/*
*   Copyright 2011 by Aaron Seigo <aseigo@kde.org>
*
*   This program is free software; you can redistribute it and/or modify
*   it under the terms of the GNU Library General Public License version 2,
*   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 Library General Public
*   License along with this program; if not, write to the
*   Free Software Foundation, Inc.,
*   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "dialogshadows_p.h"

#include <QGlobalStatic>
#include <QWindow>
#include <QPainter>
#include <config-plasma.h>

#if HAVE_X11
#include <QX11Info>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
#include <X11/Xlib-xcb.h>
#include <fixx11h.h>
#endif

#include <qdebug.h>

class DialogShadows::Private
{
public:
    Private(DialogShadows *shadows)
        : q(shadows)
#if HAVE_X11
        , _connection(0x0),
        _gc(0x0)
        , m_isX11(QX11Info::isPlatformX11())
#endif
    {
    }

    ~Private()
    {
        // Do not call clearPixmaps() from here: it creates new QPixmap(),
        // which causes a crash when application is stopping.
        freeX11Pixmaps();
    }

    void freeX11Pixmaps();
    void clearPixmaps();
    void setupPixmaps();
    Qt::HANDLE createPixmap(const QPixmap &source);
    void initPixmap(const QString &element);
    QPixmap initEmptyPixmap(const QSize &size);
    void updateShadow(const QWindow *window, Plasma::FrameSvg::EnabledBorders);
    void clearShadow(const QWindow *window);
    void updateShadows();
    void windowDestroyed(QObject *deletedObject);
    void setupData(Plasma::FrameSvg::EnabledBorders enabledBorders);

    DialogShadows *q;
    QList<QPixmap> m_shadowPixmaps;

    QPixmap m_emptyCornerPix;
    QPixmap m_emptyCornerLeftPix;
    QPixmap m_emptyCornerTopPix;
    QPixmap m_emptyCornerRightPix;
    QPixmap m_emptyCornerBottomPix;
    QPixmap m_emptyVerticalPix;
    QPixmap m_emptyHorizontalPix;

#if HAVE_X11
    //! xcb connection
    xcb_connection_t *_connection;

    //! graphical context
    xcb_gcontext_t _gc;
    bool m_isX11;
#endif

    QHash<Plasma::FrameSvg::EnabledBorders, QVector<unsigned long> > data;
    QHash<const QWindow *, Plasma::FrameSvg::EnabledBorders> m_windows;
};

class DialogShadowsSingleton
{
public:
    DialogShadowsSingleton()
    {
    }

    DialogShadows self;
};

Q_GLOBAL_STATIC(DialogShadowsSingleton, privateDialogShadowsSelf)

DialogShadows::DialogShadows(QObject *parent, const QString &prefix)
    : Plasma::Svg(parent),
      d(new Private(this))
{
    setImagePath(prefix);
    connect(this, SIGNAL(repaintNeeded()), this, SLOT(updateShadows()));
}

DialogShadows::~DialogShadows()
{
    delete d;
}

DialogShadows *DialogShadows::self()
{
    return &privateDialogShadowsSelf->self;
}

void DialogShadows::addWindow(const QWindow *window, Plasma::FrameSvg::EnabledBorders enabledBorders)
{
    if (!window) {
        return;
    }

    d->m_windows[window] = enabledBorders;
    d->updateShadow(window, enabledBorders);
    connect(window, SIGNAL(destroyed(QObject*)),
            this, SLOT(windowDestroyed(QObject*)), Qt::UniqueConnection);
}

void DialogShadows::removeWindow(const QWindow *window)
{
    if (!d->m_windows.contains(window)) {
        return;
    }

    d->m_windows.remove(window);
    disconnect(window, 0, this, 0);
    d->clearShadow(window);

    if (d->m_windows.isEmpty()) {
        d->clearPixmaps();
    }
}

void DialogShadows::Private::windowDestroyed(QObject *deletedObject)
{
    m_windows.remove(static_cast<QWindow *>(deletedObject));

    if (m_windows.isEmpty()) {
        clearPixmaps();
    }
}

void DialogShadows::Private::updateShadows()
{
    setupPixmaps();
    QHash<const QWindow *, Plasma::FrameSvg::EnabledBorders>::const_iterator i;
    for (i = m_windows.constBegin(); i != m_windows.constEnd(); ++i) {
        updateShadow(i.key(), i.value());
    }
}

Qt::HANDLE DialogShadows::Private::createPixmap(const QPixmap &source)
{

    // do nothing for invalid pixmaps
    if (source.isNull()) {
        return 0;
    }

    /*
    in some cases, pixmap handle is invalid. This is the case notably
    when Qt uses to RasterEngine. In this case, we create an X11 Pixmap
    explicitly and draw the source pixmap on it.
    */

#if HAVE_X11
    if (!m_isX11) {
        return 0;
    }

    // check connection
    if (!_connection) {
        _connection = QX11Info::connection();
    }

    const int width(source.width());
    const int height(source.height());

