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

Copyright (C) 2007 Lubos Lunak <l.lunak@kde.org>
Copyright (C) 2009 Martin Gräßlin <kde@martin-graesslin.com>
Copyright (C) 2009 Lucas Murray <lmurray@undefinedfire.com>

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 "logout.h"

#include "kwinglutils.h"

#include <math.h>
#include <kconfiggroup.h>
#include <kdebug.h>

namespace KWin
{

KWIN_EFFECT( logout, LogoutEffect )

LogoutEffect::LogoutEffect()
    : progress( 0.0 )
    , logoutWindow( NULL )
    , logoutWindowClosed( true )
    , logoutWindowPassed( false )
    {
    char net_wm_cm_name[ 100 ];
    sprintf( net_wm_cm_name, "_NET_WM_CM_S%d", DefaultScreen( display()));
    Atom net_wm_cm = XInternAtom( display(), net_wm_cm_name, False );
    Window sel = XGetSelectionOwner( display(), net_wm_cm );
    Atom hack = XInternAtom( display(), "_KWIN_LOGOUT_EFFECT", False );
    XChangeProperty( display(), sel, hack, hack, 8, PropModeReplace, (unsigned char*)&hack, 1 );
    // the atom is not removed when effect is destroyed, this is temporary anyway
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    blurTexture = NULL;
    blurTarget = NULL;
#endif
    reconfigure( ReconfigureAll );
    }

LogoutEffect::~LogoutEffect()
    {
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    delete blurTexture;
    delete blurTarget;
#endif
    }

void LogoutEffect::reconfigure( ReconfigureFlags )
    {
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    frameDelay = 0;
    KConfigGroup conf = effects->effectConfig( "Logout" );
    useBlur = conf.readEntry( "UseBlur", true );
    delete blurTexture;
    blurTexture = NULL;
    delete blurTarget;
    blurTarget = NULL;
    blurSupported = false;
#endif
    }

void LogoutEffect::prePaintScreen( ScreenPrePaintData& data, int time )
    {
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    if( !logoutWindow && progress == 0.0 )
        {
        if( blurTexture )
            {
            delete blurTexture;
            blurTexture = NULL;
            delete blurTarget;
            blurTarget = NULL;
            blurSupported = false;
            }
        }
    else if( !blurTexture )
        {
        blurSupported = false;
        delete blurTarget; // catch as we just tested the texture ;-P
        if( effects->compositingType() == OpenGLCompositing && GLTexture::NPOTTextureSupported() && useBlur )
            { // TODO: It seems that it is not possible to create a GLRenderTarget that has
            //       a different size than the display right now. Most likely a KWin core bug.
            // Create texture and render target
            blurTexture = new GLTexture( displayWidth(), displayHeight() );
            blurTexture->setFilter( GL_LINEAR_MIPMAP_LINEAR );
            blurTexture->setWrapMode( GL_CLAMP_TO_EDGE );

            blurTarget = new GLRenderTarget( blurTexture );
            if( blurTarget->valid() )
                blurSupported = true;

            // As creating the render target takes time it can cause the first two frames of the
            // blur animation to be jerky. For this reason we only start the animation after the
            // third frame.
            frameDelay = 2;
            }
        }

    if( frameDelay )
        --frameDelay;
    else
#endif
        {
        if( logoutWindow != NULL && !logoutWindowClosed )
            progress = qMin( 1.0, progress + time / animationTime( 2000.0 ));
        else if( progress > 0.0 )
            progress = qMax( 0.0, progress - time / animationTime( 500.0 ));
        }

