/****************************************************************************

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

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** Contact: Nokia Corporation (qt-info@nokia.com)

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** This file is part of the Qt Designer of the Qt Toolkit.

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** contained in the Technology Preview License Agreement accompanying

** this package.

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** GNU Lesser General Public License Usage

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** 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

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**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

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** If you have questions regarding the use of this file, please contact

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** $QT_END_LICENSE$

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****************************************************************************/

#include "qdesigner_widgetitem_p.h"

#include "qdesigner_widget_p.h"

#include "widgetfactory_p.h"

#include <QtDesigner/QDesignerFormWindowInterface>

#include <QtDesigner/QExtensionManager>

#include <QtDesigner/QDesignerFormEditorInterface>

#include <QtDesigner/QDesignerContainerExtension>

#include <QtDesigner/QDesignerWidgetDataBaseInterface>

#include <QtGui/QVBoxLayout>

#include <QtGui/QHBoxLayout>

#include <QtGui/QGridLayout>

#include <QtGui/QFormLayout>

#include <QtGui/QApplication>

#include <QtCore/QTextStream>

#include <QtCore/QDebug>

#include <private/qlayout_p.h>

QT_BEGIN_NAMESPACE

enum { DebugWidgetItem = 0 };

enum { MinimumLength = 10 };

// Widget item creation function to be registered as factory method with

// QLayoutPrivate

static QWidgetItem *createDesignerWidgetItem(const QLayout *layout, QWidget *widget)

{

    Qt::Orientations orientations;

    if (qdesigner_internal::QDesignerWidgetItem::check(layout, widget, &orientations)) {

        if (DebugWidgetItem)

            qDebug() << "QDesignerWidgetItem: Creating on " << layout << widget << orientations;

        return new qdesigner_internal::QDesignerWidgetItem(layout, widget, orientations);

    }

    if (DebugWidgetItem)

        qDebug() << "QDesignerWidgetItem: Noncontainer: " << layout << widget;

    return 0;

}

static QString sizePolicyToString(const QSizePolicy &p)

{

    QString rc; {

        QTextStream str(&rc);

        str << "Control=" << p.controlType() << " expdirs=" << p.expandingDirections()

            << " hasHeightForWidth=" << p.hasHeightForWidth()

            << " H: Policy=" << p.horizontalPolicy()

            << " stretch=" << p.horizontalStretch()

            << " V: Policy=" << p.verticalPolicy()

            << " stretch=" << p.verticalStretch();

    }

    return rc;

}

// Find the layout the item is contained in, recursing over

// child layouts

static const QLayout *findLayoutOfItem(const QLayout *haystack, const QLayoutItem *needle)

{

    const int count = haystack->count();

    for (int i = 0; i < count; i++) {

        QLayoutItem *item = haystack->itemAt(i);

        if (item == needle)

            return haystack;

        if (QLayout *childLayout =  item->layout())

            if (const QLayout *containing = findLayoutOfItem(childLayout, needle))

                return containing;

    }

    return 0;

}

namespace qdesigner_internal {

// ------------------ QDesignerWidgetItem

QDesignerWidgetItem::QDesignerWidgetItem(const QLayout *containingLayout, QWidget *w, Qt::Orientations o) :

    QWidgetItemV2(w),

    m_orientations(o),

    m_nonLaidOutMinSize(w->minimumSizeHint()),

    m_nonLaidOutSizeHint(w->sizeHint()),

    m_cachedContainingLayout(containingLayout)

{

    // Initialize the minimum size to prevent nonlaid-out frames/widgets

    // from being slammed to zero

    const QSize minimumSize = w->minimumSize();

    if (!minimumSize.isEmpty())

        m_nonLaidOutMinSize = minimumSize;

    expand(&m_nonLaidOutMinSize);

    expand(&m_nonLaidOutSizeHint);

    w->installEventFilter(this);

    connect(containingLayout, SIGNAL(destroyed()), this, SLOT(layoutChanged()));

    if (DebugWidgetItem )

        qDebug() << "QDesignerWidgetItem"  << w <<  sizePolicyToString(w->sizePolicy()) << m_nonLaidOutMinSize << m_nonLaidOutSizeHint;

