/*
    * 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.list.common.provider;
  
  import org.opencastproject.elasticsearch.api.SearchIndexException;
  import org.opencastproject.elasticsearch.api.SearchResult;
  import org.opencastproject.elasticsearch.api.SearchResultItem;
  import org.opencastproject.elasticsearch.index.ElasticsearchIndex;
  import org.opencastproject.elasticsearch.index.objects.series.Series;
  import org.opencastproject.elasticsearch.index.objects.series.SeriesIndexSchema;
  import org.opencastproject.elasticsearch.index.objects.series.SeriesSearchQuery;
  import org.opencastproject.list.api.ListProviderException;
  import org.opencastproject.list.api.ResourceListFilter;
  import org.opencastproject.list.api.ResourceListProvider;
  import org.opencastproject.list.api.ResourceListQuery;
  import org.opencastproject.list.common.query.SeriesListQuery;
  import org.opencastproject.security.api.Permissions;
  import org.opencastproject.security.api.SecurityService;
  import org.opencastproject.util.data.Tuple;
  import org.opencastproject.util.requests.SortCriterion;
  
  import org.apache.commons.lang3.StringUtils;
  import org.osgi.framework.BundleContext;
  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.Calendar;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  
  @Component(
      service = ResourceListProvider.class,
      property = {
          "service.description=Series list provider",
          "opencast.service.type=org.opencastproject.list.provider.SeriesListProvider"
      }
  )
  public class SeriesListProvider implements ResourceListProvider {
    private static final Logger logger = LoggerFactory.getLogger(SeriesListProvider.class);
  
    public static final String PROVIDER_PREFIX = "SERIES";
  
    public static final String NAME = PROVIDER_PREFIX + ".NAME";
    public static final String CONTRIBUTORS = PROVIDER_PREFIX + ".CONTRIBUTORS";
    public static final String SUBJECT = PROVIDER_PREFIX + ".SUBJECT";
    public static final String TITLE = PROVIDER_PREFIX + ".TITLE";
    public static final String TITLE_EXTENDED = PROVIDER_PREFIX + ".TITLE_EXTENDED";
    public static final String LANGUAGE = PROVIDER_PREFIX + ".LANGUAGE";
    public static final String ORGANIZERS = PROVIDER_PREFIX + ".ORGANIZERS";
    public static final String LICENSE = PROVIDER_PREFIX + ".LICENSE";
    public static final String SERIES_WRITE_ONLY = PROVIDER_PREFIX + ".WRITE_ONLY";
  
    private static final String[] NAMES = { PROVIDER_PREFIX, CONTRIBUTORS, ORGANIZERS, TITLE_EXTENDED,
        SERIES_WRITE_ONLY };
  
    /** The search index. */
    private ElasticsearchIndex searchIndex;
  
    /** The security service. */
    private SecurityService securityService;
  
    @Activate
    protected void activate(BundleContext bundleContext) {
      logger.info("Series list provider activated!");
    }
  
    /** OSGi callback for series services. */
    @Reference
    public void setSearchIndex(ElasticsearchIndex searchIndex) {
      this.searchIndex = searchIndex;
    }
 
   /** OSGi callback for security service */
   @Reference
   public void setSecurityService(SecurityService securityService) {
     this.securityService = securityService;
   }
 
