/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Quick Templates 2 module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL3$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPLv3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or later as published by the Free
** Software Foundation and appearing in the file LICENSE.GPL included in
** the packaging of this file. Please review the following information to
** ensure the GNU General Public License version 2.0 requirements will be
** met: http://www.gnu.org/licenses/gpl-2.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquickoverlay_p.h"
#include "qquickoverlay_p_p.h"
#include "qquickpopupitem_p_p.h"
#include "qquickpopup_p_p.h"
#include "qquickdrawer_p_p.h"
#include "qquickapplicationwindow_p.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
*/

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

    QVector<QQuickPopup *> popups;
    popups.reserve(children.count());

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

    return popups;
}

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

void QQuickOverlayPrivate::itemGeometryChanged(QQuickItem *, QQuickGeometryChange, const QRectF &)
{
    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 QVector<QQuickDrawer *> drawers = stackingOrderDrawers();
    for (QQuickDrawer *drawer : drawers) {
        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->windowPos()))
            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;
}

#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->touchPoints()) {
            switch (point.state()) {
            case Qt::TouchPointPressed:
                if (!target && startDrag(event, point.scenePos()))
                    handled = true;
                else
                    handled |= handlePress(source, event, target);
                break;
            case Qt::TouchPointMoved:
                handled |= handleMove(source, event, target ? target : mouseGrabberPopup.data());
                break;
            case Qt::TouchPointReleased:
                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(static_cast<QQuickDrawer *>(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)
        return;

    QPointF pos;
    QSizeF size = window->size();
    qreal rotation = 0;

    switch (window->contentOrientation()) {
    case Qt::PrimaryOrientation:
    case Qt::PortraitOrientation:
        size = window->size();
        break;
    case Qt::LandscapeOrientation:
        rotation = 90;
        pos = QPointF((size.width() - size.height()) / 2, -(size.width() - size.height()) / 2);
        size.transpose();
        break;
    case Qt::InvertedPortraitOrientation:
        rotation = 180;
        break;
    case Qt::InvertedLandscapeOrientation:
        rotation = 270;
        pos = QPointF((size.width() - size.height()) / 2, -(size.width() - size.height()) / 2);
        size.transpose();
        break;
    default:
        break;
    }

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

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

    if (parent) {
        d->updateGeometry();
        QQuickItemPrivate::get(parent)->addItemChangeListener(d, QQuickItemPrivate::Geometry);
        if (QQuickWindow *window = parent->window()) {
            window->installEventFilter(this);
            QObjectPrivate::connect(window, &QWindow::contentOrientationChanged, d, &QQuickOverlayPrivate::updateGeometry);
        }
    }
}

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

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

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

    delete d->modal;
    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;

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

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

    QQuickApplicationWindow *applicationWindow = qobject_cast<QQuickApplicationWindow *>(window);
    if (applicationWindow)
        return applicationWindow->overlay();

    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());
}

void QQuickOverlay::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    Q_D(QQuickOverlay);
    QQuickItem::geometryChanged(newGeometry, oldGeometry);
    for (QQuickPopup *popup : qAsConst(d->allPopups))
        QQuickPopupPrivate::get(popup)->resizeOverlay();
}

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)) {
            switch (event->type()) {
#if QT_CONFIG(quicktemplates2_multitouch)
            case QEvent::TouchBegin:
            case QEvent::TouchUpdate:
            case QEvent::TouchEnd:
                return d->handleTouchEvent(item, static_cast<QTouchEvent *>(event), popup);
#endif

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

            default:
                break;
            }
        }
    }
    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() & Qt::TouchPointPressed)
            emit pressed();
        if (static_cast<QTouchEvent *>(event)->touchPointStates() & Qt::TouchPointReleased)
            emit released();

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

        QQuickWindowPrivate::get(d->window)->handleTouchEvent(static_cast<QTouchEvent *>(event));

        // 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();
        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();

        QQuickWindowPrivate::get(d->window)->handleMouseEvent(static_cast<QMouseEvent *>(event));

        // 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;

    default:
        break;
    }

    return false;
}

class QQuickOverlayAttachedPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QQuickOverlayAttached)

public:
    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 qtquickcontrols2-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;

    delete d->modal;
    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 qtquickcontrols2-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;

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

QT_END_NAMESPACE