package org.apache.lucene.queryparser.flexible.standard.builders;

/*
 * 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.
 */

import java.util.List;

import org.apache.lucene.queryparser.flexible.messages.MessageImpl;
import org.apache.lucene.queryparser.flexible.core.QueryNodeException;
import org.apache.lucene.queryparser.flexible.core.builders.QueryTreeBuilder;
import org.apache.lucene.queryparser.flexible.core.messages.QueryParserMessages;
import org.apache.lucene.queryparser.flexible.core.nodes.BooleanQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.ModifierQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
import org.apache.lucene.queryparser.flexible.standard.parser.EscapeQuerySyntaxImpl;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.BooleanQuery.TooManyClauses;

/**
 * Builds a {@link BooleanQuery} object from a {@link BooleanQueryNode} object.
 * Every children in the {@link BooleanQueryNode} object must be already tagged
 * using {@link QueryTreeBuilder#QUERY_TREE_BUILDER_TAGID} with a {@link Query}
 * object. <br/>
 * <br/>
 * It takes in consideration if the children is a {@link ModifierQueryNode} to
 * define the {@link BooleanClause}.
 */
public class BooleanQueryNodeBuilder implements StandardQueryBuilder {

  public BooleanQueryNodeBuilder() {
    // empty constructor
  }

  @Override
  public BooleanQuery build(QueryNode queryNode) throws QueryNodeException {
    BooleanQueryNode booleanNode = (BooleanQueryNode) queryNode;

    BooleanQuery bQuery = new BooleanQuery();
    List<QueryNode> children = booleanNode.getChildren();

    if (children != null) {

      for (QueryNode child : children) {
        Object obj = child.getTag(QueryTreeBuilder.QUERY_TREE_BUILDER_TAGID);

        if (obj != null) {
          Query query = (Query) obj;

          try {
            bQuery.add(query, getModifierValue(child));

          } catch (TooManyClauses ex) {

            throw new QueryNodeException(new MessageImpl(
                QueryParserMessages.TOO_MANY_BOOLEAN_CLAUSES, BooleanQuery
                    .getMaxClauseCount(), queryNode
                    .toQueryString(new EscapeQuerySyntaxImpl())), ex);

          }

        }

      }

    }

    return bQuery;

  }

  private static BooleanClause.Occur getModifierValue(QueryNode node) {

    if (node instanceof ModifierQueryNode) {
      ModifierQueryNode mNode = ((ModifierQueryNode) node);
      switch (mNode.getModifier()) {

      case MOD_REQ:
        return BooleanClause.Occur.MUST;

      case MOD_NOT:
        return BooleanClause.Occur.MUST_NOT;

      case MOD_NONE:
        return BooleanClause.Occur.SHOULD;

      }

    }

    return BooleanClause.Occur.SHOULD;

  }

}
