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

**

** 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 HbCore 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 "hbpointrecorder_p.h"

#include <QPair>

#include <QTime>

#include <QDebug>

//#define POINT_DEBUG

#ifndef POINT_DEBUG

# define DEBUG if (0) qDebug

#else

# define DEBUG qDebug

#endif

/*!

   @hbcore

   \internal

   \class HbPointRecorder

   \brief Class to store and hold list of points and timestamps.

*/

/*!

    \internal

    \brief Constructor for HbPointRecorder

    \return

*/

HbPointRecorder::HbPointRecorder()

    :

    mThreshold(0)

{

}

/*!

    \internal

    \brief Destructor for HbPointRecorder

    \return

*/

HbPointRecorder::~HbPointRecorder()

{

}

/*!

    \internal

    \brief Clears all data from the recorder

    \param threshold set used threshold to detect movement and stops

*/

void HbPointRecorder::resetRecorder(qreal threshold)

{

    mThreshold = threshold;

    clear();

}

/*!

    \internal

    \brief Records point to list with timestamp.

    \param point Point to be recorded.

    \param time Time to be recorded.

    \return Nothing.

*/

void HbPointRecorder::record(qreal point, const QTime &time)

{

    // Empty list always accepts first point without tests.

    if ( !isEmpty() ) {

        // No point to record a point, if timestamp is less or equal with previous.

        if ( lastTime().msecsTo(time) == 0 ) {

            DEBUG() << "Ignoring point, because no difference in time stamps.";

            return;

        }

        // Don't tolerate points, which are too close to previously recorded point.

        if ( qAbs(lastPoint() - point) < mThreshold ) {

            DEBUG() << "Ignoring point, because it is withing threshold of previous point";

            return;

        }

    }

    // In case the list contains two or more points, direction can be

    // determined. Each new point added needs to be checked for direction

    // change.

    if ( length() > 1 ) {

        // Clear list, on direction change. Leave the last recorded point

        // to the list, as it can be considered as first point for new direction.

        if ( dirChanged( point ) ) {

            HbPointTime temp = last();

            clear();

            append(temp);

        }

    }

    // Finally check, if the position has changed. Don't record point, when no position

    // change.

    if ( isEmpty() || point != lastPoint() ) {

        // Add point and time to list.

        append(HbPointTime(point, time));

    } else {

        DEBUG() << "Ignoring point, because it equals previous.";

    }

}

/*!

    \internal

    \brief

    \return Last recorded point.

*/

qreal HbPointRecorder::lastPoint() const

{

    Q_ASSERT(!isEmpty());

    return last().first;

}

/*!

    \internal

    \brief

    \return Last recorded timestamp.

*/

const QTime& HbPointRecorder::lastTime() const

{

    Q_ASSERT(!isEmpty());

    return last().second;

}

/*!

    \internal

    \brief Checks if new point causes direction change.

    \param point The point suspected cause direction change.

    \return True, when direction changes.

*/

bool HbPointRecorder::dirChanged( qreal point ) const

{

    // Without direction, the direction cannot really change

    if ( length() < 2 ) { return false; }

    qreal pos0 = (*this)[-2].first;

    qreal pos1 = (*this)[-1].first;

    qreal dir0 = pos1 - pos0;

    qreal dir1 = point - pos1;

    // Don't react on movement, when changes happen within threshold

    if ( qAbs(dir1) <= mThreshold ) { return false; }

    // Check for '+' and '-' -signs in directions. Opposite signs means

    // direction change.

    return ( dir0 < 0 && dir1 >= 0 ) || ( dir0 > 0 && dir1 <= 0 );

}

/*!

    \internal

    \brief Operator to access the list.

    Supports negative values, which will define order from the end.

*/

HbPointTime HbPointRecorder::operator[]( int number ) const

{

    // Let's trust, that QList::at() takes care of validity checks.

    if ( number < 0 ) {

        number = count() + number;

    }

    return at(number);

}

/*!

    \internal

    \copydoc HbPointRecorder::getLastRecords

*/

QList<HbPointTime> HbPointRecorder::getLastRecords( int number ) const

{

    QList<HbPointTime> recordings;

    number = number > count() ? count() : number;

    for (int i=count()-number; i < count(); i++) {

        recordings.append((*this)[i]);

    }

    return recordings;

}