/*
   * Copyright 2015 FBK-irst.
   *
   * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0
   *
  * 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 eu.fbk.knowledgestore.elastic;
  
  import eu.fbk.knowledgestore.data.Handler;
  import eu.fbk.knowledgestore.data.Record;
  import eu.fbk.knowledgestore.data.Stream;
  import org.elasticsearch.action.search.SearchResponse;
  import org.elasticsearch.client.Client;
  import org.elasticsearch.common.unit.TimeValue;
  import org.elasticsearch.search.SearchHit;
  import org.openrdf.model.URI;
  
  /**
   *
   * @author enrico
   */
  public class SearchResponseStream extends Stream<Record>{
      SearchResponse response;
      Client client;
      TimeValue timeout;
      MappingHandler mapper;
      URIHandler uriHandler;
      URI[] properties;
      
      /**
       * 
       * @param res the SearchResponse has to be created from a SearchRequest with a setScroll.
       * @param client client where to execute
       * @param timeout duration of the scrollId
       */
      SearchResponseStream(SearchResponse res, Client client, TimeValue timeout,  MappingHandler mapper, URIHandler handler){
          response = res;
          this.client = client;
          this.timeout = timeout;
          this.mapper = mapper;
          this.uriHandler = handler;
      }
      
      @Override
      protected void doToHandler(final Handler<? super Record> handler) throws Throwable {
          while(true){            
              for(SearchHit hit : response.getHits().getHits()){
                  Record rec;
                  rec = Utility.deserialize(hit, mapper, uriHandler);
                  if(Thread.interrupted()){
                      handler.handle(null);
                      return;
                  }
                  handler.handle(rec);
              }
              response = client.prepareSearchScroll(response.getScrollId()).setScroll(timeout).execute().actionGet();
              //Break condition: No hits are returned
              if (response.getHits().getHits().length == 0){
                  handler.handle(null);
                  break;
              }
          }
      }
  }