/*
 * Copyright 1999-2006 University of Chicago
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.dcache.ftp.client;

import java.util.StringTokenizer;
import java.net.InetAddress;

/**
 * Utility class for parsing and converting host-port information from PASV
 * and PORT ftp commands.
 */
public class HostPort
{

    private int[] datainfo;

    protected HostPort()
    {
    }

    /**
     * Parses host-port from passive mode reply message.
     * Note that the argument is not the whole message, but
     * only the content of the brackets:
     * h1,h2,h3,h4,p1,p2
     *
     * @param passiveReplyMessage reply message for the PASV command
     */
    public HostPort(String passiveReplyMessage)
    {
        datainfo = new int[6];
        int i = 0;
        StringTokenizer tokens = new StringTokenizer(passiveReplyMessage, ",");
        while (tokens.hasMoreTokens()) {
            datainfo[i] = Integer.parseInt(tokens.nextToken().trim());
            i++;
        }
    }

    /**
     * Creates the HostPort object from specified ip address
     * and port number.
     *
     * @param addr ip address
     * @param port port number
     */
    public HostPort(InetAddress addr, int port)
    {
        this(addr.getHostAddress(), port);
    }

    /**
     * Creates the HostPort object from specified ip address
     * and port number.
     *
     * @param ipAddress ip address
     * @param port      port number
     */
    public HostPort(String ipAddress, int port)
    {
        datainfo = new int[6];
        int i = 0;
        StringTokenizer tokens = new StringTokenizer(ipAddress, ".");
        while (tokens.hasMoreTokens()) {
            datainfo[i] = Integer.parseInt(tokens.nextToken());
            i++;
        }

        if (i != 4) {
            throw new IllegalArgumentException("Invalid ip address: " +
                                               ipAddress);
        }

        datainfo[4] = port / 256;
        datainfo[5] = port - datainfo[4] * 256;
    }

    /**
     * Returns the port number
     *
     * @return port number
     */
    public int getPort()
    {
        return datainfo[4] * 256 + datainfo[5];
    }

    /**
     * Returns the ip address in the form "h1.h2.h3.h4"
     *
     * @return ip address
     */
    public String getHost()
    {
        return datainfo[0] + "." + datainfo[1] + "." +
               datainfo[2] + "." + datainfo[3];
    }

    /**
     * Returns the host-port information in the
     * format used by PORT command.
     * (h1,h2,h3,h4,p1,p2)
     *
     * @return host-port information in PORT command
     * representation.
     */
    public String toFtpCmdArgument()
    {
        StringBuilder msg = new StringBuilder();
        for (int i = 0; i < datainfo.length; i++) {
            msg.append(String.valueOf(datainfo[i]));
            if (i + 1 != datainfo.length) msg.append(",");
        }
        return msg.toString();
    }

}