}

void QDesignerWidgetItem::expand(QSize *s) const

{

    // Expand the size if its too small

    if (m_orientations & Qt::Horizontal && s->width() <= 0)

        s->setWidth(MinimumLength);

    if (m_orientations & Qt::Vertical && s->height() <= 0)

        s->setHeight(MinimumLength);

}

QSize QDesignerWidgetItem::minimumSize() const

{

    // Just track the size in case we are laid-out or stretched.

    const QSize baseMinSize = QWidgetItemV2::minimumSize();

    QWidget * w = constWidget();

    if (w->layout() || subjectToStretch(containingLayout(), w)) {

        m_nonLaidOutMinSize = baseMinSize;

        return baseMinSize;

    }

    // Nonlaid out: Maintain last laid-out size

    const QSize rc = baseMinSize.expandedTo(m_nonLaidOutMinSize);

    if (DebugWidgetItem > 1)

         qDebug() << "minimumSize" << constWidget() <<  baseMinSize << rc;

    return rc;

}

QSize QDesignerWidgetItem::sizeHint()    const

{

    // Just track the size in case we are laid-out or stretched.

    const QSize baseSizeHint = QWidgetItemV2::sizeHint();

    QWidget * w = constWidget();

    if (w->layout() || subjectToStretch(containingLayout(), w)) {

        m_nonLaidOutSizeHint = baseSizeHint;

        return baseSizeHint;

    }

    // Nonlaid out: Maintain last laid-out size

    const QSize rc = baseSizeHint.expandedTo(m_nonLaidOutSizeHint);

    if (DebugWidgetItem > 1)

        qDebug() << "sizeHint" << constWidget() << baseSizeHint << rc;

    return rc;

}

bool QDesignerWidgetItem::subjectToStretch(const QLayout *layout, QWidget *w)

{

    if (!layout)

        return false;

    // Are we under some stretch factor?

    if (const QBoxLayout *bl = qobject_cast<const QBoxLayout *>(layout)) {

        const int index = bl->indexOf(w);

        Q_ASSERT(index != -1);

        return bl->stretch(index) != 0;

    }

    if (const QGridLayout *cgl = qobject_cast<const QGridLayout *>(layout)) {

        QGridLayout *gl = const_cast<QGridLayout *>(cgl);

        const int index = cgl->indexOf(w);

        Q_ASSERT(index != -1);

        int row, column, rowSpan, columnSpan;

        gl->getItemPosition (index, &row, &column, &rowSpan, &columnSpan);

        const int rend = row + rowSpan;

        const int cend = column + columnSpan;

        for (int r = row; r < rend; r++)

            if (cgl->rowStretch(r) != 0)

                return true;

        for (int c = column; c < cend; c++)

            if (cgl->columnStretch(c) != 0)

                return true;

    }

    return false;

}

/* Return the orientations mask for a layout, specifying

 * in which directions squeezing should be prevented. */

static Qt::Orientations layoutOrientation(const QLayout *layout)

{

    if (const QBoxLayout *bl = qobject_cast<const QBoxLayout *>(layout)) {

        const QBoxLayout::Direction direction = bl->direction();

        return direction == QBoxLayout::LeftToRight || direction == QBoxLayout::RightToLeft ? Qt::Horizontal : Qt::Vertical;

    }

    if (qobject_cast<const QFormLayout*>(layout))

        return  Qt::Vertical;

    return Qt::Horizontal|Qt::Vertical;

}

// Check for a non-container extension container

bool  QDesignerWidgetItem::isContainer(const QDesignerFormEditorInterface *core, QWidget *w)

{

    if (!WidgetFactory::isFormEditorObject(w))

        return false;

    const QDesignerWidgetDataBaseInterface *wdb = core->widgetDataBase();

    const int widx = wdb->indexOfObject(w);

    if (widx == -1 || !wdb->item(widx)->isContainer())

        return false;

    if (qt_extension<QDesignerContainerExtension*>(core->extensionManager(), w))

        return false;

    return true;

