/**
    * Copyright 2005-2015 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.ksb.messaging;
  
  import org.apache.log4j.Logger;
  import org.kuali.rice.core.api.config.property.ConfigContext;
  import org.kuali.rice.ksb.messaging.service.MessageQueueService;
  import org.kuali.rice.ksb.service.KSBServiceLocator;
  import org.kuali.rice.ksb.util.KSBConstants;
  import org.springframework.transaction.TransactionStatus;
  import org.springframework.transaction.support.TransactionCallback;
  
  /**
   * Fetches messages from the db. Marks as 'R'. Gives messages to ThreadPool for execution
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class MessageFetcher implements Runnable {
  
      private static final Logger LOG = Logger.getLogger(MessageFetcher.class);
  
      private Integer maxMessages;
      private Long routeQueueId;
  
      public MessageFetcher(Integer maxMessages) {
          this.maxMessages = maxMessages;
      }
  
      public MessageFetcher(Long routeQueueId) {
          this.routeQueueId = routeQueueId;
      }
  
      public void run() {
          if (ConfigContext.getCurrentContextConfig().getBooleanProperty(KSBConstants.Config.MESSAGE_PERSISTENCE,
                  false)) {
              try {
                  requeueDocument();
                  requeueMessages();
              } catch (Throwable t) {
                  LOG.error("Failed to fetch messages.", t);
              }
          }
      }
  
      private void requeueMessages() {
          if (this.routeQueueId == null) {
              try {
                  for (PersistedMessageBO message : getRouteQueueService().getNextDocuments(maxMessages)) {
                      message = markEnrouteAndSaveMessage(message);
                      executeMessage(message);
                  }
              } catch (Throwable t) {
                  LOG.error("Failed to fetch or process some messages during requeueMessages", t);
              }
          }
      }
  
      private void requeueDocument() {
          try {
              if (this.routeQueueId != null) {
                  PersistedMessageBO message = getRouteQueueService().findByRouteQueueId(this.routeQueueId);
                  message.setQueueStatus(KSBConstants.ROUTE_QUEUE_ROUTING);
                  message = getRouteQueueService().save(message);
                  executeMessage(message);
              }
          } catch (Throwable t) {
              LOG.error("Failed to fetch or process some messages during requeueDocument", t);
          }
      }
  
      private void executeMessage(PersistedMessageBO message) {
          try {
              KSBServiceLocator.getThreadPool().execute(new MessageServiceInvoker(message));
          } catch (Throwable t) {
              LOG.error("Failed to place message " + message + " in thread pool for execution", t);
          }
      }
  
      private PersistedMessageBO markEnrouteAndSaveMessage(final PersistedMessageBO message) {
          try {
              return KSBServiceLocator.getTransactionTemplate().execute(new TransactionCallback<PersistedMessageBO>() {
                  public PersistedMessageBO doInTransaction(TransactionStatus status) {
                      message.setQueueStatus(KSBConstants.ROUTE_QUEUE_ROUTING);
                      return getRouteQueueService().save(message);
                  }
              });
         } catch (Throwable t) {
             LOG.error("Caught error attempting to mark message " + message + " as R", t);
         }
         return message;
     }
 
     private MessageQueueService getRouteQueueService() {
         return KSBServiceLocator.getMessageQueueService();
     }
 
 }