/*
 * USER DCE functions
 *
 * Copyright 1993 Alexandre Julliard
 *	     1996 Alex Korobka
 *
 *
 * Note: Visible regions of CS_OWNDC/CS_CLASSDC window DCs 
 * have to be updated dynamically. 
 * 
 * Internal DCX flags:
 *
 * DCX_DCEBUSY     - dce structure is in use
 * DCX_KEEPCLIPRGN - do not delete clipping region in ReleaseDC
 * DCX_WINDOWPAINT - BeginPaint specific flag
 */

#include "dce.h"
#include "class.h"
#include "win.h"
#include "gdi.h"
#include "user.h"
#include "sysmetrics.h"
#include "stddebug.h"
/* #define DEBUG_DC */
#include "debug.h"

#define NB_DCE    5  /* Number of DCEs created at startup */

static HANDLE firstDCE = 0;
static HDC defaultDCstate = 0;

BOOL   DCHook(HDC, WORD, DWORD, DWORD);

/***********************************************************************
 *           DCE_AllocDCE
*
 * Allocate a new DCE.
 */
HANDLE DCE_AllocDCE( HWND hWnd, DCE_TYPE type )
{
    DCE * dce;
    HANDLE handle = USER_HEAP_ALLOC( sizeof(DCE) );
    if (!handle) return 0;
    dce = (DCE *) USER_HEAP_LIN_ADDR( handle );
    if (!(dce->hDC = CreateDC( "DISPLAY", NULL, NULL, NULL )))
    {
	USER_HEAP_FREE( handle );
	return 0;
    }

    /* store DCE handle in DC hook data field */

    SetDCHook(dce->hDC, GDI_GetDefDCHook(), MAKELONG(handle,DC_MAGIC));

    dce->hwndCurrent = hWnd;
    dce->hNext = firstDCE;
    dce->hClipRgn = 0;
    firstDCE = handle;

    if( type != DCE_CACHE_DC )
      {
	dce->DCXflags = DCX_DCEBUSY;
	if( hWnd )
	  {
	    WND* wnd = WIN_FindWndPtr(hWnd);
	
	    if( wnd->dwStyle & WS_CLIPCHILDREN ) dce->DCXflags |= DCX_CLIPCHILDREN;
	    if( wnd->dwStyle & WS_CLIPSIBLINGS ) dce->DCXflags |= DCX_CLIPSIBLINGS;
	  }
	SetHookFlags(dce->hDC,DCHF_INVALIDATEVISRGN);
      }
    else dce->DCXflags = DCX_CACHE;

    return handle;
}


/***********************************************************************
 *           DCE_FreeDCE
 */
void DCE_FreeDCE( HANDLE hdce )
{
    DCE * dce;
    HANDLE *handle = &firstDCE;

    if (!(dce = (DCE *) USER_HEAP_LIN_ADDR( hdce ))) return;
    while (*handle && (*handle != hdce))
    {
	DCE * prev = (DCE *) USER_HEAP_LIN_ADDR( *handle );	
	handle = &prev->hNext;
    }
    if (*handle == hdce) *handle = dce->hNext;

    SetDCHook(dce->hDC,(SEGPTR)NULL,0L);

    DeleteDC( dce->hDC );
    if( dce->hClipRgn && !(dce->DCXflags & DCX_KEEPCLIPRGN) )
	DeleteObject(dce->hClipRgn);
    USER_HEAP_FREE( hdce );
}

/***********************************************************************
 *           DCE_FindDCE
 */
HANDLE DCE_FindDCE(HDC hDC)
{
 HANDLE hdce = firstDCE;
 DCE*   dce;

 while( hdce )
  {
    dce = (DCE *) USER_HEAP_LIN_ADDR(hdce);
    if( dce->hDC == hDC ) break;
    hdce = dce->hNext;
  }
 return hdce;
}

