/**
    * 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.krad.service.impl;
  
  import java.util.List;
  import java.util.concurrent.Callable;
  
  import org.apache.log4j.Logger;
  import org.apache.ojb.broker.OptimisticLockException;
  import org.kuali.rice.kew.api.KewApiConstants;
  import org.kuali.rice.kew.api.KewApiServiceLocator;
  import org.kuali.rice.kew.api.action.ActionType;
  import org.kuali.rice.kew.api.exception.WorkflowException;
  import org.kuali.rice.kew.framework.postprocessor.ActionTakenEvent;
  import org.kuali.rice.kew.framework.postprocessor.AfterProcessEvent;
  import org.kuali.rice.kew.framework.postprocessor.BeforeProcessEvent;
  import org.kuali.rice.kew.framework.postprocessor.DeleteEvent;
  import org.kuali.rice.kew.framework.postprocessor.DocumentLockingEvent;
  import org.kuali.rice.kew.framework.postprocessor.DocumentRouteLevelChange;
  import org.kuali.rice.kew.framework.postprocessor.DocumentRouteStatusChange;
  import org.kuali.rice.kew.framework.postprocessor.IDocumentEvent;
  import org.kuali.rice.kew.framework.postprocessor.ProcessDocReport;
  import org.kuali.rice.krad.UserSession;
  import org.kuali.rice.krad.datadictionary.DocumentEntry;
  import org.kuali.rice.krad.document.Document;
  import org.kuali.rice.krad.service.DocumentService;
  import org.kuali.rice.krad.service.KRADServiceLocatorWeb;
  import org.kuali.rice.krad.service.PostProcessorService;
  import org.kuali.rice.krad.util.GlobalVariables;
  import org.kuali.rice.krad.util.KRADConstants;
  import org.kuali.rice.krad.util.LegacyUtils;
  import org.springframework.transaction.annotation.Transactional;
  
  /**
   * This class is the postProcessor for the Kuali application, and it is responsible for plumbing events up to documents
   * using the built into the document methods for handling route status and other routing changes that take place
   * asyncronously and potentially on a different server.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  @Transactional
  public class PostProcessorServiceImpl implements PostProcessorService {
  
      private static Logger LOG = Logger.getLogger(PostProcessorServiceImpl.class);
  
      private DocumentService documentService;
  
      @Override
      public ProcessDocReport doRouteStatusChange(final DocumentRouteStatusChange statusChangeEvent) throws Exception {
          return LegacyUtils.doInLegacyContext(statusChangeEvent.getDocumentId(), establishPostProcessorUserSession(), new Callable<ProcessDocReport>() {
              @Override
              public ProcessDocReport call() throws Exception {
  
                  try {
                      if (LOG.isInfoEnabled()) {
                          LOG.info(new StringBuilder("started handling route status change from ").append(
                                  statusChangeEvent.getOldRouteStatus()).append(" to ").append(
                                  statusChangeEvent.getNewRouteStatus()).append(" for document ").append(
                                  statusChangeEvent.getDocumentId()));
                      }
  
                      Document document = documentService.getByDocumentHeaderId(statusChangeEvent.getDocumentId());
                      if (document == null) {
                          if (!KewApiConstants.ROUTE_HEADER_CANCEL_CD.equals(statusChangeEvent.getNewRouteStatus())) {
                              throw new RuntimeException("unable to load document " + statusChangeEvent.getDocumentId());
                          }
                      } else {
                          document.doRouteStatusChange(statusChangeEvent);
                          // PLEASE READ BEFORE YOU MODIFY:
                          // we dont want to update the document on a Save, as this will cause an
                          // OptimisticLockException in many cases, because the DB versionNumber will be
                          // incremented one higher than the document in the browser, so when the user then
                          // hits Submit or Save again, the versionNumbers are out of synch, and the
                          // OptimisticLockException is thrown. This is not the optimal solution, and will
                          // be a problem anytime where the user can continue to edit the document after a
                          // workflow state change, without reloading the form.
                          if (!document.getDocumentHeader().getWorkflowDocument().isSaved()) {
                              document = documentService.updateDocument(document);
  //                            document = KradDataServiceLocator.getDataObjectService().save(document, PersistenceOption.FLUSH);
                          }
  
                      }
                      if (LOG.isInfoEnabled()) {
                          LOG.info(new StringBuilder("finished handling route status change from ").append(
                                  statusChangeEvent.getOldRouteStatus()).append(" to ").append(
                                  statusChangeEvent.getNewRouteStatus()).append(" for document ").append(
                                 statusChangeEvent.getDocumentId()));
                     }
                 } catch (Exception e) {
                     logAndRethrow("route status", e);
                 }
                 return new ProcessDocReport(true, "");
             }
         });
     }
 
     @Override
     public ProcessDocReport doRouteLevelChange(final DocumentRouteLevelChange levelChangeEvent) throws Exception {
         return LegacyUtils.doInLegacyContext(levelChangeEvent.getDocumentId(), establishPostProcessorUserSession(), new Callable<ProcessDocReport>() {
             @Override
             public ProcessDocReport call() throws Exception {
 
