/* 
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.apache.jetspeed.security.spi.impl;
  
  import java.security.Principal;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import javax.naming.NamingException;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.jetspeed.security.SecurityException;
  import org.apache.jetspeed.security.UserPrincipal;
  import org.apache.jetspeed.security.impl.UserPrincipalImpl;
  import org.apache.jetspeed.security.spi.UserSecurityHandler;
  import org.apache.jetspeed.security.spi.impl.ldap.LdapPrincipalDao;
  import org.apache.jetspeed.security.spi.impl.ldap.LdapUserPrincipalDaoImpl;
  
  /***
   * @see org.apache.jetspeed.security.spi.UserSecurityHandler
   * @author <a href="mailto:mike.long@dataline.com">Mike Long </a>
   */
  public class LdapUserSecurityHandler implements UserSecurityHandler
  {
      /*** The logger. */
      private static final Log logger = LogFactory.getLog(LdapUserSecurityHandler.class);
  
      /*** The {@link LdapPrincipalDao}. */
      private LdapPrincipalDao ldap;
  
      /***
       * @param ldap The LdapPrincipalDao.
       */
      public LdapUserSecurityHandler(LdapPrincipalDao ldap)
      {
          this.ldap = ldap;
      }
  
      /***
       * <p>
       * Default constructor.
       * </p>
       */
      public LdapUserSecurityHandler() throws NamingException, SecurityException
      {
          this(new LdapUserPrincipalDaoImpl());
      }
  
      /***
       * <p>
       * Lookup the user by his UID attribute on the Ldap Server.
       * </p>
       * 
       * @return true if the Ldap Server finds a user with that UID; false if he
       *         is not found or some sort of NamingException occurred.
       * @see org.apache.jetspeed.security.spi.UserSecurityHandler#isUserPrincipal(java.lang.String)
       */
      public boolean isUserPrincipal(String uid)
      {
          verifyUid(uid);
          return getUserPrincipal(uid) != null;
      }
  
      /***
       * @see org.apache.jetspeed.security.spi.UserSecurityHandler#getUserPrincipal(java.lang.String)
       */
      public Principal getUserPrincipal(String uid)
      {
          verifyUid(uid);
          try
          {
              String dn = ldap.lookupByUid(uid);
  
              if (!StringUtils.isEmpty(dn))
              {
                  return new UserPrincipalImpl(uid);
              }
          }
          catch (SecurityException e)
          {
              logSecurityException(e, uid);
          }
 
         return null;
     }
 
     /***
      * <p>
      * Verify the uid.
      * </p>
      * 
      * @param uid The uid.
      */
     private void verifyUid(String uid)
     {
         if (StringUtils.isEmpty(uid))
         {
             throw new IllegalArgumentException("The uid cannot be null or empty.");
         }
     }
 
     /***
      * @param se SecurityException Throws a {@link SecurityException}.
      * @param uid The uid.
      */
     private void logSecurityException(SecurityException se, String uid)
     {
         if (logger.isErrorEnabled())
         {
             logger.error("An LDAP error has occurred for user uid:" + uid, se);
         }
     }
 
     /***
      * @see org.apache.jetspeed.security.spi.UserSecurityHandler#getUserPrincipals(java.lang.String)
      */
     public List getUserPrincipals(String filter)
     {
         try
         {
             return Arrays.asList(ldap.find(filter, UserPrincipal.PREFS_USER_ROOT));
         }
         catch (SecurityException e)
         {
             logSecurityException(e, filter);
         }
 
         return new ArrayList();
     }
 
     /***
      * @see org.apache.jetspeed.security.spi.UserSecurityHandler#addUserPrincipal(org.apache.jetspeed.security.UserPrincipal)
      */
     public void addUserPrincipal(UserPrincipal userPrincipal) throws SecurityException
     {
         verifyUserPrincipal(userPrincipal);
 
         String uid = userPrincipal.getName();
         if (isUserPrincipal(uid))
         {
             throw new SecurityException(SecurityException.USER_ALREADY_EXISTS.create(uid));
         }
         ldap.create(uid);
     }
 
     /***
      * @see org.apache.jetspeed.security.spi.UserSecurityHandler#updateUserPrincipal(org.apache.jetspeed.security.UserPrincipal)
      */
     public void updateUserPrincipal(UserPrincipal userPrincipal) throws SecurityException
     {
         verifyUserPrincipal(userPrincipal);
         String uid = userPrincipal.getName();
         if (!isUserPrincipal(uid))
         {
             ldap.create(uid);
         }
     }
 
     /***
      * @param userPrincipal
      */
     private void verifyUserPrincipal(UserPrincipal userPrincipal)
     {
         if (userPrincipal == null)
         {
             throw new IllegalArgumentException("The UserPrincipal cannot be null or empty.");
         }
     }
 
     /***
      * @see org.apache.jetspeed.security.spi.UserSecurityHandler#removeUserPrincipal(org.apache.jetspeed.security.UserPrincipal)
      */
     public void removeUserPrincipal(UserPrincipal userPrincipal) throws SecurityException
     {
         verifyUserPrincipal(userPrincipal);
 
         String uid = userPrincipal.getName();
 
         ldap.delete(uid);
     }
 }