saved_tios;
	tios.c_iflag = 0;
	tios.c_lflag &= ~ICANON;
	tios.c_lflag &= ~ECHO;
	tios.c_cc[VMIN] = 1;  /* Could be 0 but Solaris goes odd */ 
	tios.c_cc[VTIME] = 1;
	tcsetattr(0, TCSANOW, &tios);

	/* Send the magic request:
	 * get title is     CSI '2' '1' ';' ';' 't' 
	 * get icon name is CSI '2' '1' ';' ';' 't' */ 
	if (write(0, (icon) ? "\033[20;;t" : "\033[21;;t", 7) != 7) {
	    tcsetattr(0, TCSANOW, &saved_tios);
	    stdin_write_error();
	}

	/* Read the answer:
	 * Title will be      OSC 'l' <title> ST 
	 * Icon label will be OSC 'L' <label> ST 
	 * -- first, wait for start of OSC (discarding any other input) */
	while(1)
	{
	    while ((rv = read(0, &b, 1)) != 1 && (errno == EAGAIN || errno == 0)); 
	    if (rv != 1) garbage();
	waiting_for_osc:
	    if (b == '\033') break;
	}

	/* -- now, check the next two characters */	
	while ((rv = read(0, &b, 1)) != 1 && (errno == EAGAIN || errno == 0)); 
	if (rv != 1) garbage(); 
	if (b != ']') goto waiting_for_osc;
	while ((rv = read(0, &b, 1)) != 1 && (errno == EAGAIN || errno == 0));
	if (rv != 1) garbage(); 
	if (b != (icon ? 'L' : 'l')) goto waiting_for_osc;

	/* -- copy characters until we see the ST */
	while(1) {
	    while ((rv = read(0, &b, 1)) != 1 && (errno == EAGAIN || errno == 0)); 
	    if (rv != 1) garbage();
	    if (b == '\033') break;
	    fprintf(stdout, "%c", b);
	}
	while ((rv = read(0, &b, 1)) != 1 && (errno == EAGAIN || errno == 0)); 
	if (rv != 1 || b != '\\') garbage();
	
	/* -- done */
	fprintf(stdout, "\n");

	/* Disarm the timer */
	sa.sa_handler = SIG_DFL;
	sigaction(SIGALRM, &sa, NULL);

	/* Put the TTY back the way we found it */
	tcsetattr(0, TCSANOW, &saved_tios);

    }
    
    if (argv[optind]) {

	/* Use the rest of the command line to set the new title 
	 * ( OSC '0' ';' <title> BEL ) */
	i = optind;
	len = strlen(argv[i]);
	if (write(0, "\033]0;", 4) != 4 || write(0, argv[i], len) != len) 
	    stdin_write_error();
	for (i++; i<argc; i++) {
	    len = strlen(argv[i]);
	    if (write(0, " ", 1) != 1 || write(0, argv[i], len) != len)
		stdin_write_error();
	}
	if (write(0, "\007", 1) != 1) stdin_write_error();
    }
    
    return 0;
}

/*
 *  EOF (xtitle.c)
 */