/*
 * Copyright (C) 2006 Apple Computer, Inc.
 * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
*/

#ifndef HitTestResult_h
#define HitTestResult_h

#include "core/CoreExport.h"
#include "core/editing/PositionWithAffinity.h"
#include "core/layout/HitTestLocation.h"
#include "core/layout/HitTestRequest.h"
#include "platform/geometry/FloatQuad.h"
#include "platform/geometry/FloatRect.h"
#include "platform/heap/Handle.h"
#include "platform/text/TextDirection.h"
#include "wtf/Forward.h"
#include "wtf/ListHashSet.h"
#include "wtf/VectorTraits.h"

namespace blink {

class Element;
class LocalFrame;
class HTMLAreaElement;
class HTMLMediaElement;
class Image;
class KURL;
class Node;
class LayoutObject;
class Region;
class Scrollbar;

// List-based hit test testing can continue even after a hit has been found.
// This is used to support fuzzy matching with rect-based hit tests as well as
// penetrating tests which collect all nodes (see: HitTestRequest::RequestType).
enum ListBasedHitTestBehavior { ContinueHitTesting, StopHitTesting };

class CORE_EXPORT HitTestResult {
  DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();

 public:
  typedef HeapListHashSet<Member<Node>> NodeSet;

  HitTestResult();
  HitTestResult(const HitTestRequest&, const LayoutPoint&);
  // Pass positive padding values to perform a rect-based hit test.
  HitTestResult(const HitTestRequest&,
                const LayoutPoint& centerPoint,
                unsigned topPadding,
                unsigned rightPadding,
                unsigned bottomPadding,
                unsigned leftPadding);
  HitTestResult(const HitTestRequest&, const HitTestLocation&);
  HitTestResult(const HitTestResult&);
  ~HitTestResult();
  HitTestResult& operator=(const HitTestResult&);
  DECLARE_TRACE();

  bool equalForCacheability(const HitTestResult&) const;
  void cacheValues(const HitTestResult&);

  // Populate this object based on another HitTestResult; similar to assignment
  // operator but don't assign any of the request parameters. ie. This method
  // avoids setting |m_hitTestLocation|, |m_hitTestRequest|.
  void populateFromCachedResult(const HitTestResult&);

  // For point-based hit tests, these accessors provide information about the
  // node under the point. For rect-based hit tests they are meaningless
  // (reflect the last candidate node observed in the rect).
  // FIXME: Make these less error-prone for rect-based hit tests (center point
  // or fail).
  Node* innerNode() const { return m_innerNode.get(); }
  Node* innerPossiblyPseudoNode() const {
    return m_innerPossiblyPseudoNode.get();
  }
  Element* innerElement() const;

  // If innerNode is an image map or image map area, return the associated image
  // node.
  Node* innerNodeOrImageMapImage() const;

  Element* URLElement() const { return m_innerURLElement.get(); }
  Scrollbar* scrollbar() const { return m_scrollbar.get(); }
  bool isOverWidget() const { return m_isOverWidget; }

  // Forwarded from HitTestLocation
  bool isRectBasedTest() const { return m_hitTestLocation.isRectBasedTest(); }

  // The hit-tested point in the coordinates of the main frame.
  const LayoutPoint& pointInMainFrame() const {
    return m_hitTestLocation.point();
  }
  IntPoint roundedPointInMainFrame() const {
    return roundedIntPoint(pointInMainFrame());
  }

  // The hit-tested point in the coordinates of the innerNode frame, the frame
  // containing innerNode.
  const LayoutPoint& pointInInnerNodeFrame() const {
    return m_pointInInnerNodeFrame;
  }
  IntPoint roundedPointInInnerNodeFrame() const {
    return roundedIntPoint(pointInInnerNodeFrame());
  }
  LocalFrame* innerNodeFrame() const;

  // The hit-tested point in the coordinates of the inner node.
  const LayoutPoint& localPoint() const { return m_localPoint; }
  void setNodeAndPosition(Node* node, const LayoutPoint& p) {
    m_localPoint = p;
    setInnerNode(node);
  }

  PositionWithAffinity position() const;
  LayoutObject* layoutObject() const;

  void setToShadowHostIfInUserAgentShadowRoot();

  const HitTestLocation& hitTestLocation() const { return m_hitTestLocation; }
  const HitTestRequest& hitTestRequest() const { return m_hitTestRequest; }

  void setInnerNode(Node*);
  HTMLAreaElement* imageAreaForImage() const;
  void setURLElement(Element*);
  void setScrollbar(Scrollbar*);
  void setIsOverWidget(bool b) { m_isOverWidget = b; }

  bool isSelected() const;
  String title(TextDirection&) const;
  const AtomicString& altDisplayString() const;
  Image* image() const;
  IntRect imageRect() const;
  KURL absoluteImageURL() const;
  KURL absoluteMediaURL() const;
  KURL absoluteLinkURL() const;
  String textContent() const;
  bool isLiveLink() const;
  bool isContentEditable() const;

  bool isOverLink() const;

  bool isCacheable() const { return m_cacheable; }
  void setCacheable(bool cacheable) { m_cacheable = cacheable; }

  // TODO(pdr): When using the default rect argument, this function does not
  // check if the tapped area is entirely contained by the HitTestLocation's
  // bounding box. Callers should pass a LayoutRect as the third parameter so
  // hit testing can early-out when a tapped area is covered.
  ListBasedHitTestBehavior addNodeToListBasedTestResult(
      Node*,
      const HitTestLocation&,
      const LayoutRect& = LayoutRect());
  ListBasedHitTestBehavior addNodeToListBasedTestResult(Node*,
                                                        const HitTestLocation&,
                                                        const Region&);

  void append(const HitTestResult&);

  // If m_listBasedTestResult is 0 then set it to a new NodeSet. Return
  // *m_listBasedTestResult. Lazy allocation makes sense because the NodeSet is
  // seldom necessary, and it's somewhat expensive to allocate and initialize.
  // This method does the same thing as mutableListBasedTestResult(), but here
  // the return value is const.
  const NodeSet& listBasedTestResult() const;

  // Collapse the rect-based test result into a single target at the specified
  // location.
  void resolveRectBasedTest(Node* resolvedInnerNode,
                            const LayoutPoint& resolvedPointInMainFrame);

 private:
  NodeSet& mutableListBasedTestResult();  // See above.
  HTMLMediaElement* mediaElement() const;

  HitTestLocation m_hitTestLocation;
  HitTestRequest m_hitTestRequest;
  bool m_cacheable;

  Member<Node> m_innerNode;
  Member<Node> m_innerPossiblyPseudoNode;
  // FIXME: Nothing changes this to a value different from m_hitTestLocation!
  LayoutPoint m_pointInInnerNodeFrame;  // The hit-tested point in innerNode
                                        // frame coordinates.
  LayoutPoint m_localPoint;  // A point in the local coordinate space of
                             // m_innerNode's layoutObject.Allows us to
                             // efficiently determine where inside the
                             // layoutObject we hit on subsequent operations.
  Member<Element> m_innerURLElement;
  Member<Scrollbar> m_scrollbar;
  bool m_isOverWidget;  // Returns true if we are over a widget (and not in the
                        // border/padding area of a LayoutPart for example).

  mutable Member<NodeSet> m_listBasedTestResult;
};

}  // namespace blink

WTF_ALLOW_CLEAR_UNUSED_SLOTS_WITH_MEM_FUNCTIONS(blink::HitTestResult);

#endif  // HitTestResult_h