/**
    * Copyright 2005-2014 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.ken.service.impl;
  
  import org.kuali.rice.core.framework.persistence.dao.GenericDao;
  import org.kuali.rice.ken.bo.NotificationBo;
  import org.kuali.rice.ken.bo.NotificationMessageDelivery;
  import org.kuali.rice.ken.bo.NotificationRecipientBo;
  import org.kuali.rice.ken.bo.NotificationRecipientListBo;
  import org.kuali.rice.ken.bo.UserChannelSubscriptionBo;
  import org.kuali.rice.ken.deliverer.impl.KEWActionListMessageDeliverer;
  import org.kuali.rice.ken.exception.NotificationMessageDeliveryException;
  import org.kuali.rice.ken.service.NotificationMessageDeliveryResolverService;
  import org.kuali.rice.ken.service.NotificationRecipientService;
  import org.kuali.rice.ken.service.NotificationService;
  import org.kuali.rice.ken.service.ProcessingResult;
  import org.kuali.rice.ken.service.UserPreferenceService;
  import org.kuali.rice.ken.util.NotificationConstants;
  import org.kuali.rice.kim.api.KimConstants.KimGroupMemberTypes;
  import org.kuali.rice.kim.api.identity.principal.Principal;
  import org.kuali.rice.kim.api.services.KimApiServiceLocator;
  import org.springframework.transaction.PlatformTransactionManager;
  
  import java.sql.Timestamp;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.concurrent.ExecutorService;
  
  /**
   * This is the default out-of-the-box implementation that leverages the status flag on a notification (RESOLVED versus UNRESOLVED) to determine whether
   * the notification's message deliveries need to be resolved or not.  This also looks at the start and auto remove
   * dates and times.
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class NotificationMessageDeliveryResolverServiceImpl extends ConcurrentJob<NotificationBo> implements NotificationMessageDeliveryResolverService {
      private static org.apache.log4j.Logger LOG = org.apache.log4j.Logger
  	.getLogger(NotificationMessageDeliveryResolverServiceImpl.class);
  
      private NotificationRecipientService notificationRecipientService;
      private GenericDao businessObjectDao;
      private UserPreferenceService userPreferenceService;
      private NotificationService notificationService;
  
      /**
       * Constructs a NotificationMessageDeliveryDispatchServiceImpl instance.
       * @param notificationRecipientService
       * @param businessObjectDao
       * @param txManager
       * @param executor
       * @param userPreferenceService
       */
      public NotificationMessageDeliveryResolverServiceImpl(NotificationService notificationService, NotificationRecipientService notificationRecipientService,
              GenericDao businessObjectDao, PlatformTransactionManager txManager, ExecutorService executor,
  	    UserPreferenceService userPreferenceService) {
          super(txManager, executor);
          this.notificationService = notificationService;
          this.notificationRecipientService = notificationRecipientService;
          this.businessObjectDao = businessObjectDao;
          this.userPreferenceService = userPreferenceService;
      }
  
      /**
       * Obtains and marks as taken all unresolved (and untaken) notifications
       * @return a collection of available Notifications to process
       */
      @Override
      protected Collection<NotificationBo> takeAvailableWorkItems() {
          Collection<NotificationBo> nots = notificationService.takeNotificationsForResolution();
          //LOG.debug("Took " + nots.size() + " notifications");
          
          //for (Notification not: nots) {
          //   LOG.debug("Took notification: " + not.getId() + " " + not.getTitle());
          //}
          return nots;
      }
  
  
      /**
       * This method is responsible for building out the complete recipient list, which will resolve all members for groups, and add
       * them to the official list only if they are not already in the list.
       * @param notification
       * @return HashSet<String>
       */
     private HashSet<String> buildCompleteRecipientList(NotificationBo notification) {
         HashSet<String> completeRecipientList = new HashSet<String>(notification.getRecipients().size());
 
         // process the list that came in with the notification request
            for (int i = 0; i < notification.getRecipients().size(); i++) {
                NotificationRecipientBo recipient = notification.getRecipient(i);
                if (KimGroupMemberTypes.GROUP_MEMBER_TYPE.getCode().equals(recipient.getRecipientType())) {
                    // resolve group's users
                    String[] groupMembers = notificationRecipientService.getGroupMembers(recipient.getRecipientId());
                    for(int j = 0; j < groupMembers.length; j++) {
                        completeRecipientList.add(groupMembers[j]);
                    }
                } else {  // just a user, so add to the list
                    Principal principal = KimApiServiceLocator.getIdentityService().getPrincipalByPrincipalName(recipient.getRecipientId());
             	   completeRecipientList.add(principal.getPrincipalId());
                }
            }
 
