/*
    * 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.assetmanager.util;
  
  import static org.opencastproject.assetmanager.api.fn.Enrichments.enrich;
  
  import org.opencastproject.assetmanager.api.AssetManager;
  import org.opencastproject.assetmanager.api.Snapshot;
  import org.opencastproject.assetmanager.api.query.AQueryBuilder;
  import org.opencastproject.mediapackage.MediaPackage;
  import org.opencastproject.security.api.UnauthorizedException;
  import org.opencastproject.workflow.api.ConfiguredWorkflow;
  import org.opencastproject.workflow.api.WorkflowDatabaseException;
  import org.opencastproject.workflow.api.WorkflowInstance;
  import org.opencastproject.workflow.api.WorkflowParsingException;
  import org.opencastproject.workflow.api.WorkflowService;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Optional;
  
  /**
   * Utility class to apply workflows to episodes. Removed 'final class' so that we can mock it for
   * unit tests.
   */
  public class Workflows {
    /** Log facility */
    private static final Logger logger = LoggerFactory.getLogger(Workflows.class);
  
    private final AssetManager am;
    private final WorkflowService wfs;
  
    public Workflows(AssetManager am, WorkflowService wfs) {
      this.am = am;
      this.wfs = wfs;
    }
  
    /**
     * Apply a workflow to the latest version of each media package.
     */
    public List<WorkflowInstance> applyWorkflowToLatestVersion(Iterable<String> mpIds, ConfiguredWorkflow wf) {
      List<WorkflowInstance> result = new ArrayList<>();
  
      for (String mpId : mpIds) {
        List<Snapshot> snapshots = findLatestSnapshots(mpId);
        for (Snapshot snapshot : snapshots) {
          MediaPackage mp = snapshot.getMediaPackage();
          Optional<WorkflowInstance> optWorkflow = applyWorkflow(wf, mp);
          optWorkflow.ifPresent(result::add);
        }
      }
  
      return result;
    }
  
    /**
     * Apply a workflow to a media package. The function returns some workflow instance if the
     * workflow could be started successfully, none otherwise.
     */
    private Optional<WorkflowInstance> applyWorkflow(ConfiguredWorkflow wf, MediaPackage mp) {
      try {
        WorkflowInstance instance = wfs.start(wf.getWorkflowDefinition(), mp, wf.getParameters());
        return Optional.of(instance);
      } catch (WorkflowDatabaseException | WorkflowParsingException | UnauthorizedException e) {
        logger.error("Cannot start workflow on media package {}", mp.getIdentifier(), e);
        return Optional.empty();
      }
    }
  
    private List<Snapshot> findLatestSnapshots(String mpId) {
      AQueryBuilder q = am.createQuery();
      Iterable<Snapshot> snapshots = enrich(q.select(q.snapshot())
          .where(q.mediaPackageId(mpId).and(q.version().isLatest())).run())
          .getSnapshots();
  
      List<Snapshot> result = new ArrayList<>();
      for (Snapshot snapshot : snapshots) {
        result.add(snapshot);
     }
     return result;
   }
 }