/* Copyright (c) 2008-2017
 *      Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
 *      Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
 *      Micah Cowan <micah@cowan.name>
 *      Sadrul Habib Chowdhury <sadrul@users.sourceforge.net>
 *
 * Copyright (c) 1993-2002, 2003, 2005, 2006, 2007
 *      Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
 *      Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
 *
 * Copyright (c) 1987 Oliver Laumann
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (see the file COPYING); if not, see
 * https://www.gnu.org/licenses/, or contact Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
 *
 ****************************************************************
 */

#include <sys/types.h>

#include "config.h"
#include "screen.h"
#include "mark.h"
#include "extern.h"
#include "braille.h"

extern struct display *display, *displays;

extern struct mline mline_blank, mline_null;
extern struct mchar mchar_blank, mchar_null;

extern struct layer *flayer;	/* sigh */
extern struct LayFuncs WinLf;
extern struct LayFuncs BlankLf;


static struct mline *mloff __P((struct mline *, int));

/*
 * Layer subsystem.
 *
 * ...here is all the clipping code... beware!
 *
 * XXX: add some speedup code!
 *
 */

static struct mline *mloff(struct mline *ml, int off)
{
  static struct mline mml;
  if (ml == 0)
    return 0;

  mml.image = ml->image + off;
  mml.attr  = ml->attr  + off;
#ifdef FONT
  mml.font  = ml->font  + off;
  mml.fontx  = ml->fontx  + off;
#endif

#ifdef COLOR
  mml.color = ml->color + off;
# ifdef COLORS256
  mml.colorx = ml->colorx + off;
# endif
#endif

  return &mml;
}

#ifdef UTF8
# define RECODE_MCHAR(mc) ((l->l_encoding == UTF8) != (D_encoding == UTF8) ? recode_mchar(mc, l->l_encoding, D_encoding) : (mc))
# define RECODE_MLINE(ml) ((l->l_encoding == UTF8) != (D_encoding == UTF8) ? recode_mline(ml, l->l_width, l->l_encoding, D_encoding) : (ml))
#else
# define RECODE_MCHAR(mc) (mc)
# define RECODE_MLINE(ml) (ml)
#endif

#define FOR_EACH_UNPAUSED_CANVAS(l, fn) for (cv = (l)->l_cvlist; cv; cv = cv->c_lnext) \
  {	\
    if ((l)->l_pause.d && cv->c_slorient)	\
      continue;	\
    fn	\
  }

void LGotoPos(struct layer *l, int x, int y)
{
  struct canvas *cv;
  struct viewport *vp;
  int x2, y2;

  if (l->l_pause.d)
    LayPauseUpdateRegion(l, x, x, y, y);

#ifdef HAVE_BRAILLE
  if (bd.bd_refreshing)
    return;
#endif
  FOR_EACH_UNPAUSED_CANVAS(l,
    {
      display = cv->c_display;
      if (D_blocked)
        continue;
      if (cv != D_forecv)
        continue;
      x2 = x + cv->c_xoff;
      y2 = y + cv->c_yoff;
      debug2("---LGotoPos %d %d\n", x2, y2);
      if (x2 < cv->c_xs)
        x2 = cv->c_xs;
      if (y2 < cv->c_ys)
        y2 = cv->c_ys;
      if (x2 > cv->c_xe)
        x2 = cv->c_xe;
      if (y2 > cv->c_ye)
        y2 = cv->c_ye;
      for (vp = cv->c_vplist; vp; vp = vp->v_next) {
        if (x2 < vp->v_xs || x2 > vp->v_xe)
          continue;
        if (y2 < vp->v_ys || y2 > vp->v_ye)
          continue;
        GotoPos(x2, y2);
        break;
      }
    }
  );
}

void LScrollH(struct layer *l, int n, int y, int xs, int xe, int bce, struct mline *ol)
{
  struct canvas *cv;
  struct viewport *vp;
  int y2, xs2, xe2;

  if (n == 0)
    return;
  if (l->l_pause.d)
    LayPauseUpdateRegion(l, xs, xe, y, y);

  FOR_EACH_UNPAUSED_CANVAS(l,
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      y2 = y + vp->v_yoff;
      if (y2 < vp->v_ys || y2 > vp->v_ye)
        continue;
      xs2 = xs + vp->v_xoff;
      xe2 = xe + vp->v_xoff;
      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (xs2 > xe2)
        continue;
      display = cv->c_display;
      if (D_blocked)
        continue;
      ScrollH(y2, xs2, xe2, n, bce, ol ? mloff(ol, -vp->v_xoff) : 0);
      if (xe2 - xs2 == xe - xs)
        continue;
      if (n > 0) {
        xs2 = xe2 + 1 - n;
        xe2 = xe + vp->v_xoff - n;
      }
      else {
        xe2 = xs2 - 1 - n;
        xs2 = xs + vp->v_xoff - n;
      }

