/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Copyright (C) 2012 Richard Moore <rich@kde.org>
** Copyright (C) 2012 David Faure <david.faure@kdab.com>
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//
// An implementation of QX11Info for Qt5. This code only provides the
// static methods of the QX11Info, not the methods for getting information
// about particular widgets or pixmaps.
//

#include "qx11info_x11.h"

#include <qpa/qplatformnativeinterface.h>
#include <qpa/qplatformwindow.h>
#include <qscreen.h>
#include <qdesktopwidget.h>
#include <qwindow.h>
#include <qapplication.h>
#include <xcb/xcb.h>

QT_BEGIN_NAMESPACE


/*!
    \class QX11Info
    \inmodule QtX11Extras
    \since 5.1
    \brief Provides information about the X display configuration.

    The class provides two APIs: a set of non-static functions that
    provide information about a specific widget or pixmap, and a set
    of static functions that provide the default information for the
    application.

    \warning This class is only available on X11. For querying
    per-screen information in a portable way, use QDesktopWidget.
*/

/*!
    Constructs an empty QX11Info object.
*/
QX11Info::QX11Info()
{
}

/*!
    Returns true if the application is currently running on X11.

    \since 5.2
 */
bool QX11Info::isPlatformX11()
{
    return QGuiApplication::platformName() == QLatin1String("xcb");
}

/*!
    Returns the horizontal resolution of the given \a screen in terms of the
    number of dots per inch.

    The \a screen argument is an X screen number. Be aware that if
    the user's system uses Xinerama (as opposed to traditional X11
    multiscreen), there is only one X screen. Use QDesktopWidget to
    query for information about Xinerama screens.

    \sa setAppDpiX(), appDpiY()
*/
int QX11Info::appDpiX(int screen)
{
    if (screen == -1) {
        const QScreen *scr = QGuiApplication::primaryScreen();
        if (!scr)
            return 75;
        return qRound(scr->logicalDotsPerInchX());
    }

    QList<QScreen *> screens = QGuiApplication::screens();
    if (screen >= screens.size())
        return 0;

    return screens[screen]->logicalDotsPerInchX();
}

/*!
    Returns the vertical resolution of the given \a screen in terms of the
    number of dots per inch.

    The \a screen argument is an X screen number. Be aware that if
    the user's system uses Xinerama (as opposed to traditional X11
    multiscreen), there is only one X screen. Use QDesktopWidget to
    query for information about Xinerama screens.

    \sa setAppDpiY(), appDpiX()
*/
int QX11Info::appDpiY(int screen)
{
    if (screen == -1) {
        const QScreen *scr = QGuiApplication::primaryScreen();
        if (!scr)
            return 75;
        return qRound(scr->logicalDotsPerInchY());
    }

    QList<QScreen *> screens = QGuiApplication::screens();
    if (screen > screens.size())
        return 0;

    return screens[screen]->logicalDotsPerInchY();
}

/*!
    Returns a handle for the applications root window on the given \a screen.

    The \a screen argument is an X screen number. Be aware that if
    the user's system uses Xinerama (as opposed to traditional X11
    multiscreen), there is only one X screen. Use QDesktopWidget to
    query for information about Xinerama screens.

    \sa QApplication::desktop()
*/
unsigned long QX11Info::appRootWindow(int screen)
{
    if (!qApp)
        return 0;
#if 0
    // This looks like it should work, but gives the wrong value.
    QDesktopWidget *desktop = QApplication::desktop();
    QWidget *screenWidget = desktop->screen(screen);
    QWindow *window = screenWidget->windowHandle();
#else
    Q_UNUSED(screen);

    QDesktopWidget *desktop = QApplication::desktop();
    QWindow *window = desktop->windowHandle();
#endif
    return window->winId();
}

/*!
    Returns the number of the screen where the application is being
    displayed.

    This method refers to screens in the original X11 meaning with a
    different DISPLAY environment variable per screen.
    This information is only useful if your application needs to know
    on which X screen it is running.

