/********************************************************************
Copyright 2014  Martin Gräßlin <mgraesslin@kde.org>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) version 3, or any
later version accepted by the membership of KDE e.V. (or its
successor approved by the membership of KDE e.V.), which shall
act as a proxy defined in Section 6 of version 3 of the license.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library.  If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#ifndef WAYLAND_SUBSURFACE_H
#define WAYLAND_SUBSURFACE_H

#include <QObject>
#include <QPointer>

#include <KWayland/Client/kwaylandclient_export.h>

struct wl_subsurface;

namespace KWayland
{
namespace Client
{

class Surface;

/**
 * @short Wrapper for the wl_subsurface interface.
 *
 * This class is a convenient wrapper for the wl_subsurface interface.
 * To create a SubSurface call SubCompositor::createSubSurface.
 *
 * A SubSurface is bound to a Surface and has a parent Surface.
 * A SubSurface can only be created for a Surface not already used in onther way,
 * e.g. as a ShellSurface.
 *
 * The SubSurface has a position in local coordinates to the parent Surface.
 * Please note that changing the position is a double buffered state and is only
 * applied once the parent surface is committed. The same applies for manipulating
 * the stacking order of the SubSurface's siblings.
 *
 * @see SubCompositor
 * @see Surface
 **/
class KWAYLANDCLIENT_EXPORT SubSurface : public QObject
{
    Q_OBJECT
public:
    explicit SubSurface(QPointer<Surface> surface, QPointer<Surface> parentSurface, QObject *parent = nullptr);
    virtual ~SubSurface();

    /**
     * @returns @c true if managing a wl_subsurface.
     **/
    bool isValid() const;
    /**
     * Setup this SubSurface to manage the @p subsurface.
     * When using SubCompositor::createSubSurface there is no need to call this
     * method.
     **/
    void setup(wl_subsurface *subsurface);
    /**
     * Releases the wl_subsurface interface.
     * After the interface has been released the SubSurface instance is no
     * longer valid and can be setup with another wl_subsurface interface.
     **/
    void release();
    /**
     * Destroys the data held by this SubSurface.
     * This method is supposed to be used when the connection to the Wayland
     * server goes away. If the connection is not valid anymore, it's not
     * possible to call release anymore as that calls into the Wayland
     * connection and the call would fail. This method cleans up the data, so
     * that the instance can be deleted or set up to a new wl_subsurface interface
     * once there is a new connection available.
     *
     * @see release
     **/
    void destroy();

    /**
     * Operation Mode on how the Surface's commit should behave.
     **/
    enum class Mode {
        Synchronized,
        Desynchronized
    };

    /**
     * Sets the operation mode to @p mode.
     * Initially a SubSurface is in Synchronized Mode.
     **/
    void setMode(Mode mode);
    Mode mode() const;

    /**
     * Sets the position in relative coordinates to the parent surface to @p pos.
     *
     * The change is only applied after the parent Surface got committed.
     **/
    void setPosition(const QPoint &pos);
    QPoint position() const;

    /**
     * Raises this SubSurface above all siblings.
     * This is the same as calling placeAbove with the parent surface
     * as argument.
     *
     * The change is only applied after the parent surface got committed.
     * @see placeAbove
     **/
    void raise();
    /**
     * Places the SubSurface above the @p sibling.
     *
     * The change is only applied after the parent surface got committed.
     * @param sibling The SubSurface on top of which this SubSurface should be placed
     **/
    void placeAbove(QPointer<SubSurface> sibling);
    /**
     * Places the SubSurface above the @p referenceSurface.
     *
     * In case @p referenceSurface is the parent surface this SubSurface is
     * raised to the top of the stacking order. Otherwise it is put directly
     * above the @p referenceSurface in the stacking order.
     *
     * The change is only applied after the parent surface got committed.
     * @param referenceSurface Either a sibling or parent Surface
     **/
    void placeAbove(QPointer<Surface> referenceSurface);

    /**
     * Lowers this SubSurface below all siblings.
     * This is the same as calling placeBelow with the parent surface
     * as argument.
     *
     * The change is only applied after the parent surface got committed.
     * @see placeBelow
     **/
    void lower();
    /**
     * Places the SubSurface below the @p sibling.
     *
     * The change is only applied after the parent surface got committed.
     * @param sibling The SubSurface under which the SubSurface should be put
     **/
    void placeBelow(QPointer<SubSurface> sibling);
    /**
     * Places the SubSurface below the @p referenceSurface.
     *
     * In case @p referenceSurface is the parent surface this SubSurface is
     * lowered to the bottom of the stacking order. Otherwise it is put directly
     * below the @p referenceSurface in the stacking order.
     *
     * The change is only applied after the parent surface got committed.
     * @param referenceSurface Either a sibling or parent Surface
     **/
    void placeBelow(QPointer<Surface> referenceSurface);

    /**
     * @returns The Surface for which this SubSurface got created.
     **/
    QPointer<Surface> surface() const;
    /**
     * @returns The parent Surface of this SubSurface.
     **/
    QPointer<Surface> parentSurface() const;

    static QPointer<SubSurface> get(wl_subsurface *native);

    operator wl_subsurface*();
    operator wl_subsurface*() const;

private:
    class Private;
    QScopedPointer<Private> d;
};

}
}

#endif
