/****************************************************************************
**
** Copyright (C) 2012 Research In Motion
** Contact: http://www.qt-project.org/
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** This file is part of the QtSensors module of the Qt Toolkit.
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
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** file. Please review the following information to ensure the GNU General
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****************************************************************************/
#include "bbrotationsensor.h"

#include "bbutil.h"
#include <QtCore/qmath.h>
#include <QGuiApplication>
#include <QScreen>
#include <qpa/qplatformscreen.h>

BbRotationSensor::BbRotationSensor(QSensor *sensor)
    : BbSensorBackend<QRotationReading>(devicePath(), SENSOR_TYPE_ROTATION_MATRIX, sensor),
      m_orientation(Qt::PrimaryOrientation),
      m_nativeOrientation(Qt::PrimaryOrientation)
{
    updateOrientation();
    setDescription(QLatin1String("Device rotation in degrees"));
}

QString BbRotationSensor::devicePath()
{
    return QLatin1String("/dev/sensor/rotMatrix");
}

void BbRotationSensor::additionalDeviceInit()
{
    addOutputRange(-180, 180, 0 /* ? */);
}

bool BbRotationSensor::addDefaultRange()
{
    // The range we get from the OS service is only -1 to 1, which are the values of the matrix.
    // We need the values of the axes in degrees.
    return false;
}

static float getMatrixElement(const float matrix[3*3], int index0, int index1)
{
    return matrix[index0 * 3 + index1];
}

static void matrixToEulerZXY(const float matrix[3*3],
                             float &thetaX, float &thetaY, float& thetaZ)
{
    thetaX = asin( getMatrixElement(matrix, 2, 1));
    if ( thetaX < M_PI_2 ) {
        if ( thetaX > -M_PI_2 ) {
            thetaZ = atan2( -getMatrixElement(matrix, 0, 1),
                             getMatrixElement(matrix, 1, 1) );
            thetaY = atan2( -getMatrixElement(matrix, 2, 0),
                             getMatrixElement(matrix, 2, 2) );
        } else {
            // Not a unique solution
            thetaZ = -atan2( getMatrixElement(matrix, 0, 2),
                             getMatrixElement(matrix, 0, 0) );
            thetaY = 0.0;
        }
    } else {
        // Not a unique solution
        thetaZ = atan2( getMatrixElement(matrix, 0, 2),
                        getMatrixElement(matrix, 0, 0) );
        thetaY = 0.0;
    }
}

static void remapMatrix(const float inputMatrix[3*3],
                        const float mappingMatrix[4],
                        float outputMatrix[3*3])
{
    int i,j,k;

    for (i = 0; i < 3; i++) {
        for (j = 0; j < 2; j++) { //only goto 2 because last column stays unchanged

            outputMatrix[i*3+j] = 0;

            for (k = 0; k < 2; k++) { //only goto 2 because we know rotation matrix is zero in bottom row
                outputMatrix[i*3+j] += inputMatrix[i*3+k] * mappingMatrix[k*2+j];
            }
        }

        outputMatrix[i*3+2] = inputMatrix[i*3+2];
    }
}


bool BbRotationSensor::updateReadingFromEvent(const sensor_event_t &event, QRotationReading *reading)
{
    // sensor_event_t has euler angles for a Z-Y'-X'' system, but the QtMobility API
    // uses Z-X'-Y''.
    // So extract the euler angles using the Z-X'-Y'' system from the matrix.
    float xRad, yRad, zRad;

    if (isAutoAxisRemappingEnabled() && m_orientation!=m_nativeOrientation) {
        float mappedRotationMatrix[3*3];
        remapMatrix(event.rotation_matrix, m_mappingMatrix, mappedRotationMatrix);
        matrixToEulerZXY(mappedRotationMatrix, xRad, yRad, zRad);
    } else {
        matrixToEulerZXY(event.rotation_matrix, xRad, yRad, zRad);
    }

    reading->setX(radiansToDegrees(xRad));
    reading->setY(radiansToDegrees(yRad));
    reading->setZ(radiansToDegrees(zRad));

    return true;
}

qreal BbRotationSensor::convertValue(float bbValueInRad)
{
    return radiansToDegrees(bbValueInRad);
}

bool BbRotationSensor::isAutoAxisRemappingEnabled() const
{
    return sensor()->property("automaticAxisRemapping").toBool();
}

bool BbRotationSensor::eventFilter(QObject *object, QEvent *event)
{
    if (object == QCoreApplication::instance() && event->type() == QEvent::OrientationChange)
        updateOrientation();

    return BbSensorBackend<QRotationReading>::eventFilter(object, event);
}

void BbRotationSensor::updateOrientation()
{
    QScreen *screen = QGuiApplication::primaryScreen();
    if (screen) {
        const QPlatformScreen * const platformScreen = screen->handle();
        m_nativeOrientation = platformScreen->nativeOrientation();
        m_orientation = screen->orientation();

        const int rotationAngle = screen->angleBetween(m_nativeOrientation, m_orientation);

        m_mappingMatrix[0] = cos(rotationAngle*M_PI/180);
        m_mappingMatrix[1] = sin(rotationAngle*M_PI/180);
        m_mappingMatrix[2] = -sin(rotationAngle*M_PI/180);
        m_mappingMatrix[3] = cos(rotationAngle*M_PI/180);
    }
}