/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Quick Controls module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 https://www.qt.io/terms-conditions. For further
** information use the contact form at https://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.LGPL3 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-3.0.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 (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquickexclusivegroup_p.h"

#include <qvariant.h>
#include <qdebug.h>
#include "qquickaction_p.h"

#define CHECKED_PROPERTY "checked"

QT_BEGIN_NAMESPACE

static const char *checkableSignals[] = {
    CHECKED_PROPERTY"Changed()",
    "toggled(bool)",
    "toggled()",
    0
};

static bool isChecked(const QObject *o)
{
    if (!o) return false;
    QVariant checkedVariant = o->property(CHECKED_PROPERTY);
    return checkedVariant.isValid() && checkedVariant.toBool();
}

/*!
    \qmltype ExclusiveGroup
    \instantiates QQuickExclusiveGroup1
    \ingroup controls
    \inqmlmodule QtQuick.Controls
    \brief ExclusiveGroup provides a way to declare several checkable controls as mutually exclusive.

    ExclusiveGroup can contain several \l Action items, and those will automatically get their
    \l Action::exclusiveGroup property assigned.

    \code
    ExclusiveGroup {
        id: radioInputGroup

        Action {
            id: dabRadioInput
            text: "DAB"
            checkable: true
        }

        Action {
            id: fmRadioInput
            text: "FM"
            checkable: true
        }

        Action {
            id: amRadioInput
            text: "AM"
            checkable: true
        }
    }
    \endcode

    Several controls already support ExclusiveGroup, e.g. \l Action,
    \l MenuItem, \l {QtQuick.Controls::}{Button}, and \l RadioButton.

    As ExclusiveGroup only supports \l Action as child items, we need to manually
    assign the \c exclusiveGroup property for other objects.

    \code
    GroupBox {
        id: group2
        title: qsTr("Tab Position")
        Layout.fillWidth: true
        RowLayout {
            ExclusiveGroup { id: tabPositionGroup }
            RadioButton {
                id: topButton
                text: qsTr("Top")
                checked: true
                exclusiveGroup: tabPositionGroup
                Layout.minimumWidth: 100
            }
            RadioButton {
                id: bottomButton
                text: qsTr("Bottom")
                exclusiveGroup: tabPositionGroup
                Layout.minimumWidth: 100
            }
        }
    }
    \endcode

    \section1 Adding support to ExclusiveGroup

    It is possible to add support for ExclusiveGroup for an object or control. It should have a \c checked
    property, and either a \c checkedChanged, \c toggled(), or \c toggled(bool) signal. It also needs
    to be bound with \l ExclusiveGroup::bindCheckable() when its ExclusiveGroup typed property is set.

    \code
    Item {
        id: myItem

        property bool checked: false
        property ExclusiveGroup exclusiveGroup: null

        onExclusiveGroupChanged: {
            if (exclusiveGroup)
                exclusiveGroup.bindCheckable(myItem)
        }
    }
    \endcode

    The example above shows the minimum code necessary to add ExclusiveGroup support to any item.
*/

/*!
    \qmlproperty object ExclusiveGroup::current

    The currently selected object. Defaults to the first checked object bound to the ExclusiveGroup.
    If there is none, then it defaults to \c null.
*/

/*!
    \qmlmethod void ExclusiveGroup::bindCheckable(object)

    Registers \a object to the exclusive group.

    You should only need to call this function when creating a component you want to be compatible with ExclusiveGroup.

    \sa ExclusiveGroup::unbindCheckable()
*/

/*!
    \qmlmethod void ExclusiveGroup::unbindCheckable(object)

    Unregisters \a object from the exclusive group.

    You should only need to call this function when creating a component you want to be compatible with ExclusiveGroup.

    \sa ExclusiveGroup::bindCheckable()
*/

QQuickExclusiveGroup1::QQuickExclusiveGroup1(QObject *parent)
    : QObject(parent), m_current(0)
{
    int index = metaObject()->indexOfMethod("updateCurrent()");
    m_updateCurrentMethod = metaObject()->method(index);
}

QQmlListProperty<QQuickAction1> QQuickExclusiveGroup1::actions()
{
    return QQmlListProperty<QQuickAction1>(this, 0, &QQuickExclusiveGroup1::append_actions, 0, 0, 0);
}

void QQuickExclusiveGroup1::append_actions(QQmlListProperty<QQuickAction1> *list, QQuickAction1 *action)
{
    if (QQuickExclusiveGroup1 *eg = qobject_cast<QQuickExclusiveGroup1 *>(list->object))
        action->setExclusiveGroup(eg);
}

void QQuickExclusiveGroup1::setCurrent(QObject * o)
{
    if (m_current == o)
        return;

    if (m_current)
        m_current->setProperty(CHECKED_PROPERTY, QVariant(false));
    m_current = o;
    if (m_current)
        m_current->setProperty(CHECKED_PROPERTY, QVariant(true));
    emit currentChanged();
}

void QQuickExclusiveGroup1::updateCurrent()
{
    QObject *checkable = sender();
    if (isChecked(checkable))
        setCurrent(checkable);
}

void QQuickExclusiveGroup1::bindCheckable(QObject *o)
{
    for (const char **signalName = checkableSignals; *signalName; signalName++) {
        int signalIndex = o->metaObject()->indexOfSignal(*signalName);
        if (signalIndex != -1) {
            QMetaMethod signalMethod = o->metaObject()->method(signalIndex);
            connect(o, signalMethod, this, m_updateCurrentMethod, Qt::UniqueConnection);
            connect(o, SIGNAL(destroyed(QObject*)), this, SLOT(unbindCheckable(QObject*)), Qt::UniqueConnection);
            if (!m_current && isChecked(o))
                setCurrent(o);
            return;
        }
    }

    qWarning() << "QQuickExclusiveGroup1::bindCheckable(): Cannot bind to" << o;
}

void QQuickExclusiveGroup1::unbindCheckable(QObject *o)
{
    if (m_current == o)
        setCurrent(0);
    for (const char **signalName = checkableSignals; *signalName; signalName++) {
        int signalIndex = o->metaObject()->indexOfSignal(*signalName);
        if (signalIndex != -1) {
            QMetaMethod signalMethod = o->metaObject()->method(signalIndex);
            if (disconnect(o, signalMethod, this, m_updateCurrentMethod)) {
                disconnect(o, SIGNAL(destroyed(QObject*)), this, SLOT(unbindCheckable(QObject*)));
                break;
            }
        }
    }
}

QT_END_NAMESPACE