      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (xs2 <= xe2)
        RefreshArea(xs2, y2, xe2, y2, 1);
    }
  );
}

void LScrollV(struct layer *l, int n, int ys, int ye, int bce)
{
  struct canvas *cv;
  struct viewport *vp;
  int ys2, ye2, xs2, xe2;
  if (n == 0)
    return;
  if (l->l_pause.d)
    LayPauseUpdateRegion(l, 0, l->l_width - 1, ys, ye);
  FOR_EACH_UNPAUSED_CANVAS(l,
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      xs2 = vp->v_xoff;
      xe2 = l->l_width - 1 + vp->v_xoff;
      ys2 = ys + vp->v_yoff;
      ye2 = ye + vp->v_yoff;

      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (ys2 < vp->v_ys)
        ys2 = vp->v_ys;
      if (ye2 > vp->v_ye)
        ye2 = vp->v_ye;
      if (ys2 > ye2 || xs2 > xe2)
        continue;
      display = cv->c_display;
      if (D_blocked)
        continue;
#if 0
      ScrollV(xs2, ys2, xe2, ye2, n, bce);
#else
      ScrollV(vp->v_xs, ys2, vp->v_xe, ye2, n, bce);
#endif

      debug2("LScrollV: %d %d", ys, ye);
      debug2(" -> %d %d\n", ys2, ye2);
      if (ye2 - ys2 == ye - ys)
        continue;
      if (n > 0) {
        ys2 = ye2 + 1 - n;
        ye2 = ye + vp->v_yoff - n;
      }
      else {
        ye2 = ys2 - 1 - n;
        ys2 = ys + vp->v_yoff - n;
      }

      debug2("LScrollV: - %d %d\n", ys2, ye2);
      if (ys2 < vp->v_ys)
        ys2 = vp->v_ys;
      if (ye2 > vp->v_ye)
        ye2 = vp->v_ye;
      debug2("LScrollV: - %d %d\n", ys2, ye2);
      if (ys2 <= ye2)
        RefreshArea(xs2, ys2, xe2, ye2, 1);
    }
  );
}

void LInsChar(struct layer *l, struct mchar *c, int x, int y, struct mline *ol)
{
  struct canvas *cv;
  struct viewport *vp;
  int xs2, xe2, y2, f;
  struct mchar *c2, cc;
  struct mline *rol;

  if (l->l_pause.d)
    LayPauseUpdateRegion(l, x, l->l_width - 1, y, y);
  FOR_EACH_UNPAUSED_CANVAS(l,
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      y2 = y + vp->v_yoff;
      if (y2 < vp->v_ys || y2 > vp->v_ye)
        continue;
      xs2 = x + vp->v_xoff;
      xe2 = l->l_width - 1 + vp->v_xoff;
      c2 = c;
      f = 0;
      if (xs2 < vp->v_xs) {
        xs2 = vp->v_xs;
        c2 = &mchar_blank;
        if (ol) {
          int i = xs2 - vp->v_xoff - 1;
          if (i >= 0 && i < l->l_width) {
            copy_mline2mchar(&cc, ol, i);
            c2 = &cc;
          }
        }
       else
        f = 1;
      }

      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (xs2 > xe2)
        continue;
      display = cv->c_display;
      if (D_blocked)
        continue;
      rol = RECODE_MLINE(ol);
      InsChar(RECODE_MCHAR(c2), xs2, xe2, y2, mloff(rol, -vp->v_xoff));
      if (f)
        RefreshArea(xs2, y2, xs2, y2, 1);
    }
  );
}


void LPutChar(struct layer *l, struct mchar *c, int x, int y)
{
  struct canvas *cv;
  struct viewport *vp;
  int x2, y2;

#ifdef HAVE_BRAILLE
  if (bd.bd_refreshing) {
    BPutChar(l, c, x, y);
    return;
  }
#endif

  if (l->l_pause.d)
    LayPauseUpdateRegion(l, x,

#ifdef DW_CHARS
  x + (c->mbcs ? 1 : 0)
#else
  x
#endif
  , y, y);


  FOR_EACH_UNPAUSED_CANVAS(l,
    {
      display = cv->c_display;
      if (D_blocked)
        continue;
      for (vp = cv->c_vplist; vp; vp = vp->v_next) {
        y2 = y + vp->v_yoff;
        if (y2 < vp->v_ys || y2 > vp->v_ye)
          continue;
        x2 = x + vp->v_xoff;
        if (x2 < vp->v_xs || x2 > vp->v_xe)
          continue;
        PutChar(RECODE_MCHAR(c), x2, y2);
        break;
      }
    }
  );
}


void LPutStr(struct layer *l, char *s, int n, struct mchar *r, int x, int y)
{
  struct canvas *cv;
  struct viewport *vp;
  char *s2;
  int xs2, xe2, y2;

  if (x + n > l->l_width)
    n = l->l_width - x;

