/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 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 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "QtWidgets/qwidget.h"
#include "QtGui/qevent.h"
#include "QtWidgets/qapplication.h"
#include "private/qwidgetbackingstore_p.h"
#include "private/qwidget_p.h"
#include "private/qwidgetwindow_qpa_p.h"
#include "private/qapplication_p.h"
#include "QtWidgets/qdesktopwidget.h"
#include "QtGui/qplatformwindow_qpa.h"
#include "QtGui/qsurfaceformat.h"
#include "QtGui/qplatformopenglcontext_qpa.h"
#include "QtGui/private/qwindow_p.h"

#include <QtGui/QPlatformCursor>
#include <QtGui/QGuiApplication>
#include <QtGui/QScreen>

QT_BEGIN_NAMESPACE

void q_createNativeChildrenAndSetParent(QWindow *parentWindow, const QWidget *parentWidget)
{
    QObjectList children = parentWidget->children();
    for (int i = 0; i < children.size(); i++) {
        if (children.at(i)->isWidgetType()) {
            const QWidget *childWidget = qobject_cast<const QWidget *>(children.at(i));
            if (childWidget) { // should not be necessary
                if (childWidget->testAttribute(Qt::WA_NativeWindow)) {
                    if (!childWidget->windowHandle())
                        childWidget->winId();
                    if (childWidget->windowHandle()) {
                        if (childWidget->isTopLevel())
                            childWidget->windowHandle()->setTransientParent(parentWindow);
                        else
                            childWidget->windowHandle()->setParent(parentWindow);
                    }
                } else {
                    q_createNativeChildrenAndSetParent(parentWindow,childWidget);
                }
            }
        }
    }

}

void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyOldWindow)
{
    Q_Q(QWidget);

    Q_UNUSED(window);
    Q_UNUSED(initializeWindow);
    Q_UNUSED(destroyOldWindow);

    Qt::WindowFlags flags = data.window_flags;

    if (!q->testAttribute(Qt::WA_NativeWindow) && !q->isWindow())
        return; // we only care about real toplevels

    QWindow *win = topData()->window;
    // topData() ensures the extra is created but does not ensure 'window' is non-null
    // in case the extra was already valid.
    if (!win) {
        createTLSysExtra();
        win = topData()->window;
    }

    win->setWindowFlags(data.window_flags);
    win->setGeometry(q->geometry());
    win->setScreen(QGuiApplication::screens().value(topData()->screenIndex, 0));

    if (q->testAttribute(Qt::WA_TranslucentBackground)) {
        QSurfaceFormat format;
        format.setAlphaBufferSize(8);
        win->setFormat(format);
    }

    if (QWidget *nativeParent = q->nativeParentWidget()) {
        if (nativeParent->windowHandle()) {
            if (flags & Qt::Window) {
                win->setTransientParent(nativeParent->windowHandle());
                win->setParent(0);
            } else {
                win->setTransientParent(0);
                win->setParent(nativeParent->windowHandle());
            }
        }
    }

    qt_window_private(win)->positionPolicy = topData()->posFromMove ? QWindowPrivate::WindowFrameInclusive : QWindowPrivate::WindowFrameExclusive;
    win->create();

    data.window_flags = win->windowFlags();

    QBackingStore *store = q->backingStore();

    if (!store) {
        if (win)
            q->setBackingStore(new QBackingStore(win));
        else
            q->setAttribute(Qt::WA_PaintOnScreen, true);
    }

    setWinId(win->winId());

//    first check children. and create them if necessary
//    q_createNativeChildrenAndSetParent(q->windowHandle(),q);

