/*

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

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: Container for pan (drag) gesture -related data and logic.

*

*/

#include "hgdrag.h"

#include "trace.h"

HgDrag::HgDrag()

{

}

void HgDrag::reset(const qreal delta, const qreal viewPos)

{

    mViewPosAtStart = viewPos;

    mDuration.start();

    mLength = 0;

    mCumulatedDelta = 0;

    mDirection = delta;

    mDirectionChange = 0;

    INFO("Drag reset at view pos:" << mViewPosAtStart);

}

qreal HgDrag::update(const qreal delta, const qreal viewPos, const qreal itemWidth)

{

//    INFO("delta:" << delta << ", direction:" << mDirection);

    if ((delta > 0 && mDirection < 0) || (delta < 0 && mDirection > 0))

    {

        if (mDirectionChange > 2)

        {

            mDirectionChange = 0;

            reset(delta, viewPos);

        }

        else

        {

            mDirectionChange++;

        }

    }

    else

    {

        mDirection = delta;

        mDirectionChange = 0;

    }

    mCumulatedDelta = (mCumulatedDelta+delta)/2;

    mLength += delta/itemWidth;

    qreal pos = mViewPosAtStart-mLength;

//  INFO("Drag len:" << mLength << ", new pos:" << pos);

    return pos;

}

bool HgDrag::finish(const qreal viewPos, bool stopToFullItem, qreal &newPos)

{

    int dt = mDuration.elapsed();

    if (dt > 10)

    {

        qreal t = (qreal)dt/1000;

        INFO("Drag len:" << mLength << ", duration:" << t << ", cumulated:" << mCumulatedDelta);

        if (qAbs(mCumulatedDelta) > 4)

        {

            newPos = viewPos-mLength/t * 0.5f;

        }

        else

        {

            newPos = mViewPosAtStart-mLength;

        }

        if (stopToFullItem)

        {

            qreal i = floorf(newPos);

            newPos = (newPos - i > 0.5f) ? ceilf(newPos) : i;

        }

        return true;

    }

    return false;

}

qreal HgDrag::viewPosAtStart() const

{

    return mViewPosAtStart;

}