                 // on route level change we'll serialize the XML for the document. we
                 // are doing this here cause it's a heavy hitter, and we
                 // want to avoid the user waiting for this during sync processing
                 try {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("started handling route level change from ").append(
                                 levelChangeEvent.getOldNodeName()).append(" to ").append(
                                 levelChangeEvent.getNewNodeName()).append(" for document ").append(
                                 levelChangeEvent.getDocumentId()));
                     }
 
                     Document document = documentService.getByDocumentHeaderId(levelChangeEvent.getDocumentId());
                     if (document == null) {
                         throw new RuntimeException("unable to load document " + levelChangeEvent.getDocumentId());
                     }
                     document.populateDocumentForRouting();
                     document.doRouteLevelChange(levelChangeEvent);
                     document.getDocumentHeader().getWorkflowDocument().saveDocumentData();
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("finished handling route level change from ").append(
                                 levelChangeEvent.getOldNodeName()).append(" to ").append(
                                 levelChangeEvent.getNewNodeName()).append(" for document ").append(
                                 levelChangeEvent.getDocumentId()));
                     }
                 } catch (Exception e) {
                     logAndRethrow("route level", e);
                 }
                 return new ProcessDocReport(true, "");
             }
         });
     }
 
     @Override
     public ProcessDocReport doDeleteRouteHeader(DeleteEvent event) throws Exception {
         return new ProcessDocReport(true, "");
     }
 
     @Override
     public ProcessDocReport doActionTaken(final ActionTakenEvent event) throws Exception {
         return LegacyUtils.doInLegacyContext(event.getDocumentId(), establishPostProcessorUserSession(), new Callable<ProcessDocReport>() {
             @Override
             public ProcessDocReport call() throws Exception {
                 try {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("started doing action taken for action taken code").append(
                                 event.getActionTaken().getActionTaken()).append(" for document ").append(
                                 event.getDocumentId()));
                     }
                     Document document = documentService.getByDocumentHeaderId(event.getDocumentId());
                     if (document == null) {
                         // only throw an exception if we are not cancelling
                         if (!KewApiConstants.ACTION_TAKEN_CANCELED.equals(event.getActionTaken())) {
                             LOG.warn("doActionTaken() Unable to load document with id " + event.getDocumentId() +
                                     " using action taken code '" + KewApiConstants.ACTION_TAKEN_CD.get(
                                     event.getActionTaken().getActionTaken()));
                         }
                     } else {
                         document.doActionTaken(event);
                         if (LOG.isDebugEnabled()) {
                             LOG.debug(new StringBuilder("finished doing action taken for action taken code").append(
                                     event.getActionTaken().getActionTaken()).append(" for document ").append(
                                     event.getDocumentId()));
                         }
                     }
                 } catch (Exception e) {
                     logAndRethrow("do action taken", e);
                 }
                 return new ProcessDocReport(true, "");
 
             }
         });
     }
 
     @Override
     public ProcessDocReport afterActionTaken(final ActionType performed,
             final ActionTakenEvent event) throws Exception {
         return LegacyUtils.doInLegacyContext(event.getDocumentId(), establishPostProcessorUserSession(), new Callable<ProcessDocReport>() {
             @Override
             public ProcessDocReport call() throws Exception {
                 try {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("started doing after action taken for action performed code "
                                 + performed.getCode()
                                 + " and action taken code ").append(event.getActionTaken().getActionTaken()).append(
                                 " for document ").append(event.getDocumentId()));
                     }
                     Document document = documentService.getByDocumentHeaderId(event.getDocumentId());
                     if (document == null) {
                         // only throw an exception if we are not cancelling
                         if (!KewApiConstants.ACTION_TAKEN_CANCELED.equals(event.getActionTaken())) {
                             LOG.warn("afterActionTaken() Unable to load document with id " + event.getDocumentId() +
                                     " using action taken code '" + KewApiConstants.ACTION_TAKEN_CD.get(
                                     event.getActionTaken().getActionTaken()));
                         }
                     } else {
                         document.afterActionTaken(performed, event);
                         if (LOG.isDebugEnabled()) {
                             LOG.debug(new StringBuilder("finished doing after action taken for action taken code")
                                     .append(event.getActionTaken().getActionTaken()).append(" for document ").append(
                                             event.getDocumentId()));
                         }
                     }
                 } catch (Exception e) {
                     logAndRethrow("do action taken", e);
                 }
                 return new ProcessDocReport(true, "");
 
             }
         });
     }
 
     /**
      * This method first checks to see if the document can be retrieved by the {@link DocumentService}. If the document
      * is
      * found the {@link Document#afterWorkflowEngineProcess(boolean)} method will be invoked on it
      */
     @Override
     public ProcessDocReport afterProcess(final AfterProcessEvent event) throws Exception {
         return LegacyUtils.doInLegacyContext(event.getDocumentId(), establishPostProcessorUserSession(), new Callable<ProcessDocReport>() {
             @Override
             public ProcessDocReport call() throws Exception {
 
                 try {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("started after process method for document ").append(
                                 event.getDocumentId()));
                     }
 
