/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the Qt Quick Controls module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** 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
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** use the contact form at http://qt.digia.com/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 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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** $QT_END_LICENSE$
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****************************************************************************/

#include "qquickmenupopupwindow_p.h"

#include <qguiapplication.h>
#include <qpa/qwindowsysteminterface.h>
#include <qquickitem.h>
#include <QtGui/QScreen>
#include <QtQuick/QQuickRenderControl>

QT_BEGIN_NAMESPACE

QQuickMenuPopupWindow::QQuickMenuPopupWindow() :
    m_itemAt(0),
    m_logicalParentWindow(0)
{
}

void QQuickMenuPopupWindow::setParentItem(QQuickItem *item)
{
    QQuickPopupWindow::setParentItem(item);
    if (item) {
        QWindow *parentWindow = item->window();
        QWindow *renderWindow = QQuickRenderControl::renderWindowFor(static_cast<QQuickWindow *>(parentWindow));
        setParentWindow(renderWindow ? renderWindow : parentWindow, item->window());
    }
}

void QQuickMenuPopupWindow::setItemAt(QQuickItem *menuItem)
{
    if (m_itemAt) {
        disconnect(m_itemAt, SIGNAL(xChanged()), this, SLOT(updatePosition()));
        disconnect(m_itemAt, SIGNAL(yChanged()), this, SLOT(updatePosition()));
    }

    m_itemAt = menuItem;
    if (menuItem) {
        m_oldItemPos = menuItem->position().toPoint();
        connect(menuItem, SIGNAL(xChanged()), this, SLOT(updatePosition()));
        connect(menuItem, SIGNAL(yChanged()), this, SLOT(updatePosition()));
    }
}

void QQuickMenuPopupWindow::setParentWindow(QWindow *effectiveParentWindow, QQuickWindow *parentWindow)
{
    while (effectiveParentWindow && effectiveParentWindow->parent())
        effectiveParentWindow = effectiveParentWindow->parent();
    if (transientParent() != effectiveParentWindow)
        setTransientParent(effectiveParentWindow);
    m_logicalParentWindow = parentWindow;
    if (parentWindow) {
        connect(parentWindow, SIGNAL(destroyed()), this, SLOT(dismissPopup()));
        if (QQuickMenuPopupWindow *pw = qobject_cast<QQuickMenuPopupWindow *>(parentWindow))
            connect(pw, SIGNAL(popupDismissed()), this, SLOT(dismissPopup()));
    }
}

void QQuickMenuPopupWindow::setGeometry(int posx, int posy, int w, int h)
{
    QWindow *pw = transientParent();
    if (!pw && parentItem())
        pw = parentItem()->window();
    if (!pw)
        pw = this;
    QRect g = pw->screen()->virtualGeometry();

    if (posx + w > g.right()) {
        if (qobject_cast<QQuickMenuPopupWindow *>(transientParent())) {
            // reposition submenu window on the parent menu's left side
            int submenuOverlap = pw->x() + pw->width() - posx;
            posx -= pw->width() + w - 2 * submenuOverlap;
        } else {
            posx = g.right() - w;
        }
    } else {
        posx = qMax(posx, g.left());
    }

    posy = qBound(g.top(), posy, g.bottom() - h);

    QQuickWindow::setGeometry(posx, posy, w, h);
    emit geometryChanged();
}

void QQuickMenuPopupWindow::updateSize()
{
    qreal x = m_initialPos.x();
    qreal y = m_initialPos.y();
    if (qGuiApp->layoutDirection() == Qt::RightToLeft)
        x -= popupContentItem()->width();
    setGeometry(x, y, popupContentItem()->width(), popupContentItem()->height());
}

void QQuickMenuPopupWindow::updatePosition()
{
    QPointF newPos = position() + m_oldItemPos - m_itemAt->position();
    m_initialPos += m_oldItemPos - m_itemAt->position();
    setGeometry(newPos.x(), newPos.y(), width(), height());
}

void QQuickMenuPopupWindow::exposeEvent(QExposeEvent *e)
{
    // the popup will reposition at the last moment, so its
    // initial position must be captured for updateSize().
    m_initialPos = position();
    if (m_logicalParentWindow && m_logicalParentWindow->parent()) {
        // This must be a QQuickWindow embedded via createWindowContainer.
        m_initialPos += m_logicalParentWindow->geometry().topLeft();
    }
    QQuickPopupWindow::exposeEvent(e);
}

QT_END_NAMESPACE