#ifdef HAVE_BRAILLE
  if (bd.bd_refreshing) {
    BPutStr(l, s, n, r, x, y);
    return;
  }
#endif

  if (l->l_pause.d)
    LayPauseUpdateRegion(l, x, x + n - 1, y, y);

  FOR_EACH_UNPAUSED_CANVAS(l,
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      y2 = y + vp->v_yoff;
      if (y2 < vp->v_ys || y2 > vp->v_ye)
        continue;
      xs2 = x + vp->v_xoff;
      xe2 = xs2 + n - 1;
      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (xs2 > xe2)
        continue;
      display = cv->c_display;
      if (D_blocked)
        continue;
      GotoPos(xs2, y2);
      SetRendition(r);
      s2 = s + xs2 - x - vp->v_xoff;

#ifdef UTF8
      if (D_encoding == UTF8 && l->l_encoding != UTF8 && (r->font || r->fontx || l->l_encoding)) {
        struct mchar mc;
        mc = *r;
        while (xs2 <= xe2) {
          mc.image = *s2++;
          PutChar(RECODE_MCHAR(&mc), xs2++, y2);
        }
        continue;
      }
#endif

      while (xs2++ <= xe2)
        PUTCHARLP(*s2++);
    }
  );
}


void LPutWinMsg(struct layer *l, char *s, int n, struct mchar *r, int x, int y)
{
  struct canvas *cv;
  struct viewport *vp;
  int xs2, xe2, y2, len, len2;
  struct mchar or;

  if (x + n > l->l_width)
    n = l->l_width - x;

#ifdef HAVE_BRAILLE
  if (bd.bd_refreshing) {
    BPutStr(l, s, n, r, x, y);
    return;
  }
#endif

  if (l->l_pause.d)
    LayPauseUpdateRegion(l, x, x + n - 1, y, y);

  len = strlen(s);
  if (len > n)
    len = n;

  FOR_EACH_UNPAUSED_CANVAS(l,
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      y2 = y + vp->v_yoff;
      if (y2 < vp->v_ys || y2 > vp->v_ye)
        continue;
      xs2 = x + vp->v_xoff;
      xe2 = xs2 + n - 1;
      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (xs2 > xe2)
        continue;
      display = cv->c_display;
      if (D_blocked)
        continue;
      GotoPos(xs2, y2);
      SetRendition(r);
      len2 = xe2 - (x + vp->v_xoff) + 1;
      if (len2 > len)
        len2 = len;
      PutWinMsg(s, xs2 - x - vp->v_xoff, len2);
      xs2 = x + vp->v_xoff + len2;
      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      or = D_rend;
      GotoPos(xs2, y2);
      SetRendition(&or);
      while (xs2++ <= xe2)
        PUTCHARLP(' ');
    }
  );
}


void LClearLine(struct layer *l, int y, int xs, int xe, int bce, struct mline *ol)
{
  struct canvas *cv;
  struct viewport *vp;
  int y2, xs2, xe2;

  /* check for magic margin condition */
  if (xs >= l->l_width)
    xs = l->l_width - 1;
  if (xe >= l->l_width)
    xe = l->l_width - 1;
  if (l->l_pause.d)
      LayPauseUpdateRegion(l, xs, xe, y, y);

  FOR_EACH_UNPAUSED_CANVAS(l,
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      xs2 = xs + vp->v_xoff;
      xe2 = xe + vp->v_xoff;
      y2  = y + vp->v_yoff;
      if (y2 < vp->v_ys || y2 > vp->v_ye)
        continue;
      if (xs2 < vp->v_xs)
        xs2 = vp->v_xs;
      if (xe2 > vp->v_xe)
        xe2 = vp->v_xe;
      if (xs2 > xe2)
        continue;
      display = cv->c_display;
      if (D_blocked)
        continue;
      ClearLine(ol ? mloff(RECODE_MLINE(ol), -vp->v_xoff) : (struct mline *)0, y2, xs2, xe2, bce);
    }
  );
}

void LClearArea(struct layer *l, int xs, int ys, int xe, int ye, int bce, int uself)
{
  struct canvas *cv;
  struct viewport *vp;
  int xs2, ys2, xe2, ye2;

#ifdef HAVE_BRAILLE
  if (bd.bd_refreshing)
    return;
#endif

  /* Check for zero-height window */
  if (ys < 0 || ye < ys)
    return;

