/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2005 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * This program is distributed in 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.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  package ch.elca.el4j.services.security.authentication;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
  import org.springframework.security.core.Authentication;
  import org.springframework.security.core.context.SecurityContextHolder;
  
  import ch.elca.el4j.services.security.encryption.AESCipher;
  
  /**
   * This ContextPasser en/decrypts credentials using an AES-128 cipher such that no plain text passwords
   * are sent over the network.
   *
   * @svnLink $Revision: 4091 $;$Date: 2010-01-15 12:21:07 +0100 (Fr, 15. Jan 2010) $;$Author: jonasha $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/security/src/main/java/ch/elca/el4j/services/security/authentication/SecureUsernamePasswordAuthenticationServiceContextPasser.java $
   *
   * @author Stefan Wismer (SWI)
   */
  public class SecureUsernamePasswordAuthenticationServiceContextPasser extends
  	AuthenticationServiceContextPasser {
  	
  	/**
  	 * Private logger of this class.
  	 */
  	private static Logger s_logger = LoggerFactory.getLogger(SecureUsernamePasswordAuthenticationServiceContextPasser.class);
  	
  	/**
  	 * The AES cipher.
  	 */
  	private AESCipher m_cipher;
  
  	/**
  	 * @param key Is the key to set.
  	 */
  	public void setKey(String key) {
  		m_cipher = new AESCipher(key);
  	}
  	
  	/** {@inheritDoc} */
  	@Override
  	public Object getImplicitlyPassedContext() {
  		Authentication auth = SecurityContextHolder.getContext().getAuthentication();
  		if (auth instanceof UsernamePasswordAuthenticationToken) {
  			UsernamePasswordAuthenticationToken result = new UsernamePasswordAuthenticationToken(
  				auth.getPrincipal(), m_cipher.encrypt((String) auth.getCredentials()), auth.getAuthorities());
  			
  			return result;
  		} else {
  			return auth;
  		}
  	}
  	
  	/** {@inheritDoc} */
  	@Override
  	public void pushImplicitlyPassedContext(Object context) {
  		if (context == null) {
  			s_logger.warn("Authentication == null");
  			SecurityContextHolder.getContext().setAuthentication(null);
  			return;
  		}
  		
  		Authentication auth = (Authentication) context;
  		if (auth instanceof UsernamePasswordAuthenticationToken) {
  			UsernamePasswordAuthenticationToken result = new UsernamePasswordAuthenticationToken(
  				auth.getPrincipal(), m_cipher.decrypt((String) auth.getCredentials()));
  			
  			SecurityContextHolder.getContext().setAuthentication(result);
  		} else {
  			//throw new IllegalArgumentException("Context has to be of type UsernamePasswordAuthenticationToken");
  			SecurityContextHolder.getContext().setAuthentication(auth);
  		}
  	}
  	
  	
  }