/*
 * Copyright (C) 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include <WebCore/IntPoint.h>
#include <WebCore/Timer.h>
#include <wtf/CheckedPtr.h>
#include <wtf/TZoneMalloc.h>
#include <wtf/WallTime.h>

namespace WebCore {

class EventHandler;
class LocalFrame;
class LocalFrameView;
class Node;
class PlatformMouseEvent;
class RenderBox;
class RenderObject;

enum class AutoscrollType : uint8_t {
    None,
    DragAndDrop,
    Selection,
#if ENABLE(PAN_SCROLLING)
    PanCanStop,
    Pan,
#endif
};

// When the autoscroll or the panScroll is triggered when do the scroll every 50ms to make it smooth.
constexpr Seconds autoscrollInterval { 50_ms };

// AutscrollController handles autoscroll and pan scroll for EventHandler.
class AutoscrollController final : public CanMakeCheckedPtr<AutoscrollController> {
    WTF_MAKE_TZONE_ALLOCATED(AutoscrollController);
    WTF_OVERRIDE_DELETE_FOR_CHECKED_PTR(AutoscrollController);
public:
    AutoscrollController();
    RenderBox* autoscrollRenderer() const;
    bool autoscrollInProgress() const;
    bool panScrollInProgress() const;
    void startAutoscrollForSelection(RenderObject*);
    void stopAutoscrollTimer(bool rendererIsBeingDestroyed = false);
    void updateAutoscrollRenderer();
    void updateDragAndDrop(Node* targetNode, const IntPoint& eventPosition, WallTime eventTime);
#if ENABLE(PAN_SCROLLING)
    void didPanScrollStart();
    void didPanScrollStop();
    void handleMouseReleaseEvent(const PlatformMouseEvent&);
    void setPanScrollInProgress(bool);
    void startPanScrolling(RenderBox&, const IntPoint&);
#endif

private:
    void autoscrollTimerFired();
    void startAutoscrollTimer();
#if ENABLE(PAN_SCROLLING)
    void updatePanScrollState(LocalFrameView*, const IntPoint&);
#endif

    Timer m_autoscrollTimer;
    SingleThreadWeakPtr<RenderBox> m_autoscrollRenderer;
    AutoscrollType m_autoscrollType { AutoscrollType::None };
    IntPoint m_dragAndDropAutoscrollReferencePosition;
    WallTime m_dragAndDropAutoscrollStartTime;
#if ENABLE(PAN_SCROLLING)
    IntPoint m_panScrollStartPos;
#endif
};

} // namespace WebCore
