// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qquickcontrol_p_p.h"
#include "qquickoverlay_p.h"
#include "qquickoverlay_p_p.h"
#include "qquickpopupitem_p_p.h"
#include "qquickpopup_p_p.h"
#include "qquickdrawer_p.h"
#include "qquickdrawer_p_p.h"
#include "qquickapplicationwindow_p.h"
#include <QtGui/qpainterpath.h>
#include <QtQml/qqmlinfo.h>
#include <QtQml/qqmlproperty.h>
#include <QtQml/qqmlcomponent.h>
#include <algorithm>

QT_BEGIN_NAMESPACE

/*!
    \qmltype Overlay
    \inherits Item
//!     \instantiates QQuickOverlay
    \inqmlmodule QtQuick.Controls
    \since 5.10
    \brief A window overlay for popups.

    Overlay provides a layer for popups, ensuring that popups are displayed above
    other content and that the background is dimmed when a \l {Popup::}{modal} or
    \l {Popup::dim}{dimmed} popup is visible.

    The overlay is an ordinary Item that covers the entire window. It can be used
    as a visual parent to position a popup in scene coordinates.

    \include qquickoverlay-popup-parent.qdocinc

    \sa ApplicationWindow
*/

QList<QQuickPopup *> QQuickOverlayPrivate::stackingOrderPopups() const
{
    const QList<QQuickItem *> children = paintOrderChildItems();

    QList<QQuickPopup *> popups;
    popups.reserve(children.size());

    for (auto it = children.crbegin(), end = children.crend(); it != end; ++it) {
        QQuickPopup *popup = qobject_cast<QQuickPopup *>((*it)->parent());
        if (popup)
            popups += popup;
    }

    return popups;
}

QList<QQuickPopup *> QQuickOverlayPrivate::stackingOrderDrawers() const
{
    QList<QQuickPopup *> sorted(allDrawers);
    std::sort(sorted.begin(), sorted.end(), [](const QQuickPopup *one, const QQuickPopup *another) {
        return one->z() > another->z();
    });
    return sorted;
}

void QQuickOverlayPrivate::itemGeometryChanged(QQuickItem *, QQuickGeometryChange, const QRectF &)
{
    updateGeometry();
}

void QQuickOverlayPrivate::itemRotationChanged(QQuickItem *)
{
    updateGeometry();
}

bool QQuickOverlayPrivate::startDrag(QEvent *event, const QPointF &pos)
{
    Q_Q(QQuickOverlay);
    if (allDrawers.isEmpty())
        return false;

    // don't start dragging a drawer if a modal popup overlay is blocking (QTBUG-60602)
    QQuickItem *item = q->childAt(pos.x(), pos.y());
    if (item) {
        const auto popups = stackingOrderPopups();
        for (QQuickPopup *popup : popups) {
            QQuickPopupPrivate *p = QQuickPopupPrivate::get(popup);
            if (p->dimmer == item && popup->isVisible() && popup->isModal())
                return false;
        }
    }

    const QList<QQuickPopup *> drawers = stackingOrderDrawers();
    for (QQuickPopup *popup : drawers) {
        QQuickDrawer *drawer = qobject_cast<QQuickDrawer *>(popup);
        Q_ASSERT(drawer);
        QQuickDrawerPrivate *p = QQuickDrawerPrivate::get(drawer);
        if (p->startDrag(event)) {
            setMouseGrabberPopup(drawer);
            return true;
        }
    }

    return false;
}

bool QQuickOverlayPrivate::handlePress(QQuickItem *source, QEvent *event, QQuickPopup *target)
{
    if (target) {
        if (target->overlayEvent(source, event)) {
            setMouseGrabberPopup(target);
            return true;
        }
        return false;
    }

    switch (event->type()) {
    default: {
        if (mouseGrabberPopup)
            break;
#if QT_CONFIG(quicktemplates2_multitouch)
        Q_FALLTHROUGH();
    case QEvent::TouchBegin:
    case QEvent::TouchUpdate:
    case QEvent::TouchEnd:
#endif
        // allow non-modal popups to close themselves,
        // and non-dimming modal popups to block the event
        const auto popups = stackingOrderPopups();
        for (QQuickPopup *popup : popups) {
            if (popup->overlayEvent(source, event)) {
                setMouseGrabberPopup(popup);
                return true;
            }
        }
        break;
    }
    }

