/*
 * "@(#)AppConnection.java	1.1	05/06/15 SMI"
 *
 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following 
 * conditions are met:
 * 
 * -Redistributions of source code must retain the above copyright  
 * notice, this  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduct the above copyright 
 * notice, this list of conditions and the following disclaimer in 
 * the documentation and/or other materials provided with the 
 * distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY 
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY 
 * DAMAGES OR LIABILITIES  SUFFERED BY LICENSEE AS A RESULT OF  OR 
 * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR 
 * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE 
 * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, 
 * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER 
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF 
 * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that Software is not designed, licensed or 
 * intended for use in the design, construction, operation or 
 * maintenance of any nuclear facility. 
 */

import java.io.*;
import java.net.Socket;

class AppConnection {
    public static final int AUTH_CMD = 100;
    public static final int DATA_CMD = 200;

    public static final int SUCCESS = 0;
    public static final int AUTH_INPROGRESS = 1;
    public static final int FAILURE = 2;

    private DataInputStream inStream;
    private DataOutputStream outStream;
    private Socket socket;

    // Client application
    AppConnection(String hostName, int port) throws IOException {
	socket = new Socket(hostName, port);

	inStream = new DataInputStream(socket.getInputStream());
	outStream = new DataOutputStream(socket.getOutputStream());

	System.out.println("Connected to address " +
	    socket.getInetAddress());
    }

    // Server side application
    AppConnection(Socket socket) throws IOException {
	this.socket = socket;
	inStream = new DataInputStream(socket.getInputStream());
	outStream = new DataOutputStream(socket.getOutputStream());

	System.out.println("Got connection from client " +
	    socket.getInetAddress());
    }

    byte[] receive(int expected) throws IOException {
	if (expected != -1) {
	    int cmd = inStream.readInt();
	    if (expected != cmd) {
		throw new IOException("Received unexpected code: " + cmd);
	    }
	    //System.out.println("Read cmd: " + cmd);
	}

	byte[] reply = null;
	int len;
	try {
	    len = inStream.readInt();
	    //System.out.println("Read length: " + len);

	} catch (IOException e) {
	    len = 0;
	}
	if (len > 0) {
	    reply = new byte[len];
	    inStream.readFully(reply);
	} else {
	    reply = new byte[0];
	}
	return reply;
    }

    AppReply send(int cmd, byte[] bytes) throws IOException {
	//System.out.println("Write cmd: " + cmd);
	outStream.writeInt(cmd);
	if (bytes != null) {
	    //System.out.println("Write length: " + bytes.length);
	    outStream.writeInt(bytes.length);
	    if (bytes.length > 0) {
		outStream.write(bytes);
	    }
	} else {
	    //System.out.println("Write length: " + 0);
	    outStream.writeInt(0);
	}

	outStream.flush();

	if (cmd == SUCCESS || cmd == FAILURE) {
	    return null;   // Done
	}

	int returnCode = inStream.readInt();
	//System.out.println("Read cmd: " + returnCode);

	byte[] reply = null;
	if (returnCode != FAILURE) {
	    reply = receive(-1);
	}
	return new AppReply(returnCode, reply);
    }

    static class AppReply {
	private int code;
	private byte[] bytes;

	AppReply(int code, byte[] bytes) {
	    this.bytes = bytes;
	    this.code = code;
	}
	
	int getStatus() {
	    return code;
	}

	byte[] getBytes() {
	    return bytes;
	}
    }

    void close() {
	try {
	    socket.close();
	} catch (IOException e) {
	}
    }
}