/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Quick Layouts module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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** 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.
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** 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
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** included in the packaging of this file. Please review the following
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****************************************************************************/

#ifndef QQUICKSTACKLAYOUT_H
#define QQUICKSTACKLAYOUT_H

#include <QtQuickLayouts/private/qquicklayoutglobal_p.h>
#include <qquicklayout_p.h>

QT_BEGIN_NAMESPACE

class QQuickStackLayoutPrivate;
class QQuickStackLayoutAttached;

class Q_QUICKLAYOUT_PRIVATE_EXPORT QQuickStackLayout : public QQuickLayout
{
    Q_OBJECT
    Q_PROPERTY(int count READ count NOTIFY countChanged)
    Q_PROPERTY(int currentIndex READ currentIndex WRITE setCurrentIndex NOTIFY currentIndexChanged)
    QML_NAMED_ELEMENT(StackLayout)
    QML_ADDED_IN_VERSION(1, 3)
    QML_ATTACHED(QQuickStackLayoutAttached)

public:
    explicit QQuickStackLayout(QQuickItem *parent = 0);
    int count() const;
    int currentIndex() const;
    void setCurrentIndex(int index);

    void componentComplete() override;
    void itemChange(ItemChange change, const ItemChangeData &value) override;
    QSizeF sizeHint(Qt::SizeHint whichSizeHint) const override;
    void setAlignment(QQuickItem *item, Qt::Alignment align)  override;
    void invalidate(QQuickItem *childItem = 0)  override;
    void updateLayoutItems()  override;
    void rearrange(const QSizeF &) override;

    // iterator
    Q_INVOKABLE QQuickItem *itemAt(int index) const override;
    int itemCount() const override;
    int indexOf(QQuickItem *item) const;

    static QQuickStackLayoutAttached *qmlAttachedProperties(QObject *object);

signals:
    void currentIndexChanged();
    void countChanged();

public slots:

private:
    static void collectItemSizeHints(QQuickItem *item, QSizeF *sizeHints);
    bool shouldIgnoreItem(QQuickItem *item) const;
    Q_DECLARE_PRIVATE(QQuickStackLayout)

    friend class QQuickStackLayoutAttached;

    QList<QQuickItem*> m_items;

    struct SizeHints {
        inline QSizeF &min() { return array[Qt::MinimumSize]; }
        inline QSizeF &pref() { return array[Qt::PreferredSize]; }
        inline QSizeF &max() { return array[Qt::MaximumSize]; }
        QSizeF array[Qt::NSizeHints];
    };

    mutable QVector<SizeHints> m_cachedItemSizeHints;
    mutable QSizeF m_cachedSizeHints[Qt::NSizeHints];
};

class QQuickStackLayoutPrivate : public QQuickLayoutPrivate
{
    Q_DECLARE_PUBLIC(QQuickStackLayout)
public:
    QQuickStackLayoutPrivate() : count(0), currentIndex(-1), explicitCurrentIndex(false) {}
private:
    int count;
    int currentIndex;
    bool explicitCurrentIndex;
};

class QQuickStackLayoutAttached : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int index READ index NOTIFY indexChanged)
    Q_PROPERTY(bool isCurrentItem READ isCurrentItem NOTIFY isCurrentItemChanged)
    Q_PROPERTY(QQuickStackLayout *layout READ layout NOTIFY layoutChanged)

public:
    QQuickStackLayoutAttached(QObject *object);

    int index() const;
    void setIndex(int index);

    bool isCurrentItem() const;
    void setIsCurrentItem(bool isCurrentItem);

    QQuickStackLayout *layout() const;
    void setLayout(QQuickStackLayout *layout);

signals:
    void indexChanged();
    void isCurrentItemChanged();
    void layoutChanged();

private:
    int m_index = -1;
    bool m_isCurrentItem = false;
    QQuickStackLayout *m_layout = nullptr;
};

QT_END_NAMESPACE

#endif // QQUICKSTACKLAYOUT_H