    event->ignore();
    return false;
}

bool QQuickOverlayPrivate::handleMove(QQuickItem *source, QEvent *event, QQuickPopup *target)
{
    if (target)
        return target->overlayEvent(source, event);
    return false;
}

bool QQuickOverlayPrivate::handleRelease(QQuickItem *source, QEvent *event, QQuickPopup *target)
{
    if (target) {
        setMouseGrabberPopup(nullptr);
        if (target->overlayEvent(source, event)) {
            setMouseGrabberPopup(nullptr);
            return true;
        }
    } else {
        const auto popups = stackingOrderPopups();
        for (QQuickPopup *popup : popups) {
            if (popup->overlayEvent(source, event))
                return true;
        }
    }
    return false;
}

bool QQuickOverlayPrivate::handleMouseEvent(QQuickItem *source, QMouseEvent *event, QQuickPopup *target)
{
    switch (event->type()) {
    case QEvent::MouseButtonPress:
        if (!target && startDrag(event, event->scenePosition()))
            return true;
        return handlePress(source, event, target);
    case QEvent::MouseMove:
        return handleMove(source, event, target ? target : mouseGrabberPopup.data());
    case QEvent::MouseButtonRelease:
        return handleRelease(source, event, target ? target : mouseGrabberPopup.data());
    default:
        break;
    }
    return false;
}

bool QQuickOverlayPrivate::handleHoverEvent(QQuickItem *source, QHoverEvent *event, QQuickPopup *target)
{
    switch (event->type()) {
    case QEvent::HoverEnter:
    case QEvent::HoverMove:
    case QEvent::HoverLeave:
        if (target)
            return target->overlayEvent(source, event);
        return false;
    default:
        Q_UNREACHABLE(); // function must only be called on hover events
        break;
    }
    return false;
}

#if QT_CONFIG(quicktemplates2_multitouch)
bool QQuickOverlayPrivate::handleTouchEvent(QQuickItem *source, QTouchEvent *event, QQuickPopup *target)
{
    bool handled = false;
    switch (event->type()) {
    case QEvent::TouchBegin:
    case QEvent::TouchUpdate:
    case QEvent::TouchEnd:
        for (const QTouchEvent::TouchPoint &point : event->points()) {
            switch (point.state()) {
            case QEventPoint::Pressed:
                if (!target && startDrag(event, point.scenePosition()))
                    handled = true;
                else
                    handled |= handlePress(source, event, target);
                break;
            case QEventPoint::Updated:
                handled |= handleMove(source, event, target ? target : mouseGrabberPopup.data());
                break;
            case QEventPoint::Released:
                handled |= handleRelease(source, event, target ? target : mouseGrabberPopup.data());
                break;
            default:
                break;
            }
        }
        break;

    default:
        break;
    }

    return handled;
}
#endif

void QQuickOverlayPrivate::addPopup(QQuickPopup *popup)
{
    Q_Q(QQuickOverlay);
    allPopups += popup;
    if (QQuickDrawer *drawer = qobject_cast<QQuickDrawer *>(popup)) {
        allDrawers += drawer;
        q->setVisible(!allDrawers.isEmpty() || !q->childItems().isEmpty());
    }
}

void QQuickOverlayPrivate::removePopup(QQuickPopup *popup)
{
    Q_Q(QQuickOverlay);
    allPopups.removeOne(popup);
    if (allDrawers.removeOne(popup))
        q->setVisible(!allDrawers.isEmpty() || !q->childItems().isEmpty());
}

void QQuickOverlayPrivate::setMouseGrabberPopup(QQuickPopup *popup)
{
    if (popup && !popup->isVisible())
        popup = nullptr;
    mouseGrabberPopup = popup;
}

void QQuickOverlayPrivate::updateGeometry()
{
    Q_Q(QQuickOverlay);
    if (!window || !window->contentItem())
        return;

    const QSizeF size = window->contentItem()->size();
    const QPointF pos(-(size.width() - window->size().width()) / 2,
                      -(size.height() - window->size().height()) / 2);

