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


#include "qtwistsensorgesturerecognizer.h"

#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

#define RADIANS_TO_DEGREES 57.2957795

QTwistSensorGestureRecognizer::QTwistSensorGestureRecognizer(QObject *parent) :
    QSensorGestureRecognizer(parent),
    accelRange(0), lastRoll(0), active(0), pitch(0), detecting(0), lastDegree(0),
    lastX(0), lastY(0), lastZ()
{
}

QTwistSensorGestureRecognizer::~QTwistSensorGestureRecognizer()
{
}

void QTwistSensorGestureRecognizer::create()
{
    accel = new QAccelerometer(this);
    accel->connectToBackend();
    accel->setDataRate(5);
    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(500);

}

QString QTwistSensorGestureRecognizer::id() const
{
    return QString("QtSensors.twist");
}

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

bool QTwistSensorGestureRecognizer::stop()
{
    accel->stop();
    disconnect(accel,SIGNAL(readingChanged()),this,SLOT(accelChanged()));

    active = accel->isActive();
    orientation->stop();
    return !active;
}

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

#define RESTING_VARIANCE 25
#define THRESHOLD_DEGREES 60

void QTwistSensorGestureRecognizer::accelChanged()
{
    qreal x = accel->reading()->x();
    qreal y = accel->reading()->y();
    qreal z = accel->reading()->z();

    qreal diffX = lastX - x;
    qreal diffY = lastY - y;
    pitch = qAtan(y / qSqrt(x*x + z*z)) * RADIANS_TO_DEGREES;

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

    if (rollList.count() > 4) {
        if (detecting
                && isShake()) {
            // if shake-like:
            detecting = false;
            timer->stop();
            lastRoll = degrees;
        }
        if (detecting
                && qAbs(degrees) < RESTING_VARIANCE
                && qAbs(pitch) < RESTING_VARIANCE
                && (qAbs(lastRoll + degrees) > (degrees / 2))
                ) {
            if (lastRoll > 0 ) {
                Q_EMIT twistLeft();
                Q_EMIT detected("twistLeft");
            } else {
                Q_EMIT twistRight();
                Q_EMIT detected("twistRight");
            }
            // don't give two signals for same gestures
                detecting = false;
                timer->stop();
                lastRoll = degrees;
        }

        if (!detecting && qAbs(degrees) > THRESHOLD_DEGREES
                && pitch < RESTING_VARIANCE) {

            detecting = true;
            timer->start();
            lastRoll = degrees;
            lastOrientation = orientation->reading()->orientation();
        }

        if (detecting && (orientation->reading()->orientation() == QOrientationReading::TopUp
                || orientation->reading()->orientation() == QOrientationReading::TopDown)) {

            detecting = false;
            timer->stop();
            lastRoll = degrees;
        }
    }

    if (negativeList.count() > 5)
        negativeList.removeLast();

    if ((((x < 0 && lastX > 0) || (x > 0 && lastX < 0)) && qAbs(diffX) > (accelRange * 0.5))
            || (((y < 0 && lastY > 0) || (y > 0 && lastY < 0)) && qAbs(diffY) > (accelRange * 0.5))) {
        negativeList.insert(0,true);
    } else {
        negativeList.insert(0,false);
    }

    if (rollList.count() > 5)
        rollList.removeLast();
    rollList.insert(0,degrees);
    lastDegree = degrees;
    lastX = x; lastY = y;
}

void QTwistSensorGestureRecognizer::timeout()
{
    detecting = false;
    lastRoll = 0;
    lastOrientation = QOrientationReading::Undefined;
}

bool QTwistSensorGestureRecognizer::isShake()
{
    for (int i = 0; i < negativeList.count() - 1; i++) {
        if (negativeList.at(i)) {
            return true;
        }
    }
    return false;
}



QT_END_NAMESPACE