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#include "qquickoverlay_p.h"
#include "qquickpopup_p_p.h"
#include "qquickdrawer_p.h"
#include <QtQml/qqmlinfo.h>
#include <QtQml/qqmlproperty.h>
#include <QtQuick/private/qquickitem_p.h>

QT_BEGIN_NAMESPACE

class QQuickOverlayPrivate : public QQuickItemPrivate
{
    Q_DECLARE_PUBLIC(QQuickOverlay)

public:
    QQuickOverlayPrivate();

    void popupAboutToShow();
    void popupAboutToHide();
    void drawerPositionChange();
    void resizeBackground();

    QQuickItem *background;
    QVector<QQuickDrawer *> drawers;
    QVector<QQuickPopup *> popups;
    int modalPopups;
};

void QQuickOverlayPrivate::popupAboutToShow()
{
    Q_Q(QQuickOverlay);
    if (!background || modalPopups > 1)
        return;

    QQuickPopup *popup = qobject_cast<QQuickPopup *>(q->sender());
    if (!popup || !popup->isModal())
        return;

    // use QQmlProperty instead of QQuickItem::setOpacity() to trigger QML Behaviors
    QQmlProperty::write(background, QStringLiteral("opacity"), 1.0);
}

void QQuickOverlayPrivate::popupAboutToHide()
{
    Q_Q(QQuickOverlay);
    if (!background || modalPopups > 1)
        return;

    QQuickPopup *popup = qobject_cast<QQuickPopup *>(q->sender());
    if (!popup || !popup->isModal())
        return;

    // use QQmlProperty instead of QQuickItem::setOpacity() to trigger QML Behaviors
    QQmlProperty::write(background, QStringLiteral("opacity"), 0.0);
}

void QQuickOverlayPrivate::drawerPositionChange()
{
    Q_Q(QQuickOverlay);
    QQuickDrawer *drawer = qobject_cast<QQuickDrawer *>(q->sender());
    if (!background || !drawer || modalPopups > 0)
        return;

    // call QQuickItem::setOpacity() directly to avoid triggering QML Behaviors
    // which would make the fading feel laggy compared to the drawer movement
    background->setOpacity(drawer->position());
}

void QQuickOverlayPrivate::resizeBackground()
{
    Q_Q(QQuickOverlay);
    background->setWidth(q->width());
    background->setHeight(q->height());
}

QQuickOverlayPrivate::QQuickOverlayPrivate() :
    background(nullptr),
    modalPopups(0)
{
}

QQuickOverlay::QQuickOverlay(QQuickItem *parent)
    : QQuickItem(*(new QQuickOverlayPrivate), parent)
{
    setAcceptedMouseButtons(Qt::AllButtons);
    setFiltersChildMouseEvents(true);
    setVisible(false);
}


QQuickItem *QQuickOverlay::background() const
{
    Q_D(const QQuickOverlay);
    return d->background;
}

void QQuickOverlay::setBackground(QQuickItem *background)
{
    Q_D(QQuickOverlay);
    if (d->background == background)
        return;

    delete d->background;
    d->background = background;
    if (background) {
        background->setOpacity(0.0);
        background->setParentItem(this);
        if (qFuzzyIsNull(background->z()))
            background->setZ(-1);
        if (isComponentComplete())
            d->resizeBackground();
    }
    emit backgroundChanged();
}

void QQuickOverlay::itemChange(ItemChange change, const ItemChangeData &data)
{
    Q_D(QQuickOverlay);
    QQuickItem::itemChange(change, data);

    QQuickPopup *popup = nullptr;
    if (change == ItemChildAddedChange || change == ItemChildRemovedChange) {
        QQuickDrawer *drawer = qobject_cast<QQuickDrawer *>(data.item);
        if (drawer) {
            if (change == ItemChildAddedChange) {
                QObjectPrivate::connect(drawer, &QQuickDrawer::positionChanged, d, &QQuickOverlayPrivate::drawerPositionChange);
                d->drawers.append(drawer);
            } else {
                QObjectPrivate::disconnect(drawer, &QQuickDrawer::positionChanged, d, &QQuickOverlayPrivate::drawerPositionChange);
                d->drawers.removeOne(drawer);
            }
        } else {
            popup = qobject_cast<QQuickPopup *>(data.item->parent());
        }
        setVisible(!childItems().isEmpty());
    }
    if (!popup)
        return;

    if (change == ItemChildAddedChange) {
        d->popups.append(popup);
        if (popup->isModal())
            ++d->modalPopups;

        QObjectPrivate::connect(popup, &QQuickPopup::aboutToShow, d, &QQuickOverlayPrivate::popupAboutToShow);
        QObjectPrivate::connect(popup, &QQuickPopup::aboutToHide, d, &QQuickOverlayPrivate::popupAboutToHide);
    } else if (change == ItemChildRemovedChange) {
        d->popups.removeOne(popup);
        if (popup->isModal())
            --d->modalPopups;

        QObjectPrivate::disconnect(popup, &QQuickPopup::aboutToShow, d, &QQuickOverlayPrivate::popupAboutToShow);
        QObjectPrivate::disconnect(popup, &QQuickPopup::aboutToHide, d, &QQuickOverlayPrivate::popupAboutToHide);
    }
}

void QQuickOverlay::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    Q_D(QQuickOverlay);
    QQuickItem::geometryChanged(newGeometry, oldGeometry);
    if (d->background)
        d->resizeBackground();
}

bool QQuickOverlay::event(QEvent *event)
{
    Q_D(QQuickOverlay);
    switch (event->type()) {
    case QEvent::MouseButtonPress:
        emit pressed();
        break;
    case QEvent::MouseButtonRelease:
        emit released();
        break;
    default:
        break;
    }

    for (auto it = d->popups.rbegin(), end = d->popups.rend(); it != end; ++it) {
        if ((*it)->overlayEvent(this, event))
            return true;
    }

    return QQuickItem::event(event);
}

bool QQuickOverlay::childMouseEventFilter(QQuickItem *item, QEvent *event)
{
    Q_D(QQuickOverlay);
    if (d->modalPopups == 0)
        return false;
    // TODO Filter touch events
    if (event->type() != QEvent::MouseButtonPress)
        return false;
    while (item->parentItem() != this)
        item = item->parentItem();

    const QList<QQuickItem *> sortedChildren = d->paintOrderChildItems();
    for (auto it = sortedChildren.rbegin(), end = sortedChildren.rend(); it != end; ++it) {
        QQuickItem *popupItem = *it;
        if (popupItem == item)
            break;

        QQuickPopup *popup = qobject_cast<QQuickPopup *>(popupItem->parent());
        if (popup && popup->overlayEvent(item, event))
            return true;
    }

    return false;
}

QT_END_NAMESPACE