/*
 * 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 org.apache.lucene.search.ConstantScoreQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.join.ScoreMode;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.search.QParser;
import org.apache.solr.search.QueryParsing;
import org.apache.solr.search.SyntaxError;

class BlockJoinParentQParser extends QParser {
  protected String getParentFilterLocalParamName() {
    return "which";
  }

  BlockJoinParentQParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {
    super(qstr, localParams, params, req);
  }

  @Override
  public Query parse() throws SyntaxError {
    String filter = localParams.get(getParentFilterLocalParamName());
    QParser parentParser = subQuery(filter, null);
    Query parentQ = parentParser.getQuery();

    String queryText = localParams.get(QueryParsing.V);
    // there is no child query, return parent filter from cache
    if (queryText == null || queryText.length()==0) {
      return new ConstantScoreQuery(parentQ);
    }
    QParser childrenParser = subQuery(queryText, null);
    Query childrenQuery = childrenParser.getQuery();
    return createQuery(parentQ, childrenQuery);
  }

  protected Query createQuery(Query parentList, Query query) {
    return new BlockJoinParentQuery(query, parentList, ScoreMode.None); // TODO support more scores
  }
}