  /* check for magic margin condition */
  if (xs >= l->l_width)
    xs = l->l_width - 1;
  if (xe >= l->l_width)
    xe = l->l_width - 1;
  if (l->l_pause.d)
    LayPauseUpdateRegion(l, xs, xe, ys, ye);

  FOR_EACH_UNPAUSED_CANVAS(l,
    {
      display = cv->c_display;
      if (D_blocked)
        continue;
      for (vp = cv->c_vplist; vp; vp = vp->v_next) {
        xs2 = xs + vp->v_xoff;
        xe2 = xe + vp->v_xoff;
        ys2 = ys + vp->v_yoff;
        ye2 = ye + vp->v_yoff;

        if (xs2 < vp->v_xs)
          xs2 = vp->v_xs;
        if (xe2 > vp->v_xe)
          xe2 = vp->v_xe;
        if (xs2 > vp->v_xe)
          ys2++;
        if (xe2 < vp->v_xs)
          ye2--;
        if (ys2 < vp->v_ys)
          ys2 = vp->v_ys;
        if (ye2 > vp->v_ye)
          ye2 = vp->v_ye;
        if (ys2 > ye2)
          continue;
#if 0
        xcs = vp->v_xoff;
        xce = l->l_width - 1 + vp->v_xoff;
        if (xcs < vp->v_xs)
          xcs = vp->v_xs;
        if (xce > vp->v_xe)
          xce = vp->v_xe;
        if (xcs > xce)
          continue;
        if (ys2 != ys + vp->v_yoff)
          xs2 = xcs;
        if (ye2 != ye + vp->v_yoff)
          xe2 = xce;
        display = cv->c_display;
        ClearArea(xs2, ys2, xcs, xce, xe2, ye2, bce, uself);
#else

        if (xs == 0 || ys2 != ys + vp->v_yoff)
          xs2 = vp->v_xs;
        if (xe == l->l_width - 1 || ye2 != ye + vp->v_yoff)
          xe2 = vp->v_xe;
        display = cv->c_display;
        ClearArea(xs2, ys2, vp->v_xs, vp->v_xe, xe2, ye2, bce, uself);

        if (xe == l->l_width - 1 && xe2 > vp->v_xoff + xe) {
          int y;
          SetRendition(&mchar_blank);
          for (y = ys2; y <= ye2; y++) {
            GotoPos(xe + vp->v_xoff + 1, y);
            PUTCHARLP('|');
          }
        }
#endif
      }
    }
  );
}


void LCDisplayLine(struct layer *l, struct mline *ml, int y, int xs, int xe, int isblank)
{
  struct canvas *cv;
  struct viewport *vp;
  int xs2, xe2, y2;

#ifdef HAVE_BRAILLE
  if (bd.bd_refreshing) {
    BCDisplayLine(l, ml, y, xs, xe, isblank);
    return;
  }
#endif

  if (l->l_pause.d)
    LayPauseUpdateRegion(l, xs, xe, y, y);

  FOR_EACH_UNPAUSED_CANVAS(l,
    {
      display = cv->c_display;
      if (D_blocked)
        continue;
      for (vp = cv->c_vplist; vp; vp = vp->v_next) {
        xs2 = xs + vp->v_xoff;
        xe2 = xe + vp->v_xoff;
        y2  = y + vp->v_yoff;
        if (y2 < vp->v_ys || y2 > vp->v_ye)
          continue;
        if (xs2 < vp->v_xs)
          xs2 = vp->v_xs;
        if (xe2 > vp->v_xe)
          xe2 = vp->v_xe;
        if (xs2 > xe2)
          continue;
        display = cv->c_display;
        debug3("LCDisplayLine: DisplayLine %d, %d-%d", y2, xs2, xe2);
        debug1("  mloff = %d\n", -vp->v_xoff);
        DisplayLine(isblank ? &mline_blank : &mline_null, mloff(RECODE_MLINE(ml), -vp->v_xoff), y2, xs2, xe2);
      }
    }
  );
}


void LCDisplayLineWrap(struct layer *l, struct mline *ml, int y, int from, int to, int isblank)
{
  struct mchar nc;
  copy_mline2mchar(&nc, ml, 0);

#ifdef DW_CHARS
  if (dw_left(ml, 0, l->l_encoding)) {
    nc.mbcs = ml->image[1];
    from++;
  }
#endif

