/****************************************************************************
 * apps/graphics/pdcurses/pdc_overlay.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Adapted from the original public domain pdcurses by Gregory Nutt
 ****************************************************************************/

/* Name: overlay
 *
 * Synopsis:
 *       int overlay(const WINDOW *src_w, WINDOW *dst_w)
 *       int overwrite(const WINDOW *src_w, WINDOW *dst_w)
 *       int copywin(const WINDOW *src_w, WINDOW *dst_w, int src_tr,
 *                   int src_tc, int dst_tr, int dst_tc, int dst_br,
 *                   int dst_bc, bool overlay)
 *
 * Description:
 *       overlay() and overwrite() copy all the text from src_w into
 *       dst_w. The windows need not be the same size. Those characters
 *       in the source window that intersect with the destination window
 *       are copied, so that the characters appear in the same physical
 *       position on the screen. The difference between the two functions
 *       is that overlay() is non-destructive (blanks are not copied)
 *       while overwrite() is destructive (blanks are copied).
 *
 *       copywin() is similar, but doesn't require that the two windows
 *       overlap. The arguments src_tc and src_tr specify the top left
 *       corner of the region to be copied. dst_tc, dst_tr, dst_br, and
 *       dst_bc specify the region within the destination window to copy
 *       to. The argument "overlay", if true, indicates that the copy is
 *       done non-destructively (as in overlay()); blanks in the source
 *       window are not copied to the destination window. When overlay is
 *       false, blanks are copied.
 *
 * Return Value:
 *       All functions return OK on success and ERR on error.
 *
 * Portability                                X/Open    BSD    SYS V
 *       overlay                                 Y       Y       Y
 *       overwrite                               Y       Y       Y
 *       copywin                                 Y       -      3.0
 *
 *
 * Thanks to Andreas Otte <venn@@uni-paderborn.de> for the
 * corrected overlay()/overwrite() behavior.
 */

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include "curspriv.h"

/****************************************************************************
 * Private Functions
 ****************************************************************************/

static int _copy_win(const WINDOW *src_w, WINDOW *dst_w, int src_tr,
                     int src_tc, int src_br, int src_bc, int dst_tr,
                     int dst_tc, bool overlay)
{
  int col;
  int line;
  int y1;
  int fc;
  int *minchng;
  int *maxchng;
  chtype *w1ptr;
  chtype *w2ptr;

  int lc = 0;
  int xdiff = src_bc - src_tc;
  int ydiff = src_br - src_tr;

  if (!src_w || !dst_w)
    {
      return ERR;
    }

  minchng = dst_w->_firstch;
  maxchng = dst_w->_lastch;

  for (y1 = 0; y1 < dst_tr; y1++)
    {
      minchng++;
      maxchng++;
    }

  for (line = 0; line < ydiff; line++)
    {
      w1ptr = src_w->_y[line + src_tr] + src_tc;
      w2ptr = dst_w->_y[line + dst_tr] + dst_tc;

      fc = _NO_CHANGE;

      for (col = 0; col < xdiff; col++)
        {
          if ((*w1ptr) != (*w2ptr) &&
              !((*w1ptr & A_CHARTEXT) == ' ' && overlay))
            {
              *w2ptr = *w1ptr;

              if (fc == _NO_CHANGE)
                {
                  fc = col + dst_tc;
                }

              lc = col + dst_tc;
            }

          w1ptr++;
          w2ptr++;
        }

      if (*minchng == _NO_CHANGE)
        {
          *minchng = fc;
          *maxchng = lc;
        }
      else if (fc != _NO_CHANGE)
        {
          if (fc < *minchng)
            {
              *minchng = fc;
            }

          if (lc > *maxchng)
            {
              *maxchng = lc;
            }
        }

      minchng++;
      maxchng++;
    }

  return OK;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

int overlay(const WINDOW *src_w, WINDOW *dst_w)
{
  int first_line;
  int first_c;
  int last_line;
  int last_col;
  int src_start_x;
  int src_start_y;
  int dst_start_x;
  int dst_start_y;
  int xdiff;
  int ydiff;

  PDC_LOG(("overlay() - called\n"));

  if (!src_w || !dst_w)
    {
      return ERR;
    }

  first_c    = max(dst_w->_begx, src_w->_begx);
  first_line = max(dst_w->_begy, src_w->_begy);

  last_col   = min(src_w->_begx + src_w->_maxx, dst_w->_begx + dst_w->_maxx);
  last_line  = min(src_w->_begy + src_w->_maxy, dst_w->_begy + dst_w->_maxy);

