/**
 * Copyright (c) 2002-2010 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package org.neo4j.shell.apps;

import org.neo4j.helpers.Service;
import org.neo4j.shell.App;
import org.neo4j.shell.AppCommandParser;
import org.neo4j.shell.Output;
import org.neo4j.shell.Session;
import org.neo4j.shell.impl.AbstractApp;

@Service.Implementation( App.class )
public class Alias extends AbstractApp
{
    public static final String ALIAS_PREFIX = "ALIAS_";

    @Override
    public String getDescription()
    {
        return "Adds an alias so that it can be used later as a command.\n" +
                "Usage: alias <key>='<value>'";
    }

    public String execute( AppCommandParser parser, Session session,
            Output out ) throws Exception
    {
        String line = parser.getLineWithoutApp();
        if ( line.trim().length() == 0 )
        {
            printAllAliases( session, out );
            return null;
        }

        String[] keyValue = Export.splitInKeyEqualsValue( line );
        String key = ALIAS_PREFIX + keyValue[ 0 ];
        String value = keyValue[ 1 ];
        if ( value == null || value.trim().length() == 0 )
        {
            safeRemove( session, key );
        }
        else
        {
            safeSet( session, key, value );
        }
        return null;
    }

    private void printAllAliases( Session session, Output out )
            throws Exception
    {
        for ( String key : session.keys() )
        {
            if ( !key.startsWith( ALIAS_PREFIX ) )
            {
                continue;
            }
            String shortKey = key.substring( ALIAS_PREFIX.length() );
            out.println( "alias " + shortKey + "='" + session.get( key ) +
                    "'" );
        }
    }
}