}

bool QDesignerWidgetItem::check(const QLayout *layout, QWidget *w, Qt::Orientations *ptrToOrientations)

{

    // Check for form-editor non-containerextension-containers (QFrame, etc)

    // within laid-out form editor widgets. No check for managed() here as we

    // want container pages and widgets in the process of being morphed as

    // well. Avoid nested layouts (as the effective stretch cannot be easily

    // computed and may mess things up). Won't work for Q3 Group boxes.

    if (ptrToOrientations)

        *ptrToOrientations = 0;

    const QObject *layoutParent = layout->parent();

    if (!layoutParent || !layoutParent->isWidgetType() || !WidgetFactory::isFormEditorObject(layoutParent))

        return false;

    QDesignerFormWindowInterface *fw = QDesignerFormWindowInterface::findFormWindow(w);

    if (!fw || !isContainer(fw->core(), w))

        return false;

    // If it is a box, restrict to its orientation

    if (ptrToOrientations)

        *ptrToOrientations = layoutOrientation(layout);

    return true;

}

QSize QDesignerWidgetItem::nonLaidOutMinSize() const

{

    return m_nonLaidOutMinSize;

}

void QDesignerWidgetItem::setNonLaidOutMinSize(const QSize &s)

{

    if (DebugWidgetItem > 1)

        qDebug() << "setNonLaidOutMinSize" << constWidget() << s;

    m_nonLaidOutMinSize = s;

}

QSize QDesignerWidgetItem::nonLaidOutSizeHint() const

{

    return m_nonLaidOutSizeHint;

}

void QDesignerWidgetItem::setNonLaidOutSizeHint(const QSize &s)

{

    if (DebugWidgetItem > 1)

        qDebug() << "setNonLaidOutSizeHint" << constWidget() << s;

    m_nonLaidOutSizeHint = s;

}

void QDesignerWidgetItem::install()

{

    QLayoutPrivate::widgetItemFactoryMethod = createDesignerWidgetItem;

}

void QDesignerWidgetItem::deinstall()

{

    QLayoutPrivate::widgetItemFactoryMethod = 0;

}

const QLayout *QDesignerWidgetItem::containingLayout() const

{

    if (!m_cachedContainingLayout) {

        if (QWidget *parentWidget = constWidget()->parentWidget())

            if (QLayout *parentLayout = parentWidget->layout()) {

                m_cachedContainingLayout = findLayoutOfItem(parentLayout, this);

                if (m_cachedContainingLayout)

                    connect(m_cachedContainingLayout, SIGNAL(destroyed()), this, SLOT(layoutChanged()));

            }

        if (DebugWidgetItem)

            qDebug() << Q_FUNC_INFO << " found " << m_cachedContainingLayout << " after reparenting " << constWidget();

    }

    return m_cachedContainingLayout;

}

void QDesignerWidgetItem::layoutChanged()        

{

    if (DebugWidgetItem)

        qDebug() << Q_FUNC_INFO;

    m_cachedContainingLayout = 0;

}

bool QDesignerWidgetItem::eventFilter(QObject * /* watched */, QEvent *event)

{    

    if (event->type() == QEvent::ParentChange)

        layoutChanged();

    return false;

}

// ------------------   QDesignerWidgetItemInstaller

int QDesignerWidgetItemInstaller::m_instanceCount = 0;

QDesignerWidgetItemInstaller::QDesignerWidgetItemInstaller()

{

    if (m_instanceCount++ == 0) {

        if (DebugWidgetItem)

            qDebug() << "QDesignerWidgetItemInstaller: installing";

        QDesignerWidgetItem::install();

    }

}

QDesignerWidgetItemInstaller::~QDesignerWidgetItemInstaller()

{

    if (--m_instanceCount == 0) {

        if (DebugWidgetItem)

            qDebug() << "QDesignerWidgetItemInstaller: deinstalling";

        QDesignerWidgetItem::deinstall();

    }

}

}

QT_END_NAMESPACE