  LWrapChar(l, &nc, y - 1, -1, -1, 0);
  from++;
  if (from <= to)
    LCDisplayLine(l, ml, y, from, to, isblank);
}


void LSetRendition(struct layer *l, struct mchar *r)
{
  struct canvas *cv;

  for (cv = l->l_cvlist; cv; cv = cv->c_lnext) {
    display = cv->c_display;
    if (D_blocked)
      continue;
    SetRendition(r);
  }
}


void LWrapChar(struct layer *l, struct mchar *c, int y, int top, int bot, int ins)
{
  struct canvas *cv, *cvlist, *cvlnext;
  struct viewport *vp, *evp, **vpp;
  int yy, y2, yy2, top2, bot2;
  int bce;

  if (l->l_pause.d)
    /* XXX: 'y'? */
    LayPauseUpdateRegion(l, 0, l->l_width - 1, top, bot);

#ifdef COLOR
  bce = rend_getbg(c);
#else
  bce = 0;
#endif

  if (y != bot) {
  /* simple case: no scrolling */
  /* cursor after wrapping */
    yy = y == l->l_height - 1 ? y : y + 1;

    FOR_EACH_UNPAUSED_CANVAS(l,
    {
      y2 = 0;       /* gcc -Wall */
      display = cv->c_display;
      if (D_blocked)
        continue;

      /* find the viewport of the wrapped character */
      for (vp = cv->c_vplist; vp; vp = vp->v_next) {
        y2 =  y + vp->v_yoff;
        yy2 = yy + vp->v_yoff;
        if (yy2 >= vp->v_ys && yy2 <= vp->v_ye && vp->v_xoff >= vp->v_xs && vp->v_xoff <= vp->v_xe)
          break;
      }

      if (vp == 0)
        continue;	/* nothing to do, character not visible */

      /* find the viewport of the character at the end of the line*/
      for (evp = cv->c_vplist; evp; evp = evp->v_next)
        if (y2 >= evp->v_ys && y2 <= evp->v_ye && evp->v_xoff + l->l_width - 1 >= evp->v_xs && evp->v_xoff + l->l_width - 1 <= evp->v_xe)
          break;	/* gotcha! */

      if (evp == 0 || (ins && vp->v_xoff + l->l_width - 1 > vp->v_ye)) {
        /* no wrapping possible */
        debug("LWrap: can't wrap!\n");
        cvlist = l->l_cvlist;
        cvlnext = cv->c_lnext;
        l->l_cvlist = cv;
        cv->c_lnext = 0;
 
        if (ins)
          LInsChar(l, c, 0, yy, 0);
        else
          LPutChar(l, c, 0, yy);

        l->l_cvlist = cvlist;
        cv->c_lnext = cvlnext;
      }
      else
        WrapChar(RECODE_MCHAR(c), vp->v_xoff + l->l_width, y2, vp->v_xoff, -1, vp->v_xoff + l->l_width - 1, -1, ins);
    });
  }
  else
  {
  /* hard case: scroll up*/
    FOR_EACH_UNPAUSED_CANVAS(l,
    {
      display = cv->c_display;
      if (D_blocked)
        continue;

      /* search for wrap viewport */
      for (vpp = &cv->c_vplist; (vp = *vpp); vpp = &vp->v_next) {
        yy2 = bot + vp->v_yoff;
        if (yy2 >= vp->v_ys && yy2 <= vp->v_ye && vp->v_xoff >= vp->v_xs && vp->v_xoff + l->l_width - 1 <= vp->v_xe)
          break;
      }

      if (vp) {
        /* great, can use Wrap on the vp */
        /* temporarily remove vp from cvlist */
        *vpp = vp->v_next;
      }

      if (cv->c_vplist) {
        /* scroll all viewports != vp */
        cvlist = l->l_cvlist;
        cvlnext = cv->c_lnext;
        l->l_cvlist = cv;
        cv->c_lnext = 0;
        LScrollV(l, 1, top, bot, bce);
        if (!vp) {
          if (ins)
            LInsChar(l, c, 0, bot, 0);
          else
            LPutChar(l, c, 0, bot);
        }

        l->l_cvlist = cvlist;
        cv->c_lnext = cvlnext;
      }
      if (vp) {
        /* add vp back to cvlist */
        *vpp = vp;
        top2 = top + vp->v_yoff;
        bot2 = bot + vp->v_yoff;
        if (top2 < vp->v_ys)
          top2 = vp->v_ys;
        WrapChar(RECODE_MCHAR(c), vp->v_xoff + l->l_width, bot2, vp->v_xoff, top2, vp->v_xoff + l->l_width - 1, bot2, ins);
      }
    });
  }
}


void LCursorVisibility(struct layer *l, int vis)
{
  struct canvas *cv;
  for (cv = l->l_cvlist; cv; cv = cv->c_lnext) {
    display = cv->c_display;
    if (D_blocked)
      continue;
    if (cv != D_forecv)
      continue;
    CursorVisibility(vis);
  }
}