/**********************************************************************
 *          WindowFromDC   (USER.117) (USER32.580)
 */
HWND16 WindowFromDC( HDC32 hDC )
{
 HANDLE16 hdce = DCE_FindDCE(hDC); 

 if( hdce )
   {
     DCE* dce = (DCE *) USER_HEAP_LIN_ADDR(hdce);
     return dce->hwndCurrent;
   }

 return 0;
}

/***********************************************************************
 *   DCE_InvalidateDCE
 *
 * It is called from SetWindowPos - we have to invalidate all busy
 * DCE's for windows whose client rect intersects with update rectangle 
 */
BOOL DCE_InvalidateDCE(WND* wndScope, RECT16* pRectUpdate)
{
 HANDLE hdce;
 DCE*   dce;

 if( !wndScope ) return 0;

 dprintf_dc(stddeb,"InvalidateDCE: scope hwnd = %04x, (%i,%i - %i,%i)\n",
                    wndScope->hwndSelf, pRectUpdate->left,pRectUpdate->top,
				        pRectUpdate->right,pRectUpdate->bottom);
 /* walk all DCE's */

 for( hdce = firstDCE; (hdce); hdce=dce->hNext)
  { 
    dce = (DCE*)USER_HEAP_LIN_ADDR(hdce);

    if( dce->DCXflags & DCX_DCEBUSY )
      {
        WND * wndCurrent, * wnd; 

	wnd = wndCurrent = WIN_FindWndPtr(dce->hwndCurrent);

	/* desktop is not critical (DC is not owned anyway) */

	if( wnd == WIN_GetDesktop() ) continue; 

	/* check if DCE window is within z-order scope */

	for( ; wnd ; wnd = wnd->parent )
	    if( wnd == wndScope )
	      { 
	        RECT16 wndRect = wndCurrent->rectWindow;

	        dprintf_dc(stddeb,"\tgot hwnd %04x\n", wndCurrent->hwndSelf);
  
	        MapWindowPoints16(wndCurrent->parent->hwndSelf, wndScope->hwndSelf,
			 				       (LPPOINT16)&wndRect, 2);
	        if( IntersectRect16(&wndRect,&wndRect,pRectUpdate) )
	            SetHookFlags(dce->hDC, DCHF_INVALIDATEVISRGN);
	        break;
	      }
      }
  }
 return 1;
}

/***********************************************************************
 *           DCE_Init
 */
void DCE_Init()
{
    int i;
    HANDLE handle;
    DCE * dce;
        
    for (i = 0; i < NB_DCE; i++)
    {
	if (!(handle = DCE_AllocDCE( 0, DCE_CACHE_DC ))) return;
	dce = (DCE *) USER_HEAP_LIN_ADDR( handle );	
	if (!defaultDCstate) defaultDCstate = GetDCState( dce->hDC );
    }
}


/***********************************************************************
 *           DCE_GetVisRect
 *
 * Calc the visible rectangle of a window, i.e. the client or
 * window area clipped by the client area of all ancestors.
 * Return FALSE if the visible region is empty.
 */
static BOOL DCE_GetVisRect( WND *wndPtr, BOOL clientArea, RECT16 *lprect )
{
    int xoffset, yoffset;

    *lprect = clientArea ? wndPtr->rectClient : wndPtr->rectWindow;
    xoffset = lprect->left;
    yoffset = lprect->top;

    if (!(wndPtr->dwStyle & WS_VISIBLE) || (wndPtr->flags & WIN_NO_REDRAW))
    {
        SetRectEmpty16( lprect );  /* Clip everything */
        return FALSE;
    }

    while (wndPtr->parent)
    {
        wndPtr = wndPtr->parent;
        if (!(wndPtr->dwStyle & WS_VISIBLE) ||
            (wndPtr->flags & WIN_NO_REDRAW) ||
            (wndPtr->dwStyle & WS_ICONIC))
        {
            SetRectEmpty16( lprect );  /* Clip everything */
            return FALSE;
        }
	xoffset += wndPtr->rectClient.left;
	yoffset += wndPtr->rectClient.top;
	OffsetRect16( lprect, wndPtr->rectClient.left,
                      wndPtr->rectClient.top );

	  /* Warning!! we assume that IntersectRect() handles the case */
	  /* where the destination is the same as one of the sources.  */
	if (!IntersectRect16( lprect, lprect, &wndPtr->rectClient ))
            return FALSE;  /* Visible rectangle is empty */
    }
    OffsetRect16( lprect, -xoffset, -yoffset );
    return TRUE;
}