//    qDebug() << "create_sys" << q << q->internalWinId();
}

void QWidget::destroy(bool destroyWindow, bool destroySubWindows)
{
    Q_D(QWidget);

    d->aboutToDestroy();
    if (!isWindow() && parentWidget())
        parentWidget()->d_func()->invalidateBuffer(d->effectiveRectFor(geometry()));
    d->deactivateWidgetCleanup();

    if ((windowType() == Qt::Popup))
        qApp->d_func()->closePopup(this);

    if (this == QApplicationPrivate::active_window)
        QApplication::setActiveWindow(0);

    setAttribute(Qt::WA_WState_Created, false);

    if (windowType() != Qt::Desktop) {
        if (destroySubWindows) {
            QObjectList childList(children());
            for (int i = 0; i < childList.size(); i++) {
                QWidget *widget = qobject_cast<QWidget *>(childList.at(i));
                if (widget && widget->testAttribute(Qt::WA_NativeWindow)) {
                    if (widget->windowHandle()) {
                        widget->destroy();
                    }
                }
            }
        }
        if (destroyWindow) {
            d->deleteTLSysExtra();
        } else {
            if (parentWidget() && parentWidget()->testAttribute(Qt::WA_WState_Created)) {
                d->hide_sys();
            }
        }

        d->setWinId(0);
    }
}

void QWidgetPrivate::setParent_sys(QWidget *newparent, Qt::WindowFlags f)
{
    Q_Q(QWidget);

    Qt::WindowFlags oldFlags = data.window_flags;
    bool wasCreated = q->testAttribute(Qt::WA_WState_Created);

    int targetScreen = -1;
    // Handle a request to move the widget to a particular screen
    if (newparent && newparent->windowType() == Qt::Desktop) {
        // make sure the widget is created on the same screen as the
        // programmer specified desktop widget

        // get the desktop's screen number
        targetScreen = newparent->window()->d_func()->topData()->screenIndex;
        newparent = 0;
    }

    setWinId(0);

    if (parent != newparent) {
        QObjectPrivate::setParent_helper(newparent); //### why does this have to be done in the _sys function???
        if (q->windowHandle()) {
            q->windowHandle()->setWindowFlags(f);
            QWidget *parentWithWindow =
                newparent ? (newparent->windowHandle() ? newparent : newparent->nativeParentWidget()) : 0;
            if (parentWithWindow) {
                if (f & Qt::Window) {
                    q->windowHandle()->setTransientParent(parentWithWindow->windowHandle());
                    q->windowHandle()->setParent(0);
                } else {
                    q->windowHandle()->setTransientParent(0);
                    q->windowHandle()->setParent(parentWithWindow->windowHandle());
                }
            } else {
                q->windowHandle()->setTransientParent(0);
                q->windowHandle()->setParent(0);
            }
        }
    }

    if (!newparent) {
        f |= Qt::Window;
        if (targetScreen == -1) {
            if (parent)
                targetScreen = q->parentWidget()->window()->d_func()->topData()->screenIndex;
        }
    }

    bool explicitlyHidden = q->testAttribute(Qt::WA_WState_Hidden) && q->testAttribute(Qt::WA_WState_ExplicitShowHide);

    // Reparenting toplevel to child
    if (!(f&Qt::Window) && (oldFlags&Qt::Window) && !q->testAttribute(Qt::WA_NativeWindow)) {
        //qDebug() << "setParent_sys() change from toplevel";
        q->destroy();
    } else if (newparent && wasCreated) {
        q->createWinId();
    }

    adjustFlags(f, q);
    data.window_flags = f;
    q->setAttribute(Qt::WA_WState_Created, false);
    q->setAttribute(Qt::WA_WState_Visible, false);
    q->setAttribute(Qt::WA_WState_Hidden, false);

    if (q->isWindow() || (!newparent || newparent->isVisible()) || explicitlyHidden)
        q->setAttribute(Qt::WA_WState_Hidden);
    q->setAttribute(Qt::WA_WState_ExplicitShowHide, explicitlyHidden);

    // move the window to the selected screen
    if (!newparent && targetScreen != -1) {
        if (maybeTopData())
            maybeTopData()->screenIndex = targetScreen;
        // only if it is already created
        if (q->testAttribute(Qt::WA_WState_Created)) {
            q->windowHandle()->setScreen(QGuiApplication::screens().value(targetScreen, 0));
        }
    }
}

