/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//

// nsScrollbarFrame

//

#ifndef nsScrollbarFrame_h__

#define nsScrollbarFrame_h__

#include "mozilla/Attributes.h"

#include "nsIAnonymousContentCreator.h"

#include "nsBoxFrame.h"

class nsIScrollbarMediator;

nsIFrame* NS_NewScrollbarFrame(nsIPresShell* aPresShell,

                               mozilla::ComputedStyle* aStyle);

class nsScrollbarFrame final : public nsBoxFrame,

                               public nsIAnonymousContentCreator

{

public:

  explicit nsScrollbarFrame(ComputedStyle* aStyle)

    : nsBoxFrame(aStyle, kClassID)

    , mIncrement(0)

    , mSmoothScroll(false)

    , mScrollbarMediator(nullptr)

    , mUpTopButton(nullptr)

    , mDownTopButton(nullptr)

    , mSlider(nullptr)

    , mThumb(nullptr)

    , mUpBottomButton(nullptr)

    , mDownBottomButton(nullptr)

  {}

  NS_DECL_QUERYFRAME

  NS_DECL_FRAMEARENA_HELPERS(nsScrollbarFrame)

#ifdef DEBUG_FRAME_DUMP

  virtual nsresult GetFrameName(nsAString& aResult) const override {

    return MakeFrameName(NS_LITERAL_STRING("ScrollbarFrame"), aResult);

  }

#endif

  // nsIFrame overrides

  virtual nsresult AttributeChanged(int32_t aNameSpaceID,

                                    nsAtom* aAttribute,

                                    int32_t aModType) override;

  NS_IMETHOD HandlePress(nsPresContext* aPresContext,

                         mozilla::WidgetGUIEvent* aEvent,

                         nsEventStatus* aEventStatus) override;

  NS_IMETHOD HandleMultiplePress(nsPresContext* aPresContext,

                                 mozilla::WidgetGUIEvent* aEvent,

                                 nsEventStatus* aEventStatus,

                                 bool aControlHeld) override;

  NS_IMETHOD HandleDrag(nsPresContext* aPresContext,

                        mozilla::WidgetGUIEvent* aEvent,

                        nsEventStatus* aEventStatus) override;

  NS_IMETHOD HandleRelease(nsPresContext* aPresContext,

                           mozilla::WidgetGUIEvent* aEvent,

                           nsEventStatus* aEventStatus) override;

  virtual void DestroyFrom(nsIFrame* aDestructRoot, PostDestroyData& aPostDestroyData) override;

  virtual void Init(nsIContent*       aContent,

                    nsContainerFrame* aParent,

                    nsIFrame*         aPrevInFlow) override;

  virtual void Reflow(nsPresContext*           aPresContext,

                      ReflowOutput&     aDesiredSize,

                      const ReflowInput& aReflowInput,

                      nsReflowStatus&          aStatus) override;

  void SetScrollbarMediatorContent(nsIContent* aMediator);

  nsIScrollbarMediator* GetScrollbarMediator();

  // nsBox methods

  /**

   * Treat scrollbars as clipping their children; overflowing children

   * will not be allowed to set an overflow rect on this

   * frame. This means that when the scroll code decides to hide a

   * scrollframe by setting its height or width to zero, that will

   * hide the children too.

   */

  virtual bool DoesClipChildren() override { return true; }

  virtual nsresult GetXULMargin(nsMargin& aMargin) override;

  /**

   * The following three methods set the value of mIncrement when a

   * scrollbar button is pressed.

   */

  void SetIncrementToLine(int32_t aDirection);

  void SetIncrementToPage(int32_t aDirection);

  void SetIncrementToWhole(int32_t aDirection);

  /**

   * MoveToNewPosition() adds mIncrement to the current position and

   * updates the curpos attribute.

   * @returns The new position after clamping, in CSS Pixels

   * @note This method might destroy the frame, pres shell, and other objects.

   */

  int32_t MoveToNewPosition();

  int32_t GetIncrement() { return mIncrement; }

  // nsIAnonymousContentCreator

  virtual nsresult CreateAnonymousContent(nsTArray<ContentInfo>& aElements) override;

  virtual void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,

                                        uint32_t aFilter) override;

  void UpdateChildrenAttributeValue(nsAtom* aAttribute, bool aNotify);

protected:

  int32_t mIncrement; // Amount to scroll, in CSSPixels

  bool mSmoothScroll;

private:

  nsCOMPtr<nsIContent> mScrollbarMediator;

  nsCOMPtr<Element> mUpTopButton;

  nsCOMPtr<Element> mDownTopButton;

  nsCOMPtr<Element> mSlider;

  nsCOMPtr<Element> mThumb;

  nsCOMPtr<Element> mUpBottomButton;

  nsCOMPtr<Element> mDownBottomButton;

}; // class nsScrollbarFrame

#endif