/***********************************************************************
 *           DCE_ClipWindows
 *
 * Go through the linked list of windows from hwndStart to hwndEnd,
 * removing from the given region the rectangle of each window offset
 * by a given amount.  The new region is returned, and the original one
 * is destroyed.  Used to implement DCX_CLIPSIBLINGS and
 * DCX_CLIPCHILDREN styles.
 */
static HRGN DCE_ClipWindows( WND *pWndStart, WND *pWndEnd,
                             HRGN hrgn, int xoffset, int yoffset )
{
    HRGN hrgnNew;

    if (!pWndStart) return hrgn;
    if (!(hrgnNew = CreateRectRgn( 0, 0, 0, 0 )))
    {
        DeleteObject( hrgn );
        return 0;
    }
    for (; pWndStart != pWndEnd; pWndStart = pWndStart->next)
    {
        if (!(pWndStart->dwStyle & WS_VISIBLE)) continue;
        SetRectRgn( hrgnNew, pWndStart->rectWindow.left + xoffset,
                    pWndStart->rectWindow.top + yoffset,
                    pWndStart->rectWindow.right + xoffset,
                    pWndStart->rectWindow.bottom + yoffset );
        if (!CombineRgn( hrgn, hrgn, hrgnNew, RGN_DIFF )) break;
    }
    DeleteObject( hrgnNew );
    if (pWndStart != pWndEnd)  /* something went wrong */
    {
        DeleteObject( hrgn );
        return 0;
    }
    return hrgn;
}


/***********************************************************************
 *           DCE_GetVisRgn
 *
 * Return the visible region of a window, i.e. the client or window area
 * clipped by the client area of all ancestors, and then optionally
 * by siblings and children.
 */
HRGN DCE_GetVisRgn( HWND hwnd, WORD flags )
{
    RECT16 rect;
    HRGN hrgn;
    int xoffset, yoffset;
    WND *wndPtr = WIN_FindWndPtr( hwnd );

      /* Get visible rectangle and create a region with it 
       * FIXME: do we really need to calculate vis rgns for X windows? 
       */

    if (!wndPtr || !DCE_GetVisRect( wndPtr, !(flags & DCX_WINDOW), &rect ))
    {
        return CreateRectRgn( 0, 0, 0, 0 );  /* Visible region is empty */
    }
    if (!(hrgn = CreateRectRgnIndirect16( &rect ))) return 0;

      /* Clip all children from the visible region */

    if (flags & DCX_CLIPCHILDREN)
    {
        if (flags & DCX_WINDOW)
        {
            xoffset = wndPtr->rectClient.left - wndPtr->rectWindow.left;
            yoffset = wndPtr->rectClient.top - wndPtr->rectWindow.top;
        }
        else xoffset = yoffset = 0;
        hrgn = DCE_ClipWindows( wndPtr->child, NULL, hrgn, xoffset, yoffset );
        if (!hrgn) return 0;
    }

      /* Clip siblings placed above this window */

    if (flags & DCX_WINDOW)
    {
        xoffset = -wndPtr->rectWindow.left;
        yoffset = -wndPtr->rectWindow.top;
    }
    else
    {
        xoffset = -wndPtr->rectClient.left;
        yoffset = -wndPtr->rectClient.top;
    }
    if (flags & DCX_CLIPSIBLINGS)
    {
        hrgn = DCE_ClipWindows( wndPtr->parent ? wndPtr->parent->child : NULL,
                                wndPtr, hrgn, xoffset, yoffset );
        if (!hrgn) return 0;
    }

      /* Clip siblings of all ancestors that have the WS_CLIPSIBLINGS style */

    while (wndPtr->dwStyle & WS_CHILD)
    {
        wndPtr = wndPtr->parent;
        xoffset -= wndPtr->rectClient.left;
        yoffset -= wndPtr->rectClient.top;
        hrgn = DCE_ClipWindows( wndPtr->parent->child, wndPtr,
                                hrgn, xoffset, yoffset );
        if (!hrgn) return 0;
    }
    return hrgn;
}