QPoint QWidget::mapToGlobal(const QPoint &pos) const
{
    int x = pos.x(), y = pos.y();
    const QWidget *w = this;
    while (w) {
        x += w->data->crect.x();
        y += w->data->crect.y();
        w = w->isWindow() ? 0 : w->parentWidget();
    }
    return QPoint(x, y);
}

QPoint QWidget::mapFromGlobal(const QPoint &pos) const
{
    int x = pos.x(), y = pos.y();
    const QWidget *w = this;
    while (w) {
        x -= w->data->crect.x();
        y -= w->data->crect.y();
        w = w->isWindow() ? 0 : w->parentWidget();
    }
    return QPoint(x, y);
}

void QWidgetPrivate::updateSystemBackground() {}

#ifndef QT_NO_CURSOR
void QWidgetPrivate::setCursor_sys(const QCursor &cursor)
{
    Q_UNUSED(cursor);
    Q_Q(QWidget);
    qt_qpa_set_cursor(q, false);
}

void QWidgetPrivate::unsetCursor_sys()
{
    Q_Q(QWidget);
    qt_qpa_set_cursor(q, false);
}

#endif //QT_NO_CURSOR

void QWidgetPrivate::setWindowTitle_sys(const QString &caption)
{
    Q_Q(QWidget);
    if (!q->isWindow())
        return;

    if (QWindow *window = q->windowHandle())
        window->setWindowTitle(caption);

}

void QWidgetPrivate::setWindowIcon_sys(bool /*forceReset*/)
{
}

void QWidgetPrivate::setWindowIconText_sys(const QString &iconText)
{
    Q_UNUSED(iconText);
}

QWidget *qt_pressGrab = 0;
QWidget *qt_mouseGrb = 0;
static QWidget *keyboardGrb = 0;

void QWidget::grabMouse()
{
    if (qt_mouseGrb)
        qt_mouseGrb->releaseMouse();

    if (windowHandle())
        windowHandle()->setMouseGrabEnabled(true);

    qt_mouseGrb = this;
    qt_pressGrab = 0;
}

#ifndef QT_NO_CURSOR
void QWidget::grabMouse(const QCursor &cursor)
{
    Q_UNUSED(cursor);

    if (qt_mouseGrb)
        qt_mouseGrb->releaseMouse();

    if (windowHandle())
        windowHandle()->setMouseGrabEnabled(true);

    qt_mouseGrb = this;
    qt_pressGrab = 0;
}
#endif

bool QWidgetPrivate::stealMouseGrab(bool grab)
{
    // This is like a combination of grab/releaseMouse() but with error checking
    // and it has no effect on the result of mouseGrabber().
    Q_Q(QWidget);
    return q->windowHandle() ? q->windowHandle()->setMouseGrabEnabled(grab) : false;
}

void QWidget::releaseMouse()
{
    if (qt_mouseGrb == this) {
        if (windowHandle())
            windowHandle()->setMouseGrabEnabled(false);
        qt_mouseGrb = 0;
    }
}

void QWidget::grabKeyboard()
{
    if (keyboardGrb)
        keyboardGrb->releaseKeyboard();
    if (windowHandle())
        windowHandle()->setKeyboardGrabEnabled(true);
    keyboardGrb = this;
}

bool QWidgetPrivate::stealKeyboardGrab(bool grab)
{
    // This is like a combination of grab/releaseKeyboard() but with error
    // checking and it has no effect on the result of keyboardGrabber().
    Q_Q(QWidget);
    return q->windowHandle() ? q->windowHandle()->setKeyboardGrabEnabled(grab) : false;
}

void QWidget::releaseKeyboard()
{
    if (keyboardGrb == this) {
        if (windowHandle())
            windowHandle()->setKeyboardGrabEnabled(false);
        keyboardGrb = 0;
    }
}

QWidget *QWidget::mouseGrabber()
{
    if (qt_mouseGrb)
        return qt_mouseGrb;
    return qt_pressGrab;
}