#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    if( blurSupported && progress > 0.0 )
        {
        data.mask |= PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS;
        }
#endif

    effects->prePaintScreen( data, time );
    }

void LogoutEffect::paintWindow( EffectWindow* w, int mask, QRegion region, WindowPaintData& data )
    {
    if( progress > 0.0 )
        {
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
        if( effects->compositingType() == KWin::OpenGLCompositing )
            { // In OpenGL mode we add vignetting and, if supported, a slight blur
            if( blurSupported )
                { // When using blur we render everything to an FBO and as such don't do the vignetting
                  // until after we render the FBO to the screen.
                if( w == logoutWindow )
                    { // Window is rendered after the FBO
                    windowOpacity = data.opacity;
                    data.opacity = 0.0; // Cheat, we need the opacity for later but don't want to blur it
                    }
                else
                    {
                    if( logoutWindowPassed )
                        { // Window is rendered after the FBO
                        windows.append( w );
                        windowsOpacities[ w ] = data.opacity;
                        data.opacity = 0.0;
                        }
                    else // Window is added to the FBO
                        data.saturation *= ( 1.0 - progress * 0.2 );
                    }
                }
            else
                { // If we are not blurring then we are not rendering to an FBO
                if( w == logoutWindow )
                    // This is the logout window don't alter it but render our vignetting now
                    renderVignetting();
                else if( !logoutWindowPassed )
                    // Window is in the background, desaturate
                    data.saturation *= ( 1.0 - progress * 0.2 );
                // All other windows are unaltered
                }
            }
#endif
        if( effects->compositingType() == KWin::XRenderCompositing )
            { // Since we can't do vignetting in XRender just do a stronger desaturation and darken
            if( w != logoutWindow && !logoutWindowPassed )
                {
                data.saturation *= ( 1.0 - progress * 0.8 );
                data.brightness *= ( 1.0 - progress * 0.3 );
                }
            }
        if( w == logoutWindow )
            // All following windows are on top of the logout window and should not be altered either
            logoutWindowPassed = true;
        }
    effects->paintWindow( w, mask, region, data );
    }

void LogoutEffect::paintScreen( int mask, QRegion region, ScreenPaintData& data )
    {
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    if( blurSupported && progress > 0.0 )
        effects->pushRenderTarget( blurTarget );
#endif
    effects->paintScreen( mask, region, data );

#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    if( effects->compositingType() == KWin::OpenGLCompositing && progress > 0.0 )
        {
        if( !blurSupported )
            {
            if( !logoutWindowPassed )
                // The logout window has been deleted but we still want to fade out the vignetting, thus
                // render it on the top of everything if still animating. We don't check if logoutWindow
                // is set as it may still be even if it wasn't rendered.
                renderVignetting();
            }
        else
            {
            GLRenderTarget* target = effects->popRenderTarget();
            assert( target == blurTarget );
            Q_UNUSED( target );

            //--------------------------
            // Render the screen effect

            glPushAttrib( GL_CURRENT_BIT | GL_ENABLE_BIT | GL_TEXTURE_BIT );

            // Unmodified base image
            blurTexture->bind();
            glBegin( GL_QUADS );
                glTexCoord2f( 0.0, 0.0 );
                glVertex2f( 0.0, displayHeight() );
                glTexCoord2f( 1.0, 0.0 );
                glVertex2f( displayWidth(), displayHeight() );
                glTexCoord2f( 1.0, 1.0 );
                glVertex2f( displayWidth(), 0.0 );
                glTexCoord2f( 0.0, 1.0 );
                glVertex2f( 0.0, 0.0 );
            glEnd();

            // Blurred image
            GLfloat bias[1];
            glGetTexEnvfv( GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, bias );
            glTexEnvf( GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, 1.75 );
            glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
            glEnable( GL_BLEND );
            glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
            glColor4f( 1.0f, 1.0f, 1.0f, progress * 0.4 );
            glBegin( GL_QUADS );
                glTexCoord2f( 0.0, 0.0 );
                glVertex2f( 0.0, displayHeight() );
                glTexCoord2f( 1.0, 0.0 );
                glVertex2f( displayWidth(), displayHeight() );
                glTexCoord2f( 1.0, 1.0 );
                glVertex2f( displayWidth(), 0.0 );
                glTexCoord2f( 0.0, 1.0 );
                glVertex2f( 0.0, 0.0 );
            glEnd();
            glTexEnvf( GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, bias[0] );
            blurTexture->unbind();

            // Vignetting (Radial gradient with transparent middle and black edges)
            renderVignetting();

            glPopAttrib();

