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

    SPDX-FileCopyrightText: 1999, 2000 Matthias Ettrich <ettrich@kde.org>
    SPDX-FileCopyrightText: 2003 Lubos Lunak <l.lunak@kde.org>

    SPDX-License-Identifier: GPL-2.0-or-later
*/

#ifndef KWIN_UTILS_H
#define KWIN_UTILS_H

// cmake stuff
#include <config-kwin.h>
#include <kwinconfig.h>
// kwin
#include <kwinglobals.h>
// Qt
#include <QLoggingCategory>
#include <QList>
#include <QMatrix4x4>
#include <QPoint>
#include <QRect>
#include <QScopedPointer>
#include <QProcess>
// system
#include <climits>
Q_DECLARE_LOGGING_CATEGORY(KWIN_CORE)
Q_DECLARE_LOGGING_CATEGORY(KWIN_VIRTUALKEYBOARD)
namespace KWin
{
Q_NAMESPACE

const QPoint invalidPoint(INT_MIN, INT_MIN);

enum Layer {
    UnknownLayer = -1,
    FirstLayer = 0,
    DesktopLayer = FirstLayer,
    BelowLayer,
    NormalLayer,
    DockLayer,
    AboveLayer,
    NotificationLayer, // layer for windows of type notification
    ActiveLayer, // active fullscreen, or active dialog
    CriticalNotificationLayer, // layer for notifications that should be shown even on top of fullscreen
    OnScreenDisplayLayer, // layer for On Screen Display windows such as volume feedback
    UnmanagedLayer, // layer for override redirect windows.
    NumLayers, // number of layers, must be last
};
Q_ENUM_NS(Layer)

enum StrutArea {
    StrutAreaInvalid = 0, // Null
    StrutAreaTop     = 1 << 0,
    StrutAreaRight   = 1 << 1,
    StrutAreaBottom  = 1 << 2,
    StrutAreaLeft    = 1 << 3,
    StrutAreaAll     = StrutAreaTop | StrutAreaRight | StrutAreaBottom | StrutAreaLeft,
};
Q_DECLARE_FLAGS(StrutAreas, StrutArea)

class StrutRect : public QRect
{
public:
    explicit StrutRect(QRect rect = QRect(), StrutArea area = StrutAreaInvalid);
    StrutRect(int x, int y, int width, int height, StrutArea area = StrutAreaInvalid);
    StrutRect(const StrutRect& other);
    StrutRect &operator=(const StrutRect& other);
    inline StrutArea area() const {
        return m_area;
    }
private:
    StrutArea m_area;
};
typedef QVector<StrutRect> StrutRects;

enum ShadeMode {
    ShadeNone, // not shaded
    ShadeNormal, // normally shaded - isShade() is true only here
    ShadeHover, // "shaded", but visible due to hover unshade
    ShadeActivated // "shaded", but visible due to alt+tab to the window
};

/**
 * Maximize mode. These values specify how a window is maximized.
 *
 * @note these values are written to session files, don't change the order
 */
enum MaximizeMode {
    MaximizeRestore    = 0, ///< The window is not maximized in any direction.
    MaximizeVertical   = 1, ///< The window is maximized vertically.
    MaximizeHorizontal = 2, ///< The window is maximized horizontally.
    /// Equal to @p MaximizeVertical | @p MaximizeHorizontal
    MaximizeFull = MaximizeVertical | MaximizeHorizontal,
};

inline
MaximizeMode operator^(MaximizeMode m1, MaximizeMode m2)
{
    return MaximizeMode(int(m1) ^ int(m2));
}

enum class QuickTileFlag {
    None        = 0,
    Left        = 1 << 0,
    Right       = 1 << 1,
    Top         = 1 << 2,
    Bottom      = 1 << 3,
    Horizontal  = Left | Right,
    Vertical    = Top | Bottom,
    Maximize    = Left | Right | Top | Bottom,
};
Q_DECLARE_FLAGS(QuickTileMode, QuickTileFlag)

template <typename T> using ScopedCPointer = QScopedPointer<T, QScopedPointerPodDeleter>;

void KWIN_EXPORT updateXTime();
void KWIN_EXPORT grabXServer();
void KWIN_EXPORT ungrabXServer();
bool KWIN_EXPORT grabXKeyboard(xcb_window_t w = XCB_WINDOW_NONE);
void KWIN_EXPORT ungrabXKeyboard();

