package org.litesoft.GWT.client;

import java.io.*;

public enum KeyboardKeyModifier implements KeyboardKeyModifierBits,
                                           Serializable
{
    None,
    Shift
            {
                public int getBits()
                {
                    return iSHIFT;
                }
            },
    Ctrl
            {
                public int getBits()
                {
                    return iCTRL;
                }
            },
    Alt
            {
                public int getBits()
                {
                    return iALT;
                }
            },
    Meta
            {
                public int getBits()
                {
                    return iMETA;
                }
            },
    Ctrl_Alt
            {
                public int getBits()
                {
                    return iCTRL_ALT;
                }
            },
    Ctrl_Meta
            {
                public int getBits()
                {
                    return iCTRL_META;
                }
            },
    Ctrl_Shift
            {
                public int getBits()
                {
                    return iCTRL_SHIFT;
                }
            },
    Alt_Meta
            {
                public int getBits()
                {
                    return iALT_META;
                }
            },
    Alt_Shift
            {
                public int getBits()
                {
                    return iALT_SHIFT;
                }
            },
    Meta_Shift
            {
                public int getBits()
                {
                    return iMETA_SHIFT;
                }
            },
    Ctrl_Alt_Meta
            {
                public int getBits()
                {
                    return iCTRL_ALT_META;
                }
            },
    Ctrl_Alt_Shift
            {
                public int getBits()
                {
                    return iCTRL_ALT_SHIFT;
                }
            },
    Ctrl_Meta_Shift
            {
                public int getBits()
                {
                    return iCTRL_META_SHIFT;
                }
            },
    Alt_Meta_Shift
            {
                public int getBits()
                {
                    return iALT_META_SHIFT;
                }
            },
    Ctrl_Alt_Meta_Shift
            {
                public int getBits()
                {
                    return iCTRL_ALT_META_SHIFT;
                }
            };

    public static final long serialVersionUID = -8333216543216543212L;

    public static KeyboardKeyModifier deNull( KeyboardKeyModifier pModifiers )
    {
        return (pModifiers != null) ? pModifiers : None;
    }

    public int getBits()
    {
        return 0;
    }

    public boolean isCtrl()
    {
        return hasBit( iCTRL );
    }

    public boolean isAlt()
    {
        return hasBit( iALT );
    }

    public boolean isMeta()
    {
        return hasBit( iMETA );
    }

    public boolean isShift()
    {
        return hasBit( iSHIFT );
    }

    public KeyboardKeyModifier addCtrl()
    {
        return add( Ctrl );
    }

    public KeyboardKeyModifier addAlt()
    {
        return add( Alt );
    }

    public KeyboardKeyModifier addMeta()
    {
        return add( Ctrl );
    }

    public KeyboardKeyModifier addShift()
    {
        return add( Shift );
    }

    public KeyboardKeyModifier add( KeyboardKeyModifier them )
    {
        if ( them != null )
        {
            int zCurBits = this.getBits();
            int zModBits = them.getBits();
            int zNewBits = zCurBits | zModBits;
            if ( zCurBits != zNewBits )
            {
                return (zModBits == zNewBits) ? them : fromBits( zNewBits );
            }
        }
        return this;
    }

    public KeyboardKeyModifier removeCtrl()
    {
        return remove( Ctrl );
    }

    public KeyboardKeyModifier removeAlt()
    {
        return remove( Alt );
    }

    public KeyboardKeyModifier removeMeta()
    {
        return remove( Ctrl );
    }

    public KeyboardKeyModifier removeShift()
    {
        return remove( Shift );
    }

    public KeyboardKeyModifier remove( KeyboardKeyModifier them )
    {
        if ( them != null )
        {
            int zCurBits = this.getBits();
            int zModBits = them.getBits();
            int zSharedBits = zCurBits & zModBits;
            if ( zSharedBits != 0 )
            {
                int zNewBits = zCurBits - zSharedBits;
                return (zNewBits == 0) ? None : fromBits( zNewBits );
            }
        }
        return this;
    }

    private boolean hasBit( int pBit )
    {
        return 0 != (getBits() & pBit);
    }

    public static KeyboardKeyModifier fromBits( int pBits )
            throws IllegalArgumentException
    {
        KeyboardKeyModifier zModifier = LLfromBits( pBits );
        int zXtraBits = pBits - zModifier.getBits();
        if ( zXtraBits == 0 )
        {
            return zModifier;
        }
        throw new IllegalArgumentException( "KeyboardKeyModifier '" + zModifier + "' w/ extra bits: " + zXtraBits );
    }

    private static KeyboardKeyModifier LLfromBits( int pBits )
    {
        int zValidBits = pBits & iCTRL_ALT_META_SHIFT;
        for ( KeyboardKeyModifier zModifier : values() )
        {
            if ( zValidBits == zModifier.getBits() )
            {
                return zModifier;
            }
        }
        throw new Error( "No KeyboardKeyModifier w/ bits: " + pBits );
    }
}