/* $Copyright:	$
 * Copyright (c) 1984, 1985, 1986, 1987, 1988, 1989, 1990 
 * Sequent Computer Systems, Inc.   All rights reserved.
 *  
 * This software is furnished under a license and may be used
 * only in accordance with the terms of that license and with the
 * inclusion of the above copyright notice.   This software may not
 * be provided or otherwise made available to, or used by, any
 * other person.  No title to or ownership of the software is
 * hereby transferred.
 */

/* $Header: display.c 1.1 89/10/09 $ */

/* The window 'manager', initializes curses and handles the actual
 * displaying of text
 */

#include "talk.h"

xwin_t my_win;
xwin_t his_win;
WINDOW *line_win;

int curses_initialized = 0;

    /* max HAS to be a function, it is called with
     * a argument of the form --foo at least once.
     */

max(a,b)
int a, b;
{
    if (a > b) {
	return(a);
    } else {
	return(b);
    }
}

/*
 * Display some text on somebody's window, processing some control
 * characters while we are at it.
 */

display(win, text, size)
register xwin_t *win;
register char *text;
int size;
{
    register int i;
    char cch;

    for (i = 0; i < size; i++) {

	if (*text == '\n') {
	    xscroll(win, 0);
	    text++;
	    continue;
	}

	    /* erase character */

	if (*text == win->cerase) {
	    wmove(win->x_win, win->x_line, max(--win->x_col, 0));
	    getyx(win->x_win, win->x_line, win->x_col);
	    waddch(win->x_win, ' ');
	    wmove(win->x_win, win->x_line, win->x_col);
	    getyx(win->x_win, win->x_line, win->x_col);
	    text++;
	    continue;
	}
	/*
	 * On word erase search backwards until we find
	 * the beginning of a word or the beginning of
	 * the line.
	 */
	if (*text == win->werase) {
	    int endcol, xcol, i, c;

	    endcol = win->x_col;
	    xcol = endcol - 1;
	    while (xcol >= 0) {
		c = readwin(win->x_win, win->x_line, xcol);
		if (c != ' ')
			break;
		xcol--;
	    }
	    while (xcol >= 0) {
		c = readwin(win->x_win, win->x_line, xcol);
		if (c == ' ')
			break;
		xcol--;
	    }
	    wmove(win->x_win, win->x_line, xcol + 1);
	    for (i = xcol + 1; i < endcol; i++)
		waddch(win->x_win, ' ');
	    wmove(win->x_win, win->x_line, xcol + 1);
	    getyx(win->x_win, win->x_line, win->x_col);
	    continue;
	}
	    /* line kill */
	if (*text == win->kill) {
	    wmove(win->x_win, win->x_line, 0);
	    wclrtoeol(win->x_win);
	    getyx(win->x_win, win->x_line, win->x_col);
	    text++;
	    continue;
	}
	if (*text == '\f') {
	    if (win == &my_win)
		wrefresh(curscr);
	    text++;
	    continue;
	}

	if (win->x_col == COLS-1) {
		/* check for wraparound */
	    xscroll(win, 0);
	}

	if (*text < ' ' && *text != '\t') {
	    waddch(win->x_win, '^');
	    getyx(win->x_win, win->x_line, win->x_col);

	    if (win->x_col == COLS-1) {
		    /* check for wraparound */
		xscroll(win, 0);
	    }

	    cch = (*text & 63) + 64;
	    waddch(win->x_win, cch);
	} else {
	    waddch(win->x_win, *text);
	}

	getyx(win->x_win, win->x_line, win->x_col);
	text++;

    }
wrefresh(win->x_win);
}

/*
* Read the character at the indicated position in win
*/
readwin(win, line, col)
WINDOW *win;
{
int oldline, oldcol;
register int c;

getyx(win, oldline, oldcol);
wmove(win, line, col);
c = winch(win);
wmove(win, oldline, oldcol);
return(c);
}

/*
* Scroll a window, blanking out the line following the current line
* so that the current position is obvious
*/

xscroll(win, flag)
register xwin_t *win;
int flag;
{
    if (flag == -1) {
	wmove(win->x_win, 0, 0);
	win->x_line = 0;
	win->x_col = 0;
	return;
    }
    win->x_line = (win->x_line + 1) % win->x_nlines;
    win->x_col = 0;
    wmove(win->x_win, win->x_line, win->x_col);
    wclrtoeol(win->x_win);
    wmove(win->x_win, (win->x_line + 1) % win->x_nlines, win->x_col);
    wclrtoeol(win->x_win);
    wmove(win->x_win, win->x_line, win->x_col);
}