/**
 * QPainter::setWindow() doesn't work as expected when the device pixel ratio of the paint
 * device is less than 1.
 *
 * QPainter simply doesn't allow the effective scale factor to be less than 1. Use this function
 * to determine the effective device pixel ratio by which the window rect has to be scaled.
 */
qreal KWIN_EXPORT qPainterEffectiveDevicePixelRatio(const QPainter *painter);

static inline QRegion KWIN_EXPORT mapRegion(const QMatrix4x4 &matrix, const QRegion &region)
{
    QRegion result;
    for (const QRect &rect : region) {
        result += matrix.mapRect(rect);
    }
    return result;
}

/**
 * Small helper class which performs grabXServer in the ctor and
 * ungrabXServer in the dtor. Use this class to ensure that grab and
 * ungrab are matched.
 */
class XServerGrabber
{
public:
    XServerGrabber() {
        grabXServer();
    }
    ~XServerGrabber() {
        ungrabXServer();
    }
};

// the docs say it's UrgencyHint, but it's often #defined as XUrgencyHint
#ifndef UrgencyHint
#define UrgencyHint XUrgencyHint
#endif

// converting between X11 mouse/keyboard state mask and Qt button/keyboard states
Qt::MouseButton x11ToQtMouseButton(int button);
Qt::MouseButton KWIN_EXPORT x11ToQtMouseButton(int button);
Qt::MouseButtons KWIN_EXPORT x11ToQtMouseButtons(int state);
Qt::KeyboardModifiers KWIN_EXPORT x11ToQtKeyboardModifiers(int state);

/**
 * Separate the concept of an unet QPoint and 0,0
 */
class ClearablePoint
{
public:
    inline bool isValid() const {
        return m_valid;
    }

    inline void clear(){
        m_valid = false;
    }

    inline void setPoint(const QPoint &point) {
        m_point = point; m_valid = true;
    }

    inline QPoint point() const {
        return m_point;
    }

private:
    QPoint m_point;
    bool m_valid = false;
};

/**
 * QProcess subclass which unblocks SIGUSR in the child process.
 */
class KWIN_EXPORT Process : public QProcess
{
    Q_OBJECT
public:
    explicit Process(QObject *parent = nullptr);
    ~Process() override;

#ifndef KCMRULES
protected:
    void setupChildProcess() override;
#endif
};

/**
 * The DamageJournal class is a helper that tracks last N damage regions.
 */
class KWIN_EXPORT DamageJournal
{
public:
    /**
     * Returns the maximum number of damage regions that can be stored in the journal.
     */
    int capacity() const
    {
        return m_capacity;
    }

    /**
     * Sets the maximum number of damage regions that can be stored in the journal
     * to @a capacity.
     */
    void setCapacity(int capacity)
    {
        m_capacity = capacity;
    }

    /**
     * Adds the specified @a region to the journal.
     */
    void add(const QRegion &region)
    {
        while (m_log.size() >= m_capacity) {
            m_log.takeLast();
        }
        m_log.prepend(region);
    }

    /**
     * Clears the damage journal. Typically, one would want to clear the damage journal
     * if a buffer swap fails for some reason.
     */
    void clear()
    {
        m_log.clear();
    }

    /**
     * Accumulates the damage regions in the log up to the specified @a bufferAge.
     *
     * If the specified buffer age value refers to a damage region older than the last
     * one in the journal, @a fallback will be returned.
     */
    QRegion accumulate(int bufferAge, const QRegion &fallback = QRegion()) const
    {
        QRegion region;
        if (bufferAge > 0 && bufferAge <= m_log.size()) {
            for (int i = 0; i < bufferAge - 1; ++i) {
                region |= m_log[i];
            }
        } else {
            region = fallback;
        }
        return region;
    }

private:
    QList<QRegion> m_log;
    int m_capacity = 10;
};

} // namespace

// Must be outside namespace
Q_DECLARE_OPERATORS_FOR_FLAGS(KWin::StrutAreas)
Q_DECLARE_OPERATORS_FOR_FLAGS(KWin::QuickTileMode)

#endif