            //--------------------------

            // Render the logout window
            if( logoutWindow )
                {
                int winMask = logoutWindow->hasAlpha() ? PAINT_WINDOW_TRANSLUCENT : PAINT_WINDOW_OPAQUE;
                WindowPaintData winData( logoutWindow );
                winData.opacity = windowOpacity;
                effects->drawWindow( logoutWindow, winMask, region, winData );
                }

            // Render all windows on top of logout window
            foreach( EffectWindow* w, windows )
                {
                int winMask = w->hasAlpha() ? PAINT_WINDOW_TRANSLUCENT : PAINT_WINDOW_OPAQUE;
                WindowPaintData winData( w );
                winData.opacity = windowsOpacities[ w ];
                effects->drawWindow( w, winMask, region, winData );
                }

            windows.clear();
            windowsOpacities.clear();
            }
        }
#endif
    }

void LogoutEffect::postPaintScreen()
    {
#ifdef KWIN_HAVE_OPENGL_COMPOSITING
    if(( progress != 0.0 && progress != 1.0 ) || frameDelay )
        effects->addRepaintFull();
#else
    if( progress != 0.0 && progress != 1.0 )
        effects->addRepaintFull();
#endif

    if( progress > 0.0 )
        logoutWindowPassed = false;
    effects->postPaintScreen();
    }

void LogoutEffect::windowAdded( EffectWindow* w )
    {
    if( isLogoutDialog( w ))
        {
        logoutWindow = w;
        logoutWindowClosed = false; // So we don't blur the window on close
        progress = 0.0;
        effects->addRepaintFull();
        }
    }

void LogoutEffect::windowClosed( EffectWindow* w )
    {
    if( w == logoutWindow )
        {
        logoutWindowClosed = true;
        effects->addRepaintFull();
        }
    }

void LogoutEffect::windowDeleted( EffectWindow* w )
    {
    if( w == logoutWindow )
        logoutWindow = NULL;
    }

bool LogoutEffect::isLogoutDialog( EffectWindow* w )
    { // TODO there should be probably a better way (window type?)
    if( w->windowClass() == "ksmserver ksmserver"
        && ( w->windowRole() == "logoutdialog" || w->windowRole() == "logouteffect" ))
        {
        return true;
        }
    return false;
    }

#ifdef KWIN_HAVE_OPENGL_COMPOSITING
void LogoutEffect::renderVignetting()
    {
    glPushAttrib( GL_CURRENT_BIT | GL_ENABLE_BIT | GL_TEXTURE_BIT );
    glEnable( GL_BLEND ); // If not already (Such as when rendered straight to the screen)
    glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
    for( int screen = 0; screen < effects->numScreens(); screen++ )
        {
        QRect screenGeom = effects->clientArea( ScreenArea, screen, 0 );
        glScissor( screenGeom.x(), displayHeight() - screenGeom.y() - screenGeom.height(),
            screenGeom.width(), screenGeom.height() ); // GL coords are flipped
        glEnable( GL_SCISSOR_TEST ); // Geom must be set before enable
        const float cenX = screenGeom.x() + screenGeom.width() / 2;
        const float cenY = screenGeom.y() + screenGeom.height() / 2;
        const float a = M_PI / 16.0f; // Angle of increment
        const float r = float(( screenGeom.width() > screenGeom.height() )
                              ? screenGeom.width() : screenGeom.height() ) * 0.8f; // Radius
        glBegin( GL_TRIANGLE_FAN );
            glColor4f( 0.0f, 0.0f, 0.0f, 0.0f );
            glVertex3f( cenX, cenY, 0.0f );
            glColor4f( 0.0f, 0.0f, 0.0f, progress * 0.9f );
            for( float i = 0.0f; i <= M_PI * 2.01f; i += a )
                glVertex3f( cenX + r * cos( i ), cenY + r * sin( i ), 0.0f );
        glEnd();
        glDisable( GL_SCISSOR_TEST );
        }
    glPopAttrib();
    }
#endif

} // namespace
