/*

 * Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies)

 * Copyright (C) 2009 Antonio Gomes <tonikitoo@webkit.org>

 *

 * 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 SpatialNavigation_h

#define SpatialNavigation_h

#include "FocusDirection.h"

#include "Node.h"

#include <limits>

namespace WebCore {

class Element;

class Frame;

class IntRect;

class RenderObject;

using namespace std;

inline long long maxDistance()

{

    return numeric_limits<long long>::max();

}

inline int fudgeFactor()

{

    return 2;

}

// Spatially speaking, two given elements in a web page can be:

// 1) Fully aligned: There is a full intersection between the rects, either

//    vertically or horizontally.

//

// * Horizontally       * Vertically

//    _

//   |_|                   _ _ _ _ _ _

//   |_|...... _          |_|_|_|_|_|_|

//   |_|      |_|         .       .

//   |_|......|_|   OR    .       .

//   |_|      |_|         .       .

//   |_|......|_|          _ _ _ _

//   |_|                  |_|_|_|_|

//

//

// 2) Partially aligned: There is a partial intersection between the rects, either

//    vertically or horizontally.

//

// * Horizontally       * Vertically

//    _                   _ _ _ _ _

//   |_|                 |_|_|_|_|_|

//   |_|.... _      OR           . .

//   |_|    |_|                  . .

//   |_|....|_|                  ._._ _

//          |_|                  |_|_|_|

//          |_|

//

// 3) Or, otherwise, not aligned at all.

//

// * Horizontally       * Vertically

//         _              _ _ _ _

//        |_|            |_|_|_|_|

//        |_|                    .

//        |_|                     .

//       .          OR             .

//    _ .                           ._ _ _ _ _

//   |_|                            |_|_|_|_|_|

//   |_|

//   |_|

//

// "Totally Aligned" elements are preferable candidates to move

// focus to over "Partially Aligned" ones, that on its turns are

// more preferable than "Not Aligned".

enum RectsAlignment {

    None = 0,

    Partial,

    Full

};

struct FocusCandidate {

    FocusCandidate()

        : node(0)

        , enclosingScrollableBox(0)

        , distance(maxDistance())

        , parentDistance(maxDistance())

        , alignment(None)

        , parentAlignment(None)

    {

    }

    FocusCandidate(Node* n)

        : node(n)

        , enclosingScrollableBox(0)

        , distance(maxDistance())

        , parentDistance(maxDistance())

        , alignment(None)

        , parentAlignment(None)

    {

    }

    bool isNull() const { return !node; }

    bool inScrollableContainer() const { return node && enclosingScrollableBox; }

    Document* document() const { return node ? node->document() : 0; }

    Node* node;

    Node* enclosingScrollableBox;

    long long distance;

    long long parentDistance;

    RectsAlignment alignment;

    RectsAlignment parentAlignment;

};

void distanceDataForNode(FocusDirection direction, Node* start, FocusCandidate& candidate);

bool scrollInDirection(Frame*, FocusDirection, const FocusCandidate& candidate = FocusCandidate());

void scrollIntoView(Element*);

bool hasOffscreenRect(Node*);

bool isInRootDocument(Node*);

bool isScrollableContainerNode(Node*);

bool isNodeDeepDescendantOfDocument(Node*, Document*);

} // namspace WebCore

#endif // SpatialNavigation_h