/***********************************************************************
 *           DCE_SetDrawable
 *
 * Set the drawable, origin and dimensions for the DC associated to
 * a given window.
 */
static void DCE_SetDrawable( WND *wndPtr, DC *dc, WORD flags )
{
    if (!wndPtr)  /* Get a DC for the whole screen */
    {
        dc->w.DCOrgX = 0;
        dc->w.DCOrgY = 0;
        dc->u.x.drawable = rootWindow;
        XSetSubwindowMode( display, dc->u.x.gc, IncludeInferiors );
    }
    else
    {
        if (flags & DCX_WINDOW)
        {
            dc->w.DCOrgX  = wndPtr->rectWindow.left;
            dc->w.DCOrgY  = wndPtr->rectWindow.top;
        }
        else
        {
            dc->w.DCOrgX  = wndPtr->rectClient.left;
            dc->w.DCOrgY  = wndPtr->rectClient.top;
        }
        while (!wndPtr->window)
        {
            wndPtr = wndPtr->parent;
            dc->w.DCOrgX += wndPtr->rectClient.left;
            dc->w.DCOrgY += wndPtr->rectClient.top;
        }
        dc->w.DCOrgX -= wndPtr->rectWindow.left;
        dc->w.DCOrgY -= wndPtr->rectWindow.top;
        dc->u.x.drawable = wndPtr->window;
    }
}

/***********************************************************************
 *           GetDCEx    (USER.359)
 *
 * Unimplemented flags: DCX_LOCKWINDOWUPDATE
 */
HDC GetDCEx( HWND hwnd, HRGN hrgnClip, DWORD flags )
{
    HANDLE 	hdce;
    HRGN 	hrgnVisible;
    HDC 	hdc = 0;
    DCE * 	dce;
    DC * 	dc;
    WND * 	wndPtr;
    DWORD 	dcx_flags = 0;
    BOOL	need_update = TRUE;

    dprintf_dc(stddeb,"GetDCEx: hwnd %04x, hrgnClip %04x, flags %08x\n", hwnd, hrgnClip, (unsigned)flags);
    
    if (!(wndPtr = WIN_FindWndPtr( hwnd ))) return 0;

    if (flags & DCX_USESTYLE)
    {
	flags &= ~( DCX_CLIPCHILDREN | DCX_CLIPSIBLINGS | DCX_PARENTCLIP);

        if( wndPtr->dwStyle & WS_CLIPSIBLINGS )
            flags |= DCX_CLIPSIBLINGS;

	if ( !(flags & DCX_WINDOW) )
	{
            if (!(wndPtr->class->style & (CS_OWNDC | CS_CLASSDC)))
		flags |= DCX_CACHE;

            if (wndPtr->class->style & CS_PARENTDC) flags |= DCX_PARENTCLIP;

	    if (wndPtr->dwStyle & WS_CLIPCHILDREN &&
                     !(wndPtr->dwStyle & WS_MINIMIZE) ) flags |= DCX_CLIPCHILDREN;
	}
	else flags |= DCX_CACHE;
    }

    if( flags & DCX_NOCLIPCHILDREN )
      {
        flags |= DCX_CACHE;
        flags &= ~(DCX_PARENTCLIP | DCX_CLIPCHILDREN);
      }

    if (hwnd==GetDesktopWindow() || !(wndPtr->dwStyle & WS_CHILD)) flags &= ~DCX_PARENTCLIP;

    if (flags & DCX_WINDOW) flags = (flags & ~DCX_CLIPCHILDREN) | DCX_CACHE;

    if( flags & DCX_PARENTCLIP )
      {
        flags |= DCX_CACHE;
        if( !(flags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN)) )
          if( (wndPtr->dwStyle & WS_VISIBLE) && (wndPtr->parent->dwStyle & WS_VISIBLE) )
            {
              flags &= ~DCX_CLIPCHILDREN;
              if( wndPtr->parent->dwStyle & WS_CLIPSIBLINGS )
                flags |= DCX_CLIPSIBLINGS;
            }
      }

    if (flags & DCX_CACHE)
    {
	for (hdce = firstDCE; (hdce); hdce = dce->hNext)
	{
	    if (!(dce = (DCE *) USER_HEAP_LIN_ADDR( hdce ))) return 0;
	    if ((dce->DCXflags & DCX_CACHE) && !(dce->DCXflags & DCX_DCEBUSY)) break;
	}
    }
    else 
    {
        hdce = (wndPtr->class->style & CS_OWNDC)?wndPtr->hdce:wndPtr->class->hdce;
	dce = (DCE *) USER_HEAP_LIN_ADDR( hdce );

