/*
    * 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.elasticsearch.index.objects.series;
  
  import org.opencastproject.elasticsearch.api.SearchMetadata;
  import org.opencastproject.elasticsearch.impl.SearchMetadataCollection;
  import org.opencastproject.security.api.AccessControlEntry;
  import org.opencastproject.security.api.AccessControlList;
  import org.opencastproject.security.api.AccessControlParser;
  import org.opencastproject.security.api.Permissions;
  import org.opencastproject.security.api.Permissions.Action;
  import org.opencastproject.util.DateTimeSupport;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import javax.xml.bind.Unmarshaller;
  
  /**
   * Utility implementation to deal with the conversion of series and its corresponding index data structures.
   */
  public final class SeriesIndexUtils {
  
    private static final Logger logger = LoggerFactory.getLogger(SeriesIndexUtils.class);
  
    /**
     * This is a utility class and should therefore not be instantiated.
     */
    private SeriesIndexUtils() {
    }
  
    /**
     * Creates a search result item based on the data returned from the search index.
     *
     * @param metadata
     *          the search metadata
     * @param unmarshaller the unmarshaller to use
     * @return the search result item
     * @throws IOException
     *           if unmarshalling fails
     */
    public static Series toSeries(SearchMetadataCollection metadata, Unmarshaller unmarshaller) throws IOException {
      Map<String, SearchMetadata<?>> metadataMap = metadata.toMap();
      String seriesXml = (String) metadataMap.get(SeriesIndexSchema.OBJECT).getValue();
      return Series.valueOf(IOUtils.toInputStream(seriesXml, Charset.defaultCharset()), unmarshaller);
    }
  
    /**
     * Creates search metadata from a series such that the event can be stored in the search index.
     *
     * @param series
     *          the series
     * @return the set of metadata
     */
    public static SearchMetadataCollection toSearchMetadata(Series series) {
      SearchMetadataCollection metadata = new SearchMetadataCollection(
              series.getIdentifier().concat(series.getOrganization()), Series.DOCUMENT_TYPE);
      metadata.addField(SeriesIndexSchema.UID, series.getIdentifier(), false);
      metadata.addField(SeriesIndexSchema.ORGANIZATION, series.getOrganization(), false);
      metadata.addField(SeriesIndexSchema.OBJECT, series.toXML(), false);
      metadata.addField(SeriesIndexSchema.TITLE, series.getTitle(), true);
      if (StringUtils.trimToNull(series.getDescription()) != null) {
        metadata.addField(SeriesIndexSchema.DESCRIPTION, series.getDescription(), true);
      }
      if (StringUtils.trimToNull(series.getSubject()) != null) {
        metadata.addField(SeriesIndexSchema.SUBJECT, series.getSubject(), true);
      }
      if (StringUtils.trimToNull(series.getLanguage()) != null) {
        metadata.addField(SeriesIndexSchema.LANGUAGE, series.getLanguage(), false);
      }
      if (StringUtils.trimToNull(series.getCreator()) != null) {
       metadata.addField(SeriesIndexSchema.CREATOR, series.getCreator(), true);
     }
     if (StringUtils.trimToNull(series.getLicense()) != null) {
       metadata.addField(SeriesIndexSchema.LICENSE, series.getLicense(), false);
     }
     if (StringUtils.trimToNull(series.getManagedAcl()) != null) {
       metadata.addField(SeriesIndexSchema.MANAGED_ACL, series.getManagedAcl(), false);
     }
     if (series.getCreatedDateTime() != null) {
       metadata.addField(SeriesIndexSchema.CREATED_DATE_TIME,
               DateTimeSupport.toUTC(series.getCreatedDateTime().getTime()), false);
     }
     if (series.getOrganizers() != null) {
       metadata.addField(SeriesIndexSchema.ORGANIZERS, series.getOrganizers().toArray(), true);
     }
     if (series.getContributors() != null) {
       metadata.addField(SeriesIndexSchema.CONTRIBUTORS, series.getContributors().toArray(), true);
     }
     if (series.getPublishers() != null) {
       metadata.addField(SeriesIndexSchema.PUBLISHERS, series.getPublishers().toArray(), true);
     }
     if (series.getRightsHolder() != null) {
       metadata.addField(SeriesIndexSchema.RIGHTS_HOLDER, series.getRightsHolder(), true);
     }
 
     if (!series.getExtendedMetadata().isEmpty()) {
       addExtendedMetadata(metadata, series.getExtendedMetadata());
     }
 
     if (StringUtils.trimToNull(series.getAccessPolicy()) != null) {
       metadata.addField(SeriesIndexSchema.ACCESS_POLICY, series.getAccessPolicy(), false);
       addAuthorization(metadata, series.getAccessPolicy());
     }
     if (series.getTheme() != null) {
       metadata.addField(SeriesIndexSchema.THEME, series.getTheme(), false);
     }
     return metadata;
   }
 
   /**
    * Adds extended metadata fields to the input document
    *
    * @param doc
    *          the input document
    * @param extendedMetadata
    *          the extended metadata map
    */
   private static void addExtendedMetadata(SearchMetadataCollection doc, Map<String, Map<String,
           List<String>>> extendedMetadata) {
     for (String type: extendedMetadata.keySet()) {
       Map<String, List<String>> extendedMetadataByType = extendedMetadata.get(type);
       for (String name: extendedMetadataByType.keySet()) {
         List<String> values = extendedMetadataByType.get(name);
         String fieldName = SeriesIndexSchema.EXTENDED_METADATA_PREFIX.concat(type + "_" + name);
         doc.addField(fieldName, values, true);
       }
     }
   }
 
   /**
    * Adds authorization fields to the input document.
    *
    * @param doc
    *          the input document
    * @param aclString
    *          the access control list string
    */
   private static void addAuthorization(SearchMetadataCollection doc, String aclString) {
     Map<String, List<String>> permissions = new HashMap<>();
 
     // Define containers for common permissions
     for (Action action : Permissions.Action.values()) {
       permissions.put(action.toString(), new ArrayList<>());
     }
 
     AccessControlList acl = AccessControlParser.parseAclSilent(aclString);
     for (AccessControlEntry entry : acl.getEntries()) {
       if (!entry.isAllow()) {
         logger.info("Series index does not support denial via ACL, ignoring {}", entry);
         continue;
       }
       List<String> actionPermissions = permissions.get(entry.getAction());
       if (actionPermissions == null) {
         actionPermissions = new ArrayList<>();
         permissions.put(entry.getAction(), actionPermissions);
       }
       actionPermissions.add(entry.getRole());
     }
 
     // Write the permissions to the input document
     for (Map.Entry<String, List<String>> entry : permissions.entrySet()) {
       String fieldName = SeriesIndexSchema.ACL_PERMISSION_PREFIX.concat(entry.getKey());
       doc.addField(fieldName, entry.getValue(), false);
     }
   }
 }