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

 Copyright (C) 2010 Martin Gräßlin <kde@martin-graesslin.com>
 Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)

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/>.
*********************************************************************/
#include "screenshot.h"
#include <kwinglutils.h>
#include <KDE/KDebug>
#include <QtDBus/QDBusConnection>
#include <QtCore/QVarLengthArray>
#include <QtGui/QPainter>

#include <X11/extensions/Xfixes.h>
#include <QX11Info>

namespace KWin
{

KWIN_EFFECT( screenshot, ScreenShotEffect )
KWIN_EFFECT_SUPPORTED( screenshot, ScreenShotEffect::supported() )

bool ScreenShotEffect::supported()
    {
    return effects->compositingType() == KWin::OpenGLCompositing && GLRenderTarget::supported();
    }

ScreenShotEffect::ScreenShotEffect()
    : m_scheduledScreenshot( 0 )
    {
    QDBusConnection::sessionBus().registerObject( "/Screenshot", this, QDBusConnection::ExportScriptableContents );
    QDBusConnection::sessionBus().registerService( "org.kde.kwin.Screenshot" );
    }

ScreenShotEffect::~ScreenShotEffect()
    {
    QDBusConnection::sessionBus().unregisterObject( "/Screenshot" );
    QDBusConnection::sessionBus().unregisterService( "org.kde.kwin.Screenshot" );
    }
void ScreenShotEffect::postPaintScreen()
    {
    effects->postPaintScreen();
    if( m_scheduledScreenshot )
        {
        int w = displayWidth();
        int h = displayHeight();
        if( !GLTexture::NPOTTextureSupported() )
            {
            w = nearestPowerOfTwo( w );
            h = nearestPowerOfTwo( h );
            }
        GLTexture* offscreenTexture = new GLTexture( w, h );
        offscreenTexture->setFilter( GL_LINEAR );
        offscreenTexture->setWrapMode( GL_CLAMP_TO_EDGE );
        GLRenderTarget* target = new GLRenderTarget( offscreenTexture );
        if( target->valid() )
            {
            WindowPaintData d( m_scheduledScreenshot );
            double left = 0;
            double top = 0;
            double right = m_scheduledScreenshot->width();
            double bottom = m_scheduledScreenshot->height();
            if( m_scheduledScreenshot->hasDecoration() && m_type & INCLUDE_DECORATION )
                {
                foreach( const WindowQuad& quad, d.quads )
                    {
                    // we need this loop to include the decoration padding
                    left   = qMin(left, quad.left());
                    top    = qMin(top, quad.top());
                    right  = qMax(right, quad.right());
                    bottom = qMax(bottom, quad.bottom());
                    }
                }
            else if( m_scheduledScreenshot->hasDecoration() )
                {
                WindowQuadList newQuads;
                left = m_scheduledScreenshot->width();
                top = m_scheduledScreenshot->height();
                right = 0;
                bottom = 0;
                foreach( const WindowQuad& quad, d.quads )
                    {
                    if( quad.type() == WindowQuadContents )
                        {
                        newQuads << quad;
                        left   = qMin(left, quad.left());
                        top    = qMin(top, quad.top());
                        right  = qMax(right, quad.right());
                        bottom = qMax(bottom, quad.bottom());
                        }
                    }
                    d.quads = newQuads;
                }
            int width = right - left;
            int height = bottom - top;
            d.xTranslate = -m_scheduledScreenshot->x() - left;
            d.yTranslate = -m_scheduledScreenshot->y() - top;
            // render window into offscreen texture
            int mask = PAINT_WINDOW_TRANSFORMED | PAINT_WINDOW_TRANSLUCENT;
            effects->pushRenderTarget( target );
            glClear( GL_COLOR_BUFFER_BIT );
            effects->drawWindow( m_scheduledScreenshot, mask, QRegion( 0, 0, width, height ), d );
            // Create a scratch texture and copy the rendered window into it
            GLTexture* tex = new GLTexture( width, height );
            tex->setFilter( GL_LINEAR );
            tex->setWrapMode( GL_CLAMP_TO_EDGE );
            tex->bind();

