/*
 * Window management. Some of the functions are internal, and some are
 * attached to keys that the user actually types.
 */

#include        <stdio.h>
#include        "ed.h"

/*
 * Reposition dot in the current window to line "n". If the argument is
 * positive, it is that line. If it is negative it is that line from the
 * bottom. If it is 0 the window is centered (this is what the standard
 * redisplay code does). With no argument it defaults to 1. Bound to M-!.
 * Because of the default, it works like in Gosling.
 */
reposition(f, n)
    {
    curwp->w_force = n;
    curwp->w_flag |= WFFORCE;
    return (TRUE);
    }

/*
 * Refresh the screen. With no argument, it just does the refresh. With an
 * argument it recenters "." in the current window. Bound to "C-L".
 */
refresh(f, n)
    {
    if (f == FALSE)
        sgarbf = TRUE;
    else
        {
        curwp->w_force = 0;             /* Center dot. */
        curwp->w_flag |= WFFORCE;
        }

    ret = 0;
        while (lp != curwp->w_dotp) {
                ++ntrd;
                lp = lforw(lp);
        }
        lp = curwp->w_linep;
        if (ntrd <= ntru) {                     /* Old is upper window. */
                if (ntrd == ntru)               /* Hit mode line.       */
                        lp = lforw(lp);
                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;
        } else {                                /* Old is lower window  */
                wp1 = NULL;
                wp2 = wheadp;
                while (wp2 != curwp) {
                        wp1 = wp2;
                        wp2 = wp2->w_wndp;
                }
                if (wp1 == NULL)
                        wheadp = wp;
                else
                        wp1->w_wndp = wp;
                wp->w_wndp   = curwp;
                wp->w_toprow = curwp->w_toprow;
                wp->w_ntrows = ntru;
                ++ntru;                         /* Mode line.           */
                curwp->w_toprow += ntru;
                curwp->w_ntrows  = ntrl;
                while (ntru--)
                        lp = lforw(lp);
        }
        curwp->w_linep = lp;                    /* Adjust the top lines */
        wp->w_linep = lp;                       /* if necessary.        */
        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. Bound to "C-X Z".
 */
enlargewind(f, n)
{
        register WINDOW *adjwp;
        register LINE   *lp;
        register int    i;

        if (n < 0)
                return (shrinkwind(f, -n));
        if (wheadp->w_wndp == NULL) {
                mlwrite("Only one window");
                return (FALSE);
        }
        if ((adjwp=curwp->w_wndp) == NULL) {
                adjwp = wheadp;
                while (adjwp->w_wndp != curwp)
                        adjwp = adjwp->w_wndp;
        }
        if (adjwp->w_ntrows <= n) {
                mlwrite("Impossible change");
                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. Bound to
 * "C-X C-Z".
 */
shrinkwind(f, n)
{
        register WINDOW *adjwp;
        register LINE   *lp;
        register int    i;

        if (n < 0)
                return (enlargewind(f, -n));
        if (wheadp->w_wndp == NULL) {
                mlwrite("Only one window");
                return (FALSE);
        }
        if ((adjwp=curwp->w_wndp) == NULL) {
                adjwp = wheadp;
                while (adjwp->w_wndp != curwp)
                        adjwp = adjwp->w_wndp;
        }
        if (curwp->w_ntrows <= n) {
                mlwrite("Impossible change");
                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              /* Only 1 window        */
        && splitwind(FALSE, 0) == FALSE)        /* and it won't split   */
                return (NULL);
        wp = wheadp;                            /* Find window to use   */
        while (wp!=NULL && wp==curwp)
                wp = wp->w_wndp;
        return (wp);
}
ister WINDOW *adjwp;
       = 0;
        while (lp != curwp->w_dotp) {
                ++ntrd;
                lp = lforw(lp);
        }
        lp = curwp->w_linep;
        if (ntrd <= ntru) {                     /* Old is upper window. */
                if (ntrd == ntru)               /* Hit mode line.       */
                        lp = lforw(lp);
                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;
        } else {                                /* Old is lower window  */
                wp1 = NULL;
                wp2 = wheadp;
                while (wp2 != curwp) {
                        wp1 = wp2;
                        wp2 = wp2->w_wndp;
                }
                if (wp1 == NULL)
                        wheadp = wp;
                else
                        wp1->w_wndp = wp;
                wp->w_wndp   = curwp;
                wp->w_toprow = curwp->w_toprow;
                wp->w_ntrows = ntru;
                ++ntru;                         /* Mode line.           */
                curwp->w_toprow += ntru;
                curwp->w_ntrows  = ntrl;
                while (ntru--)
                        lp = lforw(lp);
        }
        curwp->w_linep = lp;                    /* Adjust the top lines */
        wp->w_linep = lp;                       /* if necessary.        */
        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. Bound to "C-X Z".
 */
enlargewind(f, n)
{
        register WINDOW *adjwp;
        register LINE   *lp;
        register int    i;

        if (n < 0)
                return (shrinkwind(f, -n));
        if (wheadp->w_wndp == NULL) {
                mlwrite("Only one window");
                return (FALSE);
        }
        if ((adjwp=curwp->w_wndp) == NULL) {
                adjwp = wheadp;
                while (adjwp->w_wndp != curwp)
                        adjwp = adjwp->w_wndp;
        }
        if (adjwp->w_ntrows <= n) {
                mlwrite("Impossible change");
                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. Bound to
 * "C-X C-Z".
 */
shrinkwind(f, n)
{
        register WINDOW *adjwp;
        register LINE   *lp;
        register int    i;

        if (n < 0)
                return (enlargewind(f, -n));
        if (wheadp->w_wndp == NULL) {
                mlwrite("Only one window");
                return (FALSE);
        }
        if ((adjwp=curwp->w_wndp) == NULL) {
                adjwp = wheadp;
                while (adjwp->w_wndp != curwp)
                        adjwp = adjwp->w_wndp;
        }
        if (curwp->w_ntrows <= n) {
                mlwrite("Impossible change");
                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              /* Only 1 window        */
        && splitwind(FALSE, 0) == FALSE)        /* and it won't split   */
                return (NULL);
        wp = wheadp;                            /* Find window to use   */
        while (wp!=NULL && wp==curwp)
                wp = wp->w_wndp;
        return (wp);
}