/*
    * 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.assetmanager;
  
  import static org.opencastproject.assetmanager.api.AssetManager.DEFAULT_OWNER;
  
  import org.opencastproject.assetmanager.api.AssetManager;
  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.MediaPackageException;
  import org.opencastproject.mediapackage.MediaPackageReference;
  import org.opencastproject.mediapackage.Publication;
  import org.opencastproject.mediapackage.selector.SimpleElementSelector;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.workflow.api.AbstractWorkflowOperationHandler;
  import org.opencastproject.workflow.api.ConfiguredTagsAndFlavors;
  import org.opencastproject.workflow.api.WorkflowInstance;
  import org.opencastproject.workflow.api.WorkflowOperationException;
  import org.opencastproject.workflow.api.WorkflowOperationHandler;
  import org.opencastproject.workflow.api.WorkflowOperationInstance;
  import org.opencastproject.workflow.api.WorkflowOperationResult;
  import org.opencastproject.workflow.api.WorkflowOperationResult.Action;
  
  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.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.List;
  
  /**
   * Workflow operation for taking a snapshot of a media package.
   *
   * @see AssetManager#takeSnapshot(String, MediaPackage)
   */
  @Component(
      immediate = true,
      name = "org.opencastproject.workflow.handler.assetmanager.AssetManagerAddWorkflowOperationHandler",
      service = WorkflowOperationHandler.class,
      property = {
          "service.description=Asset Manager Take Snapshot Workflow Operation Handler",
          "workflow.operation=snapshot"
      }
  )
  public class AssetManagerSnapshotWorkflowOperationHandler extends AbstractWorkflowOperationHandler {
    private static final Logger logger = LoggerFactory.getLogger(AssetManagerSnapshotWorkflowOperationHandler.class);
  
    /** The asset manager. */
    private AssetManager assetManager;
  
    @Activate
    @Override
    public void activate(ComponentContext cc) {
      super.activate(cc);
    }
  
    /** OSGi DI */
    @Reference
    public void setAssetManager(AssetManager assetManager) {
      this.assetManager = assetManager;
    }
  
    @Override
    public WorkflowOperationResult start(WorkflowInstance wi, JobContext ctx)
            throws WorkflowOperationException {
      final MediaPackage mpWorkflow = wi.getMediaPackage();
      final WorkflowOperationInstance currentOperation = wi.getCurrentOperation();
  
      // Check which tags have been configured
      ConfiguredTagsAndFlavors tagsAndFlavors = getTagsAndFlavors(wi,
          Configuration.many, Configuration.many, Configuration.none, Configuration.none);
      List<String> sourceTagsOption = tagsAndFlavors.getSrcTags();
      List<MediaPackageElementFlavor> sourceFlavorsOption = tagsAndFlavors.getSrcFlavors();
  
 
     if (sourceTagsOption.isEmpty() && sourceFlavorsOption.isEmpty()) {
       logger.debug("No source tags have been specified, so everything will be added to the AssetManager");
     }
 
     final List<String> tagSet;
     // If a set of tags has been specified, use it
     if (!sourceTagsOption.isEmpty()) {
       tagSet = sourceTagsOption;
     } else {
       tagSet = new ArrayList<>();
     }
 
     try {
       final MediaPackage mpAssetManager = getMediaPackageForArchival(mpWorkflow, tagSet, sourceFlavorsOption);
       if (mpAssetManager != null) {
         logger.info("Take snapshot of media package {}", mpAssetManager);
         // adding media package to the episode service
         assetManager.takeSnapshot(DEFAULT_OWNER, mpAssetManager);
         logger.debug("Snapshot operation complete");
         return createResult(mpWorkflow, Action.CONTINUE);
       } else {
         return createResult(mpWorkflow, Action.CONTINUE);
       }
     } catch (Throwable t) {
       throw new WorkflowOperationException(t);
     }
   }
 
   protected MediaPackage getMediaPackageForArchival(MediaPackage current, List<String> tags,
                                                     List<MediaPackageElementFlavor> sourceFlavors)
           throws MediaPackageException {
     MediaPackage mp = (MediaPackage) current.clone();
 
     Collection<MediaPackageElement> keep;
 
     if (tags.isEmpty() && sourceFlavors.isEmpty()) {
       keep = new ArrayList<>(Arrays.asList(current.getElementsByTags(tags)));
     } else {
       SimpleElementSelector simpleElementSelector = new SimpleElementSelector();
       for (MediaPackageElementFlavor flavor : sourceFlavors) {
         simpleElementSelector.addFlavor(flavor);
       }
       for (String tag : tags) {
         simpleElementSelector.addTag(tag);
       }
       keep = simpleElementSelector.select(current, false);
     }
 
     // Also archive the publication elements
     for (Publication publication : current.getPublications()) {
       keep.add(publication);
     }
 
     // Mark everything that is set for removal
     List<MediaPackageElement> removals = new ArrayList<MediaPackageElement>();
     for (MediaPackageElement element : mp.getElements()) {
       if (!keep.contains(element)) {
         removals.add(element);
       }
     }
 
     // Fix references and flavors
     for (MediaPackageElement element : mp.getElements()) {
 
       if (removals.contains(element)) {
         continue;
       }
 
       // Is the element referencing anything?
       MediaPackageReference reference = element.getReference();
       if (reference != null) {
         MediaPackageElement referencedElement = mp.getElementByReference(reference);
 
         // if we are distributing the referenced element, everything is fine. Otherwise...
         if (referencedElement != null && removals.contains(referencedElement)) {
 
           // Follow the references until we find a flavor
           MediaPackageElement parent;
           while ((parent = current.getElementByReference(reference)) != null) {
             if (parent.getFlavor() != null && element.getFlavor() == null) {
               element.setFlavor(parent.getFlavor());
             }
             if (parent.getReference() == null) {
               break;
             }
             reference = parent.getReference();
           }
 
           // Done. Let's cut the path but keep references to the mediapackage itself
           if (reference != null && reference.getType().equals(MediaPackageReference.TYPE_MEDIAPACKAGE)) {
             element.setReference(reference);
           } else {
             element.clearReference();
           }
         }
       }
     }
 
     // Remove everything we don't want to add to publish
     for (MediaPackageElement element : removals) {
       mp.remove(element);
     }
     return mp;
   }
 
   @Reference
   @Override
   public void setServiceRegistry(ServiceRegistry serviceRegistry) {
     super.setServiceRegistry(serviceRegistry);
   }
 
 }