/* display.c - repeatedly display command through curses
 * vix 18apr86 [written]
 * vix 15dec86 [major overhaul]
 * Dave Remien [added on demand updates and "q" to exit]
 * dar 27nov00 [ctrl-l to clear, cleanup]
 * dar 25mar01 [loop counter, current time, max lines, 
                initscr to clean screen from scratch]
 */


#include <curses.h>
#include <signal.h>
#include <ctype.h>
#include <time.h>
#include <stdio.h>

#define		DEFAULT_DELAY	5
#define         DISPLAY_VERSION "1.2"

static	char	*Command;
static	int	Delay;

static void die(), display(), parse_args(), usage();

char lt[128];
int ntimes;

main(argc, argv)
int	argc;
char	*argv[];
{
  int i, c;
  
  for(i = 0; i < 128; i++)
    {
      lt[i] = 0;
    };
  ntimes = 0;
  parse_args(argc, argv);
  
  signal(SIGHUP, die);
  signal(SIGINT, die);
  signal(SIGQUIT, die);
  signal(SIGTERM, die);
  
  initscr();
  cbreak(); 
  noecho();
  nodelay(stdscr, TRUE);
  /*halfdelay(1);*/
  clear();
  
  while (TRUE) {
    display();
    for(i = 0; i < (Delay * 5) ; i ++){
      c = getch();
      if(c == 81 || c == 113){
	die();
      }else if(c == 67 || c == 99 || c == 12){
	initscr();
	cbreak(); 
	noecho();
	nodelay(stdscr, TRUE);
	/*halfdelay(1);*/
	clear();
	i = Delay * 6;
      }else if(c != ERR){
	move(0, 0);
	clrtobot();
	refresh();
	i = Delay * 6;
      }else if(c == ERR){
	usleep(200000);
      }else{
	i = Delay * 6;
      }
    }
  }
}

void die()
{
	move(LINES-1, 0);
	clrtoeol();
	refresh();
	endwin();
	exit(0);
}


void display()
{
	FILE	*fp;
	int	ch;
	char    *dt;
	time_t  tnow;
	int nlines;
	char count[64];

	nlines=0;
	ntimes++;
	if (!(fp = popen(Command, "r"))) {
		perror("popen");
		exit(1);
	}
	move(0, 0);
	while (EOF != (ch = fgetc(fp)) && nlines < (LINES - 1))
	{
	  if (ch == '\n'){
	    clrtoeol();
	    nlines++;
	  }
	  addch(ch);
	}
	clrtoeol();
	clrtobot();
	refresh();
	move(LINES-1, 0 );
	
	time(&tnow);
	dt = ctime(&tnow);
	strncpy(lt, dt, 19);
	sprintf(count, "Loop count = %d", ntimes);
	addstr(count);
	addstr("  ");
	addstr(lt);
	refresh();
	pclose(fp);
}


void parse_args(argc, argv)
int	argc;
char	*argv[];
{
	extern	void	usage();
	auto	int	argn,
			delay_found;

	Command = NULL;
	Delay = DEFAULT_DELAY;
	delay_found = FALSE;
	for (argn = 1;  argn < argc;  argn++)
	{
		if (argv[argn][0] == '-')
			if (delay_found)
				usage();	/* already got this once */
			else if (!isdigit(argv[argn][1]))
				usage();	/* not a numeric */
			else
			{
				Delay = atoi(&argv[argn][1]);
				delay_found = TRUE;
			}
		else
			if (Command != NULL)
				usage();	/* already got this once */
			else
				Command = argv[argn];
	}
	if (Command == NULL)
		usage();			/* no Command on line */
}


void usage()
{
	extern	char	*getenv();
	auto	char	*shell = getenv("SHELL");

	fprintf(stderr, "\
usage:  display [-<delay>] <command>\n\
        <delay>   = # of seconds between displays, default=%d\n\
        <command> = command to display, quoted if it contains blanks\n\n\
        Display (a.k.a. follow) version %s\n\n",
		DEFAULT_DELAY, DISPLAY_VERSION);

	if (strcmp(shell, "/bin/sh"))
		fprintf(stderr, "\
	NOTE:  /bin/sh will be used to process the command, not SHELL (%s)\n",
			shell);
	
	exit(1);
}