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#include "qlibinputtouch_p.h"
#include <libinput.h>
#include <QtGui/QGuiApplication>
#include <QtGui/QScreen>

QT_BEGIN_NAMESPACE

QWindowSystemInterface::TouchPoint *QLibInputTouch::DeviceState::point(int32_t slot)
{
    const int id = qMax(0, slot);

    for (int i = 0; i < m_points.count(); ++i)
        if (m_points.at(i).id == id)
            return &m_points[i];

    return Q_NULLPTR;
}

QLibInputTouch::DeviceState *QLibInputTouch::deviceState(libinput_event_touch *e)
{
    libinput_device *dev = libinput_event_get_device(libinput_event_touch_get_base_event(e));
    return &m_devState[dev];
}

static inline QPointF getPos(libinput_event_touch *e)
{
    const QSize screenSize = QGuiApplication::primaryScreen()->geometry().size();
    const double x = libinput_event_touch_get_x_transformed(e, screenSize.width());
    const double y = libinput_event_touch_get_y_transformed(e, screenSize.height());
    return QPointF(x, y);
}

void QLibInputTouch::registerDevice(libinput_device *dev)
{
    QTouchDevice *&td = m_devState[dev].m_touchDevice;
    td = new QTouchDevice;
    td->setName(QString::fromUtf8(libinput_device_get_name(dev)));
    td->setType(QTouchDevice::TouchScreen);
    td->setCapabilities(QTouchDevice::Position | QTouchDevice::Area);
    QWindowSystemInterface::registerTouchDevice(td);
}

void QLibInputTouch::unregisterDevice(libinput_device *dev)
{
    Q_UNUSED(dev);
    // There is no way to remove a QTouchDevice.
}

void QLibInputTouch::processTouchDown(libinput_event_touch *e)
{
    int slot = libinput_event_touch_get_slot(e);
    DeviceState *state = deviceState(e);
    QWindowSystemInterface::TouchPoint *tp = state->point(slot);
    if (tp) {
        qWarning("Incorrect touch state");
    } else {
        QWindowSystemInterface::TouchPoint newTp;
        newTp.id = qMax(0, slot);
        newTp.state = Qt::TouchPointPressed;
        newTp.area = QRect(0, 0, 8, 8);
        newTp.area.moveCenter(getPos(e));
        state->m_points.append(newTp);
    }
}

void QLibInputTouch::processTouchMotion(libinput_event_touch *e)
{
    int slot = libinput_event_touch_get_slot(e);
    DeviceState *state = deviceState(e);
    QWindowSystemInterface::TouchPoint *tp = state->point(slot);
    if (tp) {
        const QPointF p = getPos(e);
        if (tp->area.center() != p) {
            tp->area.moveCenter(p);
            // 'down' may be followed by 'motion' within the same "frame".
            // Handle this by compressing and keeping the Pressed state until the 'frame'.
            if (tp->state != Qt::TouchPointPressed)
                tp->state = Qt::TouchPointMoved;
        } else {
            tp->state = Qt::TouchPointStationary;
        }
    } else {
        qWarning("Inconsistent touch state (got 'motion' without 'down')");
    }
}

void QLibInputTouch::processTouchUp(libinput_event_touch *e)
{
    int slot = libinput_event_touch_get_slot(e);
    DeviceState *state = deviceState(e);
    QWindowSystemInterface::TouchPoint *tp = state->point(slot);
    if (tp) {
        tp->state = Qt::TouchPointReleased;
        // There may not be a Frame event after the last Up. Work this around.
        Qt::TouchPointStates s = 0;
        for (int i = 0; i < state->m_points.count(); ++i)
            s |= state->m_points.at(i).state;
        if (s == Qt::TouchPointReleased)
            processTouchFrame(e);
    } else {
        qWarning("Inconsistent touch state (got 'up' without 'down')");
    }
}

void QLibInputTouch::processTouchCancel(libinput_event_touch *e)
{
    DeviceState *state = deviceState(e);
    if (state->m_touchDevice)
        QWindowSystemInterface::handleTouchCancelEvent(Q_NULLPTR, state->m_touchDevice, QGuiApplication::keyboardModifiers());
    else
        qWarning("TouchCancel without registered device");
}

void QLibInputTouch::processTouchFrame(libinput_event_touch *e)
{
    DeviceState *state = deviceState(e);
    if (state->m_touchDevice && !state->m_points.isEmpty()) {
        QWindowSystemInterface::handleTouchEvent(Q_NULLPTR, state->m_touchDevice, state->m_points,
                                                 QGuiApplication::keyboardModifiers());
        for (int i = 0; i < state->m_points.count(); ++i) {
            QWindowSystemInterface::TouchPoint &tp(state->m_points[i]);
            if (tp.state == Qt::TouchPointReleased)
                state->m_points.removeAt(i--);
            else if (tp.state == Qt::TouchPointPressed)
                tp.state = Qt::TouchPointStationary;
        }
    } else {
        qWarning("TouchFrame without registered device");
    }
}

QT_END_NAMESPACE