// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.configuration;

import java.util.prefs.*;

import org.litesoft.commonfoundation.typeutils.*;

public class ConfigAccessorFactoryPreferences implements ConfigDataAccessorFactory
{
    private ConfigDataAccessor mAccessor;

    public ConfigAccessorFactoryPreferences( String pLoadedFrom, ConfigDataAccessor.Level pLevel, Preferences pPrefs )
    {
        Objects.assertNotNull( "Preferences", pPrefs );
        Objects.assertNotNull( "Level", pLevel );
        mAccessor = new ConfigDataAccessorImpl( pLoadedFrom, pLevel, pPrefs );
    }

    public ConfigAccessorFactoryPreferences( String pLoadedFrom, String pPreferenceNodeKey_ApplicationName )
    {
        this( pLoadedFrom, ConfigDataAccessor.Level.MACHINE, Preferences.systemRoot().node( pPreferenceNodeKey_ApplicationName ) );
        // this( pLoadedFrom, ConfigDataAccessor.Level.USER, Preferences.userRoot().node( pPreferenceNodeKey_ApplicationName ) );
    }

    @Override
    public ConfigDataAccessor createConfigDataAccessor()
    {
        return mAccessor;
    }

    private static class ConfigDataAccessorImpl extends AbstractConfigDataAccessor
    {
        private final Preferences mPrefs;

        public ConfigDataAccessorImpl( String pLoadedFrom, Level pLevel, Preferences pPrefs )
        {
            super( null, pLoadedFrom, pLevel );
            mPrefs = pPrefs;
        }

        @Override
        protected String getExceptionPlus()
        {
            return " Preference Node: " + mPrefs;
        }

        @Override
        protected void setOtherLevelKeyValue( String pKey, String pValue )
        {
            if ( pValue == null )
            {
                try
                {
                    mPrefs.remove( pKey );
                }
                catch ( IllegalStateException e )
                {
                    return; // No Node so technically already Removed!
                }
            }
            else
            {
                mPrefs.put( pKey, pValue );
            }
            try
            {
                mPrefs.flush();
            }
            catch ( BackingStoreException e )
            {
                throw new RuntimeException( e );
            }
        }

        @Override
        protected String[] getBaseKeys()
        {
            try
            {
                return mPrefs.keys();
            }
            catch ( BackingStoreException e )
            {
                throw new RuntimeException( e );
            }
        }

        @Override
        protected String getBaseValue( String pKey )
        {
            try
            {
                return mPrefs.get( pKey, null );
            }
            catch ( IllegalStateException e )
            {
                return null; // No Node == No Value -> null!
            }
        }
    }
}