	if( dce->hwndCurrent == hwnd )
	  {
	    dprintf_dc(stddeb,"\tskipping hVisRgn update\n");
	    need_update = FALSE;
	  }

	if( hrgnClip && dce->hClipRgn && !(dce->DCXflags & DCX_KEEPCLIPRGN))
	  {
	    fprintf(stdnimp,"GetDCEx: hClipRgn collision!\n");
            DeleteObject(dce->hClipRgn); 
	    need_update = TRUE;
	  }
    }

    dcx_flags = flags & ( DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN | DCX_CACHE | DCX_WINDOW | DCX_WINDOWPAINT);

    if (!hdce) return 0;
    dce = (DCE *) USER_HEAP_LIN_ADDR( hdce );
    dce->hwndCurrent = hwnd;
    dce->hClipRgn = 0;
    dce->DCXflags = dcx_flags | DCX_DCEBUSY;
    hdc = dce->hDC;
    
    if (!(dc = (DC *) GDI_GetObjPtr( hdc, DC_MAGIC ))) return 0;

    DCE_SetDrawable( wndPtr, dc, flags );
    if( need_update || dc->w.flags & DC_DIRTY )
     {
      dprintf_dc(stddeb,"updating hDC anyway\n");

      if (flags & DCX_PARENTCLIP)
        {
            WND *parentPtr = wndPtr->parent;
            dcx_flags = flags & ~(DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
                                       DCX_WINDOW);
            if (parentPtr->dwStyle & WS_CLIPSIBLINGS)
                dcx_flags |= DCX_CLIPSIBLINGS;
            hrgnVisible = DCE_GetVisRgn( parentPtr->hwndSelf, dcx_flags );
            if (flags & DCX_WINDOW)
                OffsetRgn( hrgnVisible, -wndPtr->rectWindow.left,
                                        -wndPtr->rectWindow.top );
            else OffsetRgn( hrgnVisible, -wndPtr->rectClient.left,
                                         -wndPtr->rectClient.top );
        }
           /* optimize away GetVisRgn for desktop if it isn't there */

      else if ((hwnd == GetDesktopWindow()) &&
               (rootWindow == DefaultRootWindow(display)))
	       hrgnVisible = CreateRectRgn( 0, 0, SYSMETRICS_CXSCREEN,
                                                  SYSMETRICS_CYSCREEN);
      else hrgnVisible = DCE_GetVisRgn( hwnd, flags );

      dc->w.flags &= ~DC_DIRTY;

      SelectVisRgn( hdc, hrgnVisible );
     }
    else hrgnVisible = CreateRectRgn(0,0,0,0);

    if ((flags & DCX_INTERSECTRGN) || (flags & DCX_EXCLUDERGN))
    {
	dce->DCXflags |= flags & (DCX_KEEPCLIPRGN | DCX_INTERSECTRGN | DCX_EXCLUDERGN);
	dce->hClipRgn = hrgnClip;

	dprintf_dc(stddeb, "\tsaved VisRgn, clipRgn = %04x\n", hrgnClip);

	SaveVisRgn( hdc );
        CombineRgn( hrgnVisible, InquireVisRgn( hdc ), hrgnClip,
                    (flags & DCX_INTERSECTRGN) ? RGN_AND : RGN_DIFF );
	SelectVisRgn( hdc, hrgnVisible );
    }
    DeleteObject( hrgnVisible );

    dprintf_dc(stddeb, "GetDCEx(%04x,%04x,0x%lx): returning %04x\n", 
	       hwnd, hrgnClip, flags, hdc);
    return hdc;
}

