/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.kim.impl.group;

 import org.apache.commons.collections.ListUtils;

 import org.apache.commons.lang.StringUtils;

 import org.kuali.rice.kew.api.KewApiServiceLocator;

 import org.kuali.rice.kew.api.KewApiConstants;

 import org.kuali.rice.kim.api.group.GroupService;

 import org.kuali.rice.kim.api.services.KimApiServiceLocator;

 import org.kuali.rice.krad.service.BusinessObjectService;

 import org.kuali.rice.krad.service.KRADServiceLocator;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Set;

 /**

  * Concrete Implementation of {@link GroupInternalService}

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public class GroupInternalServiceImpl implements GroupInternalService {

     protected BusinessObjectService getBusinessObjectService() {

             return KRADServiceLocator.getBusinessObjectService();

     }

     public GroupService getGroupService(){

             return KimApiServiceLocator.getGroupService();

     }

     @Override

     public GroupBo saveWorkgroup(GroupBo group) {

             GroupService ims = getGroupService();

         List<String> oldIds = Collections.emptyList();

             if (StringUtils.isNotEmpty(group.getId())) {

             oldIds = ims.getMemberPrincipalIds(group.getId());

         }

         group = (GroupBo)getBusinessObjectService().save( group );

         List<String> newIds = ims.getMemberPrincipalIds(group.getId());

         updateForWorkgroupChange(group.getId(), oldIds, newIds);

         return group;

     }

     @Override

     public void updateForWorkgroupChange(String groupId,

                     List<String> oldPrincipalIds, List<String> newPrincipalIds) {

         MembersDiff membersDiff = getMembersDiff(oldPrincipalIds, newPrincipalIds);

         for (String removedPrincipalId : membersDiff.getRemovedPrincipalIds()) {

                 updateForUserRemovedFromGroup(removedPrincipalId, groupId);

         }

         for (String addedPrincipalId : membersDiff.getAddedPrincipalIds()) {

                 updateForUserAddedToGroup(addedPrincipalId, groupId);

         }

     }

     @Override

     public void updateForUserAddedToGroup(String principalId, String groupId) {

         // first verify that the user is still a member of the workgroup

             if(getGroupService().isMemberOfGroup(principalId, groupId))

             {

                 KewApiServiceLocator.getGroupMembershipChangeQueue()

                     .notifyMembershipChange(KewApiConstants.GroupMembershipChangeOperations.ADDED, groupId, principalId);

             }

     }

     @Override

     public void updateForUserRemovedFromGroup(String principalId, String groupId) {

         // first verify that the user is no longer a member of the workgroup

             if(!getGroupService().isMemberOfGroup(principalId, groupId))

             {

             KewApiServiceLocator.getGroupMembershipChangeQueue()

                 .notifyMembershipChange(KewApiConstants.GroupMembershipChangeOperations.REMOVED, groupId, principalId);

             }

     }

     private MembersDiff getMembersDiff(List<String> oldMemberPrincipalIds, List<String> newMemberPrincipalIds) {

             // ListUtils does not check the null case.  Which can happen when adding a new group

             // so, if they're null make them empty lists.

             if(oldMemberPrincipalIds == null) oldMemberPrincipalIds = new ArrayList<String>();

             if(newMemberPrincipalIds == null) newMemberPrincipalIds = new ArrayList<String>();

         Set<String> addedPrincipalIds = new HashSet<String>(ListUtils.subtract(newMemberPrincipalIds, oldMemberPrincipalIds));

         Set<String> removedPrincipalIds = new HashSet<String>(ListUtils.subtract(oldMemberPrincipalIds, newMemberPrincipalIds));

         return new MembersDiff(addedPrincipalIds, removedPrincipalIds);

     }

     private class MembersDiff {

         private final Set<String> addedPrincipalIds;

         private final Set<String> removedPrincipalIds;

         public MembersDiff(Set<String> addedPrincipalIds, Set<String>removedPrincipalIds) {

             this.addedPrincipalIds = addedPrincipalIds;

             this.removedPrincipalIds = removedPrincipalIds;

         }

         public Set<String> getAddedPrincipalIds() {

             return addedPrincipalIds;

         }

         public Set<String> getRemovedPrincipalIds() {

             return removedPrincipalIds;

         }

     }

 }