void LSetFlow(struct layer *l, int flow)
{
  struct canvas *cv;
  for (cv = l->l_cvlist; cv; cv = cv->c_lnext) {
    display = cv->c_display;
    if (cv != D_forecv)
      continue;
    SetFlow(flow);
  }
}


void LKeypadMode(struct layer *l, int on)
{
  struct canvas *cv;
  for (cv = l->l_cvlist; cv; cv = cv->c_lnext) {
    display = cv->c_display;
    if (D_blocked)
      continue;
    if (cv != D_forecv)
      continue;
    KeypadMode(on);
  }
}


void LCursorkeysMode(struct layer *l, int on)
{
  struct canvas *cv;
  for (cv = l->l_cvlist; cv; cv = cv->c_lnext) {
    display = cv->c_display;
    if (D_blocked)
      continue;
    if (cv != D_forecv)
      continue;
    CursorkeysMode(on);
  }
}


void LMouseMode(struct layer *l, int on)
{
  struct canvas *cv;
  for (cv = l->l_cvlist; cv; cv = cv->c_lnext) {
    display = cv->c_display;
    if (D_blocked)
      continue;
    if (cv != D_forecv)
      continue;
    MouseMode(on);
  }
}

void LClearAll(struct layer *l, int uself)
{
  LClearArea(l, 0, 0, l->l_width - 1, l->l_height - 1, 0, uself);
}


void LRefreshAll(struct layer *l, int isblank)
{
  struct layer *oldflayer;
  int y;

  debug1("LRefreshAll isblank=%d\n", isblank);
  oldflayer = flayer;
  flayer = l;
  if (!isblank)
    LClearArea(l, 0, 0, l->l_width - 1, l->l_height - 1, 0, 0);
  /* signal full refresh */
  LayRedisplayLine(-1, -1, -1, 1);
  for (y = 0; y < l->l_height; y++)
    LayRedisplayLine(y, 0, l->l_width - 1, 1);
  flayer = oldflayer;
}

void
/*VARARGS2*/
#if defined(USEVARARGS) && defined(__STDC__)
LMsg(int err, const char *fmt, VA_DOTS)
#else
LMsg(err, fmt, VA_DOTS)
int err;
const char *fmt;
VA_DECL
#endif
{
  VA_LIST(ap)
  char buf[MAXPATHLEN*2];
  char *p = buf;
  struct canvas *cv;

  VA_START(ap, fmt);
  fmt = DoNLS(fmt);
  (void)vsnprintf(p, sizeof(buf) - 100, fmt, VA_ARGS(ap));
  VA_END(ap);

  if (err) {
    p += strlen(p);
    *p++ = ':';
    *p++ = ' ';
    strncpy(p, strerror(err), buf + sizeof(buf) - p - 1);
    buf[sizeof(buf) - 1] = 0;
  }

  debug2("LMsg('%s') (%#lx);\n", buf, (long)flayer);
  for (display = displays; display; display = display->d_next) {
    for (cv = D_cvlist; cv; cv = cv->c_next)
      if (cv->c_layer == flayer)
        break;

    if (cv == 0)
      continue;
    MakeStatus(buf);
  }
}

void
LExtMouseMode(l, on)
struct layer *l;
int on;
{
  struct canvas *cv;
  for (cv = l->l_cvlist; cv; cv = cv->c_lnext)
    {
      display = cv->c_display;
      if (D_blocked)
	continue;
      if (cv != D_forecv)
	continue;
      ExtMouseMode(on);
    }
}


/*******************************************************************/
/*******************************************************************/

/*
 *  Layer creation / removal
 */

void KillLayerChain(struct layer *lay)
{
  struct canvas *cv, *ncv;
  struct layer *l, *oldflayer;

  oldflayer = flayer;
  debug1("KillLayerChain %#lx\n", (long)lay);
  for (l = lay; l; l = l->l_next) {
    if (l->l_layfn == &WinLf || l->l_layfn == &BlankLf)
      break;
    debug1("- killing %#lx\n", (long)l);
    if (oldflayer == l)
      oldflayer = 0;
    for (cv = l->l_cvlist; cv; cv = ncv) {
      ncv = cv->c_lnext;
      cv->c_layer = 0;
      cv->c_lnext = 0;
    }
  }
  flayer = lay;
  while (flayer != l)
    ExitOverlayPage();
  flayer = oldflayer;
}



int InitOverlayPage(int datasize, struct LayFuncs *lf, int block)
{
  char *data;
  struct layer *newlay;
  struct canvas *cv, *cvp, **cvpp;
  struct win *p;

