/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.solr.search.join;

import java.io.IOException;

import org.apache.lucene.index.LeafReaderContext;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.search.join.BlockJoinFieldFacetAccumulator.AggregatableDocIter;

/**
 * For each collected parent document creates matched block, which is a docSet with matched children and parent doc
 * itself. Then updates each BlockJoinFieldFacetAccumulator with the created matched block.
 */
class BlockJoinFacetAccsHolder {
  private BlockJoinFieldFacetAccumulator[] blockJoinFieldFacetAccumulators;
  private boolean firstSegment = true;
  
  BlockJoinFacetAccsHolder(SolrQueryRequest req) throws IOException {
    String[] facetFieldNames = BlockJoinFacetComponentSupport.getChildFacetFields(req);
    assert facetFieldNames != null;
    blockJoinFieldFacetAccumulators = new BlockJoinFieldFacetAccumulator[facetFieldNames.length];
    for (int i = 0; i < facetFieldNames.length; i++) {
      blockJoinFieldFacetAccumulators[i] = new BlockJoinFieldFacetAccumulator(facetFieldNames[i], req.getSearcher());
    }
  }
  

  protected void doSetNextReader(LeafReaderContext context) throws IOException {
    for (BlockJoinFieldFacetAccumulator blockJoinFieldFacetAccumulator : blockJoinFieldFacetAccumulators) {
      if(!firstSegment){
        blockJoinFieldFacetAccumulator.migrateGlobal();
      }
      blockJoinFieldFacetAccumulator.setNextReader(context);
    }
    firstSegment = false;
  }
  
  public void finish() throws IOException {
    for (BlockJoinFieldFacetAccumulator blockJoinFieldFacetAccumulator : blockJoinFieldFacetAccumulators) {
        blockJoinFieldFacetAccumulator.migrateGlobal();
    }
  }

  /** is not used 
  protected int[] includeParentDoc(int parent) {
    final int[] docNums = ArrayUtil.grow(childTracking.getChildDocs(), childTracking.getChildCount()+1);
    childTracking.setChildDocs(docNums); // we include parent into block, I'm not sure whether it makes sense
    docNums[childTracking.getChildCount()]=parent;
    return docNums;
  }*/

  protected void countFacets(final AggregatableDocIter iter) throws IOException {
    for (BlockJoinFieldFacetAccumulator blockJoinFieldFacetAccumulator : blockJoinFieldFacetAccumulators) {
      blockJoinFieldFacetAccumulator.updateCountsWithMatchedBlock( iter);
    }
  }
  
  NamedList getFacets() throws IOException {
    NamedList<NamedList<Integer>> facets = new NamedList<>(blockJoinFieldFacetAccumulators.length);
    for (BlockJoinFieldFacetAccumulator state : blockJoinFieldFacetAccumulators) {
      facets.add(state.getFieldName(), state.getFacetValue());
    }
    return facets;
  }
  
  
}