/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.index.query;

import org.apache.lucene.search.Query;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;

import java.io.IOException;

/**
 * A query that matches no document.
 */
public class MatchNoneQueryBuilder extends AbstractQueryBuilder<MatchNoneQueryBuilder> {
    public static final String NAME = "match_none";

    public MatchNoneQueryBuilder() {
    }

    /**
     * Read from a stream.
     */
    public MatchNoneQueryBuilder(StreamInput in) throws IOException {
        super(in);
    }

    @Override
    protected void doWriteTo(StreamOutput out) throws IOException {
        // all state is in the superclass
    }

    @Override
    protected void doXContent(XContentBuilder builder, Params params) throws IOException {
        builder.startObject(NAME);
        printBoostAndQueryName(builder);
        builder.endObject();
    }

    public static MatchNoneQueryBuilder fromXContent(QueryParseContext parseContext) throws IOException {
        XContentParser parser = parseContext.parser();

        String currentFieldName = null;
        XContentParser.Token token;
        String queryName = null;
        float boost = AbstractQueryBuilder.DEFAULT_BOOST;
        while (((token = parser.nextToken()) != XContentParser.Token.END_OBJECT && token != XContentParser.Token.END_ARRAY)) {
            if (token == XContentParser.Token.FIELD_NAME) {
                currentFieldName = parser.currentName();
            } else if (token.isValue()) {
                if (AbstractQueryBuilder.NAME_FIELD.match(currentFieldName)) {
                    queryName = parser.text();
                } else if (AbstractQueryBuilder.BOOST_FIELD.match(currentFieldName)) {
                    boost = parser.floatValue();
                } else {
                    throw new ParsingException(parser.getTokenLocation(), "["+MatchNoneQueryBuilder.NAME +
                            "] query does not support [" + currentFieldName + "]");
                }
            } else {
                throw new ParsingException(parser.getTokenLocation(), "[" + MatchNoneQueryBuilder.NAME +
                        "] unknown token [" + token + "] after [" + currentFieldName + "]");
            }
        }

        MatchNoneQueryBuilder matchNoneQueryBuilder = new MatchNoneQueryBuilder();
        matchNoneQueryBuilder.boost(boost);
        matchNoneQueryBuilder.queryName(queryName);
        return matchNoneQueryBuilder;
    }

    @Override
    protected Query doToQuery(QueryShardContext context) throws IOException {
        return Queries.newMatchNoDocsQuery("User requested \"" + this.getName() + "\" query.");
    }

    @Override
    protected boolean doEquals(MatchNoneQueryBuilder other) {
        return true;
    }

    @Override
    protected int doHashCode() {
        return 0;
    }

    @Override
    public String getWriteableName() {
        return NAME;
    }
}