  /* Determine the overlapping region of the two windows in real coordinates */

  /* If no overlapping region, do nothing */

  if ((last_col < first_c) || (last_line < first_line))
    {
      return OK;
    }

  /* Size of overlapping region */

  xdiff = last_col - first_c;
  ydiff = last_line - first_line;

  if (src_w->_begx <= dst_w->_begx)
    {
      src_start_x = dst_w->_begx - src_w->_begx;
      dst_start_x = 0;
    }
  else
    {
      dst_start_x = src_w->_begx - dst_w->_begx;
      src_start_x = 0;
    }

  if (src_w->_begy <= dst_w->_begy)
    {
      src_start_y = dst_w->_begy - src_w->_begy;
      dst_start_y = 0;
    }
  else
    {
      dst_start_y = src_w->_begy - dst_w->_begy;
      src_start_y = 0;
    }

  return _copy_win(src_w, dst_w, src_start_y, src_start_x,
                   src_start_y + ydiff, src_start_x + xdiff,
                   dst_start_y, dst_start_x, true);
}

int overwrite(const WINDOW *src_w, WINDOW *dst_w)
{
  int first_line;
  int first_c;
  int last_line;
  int last_col;
  int src_start_x;
  int src_start_y;
  int dst_start_x;
  int dst_start_y;
  int xdiff;
  int ydiff;

  PDC_LOG(("overwrite() - called\n"));

  if (!src_w || !dst_w)
    {
      return ERR;
    }

  first_c    = max(dst_w->_begx, src_w->_begx);
  first_line = max(dst_w->_begy, src_w->_begy);

  last_col   = min(src_w->_begx + src_w->_maxx, dst_w->_begx + dst_w->_maxx);
  last_line  = min(src_w->_begy + src_w->_maxy, dst_w->_begy + dst_w->_maxy);

  /* Determine the overlapping region of the two windows in real coordinates */

  /* If no overlapping region, do nothing */

  if ((last_col < first_c) || (last_line < first_line))
    {
      return OK;
    }

  /* Size of overlapping region */

  xdiff = last_col - first_c;
  ydiff = last_line - first_line;

  if (src_w->_begx <= dst_w->_begx)
    {
      src_start_x = dst_w->_begx - src_w->_begx;
      dst_start_x = 0;
    }
  else
    {
      dst_start_x = src_w->_begx - dst_w->_begx;
      src_start_x = 0;
    }

  if (src_w->_begy <= dst_w->_begy)
    {
      src_start_y = dst_w->_begy - src_w->_begy;
      dst_start_y = 0;
    }
  else
    {
      dst_start_y = src_w->_begy - dst_w->_begy;
      src_start_y = 0;
    }

  return _copy_win(src_w, dst_w, src_start_y, src_start_x,
                   src_start_y + ydiff, src_start_x + xdiff,
                   dst_start_y, dst_start_x, false);
}

int copywin(const WINDOW *src_w, WINDOW *dst_w, int src_tr, int src_tc,
            int dst_tr, int dst_tc, int dst_br, int dst_bc, int overlay)
{
  int src_end_x;
  int src_end_y;
  int src_rows;
  int src_cols;
  int dst_rows;
  int dst_cols;
  int min_rows;
  int min_cols;
#ifdef CONFIG_PDCURSES_MULTITHREAD
  FAR struct pdc_context_s *ctx = PDC_ctx();
#endif

  PDC_LOG(("copywin() - called\n"));

  if (!src_w || !dst_w || dst_w == curscr || dst_br > dst_w->_maxy ||
      dst_bc > dst_w->_maxx || dst_tr < 0 || dst_tc < 0)
    {
      return ERR;
    }

  src_rows  = src_w->_maxy - src_tr;
  src_cols  = src_w->_maxx - src_tc;
  dst_rows  = dst_br - dst_tr + 1;
  dst_cols  = dst_bc - dst_tc + 1;

  min_rows  = min(src_rows, dst_rows);
  min_cols  = min(src_cols, dst_cols);

  src_end_y = src_tr + min_rows;
  src_end_x = src_tc + min_cols;

  return _copy_win(src_w, dst_w, src_tr, src_tc, src_end_y, src_end_x,
                   dst_tr, dst_tc, overlay);
}