/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
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** This file is part of the Qt Quick Templates 2 module of the Qt Toolkit.
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****************************************************************************/

#include "qquicktabbar_p.h"
#include "qquicktabbutton_p.h"
#include "qquickcontainer_p_p.h"

QT_BEGIN_NAMESPACE

/*!
    \qmltype TabBar
    \inherits Container
    \instantiates QQuickTabBar
    \inqmlmodule QtQuick.Controls
    \since 5.7
    \ingroup qtquickcontrols2-navigation
    \ingroup qtquickcontrols2-containers
    \brief A bar with icons allowing to switch between different views or subtasks.

    TabBar provides a tab-based navigation model.

    \image qtquickcontrols2-tabbar-wireframe.png

    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

    \snippet qtquickcontrols2-tabbar.qml 1

    \sa TabButton, {Customizing TabBar}, {Navigation Controls}, {Container Controls}
*/

class QQuickTabBarPrivate : public QQuickContainerPrivate
{
    Q_DECLARE_PUBLIC(QQuickTabBar)

public:
    QQuickTabBarPrivate();

    void updateCurrentItem();
    void updateCurrentIndex();
    void updateLayout();

    QQuickTabBar::Position position;
};

QQuickTabBarPrivate::QQuickTabBarPrivate() : position(QQuickTabBar::Header)
{
}

void QQuickTabBarPrivate::updateCurrentItem()
{
    QQuickTabButton *button = qobject_cast<QQuickTabButton *>(contentModel->get(currentIndex));
    if (button)
        button->setChecked(true);
}

void QQuickTabBarPrivate::updateCurrentIndex()
{
    Q_Q(QQuickTabBar);
    QQuickTabButton *button = qobject_cast<QQuickTabButton *>(q->sender());
    if (button && button->isChecked())
        q->setCurrentIndex(contentModel->indexOf(button, nullptr));
}

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;
                }
            }
        }
    }
}

QQuickTabBar::QQuickTabBar(QQuickItem *parent) :
    QQuickContainer(*(new QQuickTabBarPrivate), parent)
{
    Q_D(QQuickTabBar);
    setFlag(ItemIsFocusScope);
    QObjectPrivate::connect(this, &QQuickTabBar::currentIndexChanged, d, &QQuickTabBarPrivate::updateCurrentItem);
}

/*!
    \qmlproperty enumeration QtQuick.Controls::TabBar::position

    This property holds the position of the tab bar.

    \note If the tab bar is assigned as a header or footer of ApplicationWindow
    or Page, the appropriate position is set automatically.

    Possible values:
    \value TabBar.Header The tab bar is at the top, as a window or page header.
    \value TabBar.Footer The tab bar is at the bottom, as a window or page footer.

    The default value is style-specific.

    \sa ApplicationWindow::header, ApplicationWindow::footer, Page::header, Page::footer
*/
QQuickTabBar::Position QQuickTabBar::position() const
{
    Q_D(const QQuickTabBar);
    return d->position;
}

void QQuickTabBar::setPosition(Position position)
{
    Q_D(QQuickTabBar);
    if (d->position == position)
        return;

    d->position = position;
    emit positionChanged();
}

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

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

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

bool QQuickTabBar::isContent(QQuickItem *item) const
{
    return qobject_cast<QQuickTabButton *>(item);
}

void QQuickTabBar::itemAdded(int index, QQuickItem *item)
{
    Q_D(QQuickTabBar);
    Q_UNUSED(index);
    if (QQuickTabButton *button = qobject_cast<QQuickTabButton *>(item))
        QObjectPrivate::connect(button, &QQuickTabButton::checkedChanged, d, &QQuickTabBarPrivate::updateCurrentIndex);
    if (isComponentComplete())
        polish();
}

void QQuickTabBar::itemRemoved(int index, QQuickItem *item)
{
    Q_D(QQuickTabBar);
    Q_UNUSED(index);
    if (QQuickTabButton *button = qobject_cast<QQuickTabButton *>(item))
        QObjectPrivate::disconnect(button, &QQuickTabButton::checkedChanged, d, &QQuickTabBarPrivate::updateCurrentIndex);
    if (isComponentComplete())
        polish();
}

#ifndef QT_NO_ACCESSIBILITY
QAccessible::Role QQuickTabBar::accessibleRole() const
{
    return QAccessible::PageTabList;
}
#endif

QT_END_NAMESPACE