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#include <private/qwindowsurface_p.h>
#include <qwindow.h>
#include <qpixmap.h>
#include <private/qwindow_p.h>

QT_BEGIN_NAMESPACE

class QWindowSurfacePrivate
{
public:
    QWindowSurfacePrivate(QWindow *w)
        : window(w)
    {
    }

    QWindow *window;
#if !defined(Q_WS_QPA)
    QRect geometry;
#else
    QSize size;
#endif //Q_WS_QPA
    QRegion staticContents;
};

/*!
    \class QWindowSurface
    \since 4.3
    \internal
    \preliminary
    \ingroup qws qpa

    \brief The QWindowSurface class provides the drawing area for top-level
    windows.
*/


/*!
    \fn void QWindowSurface::beginPaint(const QRegion &region)

    This function is called before painting onto the surface begins,
    with the \a region in which the painting will occur.

    \sa endPaint(), paintDevice()
*/

/*!
    \fn void QWindowSurface::endPaint(const QRegion &region)

    This function is called after painting onto the surface has ended,
    with the \a region in which the painting was performed.

    \sa beginPaint(), paintDevice()
*/

/*!
    \fn void QWindowSurface::flush(QWindow *window, const QRegion &region,
                                  const QPoint &offset)

    Flushes the given \a region from the specified \a window onto the
    screen.

    Note that the \a offset parameter is currently unused.
*/

/*!
    \fn QPaintDevice* QWindowSurface::paintDevice()

    Implement this function to return the appropriate paint device.
*/

/*!
    Constructs an empty surface for the given top-level \a window.
*/
QWindowSurface::QWindowSurface(QWindow *window, bool /*setDefaultSurface*/)
    : d_ptr(new QWindowSurfacePrivate(window))
{
    if (window)
        window->d_func()->surface = this;
}

/*!
    Destroys this surface.
*/
QWindowSurface::~QWindowSurface()
{
//    if (d_ptr->window)
//        d_ptr->window->d_func()->extra->topextra->windowSurface = 0;
    delete d_ptr;
}

/*!
    Returns a pointer to the top-level window associated with this
    surface.
*/
QWindow* QWindowSurface::window() const
{
    return d_ptr->window;
}

void QWindowSurface::beginPaint(const QRegion &)
{
}

void QWindowSurface::endPaint(const QRegion &)
{
}

#if !defined(Q_WS_QPA)
/*!
    Sets the currently allocated area to be the given \a rect.

    This function is called whenever area covered by the top-level
    window changes.

    \sa geometry()
*/
void QWindowSurface::setGeometry(const QRect &rect)
{
    d_ptr->geometry = rect;
}

/*!
    Returns the currently allocated area on the screen.
*/
QRect QWindowSurface::geometry() const
{
    return d_ptr->geometry;
}
#else

/*!
      Sets the size of the windowsurface to be \a size.

      \sa size()
*/
void QWindowSurface::resize(const QSize &size)
{
    d_ptr->size = size;
}

/*!
    Returns the current size of the windowsurface.
*/
QSize QWindowSurface::size() const
{
    return d_ptr->size;
}
#endif //Q_WS_QPA

/*!
    Scrolls the given \a area \a dx pixels to the right and \a dy
    downward; both \a dx and \a dy may be negative.

    Returns true if the area was scrolled successfully; false otherwise.
*/
bool QWindowSurface::scroll(const QRegion &area, int dx, int dy)
{
    Q_UNUSED(area);
    Q_UNUSED(dx);
    Q_UNUSED(dy);

    return false;
}

/*!
  Returns a QPixmap generated from the part of the backing store
  corresponding to \a window. Returns a null QPixmap if an error
  occurs. The contents of the pixmap are only defined for the regions
  of \a window that have received paint events since the last resize
  of the backing store.

  If \a rectangle is a null rectangle (the default), the entire window
  is grabbed. Otherwise, the grabbed area is limited to \a rectangle.

  The default implementation uses QWindowSurface::buffer().

  \sa QPixmap::grabWindow()
*/
QPixmap QWindowSurface::grabWindow(const QWindow *, const QRect &) const
{
    QPixmap result;

#if 0
    if (window->window() != window())
        return result;

    const QImage *img = const_cast<QWindowSurface *>(this)->buffer(window->window());

    if (!img || img->isNull())
        return result;

    QRect rect = rectangle.isEmpty() ? window->rect() : (window->rect() & rectangle);

    rect.translate(offset(window) - offset(window->window()));
    rect &= QRect(QPoint(), img->size());

    if (rect.isEmpty())
        return result;

    QImage subimg(img->scanLine(rect.y()) + rect.x() * img->depth() / 8,
                  rect.width(), rect.height(),
                  img->bytesPerLine(), img->format());
    subimg.detach(); //### expensive -- maybe we should have a real SubImage that shares reference count

    result = QPixmap::fromImage(subimg);
#endif
    return result;
}

/*!
  Returns the offset of \a window in the coordinates of this
  window surface.
 */
QPoint QWindowSurface::offset(const QWindow *) const
{
    QPoint offset;
#if 0
    QWindow *window = d_ptr->window;
    QPoint offset = window->mapTo(window, QPoint());
#endif
    return offset;
}

/*!
  \fn QRect QWindowSurface::rect(const QWindow *window) const

  Returns the rectangle for \a window in the coordinates of this
  window surface.
*/

void QWindowSurface::setStaticContents(const QRegion &region)
{
    d_ptr->staticContents = region;
}

QRegion QWindowSurface::staticContents() const
{
    return d_ptr->staticContents;
}

bool QWindowSurface::hasStaticContents() const
{
    return hasFeature(QWindowSurface::StaticContents) && !d_ptr->staticContents.isEmpty();
}

QWindowSurface::WindowSurfaceFeatures QWindowSurface::features() const
{
    return PartialUpdates | PreservedContents;
}

#ifdef Q_WS_QPA
#define Q_EXPORT_SCROLLRECT Q_GUI_EXPORT
#else
#define Q_EXPORT_SCROLLRECT
#endif

void Q_EXPORT_SCROLLRECT qt_scrollRectInImage(QImage &img, const QRect &rect, const QPoint &offset)
{
    // make sure we don't detach
    uchar *mem = const_cast<uchar*>(const_cast<const QImage &>(img).bits());

    int lineskip = img.bytesPerLine();
    int depth = img.depth() >> 3;

    const QRect imageRect(0, 0, img.width(), img.height());
    const QRect r = rect & imageRect & imageRect.translated(-offset);
    const QPoint p = rect.topLeft() + offset;

    if (r.isEmpty())
        return;

    const uchar *src;
    uchar *dest;

    if (r.top() < p.y()) {
        src = mem + r.bottom() * lineskip + r.left() * depth;
        dest = mem + (p.y() + r.height() - 1) * lineskip + p.x() * depth;
        lineskip = -lineskip;
    } else {
        src = mem + r.top() * lineskip + r.left() * depth;
        dest = mem + p.y() * lineskip + p.x() * depth;
    }

    const int w = r.width();
    int h = r.height();
    const int bytes = w * depth;

    // overlapping segments?
    if (offset.y() == 0 && qAbs(offset.x()) < w) {
        do {
            ::memmove(dest, src, bytes);
            dest += lineskip;
            src += lineskip;
        } while (--h);
    } else {
        do {
            ::memcpy(dest, src, bytes);
            dest += lineskip;
            src += lineskip;
        } while (--h);
    }
}

QT_END_NAMESPACE