/* $Log: pslide.c,v $
/* Revision 1.1.1.1  2000/12/16 20:45:29  stuart
/* Released TUIPeer sources
/*
 */
#include <pscreen.h>
#include "hackterm.h"

static void swaprow(int c1,int c2,int r1,int r2) {
  int c;
  CHTYPE *cp1, *cp2;
  struct rowdata p, *p1, *p2;
  p1 = &curscr->d[r1];
  p2 = &curscr->d[r2];
  p = *p1;
  *p1 = *p2;
  *p2 = p;
  p2->srow = -1;	/* will erase line */
  p2->modc = 0;
  cp1 = curscr->data + p1->data;
  cp2 = curscr->data + p2->data;
  for (c = c2;;) {
    CHTYPE ch;
    if (++c >= PScols) c = 0;
    if (c == c1) break;
    if (cp1[c] == cp2[c]) continue;
    ch = cp1[c];
    cp1[c] = cp2[c] | A_MODIFIED;
    if (c < p1->modc) p1->modc = c;
    cp2[c] = ch | A_MODIFIED;
  }
}

static void moverow(int c1,int c2,int r1,int r2) {
  int c;
  CHTYPE *cp1, *cp2;
  struct rowdata *p;
  p = &curscr->d[r1];
  cp1 = curscr->data + p->data;
  cp2 = curscr->data + curscr->d[r2].data;
  for (c = c1; c <= c2; ++c) {
    if (cp1[c] != cp2[c]) {
      cp1[c] = cp2[c] | A_MODIFIED;
      if (c < p->modc) p->modc = c;
    }
  }
}

bool PSslide(const RECT *sr,enum dir dir,int dist) {
  RECT r;
  int i;
  static int caninsdel = -1;
  if (!clip(sr,PSrows,PScols,&r) || dist == 0)
    return TRUE;
  if (caninsdel < 0)
    caninsdel = ((parm_insert_line||insert_line)
		&& (parm_delete_line||delete_line)) ? 1 : 0;
  switch (dir) {
  case DIR_UP:
    dist = -dist;
  case DIR_DOWN:
    if (dist < 0) {
      i = r.r1;
      if (i + dist < 0)
	i = -dist;
      if (caninsdel && RWIDTH(&r) > PScols/2) {
	while (i <= r.r2) {
	  swaprow(r.c1,r.c2,i + dist,i);
	  ++i;
	}
	i += dist;
	while (i <= r.r1) {	/* middle lines wiped */
	  int j;
	  struct rowdata *p = &curscr->d[i];
	  CHTYPE *cp = curscr->data + p->data;
	  p->modc = 0;
	  p->srow = -1;
	  for (j = 0; j < PScols; ++j)
	    cp[j] |= A_MODIFIED;
	  ++i;
	}
      }
      else
	while (i <= r.r2) {
	  moverow(r.c1,r.c2,i + dist,i);
	  ++i;
	}
    }
    else {
      i = r.r2;
      if (i + dist >= PSrows)
	i = PSrows - 1 - dist;
      if (caninsdel && RWIDTH(&r) > PScols/2) {
	while (i >= r.r1) {
	  swaprow(r.c1,r.c2,i + dist,i);
	  --i;
	}
	i += dist;
	while (i >= r.r2) {	/* middle lines wiped */
	  int j;
	  struct rowdata *p = &curscr->d[i];
	  CHTYPE *cp = curscr->data + p->data;
	  p->modc = 0;
	  p->srow = -1;
	  for (j = 0; j < PScols; ++j)
	    cp[j] |= A_MODIFIED;
	  --i;
	}
      }
      else
	while (i >= r.r1) {
	  moverow(r.c1,r.c2,i + dist,i);
	  --i;
	}
    }
    return TRUE;
  case DIR_LEFT:
    dist = -dist;
  case DIR_RIGHT:
    /* ins/del char not used yet */
    for (i = r.r1; i <= r.r2; ++i) {
      int c;
      struct rowdata *p = &curscr->d[i];
      CHTYPE *cp = curscr->data + p->data;
      if (dist < 0) {
	c = r.c1;
	if (c + dist < 0) c = -dist;
	while (c <= r.c2) {
	  if (cp[c] != cp[c + dist]) {
	    cp[c + dist] = cp[c] | A_MODIFIED;
	    if (c + dist < p->modc) p->modc = c + dist;
	  }
	  ++c;
	}
      }
      else {
	c = r.c2;
	if (c + dist >= PScols) c = dist - PScols + 1;
	while (c >= r.c1) {
	  if (cp[c] != cp[c + dist]) {
	    cp[c + dist] = cp[c] | A_MODIFIED;
	    if (c + dist < p->modc) p->modc = c + dist;
	  }
	  --c;
	}
      }
    }
    return TRUE;
  case DIR_NONE:
    break;
  }
  return FALSE;
}