/*
*       Window handling.
*/
#include    "def.h"

bool    mvupwind ();
bool    shrinkwind ();

extern    char    MSG_no_splt[];
extern    char    MSG_cnt_al_w[];
extern    char    MSG_one_w[];
extern    char    MSG_imp_chg[];

/*
* Reposition the window so as to center on the dot.
*/
bool reposition ()
{
	long    l_val;

	l_val = DOT_POS(curwp) - (curwp -> w_ntrows * R_BYTES(curwp) / 2L);
	move_ptr (curwp, l_val, FALSE, TRUE, FALSE);
	curwp -> w_flag |= WFHARD;
	return (TRUE);
}

/*
* The command make the next
* window (next => down the screen)
* the current window. There are no real
* errors, although the command does
* nothing if there is only 1 window on
* the screen.
*/
bool nextwind ()
{

	register    WINDOW * wp;

	if ((wp = curwp -> w_wndp) == NULL)
		wp = wheadp;
	curwp = wp;
	curbp = wp -> w_bufp;
	return (TRUE);
}


/*
* This command makes the previous
* window (previous => up the screen) the
* current window. There arn't any errors,
* although the command does not do a lot
* if there is 1 window.
*/
bool prevwind ()
{

	register    WINDOW * wp1;
	register    WINDOW * wp2;

	wp1 = wheadp;
	wp2 = curwp;
	if (wp1 == wp2)
		wp2 = NULL;
	while (wp1 -> w_wndp != wp2)
		wp1 = wp1 -> w_wndp;
	curwp = wp1;
	curbp = wp1 -> w_bufp;
	return (TRUE);
}


/*
* This command moves the current
* window down by "arg" lines. Recompute
* the top line in the window. The move up and
* move down code is almost completely the same;
* most of the work has to do with reframing the
* window, and picking a new dot. We share the
* code by having "move down" just be an interface
* to "move up".
*/
bool    mvdnwind (f, n, k)
register int    n;
{
	return (mvupwind (f, -n, KRANDOM));
}


/*
* Move the current window up by "arg"
* lines. Recompute the new top line of the window.
* Look to see if "." is still on the screen. If it is,
* you win. If it isn't, then move "." to center it
* in the new framing of the window (this command does
* not really move "."; it moves the frame).
*/
bool    mvupwind (f, n, k)
int    n;
{
	A32   l_val, l_bytes;

	l_bytes = (A32)R_BYTES(curwp);     /* number of bytes in a row */
	l_val = n * l_bytes;     /* number of bytes to move */
	move_ptr (curwp, l_val, FALSE, TRUE, TRUE);  /* move window */

	/* check that dot is in window */
	while (DOT_POS(curwp) < WIND_POS(curwp))
	{
		/* dot is before the first window line */
		move_ptr (curwp, l_bytes, TRUE, TRUE, TRUE);
	}
	while (DOT_POS (curwp) >=
	    ((l_bytes * curwp -> w_ntrows) + WIND_POS(curwp)))
	{
		/* dot is after the last window line */
		move_ptr (curwp, -l_bytes, TRUE, TRUE, TRUE);
	}
	curwp -> w_flag |= WFHARD;
	return (TRUE);
}


/*
* This command makes the current
* window the only window on the screen.
* Try to set the framing
* so that "." does not have to move on
* the display. Some care has to be taken
* to keep the values of dot and mark
* in the buffer structures right if the
* distruction of a window makes a buffer
* become undisplayed.
*/
bool    onlywind ()
{

	register    WINDOW * wp;
	register    LINE * lp;
	register int    i;

	while (wheadp != curwp)
	{

		wp = wheadp;
		wheadp = wp -> w_wndp;
		if (--wp -> w_bufp -> b_nwnd == 0)
		{

			wp -> w_bufp -> b_dotp = wp -> w_dotp;
			wp -> w_bufp -> b_doto = wp -> w_doto;
			wp -> w_bufp -> b_markp = wp -> w_markp;
			wp -> w_bufp -> b_marko = wp -> w_marko;
		}

		free ((char *) wp);
	}

	while (curwp -> w_wndp != NULL)
	{

		wp = curwp -> w_wndp;
		curwp -> w_wndp = wp -> w_wndp;
		if (--wp -> w_bufp -> b_nwnd == 0)
		{

			wp -> w_bufp -> b_dotp = wp -> w_dotp;
			wp -> w_bufp -> b_doto = wp -> w_doto;
			wp -> w_bufp -> b_markp = wp -> w_markp;
			wp -> w_bufp -> b_marko = wp -> w_marko;
		}

		free ((char *) wp);
	}

	lp = curwp -> w_linep;
	i = curwp -> w_toprow;
	while (i != 0 && lback (lp) != curbp -> b_linep)
	{