            glCopyTexSubImage2D( GL_TEXTURE_2D, 0, 0, 0, 0, offscreenTexture->height() - height, width, height );
            effects->popRenderTarget();
            // copy content from GL texture into image
            QImage img( QSize( width, height ), QImage::Format_ARGB32 );
            tex->bind();
            glGetTexImage( GL_TEXTURE_2D, 0, GL_RGBA, GL_UNSIGNED_BYTE, img.bits() );
            tex->unbind();
            delete tex;
            ScreenShotEffect::convertFromGLImage( img, width, height );
            if( m_type & INCLUDE_CURSOR )
                {
                grabPointerImage( img, m_scheduledScreenshot->x() + left, m_scheduledScreenshot->y() + top );
                }
            m_lastScreenshot = QPixmap::fromImage( img );
            emit screenshotCreated( m_lastScreenshot.handle() );
            }
        delete offscreenTexture;
        delete target;
        m_scheduledScreenshot = NULL;
        }
    }

void ScreenShotEffect::screenshotWindowUnderCursor(int mask)
    {
    m_type = (ScreenShotType)mask;
    const QPoint cursor = effects->cursorPos();
    foreach( EffectWindow* w, effects->stackingOrder() )
        {
        if( w->geometry().contains( cursor ) && w->isOnCurrentDesktop() && !w->isMinimized() )
            {
            m_scheduledScreenshot = w;
            }
        }
    if( m_scheduledScreenshot )
        {
        m_scheduledScreenshot->addRepaintFull();
        }
    }

void ScreenShotEffect::grabPointerImage( QImage& snapshot, int offsetx, int offsety )
// Uses the X11_EXTENSIONS_XFIXES_H extension to grab the pointer image, and overlays it onto the snapshot.
{
    XFixesCursorImage *xcursorimg = XFixesGetCursorImage( QX11Info::display() );
    if ( !xcursorimg )
      return;

    //Annoyingly, xfixes specifies the data to be 32bit, but places it in an unsigned long *
    //which can be 64 bit.  So we need to iterate over a 64bit structure to put it in a 32bit
    //structure.
    QVarLengthArray< quint32 > pixels( xcursorimg->width * xcursorimg->height );
    for (int i = 0; i < xcursorimg->width * xcursorimg->height; ++i)
        pixels[i] = xcursorimg->pixels[i] & 0xffffffff;

    QImage qcursorimg((uchar *) pixels.data(), xcursorimg->width, xcursorimg->height,
                       QImage::Format_ARGB32_Premultiplied);

    QPainter painter(&snapshot);
    painter.drawImage(QPointF(xcursorimg->x - xcursorimg->xhot - offsetx, xcursorimg->y - xcursorimg ->yhot - offsety), qcursorimg);

    XFree(xcursorimg);
}

void ScreenShotEffect::convertFromGLImage(QImage &img, int w, int h)
{
    // from QtOpenGL/qgl.cpp
    // Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
    // see http://qt.gitorious.org/qt/qt/blobs/master/src/opengl/qgl.cpp
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        // OpenGL gives RGBA; Qt wants ARGB
        uint *p = (uint*)img.bits();
        uint *end = p + w*h;
        while (p < end) {
            uint a = *p << 24;
            *p = (*p >> 8) | a;
            p++;
        }
    } else {
        // OpenGL gives ABGR (i.e. RGBA backwards); Qt wants ARGB
        for (int y = 0; y < h; y++) {
            uint *q = (uint*)img.scanLine(y);
            for (int x=0; x < w; ++x) {
                const uint pixel = *q;
                *q = ((pixel << 16) & 0xff0000) | ((pixel >> 16) & 0xff)
                        | (pixel & 0xff00ff00);

                q++;
            }
        }

    }
    img = img.mirrored();
}

} // namespace