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#include "qquickscrollindicator_p.h"
#include "qquickcontrol_p_p.h"

#include <QtQuick/private/qquickflickable_p.h>
#include <QtQuick/private/qquickitemchangelistener_p.h>

QT_BEGIN_NAMESPACE

/*!
    \qmltype ScrollIndicator
    \inherits Control
    \instantiates QQuickScrollIndicator
    \inqmlmodule Qt.labs.controls
    \ingroup qtlabscontrols-indicators
    \brief A non-interactive scroll indicator control.

    ScrollIndicator is a non-interactive indicator that indicates the current scroll
    position. A scroll indicator can be either \l vertical or \l horizontal, and can
    be attached to any \l Flickable, such as \l ListView and \l GridView.

    \image qtlabscontrols-scrollindicator.png

    \code
    Flickable {
        // ...
        ScrollIndicator.vertical: ScrollIndicator { }
    }
    \endcode

    \note When ScrollIndicator is attached \l {ScrollIndicator::vertical}{vertically}
    or \l {ScrollIndicator::horizontal}{horizontally} to a Flickable, its geometry and
    the following properties are automatically set and updated as appropriate:
    \list
    \li \l orientation
    \li \l position
    \li \l size
    \li \l active
    \endlist

    \sa ScrollBar, {Customizing ScrollIndicator}, {Indicator Controls}
*/

class QQuickScrollIndicatorPrivate : public QQuickControlPrivate
{
public:
    QQuickScrollIndicatorPrivate() : size(0), position(0),
        active(false), orientation(Qt::Vertical), indicator(Q_NULLPTR)
    {
    }

    qreal size;
    qreal position;
    bool active;
    Qt::Orientation orientation;
    QQuickItem *indicator;
};

QQuickScrollIndicator::QQuickScrollIndicator(QQuickItem *parent) :
    QQuickControl(*(new QQuickScrollIndicatorPrivate), parent)
{
}

QQuickScrollIndicatorAttached *QQuickScrollIndicator::qmlAttachedProperties(QObject *object)
{
    QQuickFlickable *flickable = qobject_cast<QQuickFlickable *>(object);
    if (flickable)
        return new QQuickScrollIndicatorAttached(flickable);

    qWarning() << "ScrollIndicator must be attached to a Flickable" << object;
    return Q_NULLPTR;
}

/*!
    \qmlproperty real Qt.labs.controls::ScrollIndicator::size

    This property holds the size of the indicator, scaled to \c {0.0 - 1.0}.

    \sa {Flickable::visibleArea.heightRatio}{Flickable::visibleArea}
*/
qreal QQuickScrollIndicator::size() const
{
    Q_D(const QQuickScrollIndicator);
    return d->size;
}

void QQuickScrollIndicator::setSize(qreal size)
{
    Q_D(QQuickScrollIndicator);
    if (!qFuzzyCompare(d->size, size)) {
        d->size = size;
        emit sizeChanged();
    }
}

/*!
    \qmlproperty real Qt.labs.controls::ScrollIndicator::position

    This property holds the position of the indicator, scaled to \c {0.0 - 1.0}.

    \sa {Flickable::visibleArea.yPosition}{Flickable::visibleArea}
*/
qreal QQuickScrollIndicator::position() const
{
    Q_D(const QQuickScrollIndicator);
    return d->position;
}

void QQuickScrollIndicator::setPosition(qreal position)
{
    Q_D(QQuickScrollIndicator);
    if (!qFuzzyCompare(d->position, position)) {
        d->position = position;
        emit positionChanged();
    }
}

/*!
    \qmlproperty bool Qt.labs.controls::ScrollIndicator::active

    This property holds whether the indicator is active, that is, when the
    attached Flickable is \l {Flickable::moving}{moving}.
*/
bool QQuickScrollIndicator::isActive() const
{
    Q_D(const QQuickScrollIndicator);
    return d->active;
}

void QQuickScrollIndicator::setActive(bool active)
{
    Q_D(QQuickScrollIndicator);
    if (d->active != active) {
        d->active = active;
        emit activeChanged();
    }
}

/*!
    \qmlproperty enumeration Qt.labs.controls::ScrollIndicator::orientation

    This property holds the orientation of the indicator.

    Possible values:
    \value Qt.Horizontal Horizontal
    \value Qt.Vertical Vertical (default)
*/
Qt::Orientation QQuickScrollIndicator::orientation() const
{
    Q_D(const QQuickScrollIndicator);
    return d->orientation;
}

void QQuickScrollIndicator::setOrientation(Qt::Orientation orientation)
{
    Q_D(QQuickScrollIndicator);
    if (d->orientation != orientation) {
        d->orientation = orientation;
        emit orientationChanged();
    }
}

/*!
    \qmlproperty Item Qt.labs.controls::ScrollIndicator::indicator

    This property holds the indicator item.