		--i;
		lp = lback (lp);
	}

	curwp -> w_toprow = 0;
	curwp -> w_ntrows = nrow - 2;/* 2 = mode, echo.  */
	curwp -> w_linep = lp;
	curwp -> w_flag |= WFMODE | WFHARD;
	return (TRUE);
}

/*
 * Delete the current window, placing its space in the window above,
 * or, if it is the top window, the window below. Bound to C-X 0.
 */

bool	delwind()

{
	register WINDOW *wp;	/* window to recieve deleted space */
	register WINDOW *lwp;	/* ptr window before curwp */
	register int target;	/* target line to search for */

	/* if there is only one window, don't delete it */
	if (wheadp->w_wndp == NULL) {
		return(FALSE);
	}

	/* find window before curwp in linked list */
	wp = wheadp;
	lwp = NULL;
	while (wp != NULL) {
		if (wp == curwp)
			break;
		lwp = wp;
		wp = wp->w_wndp;
	}

	/* find recieving window and give up our space */
	wp = wheadp;
	if (curwp->w_toprow == 0) {
		/* find the next window down */
		target = curwp->w_ntrows + 1;
		while (wp != NULL) {
			if (wp->w_toprow == target)
				break;
			wp = wp->w_wndp;
		}
		if (wp == NULL)
			return(FALSE);
		wp->w_toprow = 0;
		wp->w_ntrows += target;
	} else {
		/* find the next window up */
		target = curwp->w_toprow - 1;
		while (wp != NULL) {
			if ((wp->w_toprow + wp->w_ntrows) == target)
				break;
			wp = wp->w_wndp;
		}
		if (wp == NULL)
			return(FALSE);
		wp->w_ntrows += 1 + curwp->w_ntrows;
	}

	/* get rid of the current window */
	if (--curwp->w_bufp->b_nwnd == 0) {
		curwp->w_bufp->b_dotp = curwp->w_dotp;
		curwp->w_bufp->b_doto = curwp->w_doto;
		curwp->w_bufp->b_markp = curwp->w_markp;
		curwp->w_bufp->b_marko = curwp->w_marko;
	}
	if (lwp == NULL)
		wheadp = curwp->w_wndp;
	else
		lwp->w_wndp = curwp->w_wndp;
	free((char *)curwp);
	curwp = wp;
	wp -> w_flag |= WFMODE | WFHARD;
	curbp = wp->w_bufp;
	return(TRUE);
}

/*
* Split the current window. A window
* smaller than 3 lines cannot be split.
* The only other error that is possible is
* a "malloc" failure allocating the structure
* for the new window.
*/
bool splitwind ()
{

	register    WINDOW * wp;
	register int    ntru;
	register int    ntrl;
	register int    ntrd;
	register    WINDOW * wp1;
	register    WINDOW * wp2;
	char    buf[NCOL], buf1[NCOL];

	if (curwp -> w_ntrows < 3)
	{
		sprintf (buf1, MSG_no_splt, R_BYTE_FMT(curwp));
		sprintf (buf, buf1, curwp -> w_ntrows);
		writ_echo (buf);
		return (FALSE);
	}

	if ((wp = (WINDOW *) malloc (sizeof (WINDOW))) == NULL)
	{
		err_echo (MSG_cnt_al_w);
		return (FALSE);
	}

	++curbp -> b_nwnd;          /* Displayed twice.  */
	wp -> w_bufp = curbp;
	wp -> w_dotp = curwp -> w_dotp;
	wp -> w_doto = curwp -> w_doto;
	wp -> w_unit_offset = curwp -> w_unit_offset;
	wp -> w_markp = curwp -> w_markp;
	wp -> w_marko = curwp -> w_marko;
	wp -> w_flag = 0;
	wp -> w_disp_shift = curwp -> w_disp_shift;
	wp -> w_intel_mode = curwp -> w_intel_mode;
	wp -> w_fmt_ptr = curwp -> w_fmt_ptr;
	ntru = (curwp -> w_ntrows - 1) / 2;/* Upper size         */
	ntrl = (curwp -> w_ntrows - 1) - ntru;/* Lower size      */

	curwp -> w_ntrows = ntru;
	wp -> w_wndp = curwp -> w_wndp;
	curwp -> w_wndp = wp;
	wp -> w_toprow = curwp -> w_toprow + ntru + 1;
	wp -> w_ntrows = ntrl;

	wind_on_dot (curwp);        /* put window on the dot */
	wp -> w_loff = curwp -> w_loff;/* do the same for the new window */
	wp -> w_linep = curwp -> w_linep;
	curwp -> w_flag |= WFMODE | WFHARD;
	wp -> w_flag |= WFMODE | WFHARD;
	return (TRUE);
}