    q->setSize(size);
    q->setPosition(pos);
}

QQuickOverlay::QQuickOverlay(QQuickItem *parent)
    : QQuickItem(*(new QQuickOverlayPrivate), parent)
{
    Q_D(QQuickOverlay);
    setZ(1000001); // DefaultWindowDecoration+1
    setAcceptedMouseButtons(Qt::AllButtons);
#if QT_CONFIG(quicktemplates2_multitouch)
    setAcceptTouchEvents(true);
#endif
    setFiltersChildMouseEvents(true);
    setVisible(false);

    if (parent) {
        d->updateGeometry();
        QQuickItemPrivate::get(parent)->addItemChangeListener(d, QQuickItemPrivate::Geometry);
        if (QQuickWindow *window = parent->window()) {
            window->installEventFilter(this);
            if (QQuickItem *contentItem = window->contentItem())
                QQuickItemPrivate::get(contentItem)->addItemChangeListener(d, QQuickItemPrivate::Rotation);
        }
    }
}

QQuickOverlay::~QQuickOverlay()
{
    Q_D(QQuickOverlay);
    if (QQuickItem *parent = parentItem()) {
        QQuickItemPrivate::get(parent)->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
        if (QQuickWindow *window = parent->window()) {
            if (QQuickItem *contentItem = window->contentItem())
                QQuickItemPrivate::get(contentItem)->removeItemChangeListener(d, QQuickItemPrivate::Rotation);
        }
    }
}

QQmlComponent *QQuickOverlay::modal() const
{
    Q_D(const QQuickOverlay);
    return d->modal;
}

void QQuickOverlay::setModal(QQmlComponent *modal)
{
    Q_D(QQuickOverlay);
    if (d->modal == modal)
        return;

    d->modal = modal;
    emit modalChanged();
}

QQmlComponent *QQuickOverlay::modeless() const
{
    Q_D(const QQuickOverlay);
    return d->modeless;
}

void QQuickOverlay::setModeless(QQmlComponent *modeless)
{
    Q_D(QQuickOverlay);
    if (d->modeless == modeless)
        return;

    d->modeless = modeless;
    emit modelessChanged();
}

QQuickOverlay *QQuickOverlay::overlay(QQuickWindow *window)
{
    if (!window)
        return nullptr;

    const char *name = "_q_QQuickOverlay";
    QQuickOverlay *overlay = window->property(name).value<QQuickOverlay *>();
    if (!overlay) {
        QQuickItem *content = window->contentItem();
        // Do not re-create the overlay if the window is being destroyed
        // and thus, its content item no longer has a window associated.
        if (content && content->window()) {
            overlay = new QQuickOverlay(window->contentItem());
            window->setProperty(name, QVariant::fromValue(overlay));
        }
    }
    return overlay;
}

QQuickOverlayAttached *QQuickOverlay::qmlAttachedProperties(QObject *object)
{
    return new QQuickOverlayAttached(object);
}

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

    if (change == ItemChildAddedChange || change == ItemChildRemovedChange) {
        setVisible(!d->allDrawers.isEmpty() || !childItems().isEmpty());
        if (data.item->parent() == d->mouseGrabberPopup)
            d->setMouseGrabberPopup(nullptr);
    }
}

void QQuickOverlay::geometryChange(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    Q_D(QQuickOverlay);
    QQuickItem::geometryChange(newGeometry, oldGeometry);
    for (QQuickPopup *popup : std::as_const(d->allPopups))
        QQuickPopupPrivate::get(popup)->resizeDimmer();
}

void QQuickOverlay::mousePressEvent(QMouseEvent *event)
{
    Q_D(QQuickOverlay);
    d->handleMouseEvent(this, event);
}

void QQuickOverlay::mouseMoveEvent(QMouseEvent *event)
{
    Q_D(QQuickOverlay);
    d->handleMouseEvent(this, event);
}

void QQuickOverlay::mouseReleaseEvent(QMouseEvent *event)
{
    Q_D(QQuickOverlay);
    d->handleMouseEvent(this, event);
}

