/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (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.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is Mozilla Communicator client code.
 *
 * The Initial Developer of the Original Code is Netscape Communications
 * Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */
#ifndef nsGfxScrollFrame_h___
#define nsGfxScrollFrame_h___

#include "nsHTMLContainerFrame.h"
#include "nsIAnonymousContentCreator.h"
#include "nsBoxFrame.h"
#include "nsIScrollableFrame.h"

class nsISupportsArray;
class nsGfxScrollFrameInner;

/**
 * The scroll frame creates and manages the scrolling view
 *
 * It only supports having a single child frame that typically is an area
 * frame, but doesn't have to be. The child frame must have a view, though
 *
 * Scroll frames don't support incremental changes, i.e. you can't replace
 * or remove the scrolled frame
 */
class nsGfxScrollFrame : public nsIAnonymousContentCreator,
                         public nsBoxFrame,
                         public nsIScrollableFrame {
public:
  friend nsresult NS_NewGfxScrollFrame(nsIPresShell* aPresShell, nsIFrame** aNewFrame, 
                                       nsIDocument* aDocument, PRBool aIsRoot);

  NS_IMETHOD Init(nsIPresContext*  aPresContext,
                  nsIContent*      aContent,
                  nsIFrame*        aParent,
                  nsIStyleContext* aContext,
                  nsIFrame*        aPrevInFlow);

  virtual ~nsGfxScrollFrame();


  // Called to set the one and only child frame. Returns NS_ERROR_INVALID_ARG
  // if the child frame is NULL, and NS_ERROR_UNEXPECTED if the child list
  // contains more than one frame
  NS_IMETHOD SetInitialChildList(nsIPresContext* aPresContext,
                                 nsIAtom*        aListName,
                                 nsIFrame*       aChildList);

  NS_IMETHOD Reflow(nsIPresContext*          aPresContext,
                  nsHTMLReflowMetrics&     aDesiredSize,
                  const nsHTMLReflowState& aReflowState,
                  nsReflowStatus&          aStatus);

  // Because there can be only one child frame, these two function return
  // NS_ERROR_FAILURE
  NS_IMETHOD AppendFrames(nsIPresContext* aPresContext,
                          nsIPresShell&   aPresShell,
                          nsIAtom*        aListName,
                          nsIFrame*       aFrameList);
  NS_IMETHOD InsertFrames(nsIPresContext* aPresContext,
                          nsIPresShell&   aPresShell,
                          nsIAtom*        aListName,
                          nsIFrame*       aPrevFrame,
                          nsIFrame*       aFrameList);

  NS_IMETHOD Destroy(nsIPresContext* aPresContext);

  // This function returns NS_ERROR_NOT_IMPLEMENTED
  NS_IMETHOD RemoveFrame(nsIPresContext* aPresContext,
                         nsIPresShell&   aPresShell,
                         nsIAtom*        aListName,
                         nsIFrame*       aOldFrame);


  NS_IMETHOD Paint(nsIPresContext*      aPresContext,
                   nsIRenderingContext& aRenderingContext,
                   const nsRect&        aDirtyRect,
                   nsFramePaintLayer    aWhichLayer);

  NS_IMETHOD GetContentAndOffsetsFromPoint(nsIPresContext* aCX,
                                           const nsPoint&  aPoint,
                                           nsIContent **   aNewContent,
                                           PRInt32&        aContentOffset,
                                           PRInt32&        aContentOffsetEnd,
                                           PRBool&         aBeginFrameContent);

  // nsIAnonymousContentCreator
  NS_IMETHOD CreateAnonymousContent(nsIPresContext* aPresContext,
                                    nsISupportsArray& aAnonymousItems);
  NS_IMETHOD CreateFrameFor(nsIPresContext*   aPresContext,
                            nsIContent *      aContent,
                            nsIFrame**        aFrame) { if (aFrame) *aFrame = nsnull; return NS_ERROR_FAILURE; }

  // nsIBox methods
  NS_DECL_ISUPPORTS

  NS_IMETHOD GetPrefSize(nsBoxLayoutState& aBoxLayoutState, nsSize& aSize);
  NS_IMETHOD GetMinSize(nsBoxLayoutState& aBoxLayoutState, nsSize& aSize);
  NS_IMETHOD GetMaxSize(nsBoxLayoutState& aBoxLayoutState, nsSize& aSize);
  NS_IMETHOD Layout(nsBoxLayoutState& aBoxLayoutState);
  NS_IMETHOD GetPadding(nsMargin& aPadding);

  // nsIScrollableFrame
  NS_IMETHOD  SetScrolledFrame(nsIPresContext* aPresContext, nsIFrame *aScrolledFrame);
  NS_IMETHOD  GetScrolledFrame(nsIPresContext* aPresContext, nsIFrame *&aScrolledFrame) const;
  NS_IMETHOD  GetScrollbarVisibility(nsIPresContext* aPresContext,
                                     PRBool *aVerticalVisible,
                                     PRBool *aHorizontalVisible) const;
  NS_IMETHOD GetClipSize(nsIPresContext* aPresContext, 
                         nscoord *aWidth, 
                         nscoord *aHeight) const;
  /**
   * Get the "type" of the frame
   *
   * @see nsLayoutAtoms::scrollFrame
   */
  NS_IMETHOD GetFrameType(nsIAtom** aType) const;
  
#ifdef NS_DEBUG
  NS_IMETHOD GetFrameName(nsString& aResult) const;
#endif

  virtual nsresult GetContentOf(nsIContent** aContent);

protected:
  nsGfxScrollFrame(nsIPresShell* aShell, nsIDocument* aDocument, PRBool aIsRoot);
  virtual PRIntn GetSkipSides() const;

private:
  friend class nsGfxScrollFrameInner;
  nsGfxScrollFrameInner* mInner;
  nsIPresContext*        mPresContext;  // weak reference
};

#endif /* nsScrollFrame_h___ */