    // create X11 pixmap
    Pixmap pixmap = XCreatePixmap(QX11Info::display(), QX11Info::appRootWindow(), width, height, 32);

    // check gc
    if (!_gc) {
        _gc = xcb_generate_id(_connection);
        xcb_create_gc(_connection, _gc, pixmap, 0, 0x0);
    }

//         // create explicitly shared QPixmap from it
//         QPixmap dest( QPixmap::fromX11Pixmap( pixmap, QPixmap::ExplicitlyShared ) );
//
//         // create surface for pixmap
//         {
//             QPainter painter( &dest );
//             painter.setCompositionMode( QPainter::CompositionMode_Source );
//             painter.drawPixmap( 0, 0, source );
//         }
//
//
//         return pixmap;
    QImage image(source.toImage());
    xcb_put_image(
        _connection, XCB_IMAGE_FORMAT_Z_PIXMAP, pixmap, _gc,
        image.width(), image.height(), 0, 0,
        0, 32,
        image.byteCount(), image.constBits());

    return (Qt::HANDLE)pixmap;

#else
    return 0;
#endif

}

void DialogShadows::Private::initPixmap(const QString &element)
{
    m_shadowPixmaps << q->pixmap(element);
}

QPixmap DialogShadows::Private::initEmptyPixmap(const QSize &size)
{
#if HAVE_X11
    if (!m_isX11) {
        return QPixmap();
    }
    QPixmap tempEmptyPix(size);
    if (!size.isEmpty()) {
        tempEmptyPix.fill(Qt::transparent);
    }
    return tempEmptyPix;
#else
    Q_UNUSED(size)
    return QPixmap();
#endif
}

void DialogShadows::Private::setupPixmaps()
{
    clearPixmaps();
    initPixmap(QStringLiteral("shadow-top"));
    initPixmap(QStringLiteral("shadow-topright"));
    initPixmap(QStringLiteral("shadow-right"));
    initPixmap(QStringLiteral("shadow-bottomright"));
    initPixmap(QStringLiteral("shadow-bottom"));
    initPixmap(QStringLiteral("shadow-bottomleft"));
    initPixmap(QStringLiteral("shadow-left"));
    initPixmap(QStringLiteral("shadow-topleft"));

    m_emptyCornerPix = initEmptyPixmap(QSize(1, 1));
    m_emptyCornerLeftPix = initEmptyPixmap(QSize(q->elementSize(QStringLiteral("shadow-topleft")).width(), 1));
    m_emptyCornerTopPix = initEmptyPixmap(QSize(1, q->elementSize(QStringLiteral("shadow-topleft")).height()));
    m_emptyCornerRightPix = initEmptyPixmap(QSize(q->elementSize(QStringLiteral("shadow-bottomright")).width(), 1));
    m_emptyCornerBottomPix = initEmptyPixmap(QSize(1, q->elementSize(QStringLiteral("shadow-bottomright")).height()));
    m_emptyVerticalPix = initEmptyPixmap(QSize(1, q->elementSize(QStringLiteral("shadow-left")).height()));
    m_emptyHorizontalPix = initEmptyPixmap(QSize(q->elementSize(QStringLiteral("shadow-top")).width(), 1));

}

void DialogShadows::Private::setupData(Plasma::FrameSvg::EnabledBorders enabledBorders)
{
#if HAVE_X11
    if (!m_isX11) {
        return;
    }
    //shadow-top
    if (enabledBorders & Plasma::FrameSvg::TopBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[0]));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyHorizontalPix));
    }

    //shadow-topright
    if (enabledBorders & Plasma::FrameSvg::TopBorder &&
            enabledBorders & Plasma::FrameSvg::RightBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[1]));
    } else if (enabledBorders & Plasma::FrameSvg::TopBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerTopPix));
    } else if (enabledBorders & Plasma::FrameSvg::RightBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerRightPix));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerPix));
    }

    //shadow-right
    if (enabledBorders & Plasma::FrameSvg::RightBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[2]));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyVerticalPix));
    }

    //shadow-bottomright
    if (enabledBorders & Plasma::FrameSvg::BottomBorder &&
            enabledBorders & Plasma::FrameSvg::RightBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[3]));
    } else if (enabledBorders & Plasma::FrameSvg::BottomBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerBottomPix));
    } else if (enabledBorders & Plasma::FrameSvg::RightBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerRightPix));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerPix));
    }

    //shadow-bottom
    if (enabledBorders & Plasma::FrameSvg::BottomBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[4]));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyHorizontalPix));
    }

    //shadow-bottomleft
    if (enabledBorders & Plasma::FrameSvg::BottomBorder &&
            enabledBorders & Plasma::FrameSvg::LeftBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[5]));
    } else if (enabledBorders & Plasma::FrameSvg::BottomBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerBottomPix));
    } else if (enabledBorders & Plasma::FrameSvg::LeftBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerLeftPix));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerPix));
    }

    //shadow-left
    if (enabledBorders & Plasma::FrameSvg::LeftBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[6]));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyVerticalPix));
    }

