/*
    * The SmartWeb Framework
    * Copyright (C) 2004-2006
    *
    * This library is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Lesser General Public
    * License as published by the Free Software Foundation; either
    * version 2.1 of the License, or (at your option) any later version.
    *
   * This library is distributed out 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
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * For further informations on the SmartWeb Framework please visit
   *
   *                        http://smartweb.sourceforge.net
   */
  package net.smartlab.ssh;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import ch.ethz.ssh2.ChannelCondition;
  import ch.ethz.ssh2.Connection;
  import ch.ethz.ssh2.Session;
  import net.smartlab.web.BusinessException;
  
  /**
   * This class represents a secure remote shell obtained through the SSH
   * protocol.
   * 
   * @author gperrone
   * @author rlogiacco
   */
  public class Shell {
  
  	/**
  	 * TODO documentation
  	 */
  	private String username;
  
  	/**
  	 * TODO documentation
  	 */
  	private String password;
  
  	/**
  	 * TODO documentation
  	 */
  	private String host;
  
  	/**
  	 * TODO documentation
  	 */
  	private int port = 22;
  	
  	/**
  	 * TODO documentation
  	 */
  	private long timeout = 1000;
  
  	/**
  	 * TODO documentation
  	 */
  	private Connection connection;
  
  	/**
  	 * TODO documentation
  	 */
  	private Session session;
  
  	/**
  	 * TODO documentation
  	 */
  	private OutputStream out;
  
  	/**
  	 * TODO documentation
  	 */
  	private InputStream in;
  
  	/**
  	 * TODO documentation
  	 */
  	private byte[] buffer = new byte[4096];
  
  
  	/**
  	 * Returns the username.
  	 * 
  	 * @return the username.
  	 */
  	public String getUsername() {
  		return username;
 	}
 
 	/**
 	 * Sets the username.
 	 * 
 	 * @param username the username to set.
 	 */
 	public void setUsername(String username) {
 		this.username = username;
 	}
 
 	/**
 	 * Returns the password.
 	 * 
 	 * @return the password.
 	 */
 	public String getPassword() {
 		return password;
 	}
 
 	/**
 	 * Sets the password.
 	 * 
 	 * @param password the password to set.
 	 */
 	public void setPassword(String password) {
 		this.password = password;
 	}
 
 	/**
 	 * Returns the host.
 	 * 
 	 * @return the host.
 	 */
 	public String getHost() {
 		return host;
 	}
 
 	/**
 	 * Sets the host.
 	 * 
 	 * @param host the host to set.
 	 */
 	public void setHost(String host) {
 		this.host = host;
 	}
 
 	/**
 	 * Returns the port.
 	 * 
 	 * @return the port.
 	 */
 	public int getPort() {
 		return port;
 	}
 
 	/**
 	 * Sets the port.
 	 * 
 	 * @param port the port to set.
 	 */
 	public void setPort(int port) {
 		this.port = port;
 	}
 
 	
 	/**
 	 * Returns the timeout.
 	 * @return the timeout.
 	 */
 	public long getTimeout() {
 		return timeout;
 	}
 
 	
 	/**
 	 * Sets the timeout.
 	 * @param timeout the timeout to set.
 	 */
 	public void setTimeout(long timeout) {
 		this.timeout = timeout;
 	}
 
 	/**
 	 * TODO documentation
 	 * @param host
 	 * @param port
 	 * @param username
 	 * @param password
 	 * @throws BusinessException 
 	 * @throws IOException
 	 */
 	public void open() throws BusinessException, IOException {
 		connection = new Connection(host, port);
 		connection.connect();
 		if (!connection.authenticateWithPassword(username, password)) {
 			throw new BusinessException("Authentication failed");
 		}
 		session = connection.openSession();
 		session.requestPTY("dumb", 80, 200, 0, 0, null);
 		session.startShell();
 		out = session.getStdin();
 		in = session.getStdout();
 	}
 
 	/**
 	 * TODO documentation
 	 * @return
 	 * @throws IOException
 	 */
 	public String update() throws IOException {
 		StringBuffer result = new StringBuffer();
 		int status = session.waitForCondition(ChannelCondition.STDOUT_DATA, timeout);
 		while (status != 1) {
 			int read = in.read(buffer);
 			result.append(new String(buffer, 0, read));
 			status = session.waitForCondition(ChannelCondition.STDOUT_DATA, timeout);
 		}
 		return result.toString();
 	}
 
 	/**
 	 * TODO documentation
 	 * @param command
 	 * @return
 	 * @throws IOException
 	 */
 	public String execute(String command) throws IOException {
 		out.write(command.getBytes());
 		out.write('\n');
 		out.flush();
 		return this.update();
 	}
 	
 	/**
 	 * TODO documentation
 	 * @return
 	 * @throws IOException
 	 */
 	public String interrupt() throws IOException {
 		out.write(0x03); // CTRL+C
 		out.write(0x04); // CTRL+D
 		out.flush();
 		return this.update();
 	}
 
 	/**
 	 * TODO documentation
 	 */
 	public void close() {
 		session.close();
 		connection.close();
 	}
 	
 	/**
 	 * @see java.lang.Object#toString()
 	 */
 	public String toString() {
 		 return username + "@" + host + ":" + port;
 	}
 }