/* $OpenBSD: lib_overlay.c,v 1.4 2023/10/17 09:52:08 nicm Exp $ */

/****************************************************************************
 * Copyright 2020 Thomas E. Dickey                                          *
 * Copyright 1998-2013,2016 Free Software Foundation, Inc.                  *
 *                                                                          *
 * Permission is hereby granted, free of charge, to any person obtaining a  *
 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
 * without limitation the rights to use, copy, modify, merge, publish,      *
 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
 *                                                                          *
 * Except as contained in this notice, the name(s) of the above copyright   *
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/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 ****************************************************************************/

/*
**      lib_overlay.c
**
**      The routines overlay(), copywin(), and overwrite().
**
*/

#include <curses.priv.h>

MODULE_ID("$Id: lib_overlay.c,v 1.4 2023/10/17 09:52:08 nicm Exp $")

static int
overlap(const WINDOW *const src, WINDOW *const dst, int const flag)
{
    int rc = ERR;

    T((T_CALLED("overlap(%p,%p,%d)"), (const void *) src, (void *) dst, flag));

    if (src != 0 && dst != 0) {
        int sx1, sy1, sx2, sy2;
        int dx1, dy1, dx2, dy2;

        _nc_lock_global(curses);

        T(("src : begy %ld, begx %ld, maxy %ld, maxx %ld",
           (long) src->_begy,
           (long) src->_begx,
           (long) src->_maxy,
           (long) src->_maxx));
        T(("dst : begy %ld, begx %ld, maxy %ld, maxx %ld",
           (long) dst->_begy,
           (long) dst->_begx,
           (long) dst->_maxy,
           (long) dst->_maxx));

        sx1 = src->_begx;
        sy1 = src->_begy;
        sx2 = sx1 + src->_maxx;
        sy2 = sy1 + src->_maxy;

        dx1 = dst->_begx;
        dy1 = dst->_begy;
        dx2 = dx1 + dst->_maxx;
        dy2 = dy1 + dst->_maxy;

        if (dx2 >= sx1 && dx1 <= sx2 && dy2 >= sy1 && dy1 <= sy2) {
            int sminrow = max(sy1, dy1) - sy1;
            int smincol = max(sx1, dx1) - sx1;
            int dminrow = max(sy1, dy1) - dy1;
            int dmincol = max(sx1, dx1) - dx1;
            int dmaxrow = min(sy2, dy2) - dy1;
            int dmaxcol = min(sx2, dx2) - dx1;

            rc = copywin(src, dst,
                         sminrow, smincol,
                         dminrow, dmincol,
                         dmaxrow, dmaxcol,
                         flag);
        }
        _nc_unlock_global(curses);
    }
    returnCode(rc);
}

/*
**
**      overlay(win1, win2)
**
**
**      overlay() writes the overlapping area of win1 behind win2
**      on win2 non-destructively.
**
**/

NCURSES_EXPORT(int)
overlay(const WINDOW *win1, WINDOW *win2)
{
    T((T_CALLED("overlay(%p,%p)"), (const void *) win1, (void *) win2));
    returnCode(overlap(win1, win2, TRUE));
}

/*
**
**      overwrite(win1, win2)
**
**
**      overwrite() writes the overlapping area of win1 behind win2
**      on win2 destructively.
**
**/

NCURSES_EXPORT(int)
overwrite(const WINDOW *win1, WINDOW *win2)
{
    T((T_CALLED("overwrite(%p,%p)"), (const void *) win1, (void *) win2));
    returnCode(overlap(win1, win2, FALSE));
}

NCURSES_EXPORT(int)
copywin(const WINDOW *src, WINDOW *dst,
        int sminrow, int smincol,
        int dminrow, int dmincol,
        int dmaxrow, int dmaxcol,
        int over)
{
    int rc = ERR;

    T((T_CALLED("copywin(%p, %p, %d, %d, %d, %d, %d, %d, %d)"),
       (const void *) src,
       (void *) dst,
       sminrow, smincol,
       dminrow, dmincol,
       dmaxrow, dmaxcol, over));

    if (src != 0
        && dst != 0
        && dmaxrow >= dminrow
        && dmaxcol >= dmincol) {
        attr_t bk;
        attr_t mask;

        _nc_lock_global(curses);

        bk = AttrOf(dst->_nc_bkgd);
        mask = ~(attr_t) ((bk & A_COLOR) ? A_COLOR : 0);

        /* make sure rectangle exists in source */
        if ((sminrow + dmaxrow - dminrow) <= (src->_maxy + 1) &&
            (smincol + dmaxcol - dmincol) <= (src->_maxx + 1)) {

            T(("rectangle exists in source"));

            /* make sure rectangle fits in destination */
            if (dmaxrow <= dst->_maxy && dmaxcol <= dst->_maxx) {
                int sx, sy, dx, dy;
                bool copied = FALSE;

                T(("rectangle fits in destination"));

                for (dy = dminrow, sy = sminrow;
                     dy <= dmaxrow;
                     sy++, dy++) {
                    bool touched;

                    if (dy < 0 || sy < 0)
                        continue;

                    touched = FALSE;
                    for (dx = dmincol, sx = smincol;
                         dx <= dmaxcol;
                         sx++, dx++) {

                        if (dx < 0 || sx < 0)
                            continue;
                        copied = TRUE;

                        if (over) {
                            if ((CharOf(src->_line[sy].text[sx]) != L(' ')) &&
                                (!CharEq(dst->_line[dy].text[dx],
                                         src->_line[sy].text[sx]))) {
                                dst->_line[dy].text[dx] =
                                    src->_line[sy].text[sx];
                                SetAttr(dst->_line[dy].text[dx],
                                        ((AttrOf(src->_line[sy].text[sx]) &
                                          mask) | bk));
                                touched = TRUE;
                            }
                        } else {
                            if (!CharEq(dst->_line[dy].text[dx],
                                        src->_line[sy].text[sx])) {
                                dst->_line[dy].text[dx] =
                                    src->_line[sy].text[sx];
                                touched = TRUE;
                            }
                        }
                    }
                    if (touched) {
                        touchline(dst, dminrow, (dmaxrow - dminrow + 1));
                    }
                }
                T(("finished copywin"));
                if (copied)
                    rc = OK;
            }
        }
        _nc_unlock_global(curses);
    }
    returnCode(rc);
}