QWidget *QWidget::keyboardGrabber()
{
    return keyboardGrb;
}

void QWidget::activateWindow()
{
    if (windowHandle())
        windowHandle()->requestActivateWindow();
}

void QWidgetPrivate::show_sys()
{
    Q_Q(QWidget);
    q->setAttribute(Qt::WA_Mapped);
    if (q->testAttribute(Qt::WA_DontShowOnScreen)) {
        invalidateBuffer(q->rect());
        return;
    }

    QApplication::postEvent(q, new QUpdateLaterEvent(q->rect()));

    if (!q->isWindow() && !q->testAttribute(Qt::WA_NativeWindow))
        return;

    QWindow *window = q->windowHandle();
    if (window) {
        QRect geomRect = q->geometry();
        if (!q->isWindow()) {
            QPoint topLeftOfWindow = q->mapTo(q->nativeParentWidget(),QPoint());
            geomRect.moveTopLeft(topLeftOfWindow);
        }
        const QRect windowRect = window->geometry();
        if (windowRect != geomRect) {
            window->setGeometry(geomRect);
        }

        if (QBackingStore *store = q->backingStore()) {
            if (store->size() != geomRect.size()) {
                store->resize(geomRect.size());
            }
        }

        invalidateBuffer(q->rect());

        if (window)
            window->setVisible(true);
    }
}


void QWidgetPrivate::hide_sys()
{
    Q_Q(QWidget);
    q->setAttribute(Qt::WA_Mapped, false);
    deactivateWidgetCleanup();
    if (!q->isWindow()) {
        QWidget *p = q->parentWidget();
        if (p &&p->isVisible()) {
            invalidateBuffer(q->rect());
        }
        return;
    }
    if (QWindow *window = q->windowHandle()) {
         window->setVisible(false);
    }
}

void QWidgetPrivate::setMaxWindowState_helper()
{
    setFullScreenSize_helper(); //### decoration size
}

void QWidgetPrivate::setFullScreenSize_helper()
{
    Q_Q(QWidget);

    const uint old_state = data.in_set_window_state;
    data.in_set_window_state = 1;

    const QRect screen = qApp->desktop()->screenGeometry(qApp->desktop()->screenNumber(q));
    q->move(screen.topLeft());
    q->resize(screen.size());

    data.in_set_window_state = old_state;
}

static Qt::WindowState effectiveState(Qt::WindowStates state)
 {
     if (state & Qt::WindowMinimized)
         return Qt::WindowMinimized;
     else if (state & Qt::WindowFullScreen)
         return Qt::WindowFullScreen;
     else if (state & Qt::WindowMaximized)
         return Qt::WindowMaximized;
     return Qt::WindowNoState;
 }

void QWidget::setWindowState(Qt::WindowStates newstate)
{
    Q_D(QWidget);
    Qt::WindowStates oldstate = windowState();
    if (oldstate == newstate)
        return;
    if (isWindow() && !testAttribute(Qt::WA_WState_Created))
        create();

    data->window_state = newstate;
    data->in_set_window_state = 1;
    bool needShow = false;
    Qt::WindowState newEffectiveState = effectiveState(newstate);
    Qt::WindowState oldEffectiveState = effectiveState(oldstate);
    if (isWindow() && newEffectiveState != oldEffectiveState) {
        d->createTLExtra();
        if (oldEffectiveState == Qt::WindowNoState)
            d->topData()->normalGeometry = geometry();

        Q_ASSERT(windowHandle());
        windowHandle()->setWindowState(newEffectiveState);
        bool supported = windowHandle()->windowState() == newEffectiveState;

        if (!supported) {
            // undo the effects of the old emulated state
            if (oldEffectiveState == Qt::WindowFullScreen) {
                setParent(0, d->topData()->savedFlags);
                needShow = true;
            } else if (oldEffectiveState == Qt::WindowMinimized) {
                needShow = true;
            }