#if QT_CONFIG(quicktemplates2_multitouch)
void QQuickOverlay::touchEvent(QTouchEvent *event)
{
    Q_D(QQuickOverlay);
    d->handleTouchEvent(this, event);
}
#endif

#if QT_CONFIG(wheelevent)
void QQuickOverlay::wheelEvent(QWheelEvent *event)
{
    Q_D(QQuickOverlay);
    if (d->mouseGrabberPopup) {
        d->mouseGrabberPopup->overlayEvent(this, event);
        return;
    } else {
        const auto popups = d->stackingOrderPopups();
        for (QQuickPopup *popup : popups) {
            if (popup->overlayEvent(this, event))
                return;
        }
    }
    event->ignore();
}
#endif

bool QQuickOverlay::childMouseEventFilter(QQuickItem *item, QEvent *event)
{
    Q_D(QQuickOverlay);
    const auto popups = d->stackingOrderPopups();
    for (QQuickPopup *popup : popups) {
        QQuickPopupPrivate *p = QQuickPopupPrivate::get(popup);

        // Stop filtering overlay events when reaching a popup item or an item
        // that is inside the popup. Let the popup content handle its events.
        if (item == p->popupItem || p->popupItem->isAncestorOf(item))
            break;

        // Let the popup try closing itself when pressing or releasing over its
        // background dimming OR over another popup underneath, in case the popup
        // does not have background dimming.
        if (item == p->dimmer || !p->popupItem->isAncestorOf(item)) {
            bool handled = false;
            switch (event->type()) {
#if QT_CONFIG(quicktemplates2_multitouch)
            case QEvent::TouchBegin:
            case QEvent::TouchUpdate:
            case QEvent::TouchEnd:
                handled = d->handleTouchEvent(item, static_cast<QTouchEvent *>(event), popup);
                break;
#endif
            case QEvent::HoverEnter:
            case QEvent::HoverMove:
            case QEvent::HoverLeave:
                // If the control item has already been hovered, allow the hover leave event
                // to be processed by the same item for resetting its internal hovered state
                // instead of filtering it here.
                if (auto *control = qobject_cast<QQuickControl *>(item)) {
                    if (control->isHovered() && event->type() == QEvent::HoverLeave)
                        return false;
                }
                handled = d->handleHoverEvent(item, static_cast<QHoverEvent *>(event), popup);
                break;

            case QEvent::MouseButtonPress:
            case QEvent::MouseMove:
            case QEvent::MouseButtonRelease:
                handled = d->handleMouseEvent(item, static_cast<QMouseEvent *>(event), popup);
                break;

            default:
                break;
            }
            if (handled)
                return true;
        }
    }
    return false;
}

bool QQuickOverlay::eventFilter(QObject *object, QEvent *event)
{
    Q_D(QQuickOverlay);
    if (!isVisible() || object != d->window)
        return false;

    switch (event->type()) {
#if QT_CONFIG(quicktemplates2_multitouch)
    case QEvent::TouchBegin:
    case QEvent::TouchUpdate:
    case QEvent::TouchEnd:
        if (static_cast<QTouchEvent *>(event)->touchPointStates() & QEventPoint::Pressed)
            emit pressed();
        if (static_cast<QTouchEvent *>(event)->touchPointStates() & QEventPoint::Released)
            emit released();

        // allow non-modal popups to close on touch release outside
        if (!d->mouseGrabberPopup) {
            for (const QTouchEvent::TouchPoint &point : static_cast<QTouchEvent *>(event)->points()) {
                if (point.state() == QEventPoint::Released) {
                    if (d->handleRelease(d->window->contentItem(), event, nullptr))
                        break;
                }
            }
        }

        // setup currentEventDeliveryAgent like in QQuickDeliveryAgent::event
        QQuickDeliveryAgentPrivate::currentEventDeliveryAgent = d->deliveryAgent();
        d->deliveryAgentPrivate()->handleTouchEvent(static_cast<QTouchEvent *>(event));
        QQuickDeliveryAgentPrivate::currentEventDeliveryAgent = nullptr;

