/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.workflow.handler.distribution;
  
  import static org.opencastproject.mediapackage.MediaPackageSupport.Filters.ofChannel;
  import static org.opencastproject.util.data.Collections.list;
  import static org.opencastproject.util.data.Option.option;
  import static org.opencastproject.util.data.functions.Strings.toBool;
  import static org.opencastproject.util.data.functions.Strings.trimToNone;
  
  import org.opencastproject.distribution.api.StreamingDistributionService;
  import org.opencastproject.job.api.Job;
  import org.opencastproject.job.api.JobContext;
  import org.opencastproject.mediapackage.MediaPackage;
  import org.opencastproject.mediapackage.MediaPackageElement;
  import org.opencastproject.mediapackage.MediaPackageElementFlavor;
  import org.opencastproject.mediapackage.MediaPackageElementParser;
  import org.opencastproject.mediapackage.MediaPackageException;
  import org.opencastproject.mediapackage.Publication;
  import org.opencastproject.mediapackage.PublicationImpl;
  import org.opencastproject.mediapackage.selector.SimpleElementSelector;
  import org.opencastproject.publication.api.OaiPmhPublicationService;
  import org.opencastproject.publication.api.PublicationException;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.util.MimeType;
  import org.opencastproject.util.MimeTypes;
  import org.opencastproject.workflow.api.AbstractWorkflowOperationHandler;
  import org.opencastproject.workflow.api.WorkflowInstance;
  import org.opencastproject.workflow.api.WorkflowOperationException;
  import org.opencastproject.workflow.api.WorkflowOperationHandler;
  import org.opencastproject.workflow.api.WorkflowOperationResult;
  import org.opencastproject.workflow.api.WorkflowOperationResult.Action;
  
  import org.apache.commons.lang3.StringUtils;
  import org.osgi.service.component.ComponentContext;
  import org.osgi.service.component.annotations.Activate;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.net.URI;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Optional;
  import java.util.Set;
  import java.util.UUID;
  
  /**
   * The workflow definition for handling "publish" operations
   */
  @Component(
      immediate = true,
      service = WorkflowOperationHandler.class,
      property = {
          "service.description=OAI-PMH Publication Workflow Handler",
          "workflow.operation=publish-oaipmh"
      }
  )
  public class PublishOaiPmhWorkflowOperationHandler extends AbstractWorkflowOperationHandler {
  
    /** The logging facility */
    private static final Logger logger = LoggerFactory.getLogger(PublishOaiPmhWorkflowOperationHandler.class);
  
    /** Workflow configuration option keys */
    private static final String DOWNLOAD_FLAVORS = "download-flavors";
    private static final String DOWNLOAD_TAGS = "download-tags";
    private static final String STREAMING_TAGS = "streaming-tags";
    private static final String STREAMING_FLAVORS = "streaming-flavors";
    private static final String CHECK_AVAILABILITY = "check-availability";
    private static final String REPOSITORY = "repository";
    private static final String EXTERNAL_TEMPLATE = "external-template";
    private static final String EXTERNAL_CHANNEL_NAME = "external-channel";
    private static final String EXTERNAL_MIME_TYPE = "external-mime-type";
  
    /** The publication service */
    private OaiPmhPublicationService publicationService = null;
  
    /** The streaming distribution service */
    private StreamingDistributionService streamingDistributionService = null;
  
   /**
    * Callback for the OSGi declarative services configuration.
    *
    * @param publicationService
    *          the publication service
    */
   @Reference
   public void setPublicationService(OaiPmhPublicationService publicationService) {
     this.publicationService = publicationService;
   }
 
   /**
    * Callback for the OSGi declarative services configuration.
    *
    * @param streamingDistributionService
    *          the streaming distribution service
    */
   @Reference(target = "(distribution.channel=streaming)")
   protected void setStreamingDistributionService(StreamingDistributionService streamingDistributionService) {
     this.streamingDistributionService = streamingDistributionService;
   }
 
   @Reference
   @Override
   public void setServiceRegistry(ServiceRegistry serviceRegistry) {
     super.setServiceRegistry(serviceRegistry);
   }
 
   /** OSGi component activation. */
   @Override
   @Activate
   public void activate(ComponentContext cc) {
   }
 
   @Override
   public WorkflowOperationResult start(final WorkflowInstance workflowInstance, JobContext context)
           throws WorkflowOperationException {
     logger.debug("Running distribution workflow operation");
 
     MediaPackage mediaPackage = workflowInstance.getMediaPackage();
 
     // Check which tags have been configured
     String downloadTags = StringUtils
             .trimToEmpty(workflowInstance.getCurrentOperation().getConfiguration(DOWNLOAD_TAGS));
     String downloadFlavors = StringUtils
             .trimToEmpty(workflowInstance.getCurrentOperation().getConfiguration(DOWNLOAD_FLAVORS));
     String streamingTags = StringUtils
             .trimToEmpty(workflowInstance.getCurrentOperation().getConfiguration(STREAMING_TAGS));
     String streamingFlavors = StringUtils
             .trimToEmpty(workflowInstance.getCurrentOperation().getConfiguration(STREAMING_FLAVORS));
     boolean checkAvailability = option(workflowInstance.getCurrentOperation().getConfiguration(CHECK_AVAILABILITY))
             .bind(trimToNone).map(toBool).getOrElse(true);
     String repository = StringUtils.trimToNull(workflowInstance.getCurrentOperation().getConfiguration(REPOSITORY));
 