  ASSERT(flayer);

  cv = 0;
  if (display && D_forecv->c_layer == flayer)
    cv = D_forecv;	/* work only on this cv! */

  if ((newlay = (struct layer *)calloc(1, sizeof(struct layer))) == 0) {
    Msg(0, "No memory for layer struct");
      return -1;
  }
  debug2("Entering new layer on top of %#lx: %#lx\n", (long)flayer, (long)newlay);
  data = 0;
  if (datasize) {
    if ((data = calloc(1, datasize)) == 0) {
      free((char *)newlay);
      Msg(0, "No memory for layer data");
      return -1;
    }
  }
  p = Layer2Window(flayer);

  if (p && (p->w_savelayer == flayer || (block && flayer->l_next == 0))) {
    if (p->w_savelayer && p->w_savelayer != flayer && p->w_savelayer->l_cvlist == 0)
      KillLayerChain(p->w_savelayer);
    p->w_savelayer = newlay;
  }

  if (cv && flayer->l_next == 0 && !block) {
    struct display *olddisplay = display;
    display = cv->c_display;
    RemoveStatus();
    display = olddisplay;

    /* new branch -> just get canvas vps */
    for (cvpp = &flayer->l_cvlist; (cvp = *cvpp); cvpp = &cvp->c_lnext)
      if (cvp == cv)
        break;

    ASSERT(cvp);
    *cvpp = cv->c_lnext;
    newlay->l_cvlist = cv;
    cv->c_lnext = 0;
    cv->c_layer = newlay;
  }
  else {
    LAY_DISPLAYS(flayer, RemoveStatus());
    if (block)
      debug("layer is blocking\n");
    if (block && flayer->l_layfn == &WinLf) {
      debug("...and is first, so window gets blocked\n");
      ASSERT(p->w_blocked == 0);
      p->w_blocked++;
      newlay->l_blocking = 1;
    }

    /* change all canvases */
    newlay->l_cvlist = flayer->l_cvlist;

    for (cvp = newlay->l_cvlist; cvp; cvp = cvp->c_lnext)
      cvp->c_layer = newlay;
    flayer->l_cvlist = 0;
  }
  newlay->l_width = flayer->l_width;
  newlay->l_height = flayer->l_height;
  newlay->l_encoding = 0;
  newlay->l_layfn = lf;
  newlay->l_data = data;
  newlay->l_next = flayer;
  newlay->l_bottom = flayer->l_bottom;
  flayer = newlay;
  LayRestore();
  return 0;
}


extern struct layout *layouts;

void ExitOverlayPage()
{
  struct layer *oldlay;
  struct win *p;
  int doredisplay = 0;
  struct canvas *cv, *ocv;
  struct layout *lay;

  ASSERT(flayer);
  debug1("Exiting layer %#lx\n", (long)flayer);
  oldlay = flayer;
  if (oldlay->l_data) {
    if (oldlay->l_layfn->lf_LayFree)
      LayFree(oldlay->l_data);
        free(oldlay->l_data);
  }
  p = Layer2Window(flayer);

  flayer = oldlay->l_next;
  if (flayer->l_layfn == &WinLf) {
    if (oldlay->l_blocking) {
      ASSERT(p->w_blocked > 0);
      p->w_blocked--;
      debug1("layer was blocking, -> w_blocked now %d\n", p->w_blocked);
    }

    /* don't warp dead layers: check cvlist */
    if (p->w_blocked && p->w_savelayer && p->w_savelayer != flayer && oldlay->l_cvlist) {
      debug("warping to top of blocking chain!\n");
      /* warp ourself into savelayer */
      flayer = p->w_savelayer;
      doredisplay = 1;
    }
  }

  if (p && p->w_savelayer == oldlay)
    p->w_savelayer = flayer;
#ifdef COPY_PASTE
  if (p && oldlay == p->w_paster.pa_pastelayer)
    p->w_paster.pa_pastelayer = 0;
#endif

  for (lay = layouts; lay; lay = lay->lay_next)
    for (cv = lay->lay_cvlist; cv; cv = cv->c_next)
      if (cv->c_layer == oldlay)
        cv->c_layer = flayer;

  /* add all canvases back into next layer's canvas list */
  for (ocv = 0, cv = oldlay->l_cvlist; cv; cv = cv->c_lnext) {
    cv->c_layer = flayer;
    ocv = cv;
  }
  if (ocv) {
    cv = flayer->l_cvlist;
    ocv->c_lnext = 0;
    flayer->l_cvlist = oldlay->l_cvlist;