        // If a touch event hasn't been accepted after being delivered, there
        // were no items interested in touch events at any of the touch points.
        // Make sure to accept the touch event in order to receive the consequent
        // touch events, to be able to close non-modal popups on release outside.
        event->accept();
        // Since we eat the event, QQuickWindow::event never sees it to clean up the
        // grabber states. So we have to do so explicitly.
        if (QQuickWindow *window = parentItem() ? parentItem()->window() : nullptr) {
            QQuickWindowPrivate *d = QQuickWindowPrivate::get(window);
            d->clearGrabbers(static_cast<QPointerEvent *>(event));
        }
        return true;
#endif

    case QEvent::MouseButtonPress:
#if QT_CONFIG(quicktemplates2_multitouch)
        // do not emit pressed() twice when mouse events have been synthesized from touch events
        if (static_cast<QMouseEvent *>(event)->source() == Qt::MouseEventNotSynthesized)
#endif
            emit pressed();

        // setup currentEventDeliveryAgent like in QQuickDeliveryAgent::event
        QQuickDeliveryAgentPrivate::currentEventDeliveryAgent = d->deliveryAgent();
        d->deliveryAgentPrivate()->handleMouseEvent(static_cast<QMouseEvent *>(event));
        QQuickDeliveryAgentPrivate::currentEventDeliveryAgent = nullptr;

        // If a mouse event hasn't been accepted after being delivered, there
        // was no item interested in mouse events at the mouse point. Make sure
        // to accept the mouse event in order to receive the consequent mouse
        // events, to be able to close non-modal popups on release outside.
        event->accept();
        return true;

    case QEvent::MouseButtonRelease:
#if QT_CONFIG(quicktemplates2_multitouch)
        // do not emit released() twice when mouse events have been synthesized from touch events
        if (static_cast<QMouseEvent *>(event)->source() == Qt::MouseEventNotSynthesized)
#endif
            emit released();

        // allow non-modal popups to close on mouse release outside
        if (!d->mouseGrabberPopup)
            d->handleRelease(d->window->contentItem(), event, nullptr);
        break;

#if QT_CONFIG(wheelevent)
    case QEvent::Wheel: {
        // If the top item in the drawing-order is blocked by a modal popup, then
        // eat the event. There is no scenario where the top most item is blocked
        // by a popup, but an item further down in the drawing order is not.
        QWheelEvent *we = static_cast<QWheelEvent *>(event);
        const QVector<QQuickItem *> targetItems = d->deliveryAgentPrivate()->pointerTargets(
                                    d->window->contentItem(), we, we->point(0), false, false);
        if (targetItems.isEmpty())
            break;

        QQuickItem * const dimmerItem = property("_q_dimmerItem").value<QQuickItem *>();
        QQuickItem * const topItem = targetItems.first();

        QQuickItem *item = topItem;
        while ((item = item->parentItem())) {
            if (qobject_cast<QQuickPopupItem *>(item))
                break;
        }

        if (!item && dimmerItem != topItem && isAncestorOf(topItem))
            break;

        const auto popups = d->stackingOrderPopups();
        // Eat the event if receiver topItem is not a child of a popup before
        // the first modal popup.
        for (const auto &popup : popups) {
            const QQuickItem *popupItem = popup->popupItem();
            if (!popupItem)
                continue;
            // if current popup item matches with any popup in stack, deliver the event
            if (popupItem == item)
                break;
            // if the popup doesn't contain the item but is modal, eat the event
            if (popup->overlayEvent(topItem, we))
                return true;
        }
        break;
    }
#endif

    default:
        break;
    }

    return false;
}

class QQuickOverlayAttachedPrivate : public QObjectPrivate
{
public:
    Q_DECLARE_PUBLIC(QQuickOverlayAttached)

    void setWindow(QQuickWindow *newWindow);

