/*
 * Copyright (c) 1996-2001
 * Logica Mobile Networks Limited
 * All rights reserved.
 *
 * This software is distributed under Logica Open Source License Version 1.0
 * ("Licence Agreement"). You shall use it and distribute only in accordance
 * with the terms of the License Agreement.
 *
 */
package org.smpp;

import org.smpp.util.*;

import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InterruptedIOException;

import javax.net.ServerSocketFactory;
import javax.net.SocketFactory;

/**
 * Implementation of TCP/IP type of communication.
 * Covers both client (peer-to-peer) connection and server (new connections
 * from clients accepting and creating) type of connections.
 * 
 * @author Logica Mobile Networks SMPP Open Source Team
 * @version $Revision: 1.3 $
 * @see Connection
 * @see java.net.Socket
 * @see java.net.ServerSocket
 * @see java.io.BufferedInputStream
 * @see java.io.BufferedOutputStream
 */
public class TCPIPConnection extends Connection {
	/**
	 * The IP address of the remote end of the <code>socket</code>. 
	 */
	private String address = null;

	/**
	 * The port number on the remote host to which the <code>socket</code>
	 * is connected or port number where <code>receiverSocket</code>
	 * is acception connections.
	 */
	private int port = 0;

	/**
	 * The TCP/IP (client) socket.
	 *
	 * @see java.net.Socket
	 */
	private Socket socket = null;

	/**
	 * An input stream for reading bytes from the <code>socket</code>.
	 *
	 * @see java.io.BufferedInputStream
	 */
	private BufferedInputStream inputStream = null;

	/**
	 * An output stream for writting bytes to the <code>socket</code>.
	 *
	 * @see java.io.BufferedOutputStream
	 */
	private BufferedOutputStream outputStream = null;

	/**
	 * Indication if the <code>socket</code> is opened.
	 */
	private boolean opened = false;

	/**
	 * The server socket used for accepting connection on <code>port</code>.
	 *
	 * @see #port
	 * @see java.net.ServerSocket
	 */
	private ServerSocket receiverSocket = null;

	/**
	 * Indicates if the connection represents client or server socket.
	 */
	private byte connType = CONN_NONE;

	/**
	 * Indicates that the connection type hasn't been set yet.
	 */
	private static final byte CONN_NONE = 0;

	/**
	 * Indicates that the connection is client type connection.
	 * @see #socket
	 */
	private static final byte CONN_CLIENT = 1;

	/**
	 * Indicates that the connection is server type connection.
	 * @see #receiverSocket
	 */
	private static final byte CONN_SERVER = 2;

	/**
	 * Default size for socket io streams buffers.
	 * @see #initialiseIOStreams(Socket)
	 */
	private static final int DFLT_IO_BUF_SIZE = 2 * 1024;

	/**
	 * Default size for the receiving buffer.
	 */
	private static final int DFLT_RECEIVE_BUFFER_SIZE = 4 * 1024;

	/**
	 * The default maximum of bytes received in one call to
	 * the <code>receive</code> function.
	 * @see #maxReceiveSize
	 * @see #receive()
	 */
	private static final int DFLT_MAX_RECEIVE_SIZE = 128 * 1024;

	/**
	 * The size for IO stream's buffers. Used by the instances of 
	 * <code>BufferedInputStream</code> which are used as sreams for accessing
	 * the socket.
	 * @see #setIOBufferSize(int)
	 */
	private int ioBufferSize = DFLT_IO_BUF_SIZE;

	/**
	 * The receiver buffer size. Can be changed by call to the function
	 * <code>setReceiveBufferSize</code>. This is the maximum count of bytes
	 * which can be read from the socket in one call to the socket's
	 * input stream's <code>read</code>.
	 * @see #setReceiveBufferSize(int)
	 * @see #receive()
	 */
	private int receiveBufferSize;

	/**
	 * The buffer for storing of received data in the <code>receive</code>
	 * function. 
	 * @see #setReceiveBufferSize(int)
	 * @see #receive()
	 */
	private byte[] receiveBuffer;

	/**
	 * Max count of bytes which can be returned from one call
	 * to the <code>receive</code> function. If the returned data seems
	 * to be incomplete, you might want to call the <code>receive</code> again.
	 * @see #setMaxReceiveSize(int)
	 * @see #receive()
	 */
	private int maxReceiveSize = DFLT_MAX_RECEIVE_SIZE;

