/*
    * LDAPUserGroupDB.java
    *
    * Created on August 1, 2005, 10:32 AM
    *
    * To change this template, choose Tools | Options and locate the template under
    * the Source Creation and Management node. Right-click the template and choose
    * Open. You can then make changes to the template in the Source Editor.
    */
  
  package gov.bnl.gums.ldap;
  
  import gov.bnl.gums.FQAN;
  import gov.bnl.gums.GridUser;
  import gov.bnl.gums.ManualUserGroupDB;
  import gov.bnl.gums.UserGroupDB;
  import java.util.ArrayList;
  import java.util.Date;
  import java.util.Iterator;
  import java.util.List;
  import java.util.StringTokenizer;
  import javax.naming.*;
  import javax.naming.directory.*;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /***
   *
   * @author carcassi
   */
  public class LDAPUserGroupDB implements UserGroupDB, ManualUserGroupDB {
      private Log log = LogFactory.getLog(LDAPUserGroupDB.class);
  
      private LDAPPersistenceFactory factory;
      private String group;
      private String groupDN;
      private List addedMembers;
      private List removedMembers;
      
      /*** Creates a new instance of LDAPUserGroupDB */
      public LDAPUserGroupDB(LDAPPersistenceFactory factory, String group) {
          this.factory = factory;
          this.group = group;
          this.groupDN = "group=" + group + "," + factory.getDefaultGumsOU();
          createGroupIfNotExists();
          log.trace("LDAPUserGroupDB object create: group '" + group + "' factory " + factory);
      }
      
      boolean doesGroupExist() {
          DirContext context = factory.retrieveContext();
          try {
              SearchControls ctrls = new SearchControls();
              ctrls.setSearchScope(SearchControls.SUBTREE_SCOPE);
              NamingEnumeration result = context.search(factory.getDefaultGumsOU(), "(group={0})", new Object[] {group}, ctrls);
              log.trace("Checking whether group '" + group + "' exists: " + result.hasMore());
              return result.hasMore();
          } catch (Exception e) {
              log.info("Couldn't determine whether group '" + group + "' esists", e);
              throw new RuntimeException("Couldn't determine whether group '" + group + "' esists: " + e.getMessage(), e);
          } finally {
              factory.releaseContext(context);
          }
      }
      
      void createGroupIfNotExists() {
          if (!doesGroupExist())
              factory.createUserGroup(group, groupDN);
      }
  
      public boolean isMemberInGroup(gov.bnl.gums.GridUser user) {
          DirContext context = factory.retrieveContext();
          try {
              SearchControls ctrls = new SearchControls();
              ctrls.setSearchScope(SearchControls.SUBTREE_SCOPE);
              NamingEnumeration result = context.search(factory.getDefaultGumsOU(), "(&(group={0})(user={1}))", new Object[] {group, gridID(user)}, ctrls);
              log.trace("Checking whether user '" + user + "' belongs to group '" + group + "': " + result.hasMore());
              return result.hasMore();
          } catch (Exception e) {
              log.info("Couldn't check whether user '" + user + "' belongs to group '" + group + "'", e);
              throw new RuntimeException("Couldn't check whether user '" + user + "' belongs to group ': " + e.getMessage(), e);
          } finally {
              factory.releaseContext(context);
          }
      }
      
      private String gridID(GridUser user) {
          if (user.getVoFQAN() == null)
              return user.getCertificateDN();
          else
              return user.getCertificateDN()+"["+user.getVoFQAN()+"]";
      }
  
      public boolean removeMember(gov.bnl.gums.GridUser user) {
          try {
              factory.removeUserGroupEntry(gridID(user), group, groupDN);
              return true;
          } catch (RuntimeException e) {
              if (e.getCause() instanceof NoSuchAttributeException) {
                  log.trace("No entry to remove for user '" + user + "' from group '" + group + "'");
                 return false;
             }
             throw e;
         }
     }
 
     public void addMember(gov.bnl.gums.GridUser user) {
         factory.addUserGroupEntry(gridID(user), group, groupDN);
     }
 
     public void loadUpdatedList(java.util.List members) {
         Exception lastException = null;
 
         try {
             // Retrieving the current list of members
             List currentMembers = retrieveMembers();
 
             // Calculating the deltas
             List newMembers = new ArrayList(members);
             newMembers.removeAll(currentMembers);
             List oldMembers = new ArrayList(currentMembers);
             oldMembers.removeAll(members);
 
             // Removing old members
             if (log.isTraceEnabled()) {
                 log.trace("Removing old members from group " + group + ": " + oldMembers);
             }
             Iterator iter = oldMembers.iterator();
             while (iter.hasNext()) {
                 GridUser user = (GridUser) iter.next();
                 try {
                     removeMember(user);
                 } catch (Exception e) {
                     lastException = e;
                 }
             }
 
             // Adding new members
             if (log.isTraceEnabled()) {
                 log.trace("Adding new members from group " + group + ": " + newMembers);
             }
             iter = newMembers.iterator();
             while (iter.hasNext()) {
                 GridUser user = (GridUser) iter.next();
                 try {
                     addMember(user);
                 } catch (Exception e) {
                     lastException = e;
                 }
             }
 
             addedMembers = newMembers;
             removedMembers = oldMembers;
             
         } catch (Exception e) {
             log.error("Updating member list in LDAP group '" + group + "' failed", e);
             throw new RuntimeException("Updating member list in LDAP group '" + group + "' failed", e);
         }
         
         if (lastException != null) {
             throw new RuntimeException("Updating member list in LDAP group '" + group + "' wasn't completely successful: " + lastException.getMessage(), lastException);
         }
     }
 
     public java.util.List retrieveRemovedMembers() {
         return removedMembers;
     }
 
     public java.util.List retrieveMembers() {
         DirContext context = factory.retrieveContext();
         try {
             DirContext groupContext = (DirContext) context.lookup(groupDN);
             Attributes atts = groupContext.getAttributes("");
             Attribute users = atts.get("user");
             List members = new ArrayList();
             if (users == null)
                 return members;
             NamingEnumeration result = users.getAll();
             while (result.hasMore()) {
                 GridUser user = new GridUser();
                 String userGridID = (String) result.next();
                 StringTokenizer tokens = new StringTokenizer(userGridID, "[]");
                 user.setCertificateDN(tokens.nextToken());
                 if (tokens.hasMoreTokens())
                     user.setVoFQAN(new FQAN(tokens.nextToken()));
                 members.add(user);
             }
             if (log.isTraceEnabled()) {
                 log.trace("Retrieved full list of members from LDAP group '" + group + "': " + members);
             }
             return members;
         } catch (Exception e) {
             log.info("Couldn't retrieve full list of members from LDAP group '" + group + "'", e);
             throw new RuntimeException("Couldn't retrieve full list of members from LDAP group '" + group + "': " + e.getMessage(), e);
         } finally {
             factory.releaseContext(context);
         }
     }
 
     public java.util.List retrieveNewMembers() {
         return addedMembers;
     }
     
 }