#ifndef OXYGEN_HELPER_H
#define OXYGEN_HELPER_H

/*
 * Copyright 2009-2010 Hugo Pereira Da Costa <hugo.pereira@free.fr>
 * Copyright 2008 Long Huynh Huu <long.upcase@googlemail.com>
 * Copyright 2007 Matthew Woehlke <mw_triad@users.sourceforge.net>
 * Copyright 2007 Casper Boemann <cbr@boemann.dk>
 * Copyright 2007 Fredrik Höglund <fredrik@kde.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License version 2 as published by the Free Software Foundation.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "oxygentileset.h"

#include <KSharedConfig>
#include <KComponentData>
#include <KColorScheme>

#include <QtGui/QColor>
#include <QtGui/QPixmap>
#include <QtGui/QWidget>
#include <QtGui/qbrush.h>
#include <QtCore/QCache>

#ifdef Q_WS_X11
#include <X11/Xdefs.h>
#endif

namespace Oxygen
{

    template<typename T> class BaseCache: public QCache<quint64, T>
    {

        public:

        //! constructor
        BaseCache( int maxCost ):
            QCache<quint64, T>( maxCost ),
            _enabled( true )
        {}

        //! constructor
        explicit BaseCache( void ):
            _enabled( true )
            {}

        //! destructor
        ~BaseCache( void )
        {}

        //! enable
        void setEnabled( bool value )
        { _enabled = value; }

        //! enable state
        bool enabled( void ) const
        { return _enabled; }

        //! access
        T* object( const quint64& key )
        { return _enabled ? QCache<quint64, T>::object( key ) : 0; }

        //! max cost
        void setMaxCost( int cost )
        {
            if( cost <= 0 ) {

                QCache<quint64, T>::clear();
                QCache<quint64, T>::setMaxCost( 1 );
                setEnabled( false );

            } else {

                setEnabled( true );
                QCache<quint64, T>::setMaxCost( cost );

            }
        }

        private:

        //! enable flag
        bool _enabled;

    };

    template<typename T> class Cache
    {

        public:

        //! constructor
        Cache()
        {}

        //! destructor
        ~Cache()
        {}

        //! return cache matching a given key
        //typedef QCache<quint64, T> Value;
        typedef BaseCache<T> Value;
        Value* get( const QColor& color )
        {
            const quint64 key = ( color.isValid() ? color.rgba():0 );
            Value* cache = data_.object( key );

            if ( !cache )
            {
                cache = new Value( data_.maxCost() );
                data_.insert( key, cache );
            }

            return cache;
        }

        //! clear
        void clear( void )
        { data_.clear(); }

        //! max cache size
        void setMaxCacheSize( int value )
        {
            data_.setMaxCost( value );
            foreach( quint64 key, data_.keys() )
            { data_.object( key )->setMaxCost( value ); }
        }

        private:

        //! data
        BaseCache<Value> data_;

    };

    //! oxygen style helper class.
    /*! contains utility functions used at multiple places in both oxygen style and oxygen window decoration */
    class OXYGEN_EXPORT Helper
    {
        public:

        //! constructor
        explicit Helper( const QByteArray& componentName );

        //! destructor
        virtual ~Helper()
        {}

        //! reload configuration
        virtual void reloadConfig();

        //! pointer to shared config
        KSharedConfigPtr config() const;

        //! reset all caches
        virtual void invalidateCaches();

        //! update maximum cache size
        virtual void setMaxCacheSize( int );

        //!@name window background gradients
        //@{
        /*!
        \par y_shift: shift the background gradient upwards, to fit with the windec
        \par gradientHeight: the height of the generated gradient.
        for different heights, the gradient is translated so that it is always at the same position from the bottom
        */
        virtual void renderWindowBackground( QPainter* p, const QRect& clipRect, const QWidget* widget, const QPalette&  pal, int y_shift=-23, int gradientHeight = 20 )
        { renderWindowBackground( p, clipRect, widget, pal.color( widget->window()->backgroundRole() ), y_shift, gradientHeight ); }

