/*
 * 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.index.Term;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.BytesRefs;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.mapper.FieldMapper;
import org.elasticsearch.index.mapper.MapperService;

import java.io.IOException;
import java.util.List;

import static com.google.common.collect.Lists.newArrayList;
import static org.elasticsearch.common.lucene.search.Queries.fixNegativeQueryIfNeeded;
import static org.elasticsearch.common.lucene.search.Queries.optimizeQuery;
import static org.elasticsearch.index.query.support.QueryParsers.wrapSmartNameQuery;

/**
 * <pre>
 * "terms" : {
 *  "field_name" : [ "value1", "value2" ]
 *  "minimum_match" : 1
 * }
 * </pre>
 */
public class TermsQueryParser implements QueryParser {

    public static final String NAME = "terms";

    @Inject
    public TermsQueryParser() {
    }

    @Override
    public String[] names() {
        return new String[]{NAME, "in"}; // allow both "in" and "terms" (since its similar to the "terms" filter)
    }

    @Override
    public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
        XContentParser parser = parseContext.parser();

        String fieldName = null;
        boolean disableCoord = false;
        float boost = 1.0f;
        String minimumShouldMatch = null;
        List<Object> values = newArrayList();
        String queryName = null;

        String currentFieldName = null;
        XContentParser.Token token;
        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
            if (token == XContentParser.Token.FIELD_NAME) {
                currentFieldName = parser.currentName();
            } else if (token == XContentParser.Token.START_ARRAY) {
                fieldName = currentFieldName;
                while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
                    Object value = parser.objectBytes();
                    if (value == null) {
                        throw new QueryParsingException(parseContext.index(), "No value specified for terms query");
                    }
                    values.add(value);
                }
            } else if (token.isValue()) {
                if ("disable_coord".equals(currentFieldName) || "disableCoord".equals(currentFieldName)) {
                    disableCoord = parser.booleanValue();
                } else if ("minimum_match".equals(currentFieldName) || "minimumMatch".equals(currentFieldName)) {
                    minimumShouldMatch = parser.textOrNull();
                } else if ("minimum_should_match".equals(currentFieldName) || "minimumShouldMatch".equals(currentFieldName)) {
                    minimumShouldMatch = parser.textOrNull();
                } else if ("boost".equals(currentFieldName)) {
                    boost = parser.floatValue();
                } else if ("_name".equals(currentFieldName)) {
                    queryName = parser.text();
                } else {
                    throw new QueryParsingException(parseContext.index(), "[terms] query does not support [" + currentFieldName + "]");
                }
            } else {
                throw new QueryParsingException(parseContext.index(), "[terms] query does not support [" + currentFieldName + "]");
            }
        }

        if (fieldName == null) {
            throw new QueryParsingException(parseContext.index(), "No field specified for terms query");
        }

        FieldMapper mapper = null;
        MapperService.SmartNameFieldMappers smartNameFieldMappers = parseContext.smartFieldMappers(fieldName);
        String[] previousTypes = null;
        if (smartNameFieldMappers != null && smartNameFieldMappers.hasMapper()) {
            mapper = smartNameFieldMappers.mapper();
            if (smartNameFieldMappers.explicitTypeInNameWithDocMapper()) {
                previousTypes = QueryParseContext.setTypesWithPrevious(new String[]{smartNameFieldMappers.docMapper().type()});
            }
        }

        try {
            BooleanQuery booleanQuery = new BooleanQuery(disableCoord);
            for (Object value : values) {
                if (mapper != null) {
                    booleanQuery.add(new BooleanClause(mapper.termQuery(value, parseContext), BooleanClause.Occur.SHOULD));
                } else {
                    booleanQuery.add(new TermQuery(new Term(fieldName, BytesRefs.toString(value))), BooleanClause.Occur.SHOULD);
                }
            }
            booleanQuery.setBoost(boost);
            Queries.applyMinimumShouldMatch(booleanQuery, minimumShouldMatch);
            Query query = wrapSmartNameQuery(optimizeQuery(fixNegativeQueryIfNeeded(booleanQuery)), smartNameFieldMappers, parseContext);
            if (queryName != null) {
                parseContext.addNamedQuery(queryName, query);
            }
            return query;
        } finally {
            if (smartNameFieldMappers != null && smartNameFieldMappers.explicitTypeInNameWithDocMapper()) {
                QueryParseContext.setTypes(previousTypes);
            }
        }
    }
}