            // emulate the new window state
            if (newEffectiveState == Qt::WindowMinimized) {
                //### not ideal...
                hide();
                needShow = false;
            } else if (newEffectiveState == Qt::WindowFullScreen) {
                d->topData()->savedFlags = windowFlags();
                setParent(0, Qt::FramelessWindowHint | (windowFlags() & Qt::WindowStaysOnTopHint));
                d->setFullScreenSize_helper();
                raise();
                needShow = true;
            } else if (newEffectiveState == Qt::WindowMaximized) {
                createWinId();
                d->setMaxWindowState_helper();
            } else if (newEffectiveState == Qt::WindowNoState) {
                // reset old geometry
                QRect r = d->topData()->normalGeometry;
                if (r.width() >= 0) {
                    d->topData()->normalGeometry = QRect(0,0,-1,-1);
                    setGeometry(r);
                }
            }
        }
    }
    data->in_set_window_state = 0;

    if (needShow)
        show();

    if (newstate & Qt::WindowActive)
        activateWindow();

    QWindowStateChangeEvent e(oldstate);
    QApplication::sendEvent(this, &e);
}

void QWidgetPrivate::setFocus_sys()
{

}

void QWidgetPrivate::raise_sys()
{
    Q_Q(QWidget);
    if (q->isWindow()) {
        q->windowHandle()->raise();
    }
}

void QWidgetPrivate::lower_sys()
{
    Q_Q(QWidget);
    if (q->isWindow()) {
        Q_ASSERT(q->testAttribute(Qt::WA_WState_Created));
        q->windowHandle()->lower();
    } else if (QWidget *p = q->parentWidget()) {
        setDirtyOpaqueRegion();
        p->d_func()->invalidateBuffer(effectiveRectFor(q->geometry()));
    }
}

void QWidgetPrivate::stackUnder_sys(QWidget*)
{
    Q_Q(QWidget);
    if (QWidget *p = q->parentWidget()) {
        setDirtyOpaqueRegion();
        p->d_func()->invalidateBuffer(effectiveRectFor(q->geometry()));
    }
}

void QWidgetPrivate::setGeometry_sys(int x, int y, int w, int h, bool isMove)
{
    Q_Q(QWidget);
    if (extra) {                                // any size restrictions?
        w = qMin(w,extra->maxw);
        h = qMin(h,extra->maxh);
        w = qMax(w,extra->minw);
        h = qMax(h,extra->minh);
    }

    QPoint oldp = q->geometry().topLeft();
    QSize olds = q->size();
    QRect r(x, y, w, h);

    bool isResize = olds != r.size();
    isMove = oldp != r.topLeft(); //### why do we have isMove as a parameter?


    // We only care about stuff that changes the geometry, or may
    // cause the window manager to change its state
    if (r.size() == olds && oldp == r.topLeft())
        return;

    if (!data.in_set_window_state) {
        q->data->window_state &= ~Qt::WindowMaximized;
        q->data->window_state &= ~Qt::WindowFullScreen;
        if (q->isWindow())
            topData()->normalGeometry = QRect(0, 0, -1, -1);
    }

    QPoint oldPos = q->pos();
    data.crect = r;

    bool needsShow = false;

    if (w == 0 || h == 0) {
        q->setAttribute(Qt::WA_OutsideWSRange, true);
        if (q->isVisible() && q->testAttribute(Qt::WA_Mapped))
            hide_sys();
        data.crect = QRect(x, y, w, h);
    } else if (q->isVisible() && q->testAttribute(Qt::WA_OutsideWSRange)) {
        q->setAttribute(Qt::WA_OutsideWSRange, false);
        needsShow = true;
    }

    if (q->isVisible()) {
        if (!q->testAttribute(Qt::WA_DontShowOnScreen) && !q->testAttribute(Qt::WA_OutsideWSRange)) {
            if (q->windowHandle()) {
                if (q->isWindow()) {
                    qt_window_private(q->windowHandle())->positionPolicy = topData()->posFromMove ? QWindowPrivate::WindowFrameInclusive : QWindowPrivate::WindowFrameExclusive;
                    q->windowHandle()->setGeometry(q->geometry());
                } else {
                    QPoint posInNativeParent =  q->mapTo(q->nativeParentWidget(),QPoint());
                    q->windowHandle()->setGeometry(QRect(posInNativeParent,r.size()));
                }
                const QWidgetBackingStore *bs = maybeBackingStore();
                if (bs->store) {
                    if (isResize)
                        bs->store->resize(r.size());
                }

