/*
 * Copyright 1999-2010 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.globus.net;

import org.globus.common.CoGProperties;

import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.InetAddress;
import java.net.BindException;
import java.io.IOException;

/**
 * This factory allows for creating regular sockets.
 * If the tcp.source.port.range system property is set it will create
 * sockets within the specified local port range (if the local port
 * number is set to 0).
 */
public class SocketFactory {

    private static SocketFactory defaultFactory = null;

    private PortRange portRange = null;

    protected SocketFactory() {
        this.portRange = PortRange.getTcpSourceInstance();
    }

    /**
     * Returns the default instance of this class.
     *
     * @return SocketFactory instance of this class.
     */
    public static synchronized SocketFactory getDefault() {
        if (defaultFactory == null) {
            defaultFactory = new SocketFactory();
        }
        return defaultFactory;
    }

    public Socket createSocket(String host, int port)
        throws IOException {
        return createSocket(InetAddress.getByName(host), port, null, 0);
    }

    public Socket createSocket(InetAddress address, int port)
        throws IOException {
        return createSocket(address, port, null, 0);
    }

    public Socket createSocket(String host, int port,
                               InetAddress localAddr, int localPort)
        throws IOException {
        return createSocket(InetAddress.getByName(host), port,
                            localAddr, localPort);
    }

    public Socket createSocket(InetAddress address, int port,
                               InetAddress localAddr, int localPort)
        throws IOException {
        if (this.portRange.isEnabled() && localPort == 0) {
            return new PrSocket(createSocket(address, port, localAddr));
        } else {
            Socket s = new Socket();
            s.setSoTimeout(CoGProperties.getDefault().getSocketTimeout());
            s.bind(new InetSocketAddress(localAddr, localPort));
            s.connect(new InetSocketAddress(address, port), CoGProperties.getDefault().getSocketTimeout());
            return s;
        }
    }

    private Socket createSocket(InetAddress address, int port,
                                InetAddress localAddr)
        throws IOException {
        Socket socket = null;
        int localPort = 0;

        while(true) {
            localPort = this.portRange.getFreePort(localPort);

            try {
                socket = new Socket();
                socket.setSoTimeout(CoGProperties.getDefault().getSocketTimeout());
                socket.bind(new InetSocketAddress(localAddr, localPort));
                socket.connect(new InetSocketAddress(address, port), CoGProperties.getDefault().getSocketTimeout());
                this.portRange.setUsed(localPort);
                return socket;
            } catch(BindException e) {
                // continue on
                localPort++;
            }
        }
    }

    class PrSocket extends WrappedSocket {

        public PrSocket(Socket socket) {
            super(socket);
        }

        public void close()
            throws IOException {
            int port = getLocalPort();
            try {
                super.close();
            } finally {
                if (port != -1) {
                    portRange.free(port);
                }
            }
        }
    }
}