/********************************************************************
 KWin - the KDE window manager
 This file is part of the KDE project.

Copyright (C) 2013 Martin Gräßlin <mgraesslin@kde.org>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program 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 General Public License for more details.

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

// KWin includes
#include <kwinglobals.h>
// KDE includes
#include <KConfig>
#include <KSharedConfig>
// Qt includes
#include <QObject>
#include <QRect>
#include <QTimer>
#include <QVector>

namespace KWin
{
class AbstractClient;
class Platform;

class KWIN_EXPORT Screens : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int count READ count WRITE setCount NOTIFY countChanged)
    Q_PROPERTY(int current READ current WRITE setCurrent NOTIFY currentChanged)
    Q_PROPERTY(bool currentFollowsMouse READ isCurrentFollowsMouse WRITE setCurrentFollowsMouse)

public:
    virtual ~Screens();
    /**
     * @internal
     **/
    void setConfig(KSharedConfig::Ptr config);
    int count() const;
    int current() const;
    void setCurrent(int current);
    /**
    * Called e.g. when a user clicks on a window, set current screen to be the screen
    * where the click occurred
    */
    void setCurrent(const QPoint &pos);
    /**
    * Check whether a client moved completely out of what's considered the current screen,
    * if yes, set a new active screen.
    */
    void setCurrent(const AbstractClient *c);
    bool isCurrentFollowsMouse() const;
    void setCurrentFollowsMouse(bool follows);
    virtual QRect geometry(int screen) const = 0;
    /**
     * The bounding geometry of all screens combined. Overlapping areas
     * are not counted multiple times.
     * @see geometryChanged()
     **/
    QRect geometry() const;
    /**
     * The output name of the screen (usually eg. LVDS-1, VGA-0 or DVI-I-1 etc.)
     */
    virtual QString name(int screen) const;
    /**
     * @returns current refreshrate of the @p screen.
     **/
    virtual float refreshRate(int screen) const;
    /**
     * @returns size of the @p screen.
     *
     * To get the size of all screens combined use size().
     * @see size()
     **/
    virtual QSize size(int screen) const = 0;

    /*
     * The output scale for this display, for use by high DPI displays
     */
    virtual qreal scale(int screen) const;
    /**
     * The bounding size of all screens combined. Overlapping areas
     * are not counted multiple times.
     *
     * @see geometry()
     * @see sizeChanged()
     **/
    QSize size() const;
    virtual int number(const QPoint &pos) const = 0;

    inline bool isChanging() { return m_changedTimer->isActive(); }

    int intersecting(const QRect &r) const;

public Q_SLOTS:
    void reconfigure();

Q_SIGNALS:
    void countChanged(int previousCount, int newCount);
    /**
     * Emitted whenever the screens are changed either count or geometry.
     **/
    void changed();
    void currentChanged();
    /**
     * Emitted when the geometry of all screens combined changes.
     * Not emitted when the geometry of an individual screen changes.
     * @see geometry()
     **/
    void geometryChanged();
    /**
     * Emitted when the size of all screens combined changes.
     * Not emitted when the size of an individual screen changes.
     * @see size()
     **/
    void sizeChanged();

protected Q_SLOTS:
    void setCount(int count);
    void startChangedTimer();
    virtual void updateCount() = 0;

protected:
    /**
     * Called once the singleton instance has been created.
     * Any initialization code should go into this method. Overriding classes have to call
     * the base implementation first.
     **/
    virtual void init();

private Q_SLOTS:
    void updateSize();

private:
    int m_count;
    int m_current;
    bool m_currentFollowsMouse;
    QTimer *m_changedTimer;
    KSharedConfig::Ptr m_config;
    QSize m_boundingSize;

    KWIN_SINGLETON(Screens)
};

/**
 * @brief A base implementation for backends with just a (nested) window
 **/
class KWIN_EXPORT BasicScreens : public Screens
{
    Q_OBJECT
public:
    BasicScreens(Platform *backend, QObject *parent = nullptr);
    virtual ~BasicScreens();

    void init() override;
    QRect geometry(int screen) const override;
    int number(const QPoint &pos) const override;
    QSize size(int screen) const override;
    qreal scale(int screen) const override;
    void updateCount() override;

private:
    Platform *m_backend;
    QVector<QRect> m_geometries;
    QVector<qreal> m_scales;
};

inline
void Screens::setConfig(KSharedConfig::Ptr config)
{
    m_config = config;
}

inline
int Screens::count() const
{
    return m_count;
}

inline
bool Screens::isCurrentFollowsMouse() const
{
    return m_currentFollowsMouse;
}

inline
void Screens::startChangedTimer()
{
    m_changedTimer->start();
}

inline
QSize Screens::size() const
{
    return m_boundingSize;
}

inline
QRect Screens::geometry() const
{
    return QRect(QPoint(0,0), size());
}

inline
Screens *screens()
{
    return Screens::self();
}

}

#endif // KWIN_SCREENS_H