/*
    * 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.graphql.datafetcher.series;
  
  import org.opencastproject.elasticsearch.api.SearchIndexException;
  import org.opencastproject.elasticsearch.api.SearchResult;
  import org.opencastproject.elasticsearch.index.ElasticsearchIndex;
  import org.opencastproject.elasticsearch.index.objects.series.Series;
  import org.opencastproject.elasticsearch.index.objects.series.SeriesSearchQuery;
  import org.opencastproject.graphql.datafetcher.ContextDataFetcher;
  import org.opencastproject.graphql.exception.GraphQLRuntimeException;
  import org.opencastproject.graphql.exception.OpencastErrorType;
  import org.opencastproject.graphql.execution.context.OpencastContext;
  import org.opencastproject.graphql.series.GqlSeries;
  import org.opencastproject.security.api.SecurityService;
  
  import java.util.Objects;
  
  import graphql.schema.DataFetchingEnvironment;
  
  
  /**
   * The SeriesDataFetcher class implements the ContextDataFetcher interface with GqlSeries as the generic type.
   * This class is used to fetch series data in a GraphQL context.
   * <p>
   * If the requested series is not found, a null value is returned.
   */
  public class SeriesDataFetcher implements ContextDataFetcher<GqlSeries> {
  
    private final String seriesId;
  
    public SeriesDataFetcher(String seriesId) {
      Objects.requireNonNull(seriesId, "Series identifier must not be null.");
      this.seriesId = seriesId;
    }
  
  
    @Override
    public GqlSeries get(OpencastContext opencastContext, DataFetchingEnvironment dataFetchingEnvironment) {
      SecurityService securityService = opencastContext.getService(SecurityService.class);
      ElasticsearchIndex searchIndex = opencastContext.getService(ElasticsearchIndex.class);
  
      try {
        SearchResult<Series> result = searchIndex.getByQuery(
            new SeriesSearchQuery(securityService.getOrganization().getId(), securityService.getUser())
            .withIdentifier(seriesId)
        );
        if (result.getDocumentCount() == 0) {
          return null;
        } else if (result.getDocumentCount() == 1) {
          return new GqlSeries(result.getItems()[0].getSource());
        }
        throw new GraphQLRuntimeException(
            "Multiple series found with the same identifier",
            OpencastErrorType.InternalError
        );
      } catch (SearchIndexException e) {
        throw new GraphQLRuntimeException(OpencastErrorType.InternalError, e);
      }
    }
  }