/***********************************************************************
 *           GetDC    (USER.66)
 */
HDC GetDC( HWND hwnd )
{
    if( !hwnd ) return GetDCEx( GetDesktopWindow(), 0, DCX_CACHE | DCX_WINDOW );

    return GetDCEx( hwnd, 0, DCX_USESTYLE );
}


/***********************************************************************
 *           GetWindowDC    (USER.67)
 */
HDC GetWindowDC( HWND hwnd )
{
    if (hwnd)
    {
	WND * wndPtr;
	if (!(wndPtr = WIN_FindWndPtr( hwnd ))) return 0;
    }
    else hwnd = GetDesktopWindow();

    return GetDCEx( hwnd, 0, DCX_USESTYLE | DCX_WINDOW );
}


/***********************************************************************
 *           ReleaseDC    (USER.68)
 */
int ReleaseDC( HWND hwnd, HDC hdc )
{
    HANDLE hdce;
    DCE * dce = NULL;
    
    dprintf_dc(stddeb, "ReleaseDC: %04x %04x\n", hwnd, hdc );
        
    for (hdce = firstDCE; (hdce); hdce = dce->hNext)
    {
	if (!(dce = (DCE *) USER_HEAP_LIN_ADDR( hdce ))) return 0;
	if (dce->hDC == hdc) break;
    }
    if (!hdce) return 0;
    if (!(dce->DCXflags & DCX_DCEBUSY) ) return 0;

    /* restore previous visible region */

    if ( dce->DCXflags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN) &&
	(dce->DCXflags & DCX_CACHE || dce->DCXflags & DCX_WINDOWPAINT) )
    {
	dprintf_dc(stddeb,"\tcleaning up visrgn...\n");
	dce->DCXflags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN | DCX_WINDOWPAINT);

	if( dce->DCXflags & DCX_KEEPCLIPRGN )
	    dce->DCXflags &= ~DCX_KEEPCLIPRGN;
	else
	    if( dce->hClipRgn > 1 )
	        DeleteObject( dce->hClipRgn );

        dce->hClipRgn = 0;
	RestoreVisRgn(dce->hDC);
    }

    if (dce->DCXflags & DCX_CACHE)
    {
	SetDCState( dce->hDC, defaultDCstate );
	dce->DCXflags = DCX_CACHE;
	dce->hwndCurrent = 0;
    }
    return 1;
}

/***********************************************************************
 *           DCHook    (USER.362)
 *
 * See "Undoc. Windows" for hints (DC, SetDCHook, SetHookFlags)..  
 */
BOOL DCHook(HDC hDC, WORD code, DWORD data, DWORD lParam)
{
  HANDLE hdce;
  HRGN hVisRgn;

  dprintf_dc(stddeb,"DCHook: hDC = %04x, %i\n", hDC, code);

  if( HIWORD(data) == DC_MAGIC )
      hdce = (HANDLE)LOWORD(data);
  else
      hdce = DCE_FindDCE(hDC);

  if( !hdce ) return 0;

  switch( code )
    {
      case DCHC_INVALIDVISRGN:
         {
           DCE* dce = (DCE*) USER_HEAP_LIN_ADDR(hdce);

           if( dce->DCXflags & DCX_DCEBUSY )
 	     {
	       SetHookFlags(hDC, DCHF_VALIDATEVISRGN);
	       hVisRgn = DCE_GetVisRgn(dce->hwndCurrent, dce->DCXflags);

	       dprintf_dc(stddeb,"\tapplying saved clipRgn\n");
  
	       /* clip this region with saved clipping region */

               if ( (dce->DCXflags & DCX_INTERSECTRGN && dce->hClipRgn != 1) ||
                  (  dce->DCXflags & DCX_EXCLUDERGN && dce->hClipRgn) )
                  {

                    if( (!dce->hClipRgn && dce->DCXflags & DCX_INTERSECTRGN) ||
                         (dce->hClipRgn == 1 && dce->DCXflags & DCX_EXCLUDERGN) )            
                         SetRectRgn(hVisRgn,0,0,0,0);
                    else
                         CombineRgn(hVisRgn, hVisRgn, dce->hClipRgn, 
                                      (dce->DCXflags & DCX_EXCLUDERGN)? RGN_DIFF:RGN_AND);
	          }  
	       SelectVisRgn(hDC, hVisRgn);
	       DeleteObject(hVisRgn);
	     }
           else
	     dprintf_dc(stddeb,"DCHook: DC is not in use!\n");
         }
	 break;

      case DCHC_DELETEDC: /* FIXME: ?? */
	 break;

      default:
	 fprintf(stdnimp,"DCHook: unknown code\n");
    }
  return 0;
}