	/**
	 * Instanciate a SocketFactory which will be used to create sockets later.
	 * Subclasses can override this field with e.g. a SSLSocketFactory
	 */
	protected SocketFactory socketFactory = SocketFactory.getDefault();

	/**
	 * Instanciate a ServerSocketFactory which will be used to create server sockets later.
	 * Subclasses can override this field with e.g. a SSLServerSocketFactory
	 */
	protected ServerSocketFactory serverSocketFactory = ServerSocketFactory.getDefault();
	
	/**
	 * Initialises the connection with port only, which means that
	 * the connection will serve as connection receiving server.
	 * The accepting of the connection must be invoked explicitly by
	 * calling of <code>accept</code> method.
	 *
	 * @param port the port number to listen on
	 */
	public TCPIPConnection(int port) {
		if ((port >= Data.MIN_VALUE_PORT) && (port <= Data.MAX_VALUE_PORT)) {
			this.port = port;
		} else {
			debug.write("Invalid port.");
		}
		connType = CONN_SERVER;
	}

	/**
	 * Initialises the connection for client communication.
	 *
	 * @param address  the address of the remote end
	 *                 of the <code>socket</code>
	 * @param port     the port number on the remote host
	 */
	public TCPIPConnection(String address, int port) {
		if (address.length() >= Data.MIN_LENGTH_ADDRESS) {
			this.address = address;
		} else {
			debug.write("Invalid address.");
		}
		if ((port >= Data.MIN_VALUE_PORT) && (port <= Data.MAX_VALUE_PORT)) {
			this.port = port;
		} else {
			debug.write("Invalid port.");
		}
		connType = CONN_CLIENT;
		setReceiveBufferSize(DFLT_RECEIVE_BUFFER_SIZE);
	}

	/**
	 * Initialises the connection with existing socket.
	 * It's intended for use with one server connection which generates
	 * new sockets and creates connections with the sockets.
	 *
	 * @param socket the socket to use for communication
	 * @see #accept()
	 */
	public TCPIPConnection(Socket socket) throws IOException {
		connType = CONN_CLIENT;
		this.socket = socket;
		address = socket.getInetAddress().getHostAddress();
		port = socket.getPort();
		initialiseIOStreams(socket);
		opened = true;
		setReceiveBufferSize(DFLT_RECEIVE_BUFFER_SIZE);
	}

	/**
	 * Opens the connection by creating new <code>Socket</code> (for client
	 * type connection) or by creating <code>ServerSocket</code> (for
	 * server type connection). If the connection is already opened,
	 * the method is not doing anything.
	 *
	 * @see #connType
	 * @see java.net.ServerSocket
	 * @see java.net.Socket
	 */
	public void open() throws IOException {
		debug.enter(DCOM, this, "open");
		IOException exception = null;

		if (!opened) {
			if (connType == CONN_CLIENT) {
				try {
					socket = socketFactory.createSocket(address, port);
					initialiseIOStreams(socket);
					opened = true;
					debug.write(DCOM, "opened client tcp/ip connection to " + address + " on port " + port);
				} catch (IOException e) {
					debug.write("IOException opening TCPIPConnection " + e);
					event.write(e, "IOException opening TCPIPConnection");
					exception = e;
				}
			} else if (connType == CONN_SERVER) {
				try {
					receiverSocket = serverSocketFactory.createServerSocket(port);
					opened = true;
					debug.write(DCOM, "listening tcp/ip on port " + port);
				} catch (IOException e) {
					debug.write("IOException creating listener socket " + e);
					exception = e;
				}
			} else {
				debug.write("Unknown connection type = " + connType);
			}
		} else {
			debug.write("attempted to open already opened connection ");
		}

		debug.exit(DCOM, this);
		if (exception != null) {
			throw exception;
		}
	}

	/**
	 * Closes the client or server connection.
	 *
	 * @see #connType
	 * @see #open()
	 */
	public void close() throws IOException {
		debug.enter(DCOM, this, "close");
		IOException exception = null;

		if (connType == CONN_CLIENT) {
			try {
				if(inputStream != null)
					inputStream.close();
				if(outputStream != null)
					outputStream.close();
				if(socket != null)
					socket.close();
				inputStream = null;
				outputStream = null;
				socket = null;