    /* redisplay only the warped cvs */
    if (doredisplay)
      LRefreshAll(flayer, 0);
    ocv->c_lnext = cv;
  }
  oldlay->l_cvlist = 0;
  LayerCleanupMemory(oldlay);
  free((char *)oldlay);
  LayRestore();
  LaySetCursor();
}

int LayProcessMouse(struct layer *l, unsigned char ch)
{
  /* XXX: Make sure the layer accepts mouse events */
  int len;
  if (l->l_mouseevent.len >= sizeof(l->l_mouseevent.buffer))
    return -1;

  len = l->l_mouseevent.len++;
  l->l_mouseevent.buffer[len] = (len > 0 ? ch - 33 : ch);
  return (l->l_mouseevent.len == sizeof(l->l_mouseevent.buffer));
}

void LayProcessMouseSwitch(struct layer *l, int s)
{
  if ((l->l_mouseevent.start = s))
    l->l_mouseevent.len = 0;
}


void LayPause(struct layer *layer, int pause)
{
  struct canvas *cv;
  int line;
  struct win *win;
  pause = !!pause;

  if (layer->l_pause.d == pause)
    return;

  if ((layer->l_pause.d = pause)) {
    /* Start pausing */
    layer->l_pause.top = layer->l_pause.bottom = -1;
    return;
  }

  /* Unpause. So refresh the regions in the displays! */
  if (layer->l_pause.top == -1 && layer->l_pause.bottom == -1)
    return;

  if (layer->l_layfn == &WinLf)  /* Currently, this will always be the case! */
    win = layer->l_data;
  else
    win = NULL;

  for (cv = layer->l_cvlist; cv; cv = cv->c_lnext) {
    struct viewport *vp;

    if (!cv->c_slorient)
      continue;              /* Wasn't split, so already updated. */
    display = cv->c_display;
    for (vp = cv->c_vplist; vp; vp = vp->v_next) {
      for (line = layer->l_pause.top; line <= layer->l_pause.bottom; line++) {
        int xs, xe;
        if (line + vp->v_yoff >= vp->v_ys && line + vp->v_yoff <= vp->v_ye &&
             ((xs = layer->l_pause.left[line]) >= 0) &&
             ((xe = layer->l_pause.right[line]) >= 0)) {
           xs += vp->v_xoff;
           xe += vp->v_xoff;

          if (xs < vp->v_xs) xs = vp->v_xs;
          if (xe > vp->v_xe) xe = vp->v_xe;

#if defined(DW_CHARS) && defined(UTF8)
          if (layer->l_encoding == UTF8 && xe < vp->v_xe && win) {
            struct mline *ml = win->w_mlines + line;
            if (dw_left(ml, xe, UTF8))
              xe++;
          }
#endif

          if (xs <= xe)
            RefreshLine(line + vp->v_yoff, xs, xe, 0);
        }
      }
    }

    if (cv == D_forecv) {
      int cx = layer->l_x + cv->c_xoff;
      int cy = layer->l_y + cv->c_yoff;

      if (cx < cv->c_xs) cx = cv->c_xs;
      if (cy < cv->c_ys) cy = cv->c_ys;
      if (cx > cv->c_xe) cx = cv->c_xe;
      if (cy > cv->c_ye) cy = cv->c_ye;

      GotoPos(cx, cy);
    }
  }

  for (line = layer->l_pause.top; line <= layer->l_pause.bottom; line++)
    layer->l_pause.left[line] = layer->l_pause.right[line] = -1;
}

void LayPauseUpdateRegion(struct layer *layer, int xs, int xe, int ys, int ye)
{
  if (!layer->l_pause.d)
    return;
  if (ys < 0)
    ys = 0;
  if (ye >= layer->l_height)
    ye = layer->l_height - 1;
  if (xe >= layer->l_width)
    xe = layer->l_width - 1;

  if (layer->l_pause.top == -1 || layer->l_pause.top > ys)
    layer->l_pause.top = ys;
  if (layer->l_pause.bottom < ye) {
    layer->l_pause.bottom = ye;

    if (layer->l_pause.lines <= ye) {
      int o = layer->l_pause.lines;
      layer->l_pause.lines = ye + 32;
      layer->l_pause.left = realloc(layer->l_pause.left, sizeof(int) * layer->l_pause.lines);
      layer->l_pause.right = realloc(layer->l_pause.right, sizeof(int) * layer->l_pause.lines);
      while (o < layer->l_pause.lines) {
        layer->l_pause.left[o] = layer->l_pause.right[o] = -1;
        o++;
      }
    }
  }
  while (ys <= ye) {
    if (layer->l_pause.left[ys] == -1 || layer->l_pause.left[ys] > xs)
    layer->l_pause.left[ys] = xs;
      if (layer->l_pause.right[ys] < xe)
    layer->l_pause.right[ys] = xe;
      ys++;
  }
}

void LayerCleanupMemory(struct layer *layer)
{
  if (layer->l_pause.left)
    free(layer->l_pause.left);
  if (layer->l_pause.right)
    free(layer->l_pause.right);
}
