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#include "qstandardgestures_p.h"
#include "qgesture.h"
#include "qgesture_p.h"
#include "qevent.h"
#include "qwidget.h"
#include "qabstractscrollarea.h"

QT_BEGIN_NAMESPACE

QPanGestureRecognizer::QPanGestureRecognizer()
{
}

QGesture *QPanGestureRecognizer::create(QObject *target)
{
    if (target && target->isWidgetType()) {
#if defined(Q_OS_WIN)
        // for scroll areas on Windows we want to use native gestures instead
        if (!qobject_cast<QAbstractScrollArea *>(target->parent()))
            static_cast<QWidget *>(target)->setAttribute(Qt::WA_AcceptTouchEvents);
#else
        static_cast<QWidget *>(target)->setAttribute(Qt::WA_AcceptTouchEvents);
#endif
    }
    return new QPanGesture;
}

QGestureRecognizer::Result QPanGestureRecognizer::recognize(QGesture *state, QObject *, QEvent *event)
{
    QPanGesture *q = static_cast<QPanGesture *>(state);
    QPanGesturePrivate *d = q->d_func();

    const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);

    QGestureRecognizer::Result result;

    switch (event->type()) {
    case QEvent::TouchBegin: {
        result = QGestureRecognizer::MayBeGesture;
        QTouchEvent::TouchPoint p = ev->touchPoints().at(0);
        d->lastOffset = d->offset = QPointF();
        break;
    }
    case QEvent::TouchEnd: {
        if (q->state() != Qt::NoGesture) {
            if (ev->touchPoints().size() == 2) {
                QTouchEvent::TouchPoint p1 = ev->touchPoints().at(0);
                QTouchEvent::TouchPoint p2 = ev->touchPoints().at(1);
                d->lastOffset = d->offset;
                d->offset =
                        QPointF(p1.pos().x() - p1.startPos().x() + p2.pos().x() - p2.startPos().x(),
                              p1.pos().y() - p1.startPos().y() + p2.pos().y() - p2.startPos().y()) / 2;
            }
            result = QGestureRecognizer::FinishGesture;
        } else {
            result = QGestureRecognizer::CancelGesture;
        }
        break;
    }
    case QEvent::TouchUpdate: {
        if (ev->touchPoints().size() >= 2) {
            QTouchEvent::TouchPoint p1 = ev->touchPoints().at(0);
            QTouchEvent::TouchPoint p2 = ev->touchPoints().at(1);
            d->lastOffset = d->offset;
            d->offset =
                    QPointF(p1.pos().x() - p1.startPos().x() + p2.pos().x() - p2.startPos().x(),
                          p1.pos().y() - p1.startPos().y() + p2.pos().y() - p2.startPos().y()) / 2;
            if (d->offset.x() > 10  || d->offset.y() > 10 ||
                d->offset.x() < -10 || d->offset.y() < -10) {
                result = QGestureRecognizer::TriggerGesture;
            } else {
                result = QGestureRecognizer::MayBeGesture;
            }
        }
        break;
    }
    case QEvent::MouseButtonPress:
    case QEvent::MouseMove:
    case QEvent::MouseButtonRelease:
        result = QGestureRecognizer::Ignore;
        break;
    default:
        result = QGestureRecognizer::Ignore;
        break;
    }
    return result;
}

void QPanGestureRecognizer::reset(QGesture *state)
{
    QPanGesture *pan = static_cast<QPanGesture*>(state);
    QPanGesturePrivate *d = pan->d_func();

    d->lastOffset = d->offset = QPointF();
    d->acceleration = 0;

    QGestureRecognizer::reset(state);
}


//
// QPinchGestureRecognizer
//

QPinchGestureRecognizer::QPinchGestureRecognizer()
{
}

QGesture *QPinchGestureRecognizer::create(QObject *target)
{
    if (target && target->isWidgetType()) {
        static_cast<QWidget *>(target)->setAttribute(Qt::WA_AcceptTouchEvents);
    }
    return new QPinchGesture;
}

QGestureRecognizer::Result QPinchGestureRecognizer::recognize(QGesture *state, QObject *, QEvent *event)
{
    QPinchGesture *q = static_cast<QPinchGesture *>(state);
    QPinchGesturePrivate *d = q->d_func();

    const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);

    QGestureRecognizer::Result result;

    switch (event->type()) {
    case QEvent::TouchBegin: {
        result = QGestureRecognizer::MayBeGesture;
        break;
    }
    case QEvent::TouchEnd: {
        if (q->state() != Qt::NoGesture) {
            result = QGestureRecognizer::FinishGesture;
        } else {
            result = QGestureRecognizer::CancelGesture;
        }
        break;
    }
    case QEvent::TouchUpdate: {
        d->changeFlags = 0;
        if (ev->touchPoints().size() == 2) {
            QTouchEvent::TouchPoint p1 = ev->touchPoints().at(0);
            QTouchEvent::TouchPoint p2 = ev->touchPoints().at(1);

            d->hotSpot = p1.screenPos();
            d->isHotSpotSet = true;

            if (d->isNewSequence) {
                d->startPosition[0] = p1.screenPos();
                d->startPosition[1] = p2.screenPos();
            }
            QLineF line(p1.screenPos(), p2.screenPos());
            QLineF tmp(line);
            tmp.setLength(line.length() / 2.);
            QPointF centerPoint = tmp.p2();

            d->lastCenterPoint = d->centerPoint;
            d->centerPoint = centerPoint;
            d->changeFlags |= QPinchGesture::CenterPointChanged;

            const qreal scaleFactor = QLineF(p1.pos(), p2.pos()).length()
                                      / QLineF(d->startPosition[0],  d->startPosition[1]).length();
            if (d->isNewSequence) {
                d->lastScaleFactor = scaleFactor;
            } else {
                d->lastScaleFactor = d->scaleFactor;
            }
            d->scaleFactor = scaleFactor;
            d->totalScaleFactor += d->scaleFactor - d->lastScaleFactor;
            d->changeFlags |= QPinchGesture::ScaleFactorChanged;

            const qreal rotationAngle = -line.angle();
            if (d->isNewSequence)
                d->lastRotationAngle = rotationAngle;
            else
                d->lastRotationAngle = d->rotationAngle;
            d->rotationAngle = rotationAngle;
            d->totalRotationAngle += d->rotationAngle - d->lastRotationAngle;
            d->changeFlags |= QPinchGesture::RotationAngleChanged;

            d->totalChangeFlags |= d->changeFlags;
            d->isNewSequence = false;
            result = QGestureRecognizer::TriggerGesture;
        } else {
            d->isNewSequence = true;
            result = QGestureRecognizer::MayBeGesture;
        }
        break;
    }
    case QEvent::MouseButtonPress:
    case QEvent::MouseMove:
    case QEvent::MouseButtonRelease:
        result = QGestureRecognizer::Ignore;
        break;
    default:
        result = QGestureRecognizer::Ignore;
        break;
    }
    return result;
}

void QPinchGestureRecognizer::reset(QGesture *state)
{
    QPinchGesture *pinch = static_cast<QPinchGesture *>(state);
    QPinchGesturePrivate *d = pinch->d_func();

    d->totalChangeFlags = d->changeFlags = 0;

    d->startCenterPoint = d->lastCenterPoint = d->centerPoint = QPointF();
    d->totalScaleFactor = d->lastScaleFactor = d->scaleFactor = 0;
    d->totalRotationAngle = d->lastRotationAngle = d->rotationAngle = 0;

    d->isNewSequence = true;

    QGestureRecognizer::reset(state);
}

QT_END_NAMESPACE