/*
* Enlarge the current window.
* Find the window that loses space. Make
* sure it is big enough. If so, hack the window
* descriptions, and ask redisplay to do all the
* hard work. You don't just set "force reframe"
* because dot would move.
*/
bool enlargewind (f, n, k)
{
	register    WINDOW * adjwp;
	register    LINE * lp;
	register int    i;

	if (n < 0)
		return (shrinkwind (f, -n, KRANDOM));
	if (wheadp -> w_wndp == NULL)
	{

		writ_echo (MSG_one_w);
		return (FALSE);
	}

	if ((adjwp = curwp -> w_wndp) == NULL)
	{
		adjwp = wheadp;
		while (adjwp -> w_wndp != curwp)
			adjwp = adjwp -> w_wndp;
	}

	if (adjwp -> w_ntrows <= n)
	{
		writ_echo (MSG_imp_chg);
		return (FALSE);
	}

	if (curwp -> w_wndp == adjwp)
	{
		/* Shrink below.     */
		lp = adjwp -> w_linep;
		for (i = 0; i < n && lp != adjwp -> w_bufp -> b_linep; ++i)
			lp = lforw (lp);
		adjwp -> w_linep = lp;
		adjwp -> w_toprow += n;
	}
	else
	{
		/* Shrink above.     */
		lp = curwp -> w_linep;
		for (i = 0; i < n && lback (lp) != curbp -> b_linep; ++i)
			lp = lback (lp);
		curwp -> w_linep = lp;
		curwp -> w_toprow -= n;
	}

	curwp -> w_ntrows += n;
	adjwp -> w_ntrows -= n;
	curwp -> w_flag |= WFMODE | WFHARD;
	adjwp -> w_flag |= WFMODE | WFHARD;
	return (TRUE);
}


/*
* Shrink the current window.
* Find the window that gains space. Hack at
* the window descriptions. Ask the redisplay to
* do all the hard work.
*/
bool shrinkwind (f, n, k)
{
	register    WINDOW * adjwp;
	register    LINE * lp;
	register int    i;

	if (n < 0)
		return (enlargewind (f, -n, KRANDOM));
	if (wheadp -> w_wndp == NULL)
	{
		writ_echo (MSG_one_w);
		return (FALSE);
	}

	if ((adjwp = curwp -> w_wndp) == NULL)
	{
		adjwp = wheadp;
		while (adjwp -> w_wndp != curwp)
			adjwp = adjwp -> w_wndp;
	}

	if (curwp -> w_ntrows <= n)
	{
		writ_echo (MSG_imp_chg);
		return (FALSE);
	}

	if (curwp -> w_wndp == adjwp)
	{
		/* Grow below.       */
		lp = adjwp -> w_linep;
		for (i = 0; i < n && lback (lp) != adjwp -> w_bufp -> b_linep; ++i)
			lp = lback (lp);
		adjwp -> w_linep = lp;
		adjwp -> w_toprow -= n;
	}
	else
	{
		/* Grow above.       */
		lp = curwp -> w_linep;
		for (i = 0; i < n && lp != curbp -> b_linep; ++i)
			lp = lforw (lp);
		curwp -> w_linep = lp;
		curwp -> w_toprow += n;
	}

	curwp -> w_ntrows -= n;
	adjwp -> w_ntrows += n;
	curwp -> w_flag |= WFMODE | WFHARD;
	adjwp -> w_flag |= WFMODE | WFHARD;
	return (TRUE);
}


/*
* Pick a window for a pop-up.
* Split the screen if there is only
* one window. Pick the uppermost window that
* isn't the current window. An LRU algorithm
* might be better. Return a pointer, or
* NULL on error.
*/
WINDOW * wpopup ()
{

	register    WINDOW * wp;

	if (wheadp -> w_wndp == NULL
	    && splitwind () == FALSE)
		return (NULL);
	wp = wheadp;                /* Find window to use    */
	while (wp != NULL && wp == curwp)
		wp = wp -> w_wndp;
	return (wp);
}


/*
* Refresh the display. 
* In the normal case the
* call to "update" in "main.c" refreshes the screen,
* and all of the windows need not be recomputed.
*/
bool refresh ()
{
	sgarbf = TRUE;
	return (TRUE);
}