                     Document document = documentService.getByDocumentHeaderId(event.getDocumentId());
                     if (document == null) {
                         // no way to verify if this is the processing as a result of a cancel so assume null document is ok to process
                         LOG.warn("afterProcess() Unable to load document with id "
                                 + event.getDocumentId()
                                 + "... ignoring post processing");
                     } else {
                         document.afterWorkflowEngineProcess(event.isSuccessfullyProcessed());
                         if (LOG.isDebugEnabled()) {
                             LOG.debug(new StringBuilder("finished after process method for document ").append(
                                     event.getDocumentId()));
                         }
                     }
                 } catch (Exception e) {
                     logAndRethrow("after process", e);
                 }
                 return new ProcessDocReport(true, "");
             }
         });
     }
 
     /**
      * This method first checks to see if the document can be retrieved by the {@link DocumentService}. If the document
      * is found the {@link Document#beforeWorkflowEngineProcess()} method will be invoked on it
      */
     @Override
     public ProcessDocReport beforeProcess(final BeforeProcessEvent event) throws Exception {
         return LegacyUtils.doInLegacyContext(event.getDocumentId(), establishPostProcessorUserSession(), new Callable<ProcessDocReport>() {
             @Override
             public ProcessDocReport call() throws Exception {
 
                 try {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("started before process method for document ").append(
                                 event.getDocumentId()));
                     }
                     Document document = documentService.getByDocumentHeaderId(event.getDocumentId());
                     if (document == null) {
                         // no way to verify if this is the processing as a result of a cancel so assume null document is ok to process
                         LOG.warn("beforeProcess() Unable to load document with id "
                                 + event.getDocumentId()
                                 + "... ignoring post processing");
                     } else {
                         document.beforeWorkflowEngineProcess();
                         if (LOG.isDebugEnabled()) {
                             LOG.debug(new StringBuilder("finished before process method for document ").append(
                                     event.getDocumentId()));
                         }
                     }
                 } catch (Exception e) {
                     logAndRethrow("before process", e);
                 }
                 return new ProcessDocReport(true, "");
             }
         });
     }
 
     /**
      * This method first checks to see if the document can be retrieved by the {@link DocumentService}. If the document
      * is
      * found the {@link Document#beforeWorkflowEngineProcess()} method will be invoked on it
      */
     @Override
     public List<String> getDocumentIdsToLock(final DocumentLockingEvent event) throws Exception {
         return LegacyUtils.doInLegacyContext(event.getDocumentId(), establishPostProcessorUserSession(), new Callable<List<String>>() {
             @Override
             public List<String> call() throws Exception {
 
                 try {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug(new StringBuilder("started get document ids to lock method for document ").append(
                                 event.getDocumentId()));
                     }
                     Document document = documentService.getByDocumentHeaderId(event.getDocumentId());
                     if (document == null) {
                         // no way to verify if this is the processing as a result of a cancel so assume null document is ok to process
                         LOG.warn("getDocumentIdsToLock() Unable to load document with id "
                                 + event.getDocumentId()
                                 + "... ignoring post processing");
                     } else {
                         List<String> documentIdsToLock = document.getWorkflowEngineDocumentIdsToLock();
                         if (LOG.isDebugEnabled()) {
                             LOG.debug(new StringBuilder("finished get document ids to lock method for document ").append(
                                     event.getDocumentId()));
                         }
                         if (documentIdsToLock == null) {
                             return null;
                         }
                         return documentIdsToLock;
                     }
                 } catch (Exception e) {
                     logAndRethrow("before process", e);
                 }
                 return null;
             }
         });
     }
 
     private void logAndRethrow(String changeType, Exception e) throws RuntimeException {
         LOG.error("caught exception while handling " + changeType + " change", e);
         logOptimisticDetails(5, e);
 
         throw new RuntimeException("post processor caught exception while handling " + changeType + " change: " + e.getMessage(), e);
     }
 
     /**
      * Logs further details of OptimisticLockExceptions, using the given depth value to limit recursion Just In Case
      *
      * @param depth
      * @param t
      */
     private void logOptimisticDetails(int depth, Throwable t) {
         if ((depth > 0) && (t != null)) {
             if (t instanceof OptimisticLockException) {
                 OptimisticLockException o = (OptimisticLockException) t;
 
                 LOG.error("source of OptimisticLockException = " + o.getSourceObject().getClass().getName() + " ::= " + o.getSourceObject());
             }
             else {
                 Throwable cause = t.getCause();
                 if (cause != t) {
                     logOptimisticDetails(--depth, cause);
                 }
             }
         }
     }
 
     /**
      * Sets the documentService attribute value.
      * @param documentService The documentService to set.
      */
     public final void setDocumentService(DocumentService documentService) {
         this.documentService = documentService;
     }
 
     /**
      * Establishes the UserSession if one does not already exist.
      */
     protected UserSession establishPostProcessorUserSession() throws WorkflowException {
        if (GlobalVariables.getUserSession() == null) {
             return new UserSession(KRADConstants.SYSTEM_USER);
         } else {
             return GlobalVariables.getUserSession();
         }
     }
 
 }