                if (needsShow)
                    show_sys();
            } else {
                if (isMove && !isResize)
                    moveRect(QRect(oldPos, olds), x - oldPos.x(), y - oldPos.y());
                else
                    invalidateBuffer_resizeHelper(oldPos, olds);
            }
        }

        if (isMove) {
            QMoveEvent e(q->pos(), oldPos);
            QApplication::sendEvent(q, &e);
        }
        if (isResize) {
            QResizeEvent e(r.size(), olds);
            QApplication::sendEvent(q, &e);
            if (q->windowHandle())
                q->update();
        }
    } else { // not visible
        if (isMove && q->pos() != oldPos)
            q->setAttribute(Qt::WA_PendingMoveEvent, true);
        if (isResize)
            q->setAttribute(Qt::WA_PendingResizeEvent, true);
    }

}

void QWidgetPrivate::setConstraints_sys()
{
    Q_Q(QWidget);
    if (extra && q->windowHandle()) {
        QWindow *win = q->windowHandle();
        QWindowPrivate *winp = qt_window_private(win);

        winp->minimumSize = QSize(extra->minw, extra->minh);
        winp->maximumSize = QSize(extra->maxw, extra->maxh);

        if (extra->topextra) {
            winp->baseSize = QSize(extra->topextra->basew, extra->topextra->baseh);
            winp->sizeIncrement = QSize(extra->topextra->incw, extra->topextra->inch);
        }

        if (winp->platformWindow)
            winp->platformWindow->propagateSizeHints();
    }
}

void QWidgetPrivate::scroll_sys(int dx, int dy)
{
    Q_Q(QWidget);
    scrollChildren(dx, dy);
    scrollRect(q->rect(), dx, dy);
}

void QWidgetPrivate::scroll_sys(int dx, int dy, const QRect &r)
{
    scrollRect(r, dx, dy);
}

int QWidget::metric(PaintDeviceMetric m) const
{
    Q_D(const QWidget);

    QPlatformScreen *screen = 0;
    if (QWidget *topLevel = window())
        if (QWindow *topLevelWindow = topLevel->windowHandle())
            screen = QPlatformScreen::platformScreenForWindow(topLevelWindow);
    if (!screen && QGuiApplication::primaryScreen())
        screen = QGuiApplication::primaryScreen()->handle();

    if (!screen) {
        if (m == PdmDpiX || m == PdmDpiY)
              return 72;
        return QPaintDevice::metric(m);
    }
    int val;
    if (m == PdmWidth) {
        val = data->crect.width();
    } else if (m == PdmWidthMM) {
        val = data->crect.width() * screen->physicalSize().width() / screen->geometry().width();
    } else if (m == PdmHeight) {
        val = data->crect.height();
    } else if (m == PdmHeightMM) {
        val = data->crect.height() * screen->physicalSize().height() / screen->geometry().height();
    } else if (m == PdmDepth) {
        return screen->depth();
    } else if (m == PdmDpiX || m == PdmPhysicalDpiX) {
        if (d->extra && d->extra->customDpiX)
            return d->extra->customDpiX;
        else if (d->parent)
            return static_cast<QWidget *>(d->parent)->metric(m);
        return qRound(screen->geometry().width() / double(screen->physicalSize().width() / 25.4));
    } else if (m == PdmDpiY || m == PdmPhysicalDpiY) {
        if (d->extra && d->extra->customDpiY)
            return d->extra->customDpiY;
        else if (d->parent)
            return static_cast<QWidget *>(d->parent)->metric(m);
        return qRound(screen->geometry().height() / double(screen->physicalSize().height() / 25.4));
    } else {
        val = QPaintDevice::metric(m);// XXX
    }
    return val;
}