    \sa {Customizing ScrollIndicator}
*/
QQuickItem *QQuickScrollIndicator::indicator() const
{
    Q_D(const QQuickScrollIndicator);
    return d->indicator;
}

void QQuickScrollIndicator::setIndicator(QQuickItem *indicator)
{
    Q_D(QQuickScrollIndicator);
    if (d->indicator != indicator) {
        delete d->indicator;
        d->indicator = indicator;
        if (indicator && !indicator->parentItem())
            indicator->setParentItem(this);
        emit indicatorChanged();
    }
}

class QQuickScrollIndicatorAttachedPrivate : public QObjectPrivate, public QQuickItemChangeListener
{
public:
    QQuickScrollIndicatorAttachedPrivate(QQuickFlickable *flickable) : flickable(flickable), horizontal(Q_NULLPTR), vertical(Q_NULLPTR) { }

    void activateHorizontal();
    void activateVertical();

    void layoutHorizontal(bool move = true);
    void layoutVertical(bool move = true);

    void itemGeometryChanged(QQuickItem *item, const QRectF &newGeometry, const QRectF &oldGeometry) Q_DECL_OVERRIDE;

    QQuickFlickable *flickable;
    QQuickScrollIndicator *horizontal;
    QQuickScrollIndicator *vertical;
};

void QQuickScrollIndicatorAttachedPrivate::activateHorizontal()
{
    horizontal->setActive(flickable->isMovingHorizontally());
}

void QQuickScrollIndicatorAttachedPrivate::activateVertical()
{
    vertical->setActive(flickable->isMovingVertically());
}

void QQuickScrollIndicatorAttachedPrivate::layoutHorizontal(bool move)
{
    Q_ASSERT(horizontal && flickable);
    horizontal->setWidth(flickable->width());
    if (move)
        horizontal->setY(flickable->height() - horizontal->height());
}

void QQuickScrollIndicatorAttachedPrivate::layoutVertical(bool move)
{
    Q_ASSERT(vertical && flickable);
    vertical->setHeight(flickable->height());
    if (move && !QQuickItemPrivate::get(vertical)->isMirrored())
        vertical->setX(flickable->width() - vertical->width());
}

void QQuickScrollIndicatorAttachedPrivate::itemGeometryChanged(QQuickItem *item, const QRectF &newGeometry, const QRectF &oldGeometry)
{
    Q_UNUSED(item);
    Q_UNUSED(newGeometry);
    if (horizontal && horizontal->height() > 0) {
        bool move = qFuzzyIsNull(horizontal->y()) || qFuzzyCompare(horizontal->y(), oldGeometry.height() - horizontal->height());
        layoutHorizontal(move);
    }
    if (vertical && vertical->width() > 0) {
        bool move = qFuzzyIsNull(vertical->x()) || qFuzzyCompare(vertical->x(), oldGeometry.width() - vertical->width());
        layoutVertical(move);
    }
}

QQuickScrollIndicatorAttached::QQuickScrollIndicatorAttached(QQuickFlickable *flickable) :
    QObject(*(new QQuickScrollIndicatorAttachedPrivate(flickable)), flickable)
{
    Q_D(QQuickScrollIndicatorAttached);
    QQuickItemPrivate *p = QQuickItemPrivate::get(flickable);
    p->updateOrAddGeometryChangeListener(d, QQuickItemPrivate::SizeChange);
}

QQuickScrollIndicatorAttached::~QQuickScrollIndicatorAttached()
{
    Q_D(QQuickScrollIndicatorAttached);
    if (d->horizontal)
        QQuickItemPrivate::get(d->horizontal)->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
    if (d->vertical)
        QQuickItemPrivate::get(d->vertical)->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
}

/*!
    \qmlattachedproperty ScrollIndicator Qt.labs.controls::ScrollIndicator::horizontal

    This property attaches a horizontal scroll indicator to a \l Flickable.

