/***********************/
/* vt100resize.c 1.04  */
/* by Adam M. Costello */
/* <amc@cs.wustl.edu>  */
/*                     */
/* vt100resize [ -q ]  */
/*                     **************/
/* Asks the terminal (which must be */
/* vt100-compatible) how large it   */
/* is, calls stty to inform the tty */
/* of this information, and resets  */
/* the margins to the full screen.  */
/* Unless -q is supplied, prints a  */
/* message to stdout with the form  */
/* "N rows, M columns".             */
/************************************/

/* This is ANSI C plus POSIX code. */


#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>

#ifdef NeXT
/* Compile with cc -posix, requires NeXTSTEP 3.2 or later. */
#include <sys/termios.h>
#include <sys/ioctl.h>
#endif

#ifdef __osf__
#include <sys/ioctl.h>
#endif


void usage(const char *progname)
{
  fprintf(stderr, "usage:\n%s [ -q ]\n", progname);
  exit(1);
}


int getcsi(FILE *f)
{
  int c;

  c = fgetc(f);
  if (c == '\233') return 1;
  if (c != '\033') return 0;
  c = fgetc(f);
  return c == '[';
}


int main(int argc, char **argv)
{
  int fd, rows, cols, quiet;
  struct termios oldattr, newattr;
  struct winsize size;
  FILE *f;

  if (argc > 2) usage(argv[0]);

  if (argc == 2) {
    if (strcmp(argv[1], "-q")) usage(argv[0]);
    quiet = 1;
  }
  else quiet = 0;

  fd = open("/dev/tty", O_RDONLY);
  if (fd < 0) {
    perror("open");
    exit(1);
  }

  if (tcgetattr(fd, &oldattr)) {
    perror("tcgetattr");
    exit(1);
  }

  newattr = oldattr;
  newattr.c_lflag &= ~ICANON;
  newattr.c_cc[VMIN] = 1;
  newattr.c_cc[VTIME] = 0;

  if (tcsetattr(fd, TCSANOW, &newattr)) {
    perror("tcsetattr");
    exit(1);
  }

  f = fopen("/dev/tty", "r+");
  if (!f) {
    perror("fopen");
    tcsetattr(fd, TCSANOW, &oldattr);
    exit(1);
  }

  /* Allow movement outside of margins.  Move */
  /* to 999,999.  Query cursor position.      */

  fputs("\033[?6l\033[999;999H\033[6n", f);
  fflush(f);

  if (!getcsi(f) || fscanf(f, "%d;%dR", &rows, &cols) != 2) {
    fputs("terminal did not respond properly", stderr);
    tcsetattr(fd, TCSANOW, &oldattr);
    exit(1);
  }

  if (tcsetattr(fd, TCSANOW, &oldattr)) {
    perror("tcsetattr");
    exit(1);
  }

  size.ws_row = rows;
  size.ws_col = cols;

  if (ioctl(fd, TIOCSWINSZ, &size) < 0) {
    perror("ioctl");
    exit(1);
  }

  close(fd);

  /* Set margins to 1,rows.  Move cursor to  */
  /* beginning of last row.  Erase the line. */

  fprintf(f, "\033[1;%dr\033[%dH\033[2K", rows, rows);
  fflush(f);

  if (!quiet) printf("%d rows, %d columns\n", rows, cols);

  exit(0);
}