    In a typical multi-head configuration, multiple physical monitors
    are combined in one X11 screen. This means this method returns the
    same number for each of the physical monitors. In such a setup you
    are interested in the monitor information as provided by the X11
    RandR extension. This is available through QDesktopWidget and QScreen.

    \sa display(), screen()
*/
int QX11Info::appScreen()
{
    if (!qApp)
        return 0;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return 0;
    return reinterpret_cast<qintptr>(native->nativeResourceForIntegration(QByteArrayLiteral("x11screen")));
}

/*!
    Returns the X11 time.

    \sa setAppTime(), appUserTime()
*/
unsigned long QX11Info::appTime()
{
    if (!qApp)
        return 0;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return 0;
    QScreen* screen = QGuiApplication::primaryScreen();
    return static_cast<xcb_timestamp_t>(reinterpret_cast<quintptr>(native->nativeResourceForScreen("apptime", screen)));
}

/*!
    Returns the X11 user time.

    \sa setAppUserTime(), appTime()
*/
unsigned long QX11Info::appUserTime()
{
    if (!qApp)
        return 0;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return 0;
    QScreen* screen = QGuiApplication::primaryScreen();
    return static_cast<xcb_timestamp_t>(reinterpret_cast<quintptr>(native->nativeResourceForScreen("appusertime", screen)));
}

/*!
    Sets the X11 time to the value specified by \a time.

    \sa appTime(), setAppUserTime()
*/
void QX11Info::setAppTime(unsigned long time)
{
    if (!qApp)
        return;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return;
    typedef void (*SetAppTimeFunc)(QScreen *, xcb_timestamp_t);
    QScreen* screen = QGuiApplication::primaryScreen();
    SetAppTimeFunc func = reinterpret_cast<SetAppTimeFunc>(native->nativeResourceFunctionForScreen("setapptime"));
    if (func)
        func(screen, time);
    else
        qWarning("Internal error: QPA plugin doesn't implement setAppTime");
}

/*!
    Sets the X11 user time as specified by \a time.

    \sa appUserTime(), setAppTime()
*/
void QX11Info::setAppUserTime(unsigned long time)
{
    if (!qApp)
        return;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return;
    typedef void (*SetAppUserTimeFunc)(QScreen *, xcb_timestamp_t);
    QScreen* screen = QGuiApplication::primaryScreen();
    SetAppUserTimeFunc func = reinterpret_cast<SetAppUserTimeFunc>(native->nativeResourceFunctionForScreen("setappusertime"));
    if (func)
        func(screen, time);
    else
        qWarning("Internal error: QPA plugin doesn't implement setAppUserTime");
}

/*!
    Fetches the current X11 time stamp from the X Server.

    This method creates a property notify event and blocks till it is
    received back from the X Server.

    \since 5.2
*/
unsigned long QX11Info::getTimestamp()
{
    if (!qApp)
        return 0;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return 0;
    QScreen* screen = QGuiApplication::primaryScreen();
    return static_cast<xcb_timestamp_t>(reinterpret_cast<quintptr>(native->nativeResourceForScreen("gettimestamp", screen)));
}

/*!
    Returns the default display for the application.

    \sa appScreen()
*/
Display *QX11Info::display()
{
    if (!qApp)
        return NULL;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return NULL;

    void *display = native->nativeResourceForScreen(QByteArray("display"), QGuiApplication::primaryScreen());
    return reinterpret_cast<Display *>(display);
}

/*!
    Returns the default XCB connection for the application.

    \sa display()
*/
xcb_connection_t *QX11Info::connection()
{
    if (!qApp)
        return NULL;
    QPlatformNativeInterface *native = qApp->platformNativeInterface();
    if (!native)
        return NULL;

    void *connection = native->nativeResourceForWindow(QByteArray("connection"), 0);
    return reinterpret_cast<xcb_connection_t *>(connection);
}

QT_END_NAMESPACE