        /*!
        y_shift: shift the background gradient upwards, to fit with the windec
        gradientHeight: the height of the generated gradient.
        for different heights, the gradient is translated so that it is always at the same position from the bottom
        */
        virtual void renderWindowBackground( QPainter* p, const QRect& clipRect, const QWidget* widget, const QWidget* window, const QPalette&  pal, int y_shift=-23, int gradientHeight = 20 )
        { renderWindowBackground( p, clipRect, widget, window, pal.color( window->backgroundRole() ), y_shift, gradientHeight ); }

        //! render window background using a given color as a reference
        virtual void renderWindowBackground( QPainter* p, const QRect& clipRect, const QWidget* widget, const QColor& color, int y_shift=-23, int gradientHeight = 20 )
        { renderWindowBackground( p, clipRect, widget, widget->window(), color, y_shift, gradientHeight ); }

        //! render window background using a given color as a reference
        virtual void renderWindowBackground( QPainter* p, const QRect& clipRect, const QWidget* widget, const QWidget* window, const QColor& color, int y_shift=-23, int gradientHeight = 20 );

        //@}

        //! dots
        void renderDot( QPainter*, const QPoint&, const QColor& );

        //! returns true for too 'dark' colors
        bool lowThreshold( const QColor& color );

        //! returns true for too 'light' colors
        bool highThreshold( const QColor& color );

        //! add alpha channel multiplier to color
        static QColor alphaColor( QColor color, qreal alpha );

        //! calculated light color from argument
        virtual const QColor& calcLightColor( const QColor& color );

        //! calculated dark color from argument
        virtual const QColor& calcDarkColor( const QColor& color );

        //! calculated shadow color from argument
        virtual const QColor& calcShadowColor( const QColor& color );

        //! returns menu background color matching position in a given top level widget
        virtual const QColor& backgroundColor( const QColor& color, const QWidget* w, const QPoint& point )
        {
            if( !( w && w->window() ) || checkAutoFillBackground( w ) ) return color;
            else return backgroundColor( color, w->window()->height(), w->mapTo( w->window(), point ).y() );
        }

        //! returns menu background color matching position in a top level widget of given height
        virtual const QColor& backgroundColor( const QColor& color, int height, int y )
        { return backgroundColor( color, qMin( qreal( 1.0 ), qreal( y )/qMin( 300, 3*height/4 ) ) ); }

        //! color used for background radial gradient
        virtual const QColor& backgroundRadialColor( const QColor& color );

        //! color used at the top of window background
        virtual const QColor& backgroundTopColor( const QColor& color );

        //! color used at the bottom of window background
        virtual const QColor& backgroundBottomColor( const QColor& color );

        //! vertical gradient for window background
        virtual QPixmap verticalGradient( const QColor& color, int height, int offset = 0 );

        //! radial gradient for window background
        virtual QPixmap radialGradient( const QColor& color, int width, int height = 20 );

        //! merge background and front color for check marks, arrows, etc. using _contrast
        virtual const QColor& decoColor( const QColor& background, const QColor& color );

        //! returns a region matching given rect, with rounded corners, based on the multipliers
        /*! setting any of the multipliers to zero will result in no corners shown on the corresponding side */
        virtual QRegion roundedMask( const QRect&, int left = 1, int right = 1, int top = 1, int bottom = 1 ) const;

        //! draw frame that mimics some sort of shadows around a panel
        /*! it is used for menus, detached dock panels and toolbar, as well as window decoration when compositing is disabled */
        virtual void drawFloatFrame(
            QPainter* p, const QRect r, const QColor& color,
            bool drawUglyShadow=true, bool isActive=false,
            const QColor& frameColor=QColor(),
            TileSet::Tiles tiles = TileSet::Ring
            );

        //! draw dividing line
        virtual void drawSeparator( QPainter*, const QRect&, const QColor&, Qt::Orientation );

        //! default slab
        virtual TileSet* slab( const QColor& color, qreal shade, int size = 7 )
        { return slab( color, QColor(), shade, size );  }