    //shadow-topleft
    if (enabledBorders & Plasma::FrameSvg::TopBorder &&
            enabledBorders & Plasma::FrameSvg::LeftBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_shadowPixmaps[7]));
    } else if (enabledBorders & Plasma::FrameSvg::TopBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerTopPix));
    } else if (enabledBorders & Plasma::FrameSvg::LeftBorder) {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerLeftPix));
    } else {
        data[enabledBorders] << reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerPix));
    }
#endif

    int left, top, right, bottom = 0;

    QSize marginHint;
    if (enabledBorders & Plasma::FrameSvg::TopBorder) {
        marginHint = q->elementSize(QStringLiteral("shadow-hint-top-margin"));
        if (marginHint.isValid()) {
            top = marginHint.height();
        } else {
            top = m_shadowPixmaps[0].height(); // top
        }
    } else {
        top = 1;
    }

    if (enabledBorders & Plasma::FrameSvg::RightBorder) {
        marginHint = q->elementSize(QStringLiteral("shadow-hint-right-margin"));
        if (marginHint.isValid()) {
            right = marginHint.width();
        } else {
            right = m_shadowPixmaps[2].width(); // right
        }
    } else {
        right = 1;
    }

    if (enabledBorders & Plasma::FrameSvg::BottomBorder) {
        marginHint = q->elementSize(QStringLiteral("shadow-hint-bottom-margin"));
        if (marginHint.isValid()) {
            bottom = marginHint.height();
        } else {
            bottom = m_shadowPixmaps[4].height(); // bottom
        }
    } else {
        bottom = 1;
    }

    if (enabledBorders & Plasma::FrameSvg::LeftBorder) {
        marginHint = q->elementSize(QStringLiteral("shadow-hint-left-margin"));
        if (marginHint.isValid()) {
            left = marginHint.width();
        } else {
            left = m_shadowPixmaps[6].width(); // left
        }
    } else {
        left = 1;
    }

    data[enabledBorders] << top << right << bottom << left;
}

void DialogShadows::Private::freeX11Pixmaps()
{
#if HAVE_X11
    if (!m_isX11) {
        return;
    }

    auto *display = QX11Info::display();
    if (!display) {
        return;
    }

    foreach (const QPixmap &pixmap, m_shadowPixmaps) {
        if (!pixmap.isNull()) {
            XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(pixmap)));
        }
    }

    if (!m_emptyCornerPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerPix)));
    }
    if (!m_emptyCornerBottomPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerBottomPix)));
    }
    if (!m_emptyCornerLeftPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerLeftPix)));
    }
    if (!m_emptyCornerRightPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerRightPix)));
    }
    if (!m_emptyCornerTopPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyCornerTopPix)));
    }
    if (!m_emptyVerticalPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyVerticalPix)));
    }
    if (!m_emptyHorizontalPix.isNull()) {
        XFreePixmap(display, reinterpret_cast<unsigned long>(createPixmap(m_emptyHorizontalPix)));
    }
#endif
}

void DialogShadows::Private::clearPixmaps()
{
#if HAVE_X11
    freeX11Pixmaps();

    m_emptyCornerPix = QPixmap();
    m_emptyCornerBottomPix = QPixmap();
    m_emptyCornerLeftPix = QPixmap();
    m_emptyCornerRightPix = QPixmap();
    m_emptyCornerTopPix = QPixmap();
    m_emptyVerticalPix = QPixmap();
    m_emptyHorizontalPix = QPixmap();
#endif
    m_shadowPixmaps.clear();
    data.clear();
}

void DialogShadows::Private::updateShadow(const QWindow *window, Plasma::FrameSvg::EnabledBorders enabledBorders)
{
#if HAVE_X11
    if (!m_isX11) {
        return;
    }
    if (m_shadowPixmaps.isEmpty()) {
        setupPixmaps();
    }

    if (!data.contains(enabledBorders)) {
        setupData(enabledBorders);
    }

    Display *dpy = QX11Info::display();
    Atom atom = XInternAtom(dpy, "_KDE_NET_WM_SHADOW", False);

    //qDebug() << "going to set the shadow of" << window->winId() << "to" << data;
    XChangeProperty(dpy, window->winId(), atom, XA_CARDINAL, 32, PropModeReplace,
                    reinterpret_cast<const unsigned char *>(data[enabledBorders].constData()), data[enabledBorders].size());
#else
    Q_UNUSED(window)
    Q_UNUSED(enabledBorders)
#endif
}

void DialogShadows::Private::clearShadow(const QWindow *window)
{
#if HAVE_X11
    if (!m_isX11) {
        return;
    }
    Display *dpy = QX11Info::display();
    Atom atom = XInternAtom(dpy, "_KDE_NET_WM_SHADOW", False);
    XDeleteProperty(dpy, window->winId(), atom);
#else
    Q_UNUSED(window)
#endif
}

bool DialogShadows::enabled() const
{
    return hasElement(QStringLiteral("shadow-left"));
}

#include "moc_dialogshadows_p.cpp"

