/****************************************************************************
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** This file is part of the QtSensors module of the Qt Toolkit.
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****************************************************************************/


#include "qwhipsensorgesturerecognizer.h"

#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

QWhipSensorGestureRecognizer::QWhipSensorGestureRecognizer(QObject *parent) :
    QSensorGestureRecognizer(parent), whipIt(0), lastX(0),
    detectedX(0)
{
}

QWhipSensorGestureRecognizer::~QWhipSensorGestureRecognizer()
{
}

void QWhipSensorGestureRecognizer::create()
{
    accel = new QAccelerometer(this);
    accel->connectToBackend();

    orientation = new QOrientationSensor(this);
    orientation->connectToBackend();

    timer = new QTimer(this);

    qoutputrangelist outputranges = accel->outputRanges();

    if (outputranges.count() > 0)
        accelRange = (int)(outputranges.at(0).maximum);
    else
        accelRange = 44; //this should never happen

    connect(timer,SIGNAL(timeout()),this,SLOT(timeout()));
    timer->setSingleShot(true);
    timer->setInterval(750);

}

QString QWhipSensorGestureRecognizer::id() const
{
    return QString("QtSensors.whip");
}

bool QWhipSensorGestureRecognizer::start()
{
    connect(accel,SIGNAL(readingChanged()),this,SLOT(accelChanged()));
    active = accel->start();
    orientation->start();
    return active;
}

bool QWhipSensorGestureRecognizer::stop()
{
    accel->stop();
    active = accel->isActive();
    orientation->stop();
    disconnect(accel,SIGNAL(readingChanged()),this,SLOT(accelChanged()));
    return !active;
}

bool QWhipSensorGestureRecognizer::isActive()
{
    return active;
}

#define WHIP_THRESHOLD_FACTOR 0.85 //37
#define WHIP_DETECTION_FACTOR 0.3 // 11.7

#define WHIP_DEGREES 25

#define WHIP_Y_DEGREES 15
#define WHIP_DEGREES_BELOW

#define RADIANS_TO_DEGREES 57.2957795


void QWhipSensorGestureRecognizer::accelChanged()
{
    qreal x = accel->reading()->x();
    qreal difference = lastX - x;
    if (qAbs(difference) < 1)
        return;

    qreal y = accel->reading()->y();
    qreal z = accel->reading()->z();

    qreal roll = qAtan(x / qSqrt(y*y + z*z)) * RADIANS_TO_DEGREES;

    QOrientationReading::Orientation currentOrientation = orientation->reading()->orientation();

    if (whipIt) {

        if (currentOrientation == QOrientationReading::TopUp
                &&  roll > WHIP_Y_DEGREES
                && ((!wasNegative && qAbs(detectedX - x) > accelRange * WHIP_THRESHOLD_FACTOR)
                    || (wasNegative && detectedX - x > (accelRange * WHIP_THRESHOLD_FACTOR))) ) {
            Q_EMIT whip();
            Q_EMIT detected("whip");
            whipIt = false;
            timer->stop();
        }
    } else if (!timer->isActive()
               && currentOrientation == QOrientationReading::TopUp
               && roll < -WHIP_Y_DEGREES
               && ((difference > accelRange * WHIP_DETECTION_FACTOR)
                || (difference < -accelRange * WHIP_DETECTION_FACTOR))) {
        detectedX = x;
//        start of gesture
        timer->start();
        whipIt = true;
        if (difference > 0)
            wasNegative = false;
        else
            wasNegative = true;
    }
    lastX = x;
}

void QWhipSensorGestureRecognizer::timeout()
{
    whipIt = false;
}

QT_END_NAMESPACE