        //! default slab (with glow)
        virtual TileSet* slab( const QColor&, const QColor& glow, qreal shade, int size = 7 );

        //! sunken slab
        virtual TileSet *slabSunken( const QColor&, int size = 7 );

        //! fill a slab of given size with brush set on painter
        void fillSlab( QPainter&, const QRect&, int size = 7 ) const;

        //! linear gradient used to fill buttons
        virtual void fillButtonSlab( QPainter&, const QRect&, const QColor&, bool sunken );

        //! inverse (inner-hole) shadow
        /*! this method must be public because it is used directly by OxygenStyle to draw dials */
        void drawInverseShadow( QPainter&, const QColor&, int pad, int size, qreal fuzz ) const;

        //! focus brush
        const KStatefulBrush& viewFocusBrush( void ) const
        { return _viewFocusBrush; }

        //! hover brush
        const KStatefulBrush& viewHoverBrush( void ) const
        { return _viewHoverBrush; }

        //! negative text brush ( used for close button hover )
        const KStatefulBrush& viewNegativeTextBrush( void ) const
        { return _viewNegativeTextBrush; }

        /*!
        returns first widget in parent chain that sets autoFillBackground to true,
        or NULL if none
        */
        const QWidget* checkAutoFillBackground( const QWidget* ) const;

        //!@name background gradient XProperty
        //@{

        //! set background gradient hint to widget
        virtual void setHasBackgroundGradient( WId, bool ) const;

        //! true if background gradient hint is set
        virtual bool hasBackgroundGradient( WId ) const;

        //@}

        protected:

        //! return color key for a given color, properly accounting for invalid colors
        quint64 colorKey( const QColor& color ) const
        { return color.isValid() ? color.rgba():0; }

        //! generic slab painting (to be stored in tilesets)
        virtual void drawSlab( QPainter&, const QColor&, qreal shade );

        //! generic outer shadow (to be stored in tilesets)
        virtual void drawShadow( QPainter&, const QColor&, int size );

        //! generic outer glow (to be stored in tilesets)
        virtual void drawOuterGlow( QPainter&, const QColor&, int size );

        //! return background adjusted color matching relative vertical position in window
        const QColor& backgroundColor( const QColor&, qreal ratio );

        //!@name global configuration parameters
        //@{

        static const qreal _glowBias;
        static const qreal _slabThickness;
        static const qreal _shadowGain;
        qreal _contrast;

        //@}

        //! shortcut to color caches
        /*! it is made protected because it is also used in the style helper */
        typedef BaseCache<QColor> ColorCache;

        //! shortcut to pixmap cache
        typedef BaseCache<QPixmap> PixmapCache;

        private:

        //!@name tileset caches
        //!@{

        //! slabs
        Oxygen::Cache<TileSet> _slabCache;

        //! sunken slabs
        BaseCache<TileSet> _slabSunkenCache;

        //@}

        //!@name brushes
        //@{
        KStatefulBrush _viewFocusBrush;
        KStatefulBrush _viewHoverBrush;
        KStatefulBrush _viewNegativeTextBrush;
        //@}

        KComponentData _componentData;
        KSharedConfigPtr _config;
        qreal _bgcontrast;

        //!@name color caches
        //@{
        ColorCache _decoColorCache;
        ColorCache _lightColorCache;
        ColorCache _darkColorCache;
        ColorCache _shadowColorCache;
        ColorCache _backgroundTopColorCache;
        ColorCache _backgroundBottomColorCache;
        ColorCache _backgroundRadialColorCache;
        ColorCache _backgroundColorCache;
        //@}

        PixmapCache _backgroundCache;
        PixmapCache _dotCache;

        //! high threshold colors
        typedef QMap<quint32, bool> ColorMap;
        ColorMap _highThreshold;
        ColorMap _lowThreshold;

        #ifdef Q_WS_X11

        //! set value for given hint
        void setHasHint( WId, Atom, bool ) const;

        //! value for given hint
        bool hasHint( WId, Atom ) const;

        //! background gradient hint atom
        Atom _backgroundGradientAtom;

        #endif
    };

}

#endif