    \code
    Flickable {
        contentWidth: 2000
        ScrollIndicator.horizontal: ScrollIndicator { }
    }
    \endcode
*/
QQuickScrollIndicator *QQuickScrollIndicatorAttached::horizontal() const
{
    Q_D(const QQuickScrollIndicatorAttached);
    return d->horizontal;
}

void QQuickScrollIndicatorAttached::setHorizontal(QQuickScrollIndicator *horizontal)
{
    Q_D(QQuickScrollIndicatorAttached);
    if (d->horizontal != horizontal) {
        if (d->horizontal) {
            QQuickItemPrivate::get(d->horizontal)->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
            QObjectPrivate::disconnect(d->flickable, &QQuickFlickable::movingHorizontallyChanged, d, &QQuickScrollIndicatorAttachedPrivate::activateHorizontal);

            // TODO: export QQuickFlickableVisibleArea
            QObject *area = d->flickable->property("visibleArea").value<QObject *>();
            disconnect(area, SIGNAL(widthRatioChanged(qreal)), d->horizontal, SLOT(setSize(qreal)));
            disconnect(area, SIGNAL(xPositionChanged(qreal)), d->horizontal, SLOT(setPosition(qreal)));
        }

        d->horizontal = horizontal;

        if (horizontal) {
            if (!horizontal->parentItem())
                horizontal->setParentItem(d->flickable);
            horizontal->setOrientation(Qt::Horizontal);

            QQuickItemPrivate::get(horizontal)->updateOrAddGeometryChangeListener(d, QQuickItemPrivate::SizeChange);
            QObjectPrivate::connect(d->flickable, &QQuickFlickable::movingHorizontallyChanged, d, &QQuickScrollIndicatorAttachedPrivate::activateHorizontal);

            // TODO: export QQuickFlickableVisibleArea
            QObject *area = d->flickable->property("visibleArea").value<QObject *>();
            connect(area, SIGNAL(widthRatioChanged(qreal)), horizontal, SLOT(setSize(qreal)));
            connect(area, SIGNAL(xPositionChanged(qreal)), horizontal, SLOT(setPosition(qreal)));

            d->layoutHorizontal();
            horizontal->setSize(area->property("widthRatio").toReal());
            horizontal->setPosition(area->property("xPosition").toReal());
        }
        emit horizontalChanged();
    }
}

/*!
    \qmlattachedproperty ScrollIndicator Qt.labs.controls::ScrollIndicator::vertical

    This property attaches a vertical scroll indicator to a \l Flickable.

    \code
    Flickable {
        contentHeight: 2000
        ScrollIndicator.vertical: ScrollIndicator { }
    }
    \endcode
*/
QQuickScrollIndicator *QQuickScrollIndicatorAttached::vertical() const
{
    Q_D(const QQuickScrollIndicatorAttached);
    return d->vertical;
}

void QQuickScrollIndicatorAttached::setVertical(QQuickScrollIndicator *vertical)
{
    Q_D(QQuickScrollIndicatorAttached);
    if (d->vertical != vertical) {
        if (d->vertical) {
            QQuickItemPrivate::get(d->vertical)->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
            QObjectPrivate::disconnect(d->flickable, &QQuickFlickable::movingVerticallyChanged, d, &QQuickScrollIndicatorAttachedPrivate::activateVertical);

            // TODO: export QQuickFlickableVisibleArea
            QObject *area = d->flickable->property("visibleArea").value<QObject *>();
            disconnect(area, SIGNAL(heightRatioChanged(qreal)), d->vertical, SLOT(setSize(qreal)));
            disconnect(area, SIGNAL(yPositionChanged(qreal)), d->vertical, SLOT(setPosition(qreal)));
        }

        d->vertical = vertical;

        if (vertical) {
            if (!vertical->parentItem())
                vertical->setParentItem(d->flickable);
            vertical->setOrientation(Qt::Vertical);

            QQuickItemPrivate::get(vertical)->updateOrAddGeometryChangeListener(d, QQuickItemPrivate::SizeChange);
            QObjectPrivate::connect(d->flickable, &QQuickFlickable::movingVerticallyChanged, d, &QQuickScrollIndicatorAttachedPrivate::activateVertical);

            // TODO: export QQuickFlickableVisibleArea
            QObject *area = d->flickable->property("visibleArea").value<QObject *>();
            connect(area, SIGNAL(heightRatioChanged(qreal)), vertical, SLOT(setSize(qreal)));
            connect(area, SIGNAL(yPositionChanged(qreal)), vertical, SLOT(setPosition(qreal)));

            d->layoutVertical();
            vertical->setSize(area->property("heightRatio").toReal());
            vertical->setPosition(area->property("yPosition").toReal());
        }
        emit verticalChanged();
    }
}

#ifndef QT_NO_ACCESSIBILITY
QAccessible::Role QQuickScrollIndicator::accessibleRole() const
{
    return QAccessible::Indicator;
}
#endif

QT_END_NAMESPACE