/****************************************************************************

**

** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (developer.feedback@nokia.com)

**

** This file is part of the HbWidgets module of the UI Extensions for Mobile.

**

** GNU Lesser General Public License Usage

** This file may be used under the terms of the GNU Lesser General Public

** License version 2.1 as published by the Free Software Foundation and

** appearing in the file LICENSE.LGPL included in the packaging of this file.

** Please review the following information to ensure the GNU Lesser General

** Public License version 2.1 requirements will be met:

** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at developer.feedback@nokia.com.

**

****************************************************************************/

#include "hbtreemodeliterator_p_p.h"

#include "hbabstractitemcontainer_p_p.h"

#include <QAbstractItemModel>

HbTreeModelIteratorPrivate::HbTreeModelIteratorPrivate()

    : HbModelIteratorPrivate(),

    mCachedCount(CachedIndexCount()), mCachedPosition(CachedIndexCount()),

    mItemContainer(0), mUseCache(true)

{

}

HbTreeModelIteratorPrivate::~HbTreeModelIteratorPrivate()

{

}

/*

    Return first visible index belonging to specified parent.

    If parent is collapsed QModelIndex is returned.

*/

QModelIndex HbTreeModelIteratorPrivate::first(const QModelIndex &parent) const

{

    if (mModel) {

        if (!parent.isValid()

            || isExpanded(parent)) {

            return mModel->index(0, 0, parent);

        }

    }

    return QModelIndex();

}

/*

    Return last visible index belonging to specified parent - last child in whole parent branch.

    If parent is collapsed QModelIndex is returned.

*/

QModelIndex HbTreeModelIteratorPrivate::last(const QModelIndex &parent) const

{

    // last(mRootIndex) when mRootIndex is not expanded return invalid index

    if (mModel) {

        if (!parent.isValid()

            || isExpanded(parent)) {

            // parent can be invalid, mModel->index instead of index.child

            QModelIndex index = mModel->index(mModel->rowCount(parent)-1, 0, parent);

            if (index.isValid()) {

                while (isExpanded(index)) {

                    QModelIndex lastChild = mModel->index(mModel->rowCount(index)-1, 0, index);

                    if (!lastChild.isValid()) break;

                    index = lastChild;

                }

            }

            return index;

        }

    }

    return QModelIndex();

}

int HbTreeModelIteratorPrivate::childIndexCount(const QModelIndex &index) const

{

    int itemCount = 0;

    int rowCount = 0;

    if (isExpanded(index)) {

        rowCount = mModel->rowCount(index);

        itemCount += rowCount;

        for (int row = 0; row < rowCount; ++row) {

            itemCount += childIndexCount(mModel->index(row, 0, index));

        }

    }

    return itemCount;

}

void HbTreeModelIteratorPrivate::resetCache()

{

    mCachedCount.count = -1;

    mCachedCount.index = QModelIndex();

    mCachedPosition.count = -1;

    mCachedPosition.index = QModelIndex();

}

int HbTreeModelIteratorPrivate::searchForward(const QModelIndex &index) const

{

    Q_Q(const HbTreeModelIterator);

    int result = mCachedPosition.count;

    QModelIndex startIndex = mCachedPosition.index;

    while (startIndex != index) {

        startIndex = q->nextIndex(startIndex);

        result++;

        if (!startIndex.isValid()) { //end reached, not found

            return -1;

        }

    }

    if (mUseCache) {

        mCachedPosition.count = result;

        mCachedPosition.index = index;

    }

    return result;

}

int HbTreeModelIteratorPrivate::searchBackward(const QModelIndex &index) const

{

    Q_Q(const HbTreeModelIterator);

    int result = mCachedPosition.count;

    QModelIndex startIndex = mCachedPosition.index;

    while (startIndex != index) {

        startIndex = q->previousIndex(startIndex);

        result--;

        if (startIndex == mRootIndex

            || !startIndex.isValid()) { //start reached, not found

            return -1;

        }

    }

    if (mUseCache) {

        mCachedPosition.count = result;

        mCachedPosition.index = index;

    }

    return result;

}

QModelIndexList HbTreeModelIteratorPrivate::createParentChainList(const QModelIndex &index) const

{

    QModelIndex loopIndex = index;

    QModelIndexList indexList;

    indexList.append(loopIndex);

    while (loopIndex != mRootIndex

           && loopIndex.isValid()) {

        loopIndex = loopIndex.parent();

        indexList.prepend(loopIndex);

    }

    return indexList;

}

bool HbTreeModelIteratorPrivate::isExpanded(const QModelIndex &index) const

{

    Q_ASSERT(mItemContainer);

    //if (index == mRootIndex) return true; // must be expanded, otherwise mean empty view

    QVariant flags = mItemContainer->itemTransientState(index).value("expanded");

    if (flags.isValid() && flags.toBool() == true) {

        return true;

    } else {

        return false;

    }

}

bool HbTreeModelIteratorPrivate::isExpandedBranch(const QModelIndex &index) const

{

    if (!index.isValid()) {

        // root index is expanded!

        return (index == mRootIndex);

    }

    QModelIndexList parents = createParentChainList(index);

    if (!parents.isEmpty()

        && !parents.first().isValid()) {

        // returned list contain root, it root is invalid then

        // isExpanded return false for it, so first invalid need to be removed

        parents.removeFirst();

    }

    while (!parents.isEmpty()) {

        if (!isExpanded(parents.first())) {

            return false;

        }

        parents.removeFirst();

    }

    return true;

}