/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Labs Templates 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 "qquicktabbar_p.h"
#include "qquickcontainer_p_p.h"
#include "qquickexclusivegroup_p.h"

QT_BEGIN_NAMESPACE

/*!
    \qmltype TabBar
    \inherits Container
    \instantiates QQuickTabBar
    \inqmlmodule QtQuick.Controls
    \ingroup tabs
    \brief A tab bar control.

    TabBar provides a tab-based navigation model. TabBar is populated with
    TabButton controls, and can be used together with any layout or container
    control that provides \c currentIndex -property, such as \l StackLayout
    or \l SwipeView

    ### TODO: screenshot

    \code
    ApplicationWindow {
        visible:true

        header: TabBar {
            id: bar
            TabButton {
                text: qsTr("Home")
            }
            TabButton {
                text: qsTr("Discover")
            }
            TabButton {
                text: qsTr("Activity")
            }
        }

        StackLayout {
            anchors.fill: parent
            currentIndex: bar.currentIndex
            Item {
                id: homeTab
            }
            Item {
                id: discoverTab
            }
            Item {
                id: activityTab
            }
        }
    }
    \endcode

    \sa TabButton, {Customizing TabBar}
*/

class QQuickTabBarPrivate : public QQuickContainerPrivate
{
    Q_DECLARE_PUBLIC(QQuickTabBar)

public:
    QQuickTabBarPrivate() : group(Q_NULLPTR) { }

    void updateLayout();
    void updateCurrent();

    void itemInserted(int index, QQuickItem *item)  Q_DECL_OVERRIDE;
    void itemMoved(int from, int to) Q_DECL_OVERRIDE;
    void itemRemoved(QQuickItem *item) Q_DECL_OVERRIDE;

    void onCurrentIndexChanged();

    QQuickExclusiveGroup *group;
};

void QQuickTabBarPrivate::updateLayout()
{
    Q_Q(QQuickTabBar);
    const int count = contentModel->count();
    if (count > 0 && contentItem) {
        const qreal itemWidth = (contentItem->width() - qMax(0, count - 1) * spacing) / count;

        for (int i = 0; i < count; ++i) {
            QQuickItem *item = q->itemAt(i);
            if (item) {
                QQuickItemPrivate *p = QQuickItemPrivate::get(item);
                if (!p->widthValid) {
                    item->setWidth(itemWidth);
                    p->widthValid = false;
                }
            }
        }
    }
}

void QQuickTabBarPrivate::updateCurrent()
{
    Q_Q(QQuickTabBar);
    q->setCurrentIndex(contentModel->indexOf(group->current(), Q_NULLPTR));
}

void QQuickTabBarPrivate::itemInserted(int, QQuickItem *item)
{
    group->addCheckable(item);
}

void QQuickTabBarPrivate::itemMoved(int, int)
{
    updateCurrent();
}

void QQuickTabBarPrivate::itemRemoved(QQuickItem *item)
{
    group->removeCheckable(item);
}

void QQuickTabBarPrivate::onCurrentIndexChanged()
{
    Q_Q(QQuickTabBar);
    if (q->isComponentComplete())
        group->setCurrent(contentModel->get(currentIndex));
}

QQuickTabBar::QQuickTabBar(QQuickItem *parent) :
    QQuickContainer(*(new QQuickTabBarPrivate), parent)
{
    Q_D(QQuickTabBar);
    setFlag(ItemIsFocusScope);
    setAccessibleRole(0x0000003C); //QAccessible::PageTabList

    d->group = new QQuickExclusiveGroup(this);
    connect(d->group, &QQuickExclusiveGroup::currentChanged, this, &QQuickTabBar::currentItemChanged);
    QObjectPrivate::connect(d->group, &QQuickExclusiveGroup::currentChanged, d, &QQuickTabBarPrivate::updateCurrent);

    QObjectPrivate::connect(this, &QQuickContainer::currentIndexChanged, d, &QQuickTabBarPrivate::onCurrentIndexChanged);
}

void QQuickTabBar::updatePolish()
{
    Q_D(QQuickTabBar);
    QQuickContainer::updatePolish();
    d->updateLayout();
}

void QQuickTabBar::componentComplete()
{
    Q_D(QQuickTabBar);
    QQuickContainer::componentComplete();
    d->updateCurrent();
    d->updateLayout();
}

void QQuickTabBar::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    Q_D(QQuickTabBar);
    QQuickContainer::geometryChanged(newGeometry, oldGeometry);
    d->updateLayout();
}

QT_END_NAMESPACE