            // now process the default recipient lists that are associated with the channel
            Iterator<NotificationRecipientListBo> i = notification.getChannel().getRecipientLists().iterator();
            while (i.hasNext()) {
                NotificationRecipientListBo listRecipient  = i.next();
                if (KimGroupMemberTypes.GROUP_MEMBER_TYPE.getCode().equals(listRecipient.getRecipientType())) {
                    // resolve group's users
                    String[] groupMembers = notificationRecipientService.getGroupMembers(listRecipient.getRecipientId());
                    for (int j = 0; j < groupMembers.length; j++) {
                        completeRecipientList.add(groupMembers[j]);
                    }
                } else {  // just a user, so add to the list
                    Principal principal = KimApiServiceLocator.getIdentityService().getPrincipalByPrincipalName(listRecipient.getRecipientId());
     	 	 	   completeRecipientList.add(principal.getPrincipalId());
                }
            }
 
            // now process the subscribers that are associated with the channel
            List<UserChannelSubscriptionBo> subscriptions = notification.getChannel().getSubscriptions();
            for (UserChannelSubscriptionBo subscription: subscriptions) {
                // NOTE: at this time channel subscriptions are USER-only - GROUP is not supported
                // this could be implemented by adding a recipientType/userType column as we do in
                // other recipient/user-related tables/BOs
                completeRecipientList.add(subscription.getUserId());
            }
 
            return completeRecipientList;
     }
 
     /**
      * Generates all message deliveries for a given notification and save thems to the database.
      * Updates each Notification record to indicate it has been resolved.
      * Should be performed within a separate transaction
      * @param notification the Notification for which to generate message deliveries
      * @return a count of the number of message deliveries generated
      */
     /* Perform within transaction */
     @Override
     protected Collection<Object> processWorkItems(Collection<NotificationBo> notifications) {
         List<Object> successes = new ArrayList<Object>();
 
         // because this concurrent job does not performed grouping of work items, there should only
         // ever be one notification object per work unit anyway...
         for (NotificationBo notification: notifications) {
             // now figure out each unique recipient for this notification
             HashSet<String> uniqueRecipients = buildCompleteRecipientList(notification);
 
             // now for each unique recipient, figure out each delivery end point and create a NotificationMessageDelivery record
             Iterator<String> j = uniqueRecipients.iterator();
             while(j.hasNext()) {
                 String userRecipientId = j.next();
 
                 NotificationMessageDelivery defaultMessageDelivery = new NotificationMessageDelivery();
                 defaultMessageDelivery.setMessageDeliveryStatus(NotificationConstants.MESSAGE_DELIVERY_STATUS.UNDELIVERED);
                 defaultMessageDelivery.setNotification(notification);
                 defaultMessageDelivery.setUserRecipientId(userRecipientId);
 
                 //now save that delivery end point; this record will be later processed by the dispatch service which will actually deliver it
                 businessObjectDao.save(defaultMessageDelivery);
 
                 try {
                     new KEWActionListMessageDeliverer().deliverMessage(defaultMessageDelivery);
                 } catch (NotificationMessageDeliveryException e) {
                     throw new RuntimeException(e);
                 }
 
                 // we have no delivery stage any more, anything we send to KCB needs to be considered "delivered" from
                 // the perspective of KEN
                 defaultMessageDelivery.setMessageDeliveryStatus(NotificationConstants.MESSAGE_DELIVERY_STATUS.DELIVERED);
                 businessObjectDao.save(defaultMessageDelivery);
 
                 successes.add(defaultMessageDelivery);
 
                 // also, update the status of the notification so that it's message deliveries are not resolved again
                 notification.setProcessingFlag(NotificationConstants.PROCESSING_FLAGS.RESOLVED);
                 // unlock the record now
                 notification.setLockedDateValue(null);
                 businessObjectDao.save(notification);
             }
 
         }
 
         return successes;
     }
 
     /**
      * @see org.kuali.rice.ken.service.impl.ConcurrentJob#unlockWorkItem(java.lang.Object)
      */
     @Override
     protected void unlockWorkItem(NotificationBo notification) {
         LOG.debug("Unlocking notification: " + notification.getId() + " " + notification.getTitle());
         notificationService.unlockNotification(notification);
     }
 
     /**
      * This method is responsible for resolving the list of NotificationMessageDelivery records for a given notification.  This service will look
      * at all notifications that are ready to be delivered and will "explode" out specific message delivery records for given delivery end points.
      * @see org.kuali.rice.ken.service.NotificationMessageDeliveryResolverService#resolveNotificationMessageDeliveries()
      */
     public ProcessingResult resolveNotificationMessageDeliveries() {
         LOG.debug("[" + new Timestamp(System.currentTimeMillis()).toString() + "] STARTING RESOLUTION OF NOTIFICATION MESSAGE DELIVERIES");
 
         ProcessingResult result = run();
 
         LOG.debug("[" + new Timestamp(System.currentTimeMillis()).toString() + "] FINISHED RESOLUTION OF NOTIFICATION MESSAGE DELIVERIES - " +
                   "Message Delivery End Points Resolved = " + result.getSuccesses().size());
 
         return result;
     }
 }