   @Override
   public String[] getListNames() {
     return NAMES;
   }
 
   @Override
   public Map<String, String> getList(String listName, ResourceListQuery query)
           throws ListProviderException {
     SeriesSearchQuery seriesQuery = toSearchQuery(query);
     Map<String, String> result = new HashMap<>();
     if (TITLE.equals(listName)) {
       seriesQuery.sortByTitle(SortCriterion.Order.Ascending);
       for (String title : searchIndex.getTermsForField(SeriesIndexSchema.TITLE, Series.DOCUMENT_TYPE)) {
         result.put(title, title);
       }
     } else if (CONTRIBUTORS.equals(listName)) {
       seriesQuery.sortByContributors(SortCriterion.Order.Ascending);
       for (String contributor : searchIndex.getTermsForField(SeriesIndexSchema.CONTRIBUTORS, Series.DOCUMENT_TYPE)) {
         result.put(contributor, contributor);
       }
     } else if (ORGANIZERS.equals(listName)) {
       seriesQuery.sortByOrganizers(SortCriterion.Order.Ascending);
       for (String organizer : searchIndex.getTermsForField(SeriesIndexSchema.ORGANIZERS, Series.DOCUMENT_TYPE)) {
         result.put(organizer, organizer);
       }
     } else {
       try {
         seriesQuery.sortByTitle(SortCriterion.Order.Ascending);
         seriesQuery.sortByCreatedDateTime(SortCriterion.Order.Descending);
         seriesQuery.sortByOrganizers(SortCriterion.Order.Ascending);
         if (SERIES_WRITE_ONLY.equals(listName)) {
           seriesQuery.withAction(Permissions.Action.WRITE);
         }
         SearchResult<Series> searchResult = searchIndex.getByQuery(seriesQuery);
         Calendar calendar = Calendar.getInstance();
         //We might have duplicate series names, so let's count them and see
         Map<String, Long> duplicates = Arrays.stream(searchResult.getItems())
             .map(series -> series.getSource().getTitle())
             .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
         for (SearchResultItem<Series> item : searchResult.getItems()) {
           Series s = item.getSource();
           if (TITLE_EXTENDED.equals(listName)) {
             Date created = s.getCreatedDateTime();
             List<String> organizers = s.getOrganizers();
             StringBuilder sb = new StringBuilder(s.getTitle());
             if (created != null || (organizers != null && !organizers.isEmpty())) {
               List<String> extendedTitleData = new ArrayList<>();
               if (created != null) {
                 calendar.setTime(created);
                 extendedTitleData.add(Integer.toString(calendar.get(Calendar.YEAR)));
               }
               if (organizers != null && !organizers.isEmpty()) {
                 extendedTitleData.addAll(organizers);
               }
               sb.append(" (").append(StringUtils.join(extendedTitleData, ", ")).append(")");
             }
             result.put(s.getIdentifier(), sb.toString());
           } else if (PROVIDER_PREFIX.equals(listName)) {
             String newSeriesName = s.getTitle();
             if (duplicates.get(newSeriesName) > 1L) {
               // If a series name is repeated, will add the first 7 characters of the series ID to the display name on
               // the admin-ui
               if (s.getIdentifier().length() > 8) {
                 newSeriesName += " " + "(ID: " + s.getIdentifier().substring(0, 8) + "...)";
               } else {
                 newSeriesName += " " + "(ID: " + s.getIdentifier() + ")";
               }
               logger.trace(String.format("Repeated series title \"%s\" found, changing to \"%s\" for admin-ui display",
                   s.getTitle(), newSeriesName));
             }
             result.put(s.getIdentifier(), newSeriesName);
           } else {
             result.put(s.getIdentifier(), s.getTitle());
           }
         }
       } catch (SearchIndexException e) {
         logger.warn("Unable to query series.", e);
       }
     }
     return result;
   }
 
   @Override
   public boolean isTranslatable(String listName) {
     return false;
   }
 
   @Override
   public String getDefault() {
     return null;
   }
 
   /**
    * Creates a series search query from resource list query.
    *
    * @param query a resource list query
    * @return a series search query
    */
   protected SeriesSearchQuery toSearchQuery(ResourceListQuery query) {
     SeriesSearchQuery seriesQuery = new SeriesSearchQuery(securityService.getOrganization().getId(),
         securityService.getUser());
     if (query.getLimit().isPresent()) {
       seriesQuery.withLimit(query.getLimit().get());
     }
     if (query.getOffset().isPresent()) {
       seriesQuery.withOffset(query.getOffset().get());
     }
 
     for (ResourceListFilter filter : query.getFilters()) {
       if (filter.getValue().isEmpty()) {
         continue;
       } else if (SeriesListQuery.FILTER_CREATIONDATE_NAME.equals(filter.getName())) {
         Tuple<Date, Date> creationDate = (Tuple<Date, Date>) filter.getValue().get();
         if (creationDate.getA() != null) {
           seriesQuery.withCreatedFrom(creationDate.getA());
         }
         if (creationDate.getB() != null) {
           seriesQuery.withCreatedTo(creationDate.getB());
         }
       } else if (SeriesListQuery.FILTER_CREATOR_NAME.equals(filter.getName())) {
         seriesQuery.withCreator((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_CONTRIBUTORS_NAME.equals(filter.getName())) {
         seriesQuery.withContributor((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_LANGUAGE_NAME.equals(filter.getName())) {
         seriesQuery.withLanguage((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_LICENSE_NAME.equals(filter.getName())) {
         seriesQuery.withLicense((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_ORGANIZERS_NAME.equals(filter.getName())) {
         seriesQuery.withOrganizer((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_SUBJECT_NAME.equals(filter.getName())) {
         seriesQuery.withSubject((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_TEXT_NAME.equals(filter.getName())) {
         seriesQuery.withText((String)filter.getValue().get());
       } else if (SeriesListQuery.FILTER_TITLE_NAME.equals(filter.getName())) {
         seriesQuery.withTitle((String)filter.getValue().get());
       }
     }
 
     if (query instanceof SeriesListQuery) {
       if (((SeriesListQuery) query).getReadPermission().isPresent()
           || ((SeriesListQuery) query).getWritePermission().isPresent()) {
         seriesQuery.withoutActions();
         if (((SeriesListQuery) query).getReadPermission().orElse(true)) {
           seriesQuery.withAction(Permissions.Action.READ);
         }
         if (((SeriesListQuery) query).getWritePermission().orElse(false)) {
           seriesQuery.withAction(Permissions.Action.WRITE);
         }
       }
     }
     return seriesQuery;
   }
 }