/*!
    \preliminary

    Returns the QPlatformWindow this widget will be drawn into.
*/
QWindow *QWidget::windowHandle() const
{
    Q_D(const QWidget);
    QTLWExtra *extra = d->maybeTopData();
    if (extra)
        return extra->window;

    return 0;
}

void QWidgetPrivate::createSysExtra()
{
}

void QWidgetPrivate::deleteSysExtra()
{

}

void QWidgetPrivate::createTLSysExtra()
{
    Q_Q(QWidget);
    extra->topextra->screenIndex = 0;
    extra->topextra->window = 0;
    if (q->testAttribute(Qt::WA_NativeWindow) || q->isWindow())
        extra->topextra->window = new QWidgetWindow(q);
}

void QWidgetPrivate::deleteTLSysExtra()
{
    if (extra && extra->topextra) {
        //the toplevel might have a context with a "qglcontext associated with it. We need to
        //delete the qglcontext before we delete the qplatformopenglcontext.
        //One unfortunate thing about this is that we potentially create a glContext just to
        //delete it straight afterwards.
        if (extra->topextra->window) {
            extra->topextra->window->destroy();
        }
        setWinId(0);
        //hmmm. should we delete window..
        delete extra->topextra->window;
        extra->topextra->window = 0;
    }
}

void QWidgetPrivate::registerDropSite(bool on)
{
    Q_UNUSED(on);
}

void QWidgetPrivate::setMask_sys(const QRegion &region)
{
    Q_UNUSED(region);
    // XXX
}

void QWidgetPrivate::updateFrameStrut()
{
    // XXX
}

void QWidgetPrivate::setWindowOpacity_sys(qreal level)
{
    Q_Q(QWidget);
    if (q->windowHandle())
        q->windowHandle()->setOpacity(level);
}

void QWidgetPrivate::setWSGeometry(bool dontShow, const QRect &oldRect)
{
    Q_UNUSED(dontShow);
    Q_UNUSED(oldRect);
    // XXX
}

QPaintEngine *QWidget::paintEngine() const
{
    qWarning("QWidget::paintEngine: Should no longer be called");
    return 0; //##### @@@
}

void QWidgetPrivate::setModal_sys()
{
    Q_Q(QWidget);
    if (q->windowHandle())
        q->windowHandle()->setWindowModality(q->windowModality());
}

#ifndef QT_NO_CURSOR
static void applyCursor(QWidget *w, const QCursor &c)
{
    QCursor cc = c;
    QList<QWeakPointer<QPlatformCursor> > cursors = QPlatformCursorPrivate::getInstances();
    int cursorCount = cursors.count();
    for (int i = 0; i < cursorCount; ++i) {
        const QWeakPointer<QPlatformCursor> &cursor(cursors.at(i));
        if (cursor)
            cursor.data()->changeCursor(&cc, w->window()->windowHandle());
    }
}

void qt_qpa_set_cursor(QWidget *w, bool force)
{
    if (!w->testAttribute(Qt::WA_WState_Created))
        return;

    static QPointer<QWidget> lastUnderMouse = 0;
    if (force) {
        lastUnderMouse = w;
    } else if (lastUnderMouse && lastUnderMouse->effectiveWinId() == w->effectiveWinId()) {
        w = lastUnderMouse;
    } else if (!w->internalWinId()) {
        return; // The mouse is not under this widget, and it's not native, so don't change it.
    }

    while (!w->internalWinId() && w->parentWidget() && !w->isWindow()
           && !w->testAttribute(Qt::WA_SetCursor))
        w = w->parentWidget();

    QWidget *nativeParent = w;
    if (!w->internalWinId())
        nativeParent = w->nativeParentWidget();
    if (!nativeParent || !nativeParent->internalWinId())
        return;

    if (w->isWindow() || w->testAttribute(Qt::WA_SetCursor)) {
        QCursor *oc = QApplication::overrideCursor();
        if (oc)
            applyCursor(nativeParent, *oc);
        else if (w->isEnabled())
            applyCursor(nativeParent, w->cursor());
        else
            // Enforce the windows behavior of clearing the cursor on
            // disabled widgets.
            applyCursor(nativeParent, Qt::ArrowCursor);
    } else {
        applyCursor(nativeParent, Qt::ArrowCursor);
    }
}
#endif //QT_NO_CURSOR 

QT_END_NAMESPACE