     Optional<String> externalChannel = Optional.ofNullable(
         getOptConfig(workflowInstance.getCurrentOperation(), EXTERNAL_CHANNEL_NAME).orNull());
     Optional<String> externalTemplate = Optional.ofNullable(
         getOptConfig(workflowInstance.getCurrentOperation(), EXTERNAL_TEMPLATE).orNull());
     Optional<MimeType> externalMimetype = Optional.ofNullable(
         getOptConfig(workflowInstance.getCurrentOperation(), EXTERNAL_MIME_TYPE).orNull())
         .flatMap(MimeTypes::toMimeType);
 
     if (repository == null) {
       throw new IllegalArgumentException("No repository has been specified");
     }
 
     String[] sourceDownloadTags = StringUtils.split(downloadTags, ",");
     String[] sourceDownloadFlavors = StringUtils.split(downloadFlavors, ",");
     String[] sourceStreamingTags = StringUtils.split(streamingTags, ",");
     String[] sourceStreamingFlavors = StringUtils.split(streamingFlavors, ",");
 
     if (sourceDownloadTags.length == 0 && sourceDownloadFlavors.length == 0 && sourceStreamingTags.length == 0
             && sourceStreamingFlavors.length == 0) {
       logger.warn("No tags or flavors have been specified, so nothing will be published to the engage");
       return createResult(mediaPackage, Action.CONTINUE);
     }
 
     final SimpleElementSelector downloadElementSelector = new SimpleElementSelector();
     for (String flavor : sourceDownloadFlavors) {
       downloadElementSelector.addFlavor(MediaPackageElementFlavor.parseFlavor(flavor));
     }
     for (String tag : sourceDownloadTags) {
       downloadElementSelector.addTag(tag);
     }
     final Collection<MediaPackageElement> downloadElements = downloadElementSelector.select(mediaPackage, false);
 
     final Collection<MediaPackageElement> streamingElements;
     if (streamingDistributionService != null && streamingDistributionService.publishToStreaming()) {
       final SimpleElementSelector streamingElementSelector = new SimpleElementSelector();
       for (String flavor : sourceStreamingFlavors) {
         streamingElementSelector.addFlavor(MediaPackageElementFlavor.parseFlavor(flavor));
       }
       for (String tag : sourceStreamingTags) {
         streamingElementSelector.addTag(tag);
       }
       streamingElements = streamingElementSelector.select(mediaPackage, false);
     } else {
       streamingElements = list();
     }
 
     try {
       Set<String> downloadElementIds = new HashSet<>();
       Set<String> streamingElementIds = new HashSet<>();
 
       // Look for elements matching the tag
       for (MediaPackageElement elem : downloadElements) {
         downloadElementIds.add(elem.getIdentifier());
       }
       for (MediaPackageElement elem : streamingElements) {
         streamingElementIds.add(elem.getIdentifier());
       }
 
       Job publishJob = null;
       try {
         publishJob = publicationService.publish(mediaPackage, repository, downloadElementIds, streamingElementIds,
                 checkAvailability);
       } catch (MediaPackageException e) {
         throw new WorkflowOperationException("Error parsing media package", e);
       } catch (PublicationException e) {
         throw new WorkflowOperationException("Error parsing media package", e);
       }
 
       // Wait until the publication job has returned
       if (!waitForStatus(publishJob).isSuccess()) {
         throw new WorkflowOperationException("Mediapackage " + mediaPackage.getIdentifier()
                 + " could not be published to OAI-PMH repository " + repository);
       }
 
       // The job has passed
       Job job = serviceRegistry.getJob(publishJob.getId());
 
       // If there is no payload, then the item has not been published.
       if (job.getPayload() == null) {
         logger.warn("Publish to OAI-PMH repository '{}' failed, no payload from publication job: {}", repository, job);
         return createResult(mediaPackage, Action.CONTINUE);
       }
 
       Publication newElement = null;
       try {
         newElement = (Publication) MediaPackageElementParser.getFromXml(job.getPayload());
       } catch (MediaPackageException e) {
         throw new WorkflowOperationException(e);
       }
 
       if (newElement == null) {
         logger.warn(
             "Publication to OAI-PMH repository '{}' failed, unable to parse the payload '{}' from "
                 + "job '{}' to a mediapackage element",
             repository, job.getPayload(), job.toString());
         return createResult(mediaPackage, Action.CONTINUE);
       }
 
       for (Publication existingPublication : mediaPackage.getPublications()) {
         if (ofChannel(newElement.getChannel()).apply(existingPublication)) {
           mediaPackage.remove(existingPublication);
         }
       }
       mediaPackage.add(newElement);
 
       if (externalChannel.isPresent() && externalMimetype.isPresent() && externalTemplate.isPresent()) {
         String template = externalTemplate.get().replace("{event}", mediaPackage.getIdentifier().toString());
         if (StringUtils.isNotBlank(mediaPackage.getSeries())) {
           template = template.replace("{series}", mediaPackage.getSeries());
         }
 
         Publication externalElement = PublicationImpl.publication(UUID.randomUUID().toString(), externalChannel.get(),
                 URI.create(template), externalMimetype.get());
         for (Publication existingPublication : mediaPackage.getPublications()) {
           if (ofChannel(externalChannel.get()).apply(existingPublication)) {
             mediaPackage.remove(existingPublication);
           }
         }
         mediaPackage.add(externalElement);
       }
 
       logger.debug("Publication to OAI-PMH repository '{}' operation completed", repository);
     } catch (Exception e) {
       if (e instanceof WorkflowOperationException) {
         throw (WorkflowOperationException) e;
       } else {
         throw new WorkflowOperationException(e);
       }
     }
     return createResult(mediaPackage, Action.CONTINUE);
   }
 
 }