    QQuickWindow *window = nullptr;
    QQmlComponent *modal = nullptr;
    QQmlComponent *modeless = nullptr;
};

void QQuickOverlayAttachedPrivate::setWindow(QQuickWindow *newWindow)
{
    Q_Q(QQuickOverlayAttached);
    if (window == newWindow)
        return;

    if (QQuickOverlay *oldOverlay = QQuickOverlay::overlay(window)) {
        QObject::disconnect(oldOverlay, &QQuickOverlay::pressed, q, &QQuickOverlayAttached::pressed);
        QObject::disconnect(oldOverlay, &QQuickOverlay::released, q, &QQuickOverlayAttached::released);
    }

    if (QQuickOverlay *newOverlay = QQuickOverlay::overlay(newWindow)) {
        QObject::connect(newOverlay, &QQuickOverlay::pressed, q, &QQuickOverlayAttached::pressed);
        QObject::connect(newOverlay, &QQuickOverlay::released, q, &QQuickOverlayAttached::released);
    }

    window = newWindow;
    emit q->overlayChanged();
}

/*!
    \qmlattachedsignal QtQuick.Controls::Overlay::pressed()

    This attached signal is emitted when the overlay is pressed by the user while
    a popup is visible.

    The signal can be attached to any item, popup, or window. When attached to an
    item or a popup, the signal is only emitted if the item or popup is in a window.
*/

/*!
    \qmlattachedsignal QtQuick.Controls::Overlay::released()

    This attached signal is emitted when the overlay is released by the user while
    a popup is visible.

    The signal can be attached to any item, popup, or window. When attached to an
    item or a popup, the signal is only emitted if the item or popup is in a window.
*/

QQuickOverlayAttached::QQuickOverlayAttached(QObject *parent)
    : QObject(*(new QQuickOverlayAttachedPrivate), parent)
{
    Q_D(QQuickOverlayAttached);
    if (QQuickItem *item = qobject_cast<QQuickItem *>(parent)) {
        d->setWindow(item->window());
        QObjectPrivate::connect(item, &QQuickItem::windowChanged, d, &QQuickOverlayAttachedPrivate::setWindow);
    } else if (QQuickPopup *popup = qobject_cast<QQuickPopup *>(parent)) {
        d->setWindow(popup->window());
        QObjectPrivate::connect(popup, &QQuickPopup::windowChanged, d, &QQuickOverlayAttachedPrivate::setWindow);
    } else {
        d->setWindow(qobject_cast<QQuickWindow *>(parent));
    }
}

/*!
    \qmlattachedproperty Overlay QtQuick.Controls::Overlay::overlay
    \readonly

    This attached property holds the window overlay item.

    The property can be attached to any item, popup, or window. When attached to an
    item or a popup, the value is \c null if the item or popup is not in a window.
*/
QQuickOverlay *QQuickOverlayAttached::overlay() const
{
    Q_D(const QQuickOverlayAttached);
    return QQuickOverlay::overlay(d->window);
}

/*!
    \qmlattachedproperty Component QtQuick.Controls::Overlay::modal

    This attached property holds a component to use as a visual item that implements
    background dimming for modal popups. It is created for and stacked below visible
    modal popups.

    The property can be attached to any popup.

    For example, to change the color of the background dimming for a modal
    popup, the following code can be used:

    \snippet qtquickcontrols-overlay-modal.qml 1

    \sa Popup::modal
*/
QQmlComponent *QQuickOverlayAttached::modal() const
{
    Q_D(const QQuickOverlayAttached);
    return d->modal;
}

void QQuickOverlayAttached::setModal(QQmlComponent *modal)
{
    Q_D(QQuickOverlayAttached);
    if (d->modal == modal)
        return;

    d->modal = modal;
    emit modalChanged();
}

/*!
    \qmlattachedproperty Component QtQuick.Controls::Overlay::modeless

    This attached property holds a component to use as a visual item that implements
    background dimming for modeless popups. It is created for and stacked below visible
    dimming popups.

    The property can be attached to any popup.

    For example, to change the color of the background dimming for a modeless
    popup, the following code can be used:

    \snippet qtquickcontrols-overlay-modeless.qml 1

    \sa Popup::dim
*/
QQmlComponent *QQuickOverlayAttached::modeless() const
{
    Q_D(const QQuickOverlayAttached);
    return d->modeless;
}

void QQuickOverlayAttached::setModeless(QQmlComponent *modeless)
{
    Q_D(QQuickOverlayAttached);
    if (d->modeless == modeless)
        return;

    d->modeless = modeless;
    emit modelessChanged();
}

QT_END_NAMESPACE

#include "moc_qquickoverlay_p.cpp"
