/*
 * 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 com.google.common.collect.ImmutableMap;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.CloseableThreadLocal;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.cache.recycler.CacheRecycler;
import org.elasticsearch.Version;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.AbstractIndexComponent;
import org.elasticsearch.index.Index;
import org.elasticsearch.index.analysis.AnalysisService;
import org.elasticsearch.index.cache.IndexCache;
import org.elasticsearch.index.engine.IndexEngine;
import org.elasticsearch.index.cache.fixedbitset.FixedBitSetFilterCache;
import org.elasticsearch.index.fielddata.IndexFieldDataService;
import org.elasticsearch.index.mapper.MapperService;
import org.elasticsearch.index.mapper.internal.AllFieldMapper;
import org.elasticsearch.index.settings.IndexSettings;
import org.elasticsearch.index.similarity.SimilarityService;
import org.elasticsearch.indices.query.IndicesQueriesRegistry;
import org.elasticsearch.script.ScriptService;

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

import static com.google.common.collect.Lists.newArrayList;
import static com.google.common.collect.Maps.newHashMap;
import static org.elasticsearch.common.settings.ImmutableSettings.Builder.EMPTY_SETTINGS;

/**
 *
 */
public class IndexQueryParserService extends AbstractIndexComponent {

    public static final class Defaults {
        public static final String QUERY_PREFIX = "index.queryparser.query";
        public static final String FILTER_PREFIX = "index.queryparser.filter";
    }

    public static final String DEFAULT_FIELD = "index.query.default_field";
    public static final String QUERY_STRING_LENIENT = "index.query_string.lenient";
    public static final String PARSE_STRICT = "index.query.parse.strict";
    public static final String ALLOW_UNMAPPED = "index.query.parse.allow_unmapped_fields";

    private CloseableThreadLocal<QueryParseContext> cache = new CloseableThreadLocal<QueryParseContext>() {
        @Override
        protected QueryParseContext initialValue() {
            return new QueryParseContext(index, IndexQueryParserService.this);
        }
    };

    final CacheRecycler cacheRecycler;

    final AnalysisService analysisService;

    final ScriptService scriptService;

    final MapperService mapperService;

    final SimilarityService similarityService;

    final IndexCache indexCache;

    final IndexFieldDataService fieldDataService;

    final FixedBitSetFilterCache fixedBitSetFilterCache;

    final IndexEngine indexEngine;

    private final Map<String, QueryParser> queryParsers;

    private final Map<String, FilterParser> filterParsers;

    private String defaultField;
    private boolean queryStringLenient;
    private final boolean strict;
    private final boolean defaultAllowUnmappedFields;

    @Inject
    public IndexQueryParserService(Index index, @IndexSettings Settings indexSettings,
                                   IndicesQueriesRegistry indicesQueriesRegistry, CacheRecycler cacheRecycler,
                                   ScriptService scriptService, AnalysisService analysisService,
                                   MapperService mapperService, IndexCache indexCache, IndexFieldDataService fieldDataService,
                                   IndexEngine indexEngine, FixedBitSetFilterCache fixedBitSetFilterCache,
                                   @Nullable SimilarityService similarityService,
                                   @Nullable Map<String, QueryParserFactory> namedQueryParsers,
                                   @Nullable Map<String, FilterParserFactory> namedFilterParsers) {
        super(index, indexSettings);
        this.cacheRecycler = cacheRecycler;
        this.scriptService = scriptService;
        this.analysisService = analysisService;
        this.mapperService = mapperService;
        this.similarityService = similarityService;
        this.indexCache = indexCache;
        this.fieldDataService = fieldDataService;
        this.indexEngine = indexEngine;
        this.fixedBitSetFilterCache = fixedBitSetFilterCache;

        this.defaultField = indexSettings.get(DEFAULT_FIELD, AllFieldMapper.NAME);
        this.queryStringLenient = indexSettings.getAsBoolean(QUERY_STRING_LENIENT, false);
        this.strict = indexSettings.getAsBoolean(PARSE_STRICT, false);
        this.defaultAllowUnmappedFields = indexSettings.getAsBoolean(ALLOW_UNMAPPED, true);

        List<QueryParser> queryParsers = newArrayList();
        if (namedQueryParsers != null) {
            Map<String, Settings> queryParserGroups = indexSettings.getGroups(IndexQueryParserService.Defaults.QUERY_PREFIX);
            for (Map.Entry<String, QueryParserFactory> entry : namedQueryParsers.entrySet()) {
                String queryParserName = entry.getKey();
                QueryParserFactory queryParserFactory = entry.getValue();
                Settings queryParserSettings = queryParserGroups.get(queryParserName);
                if (queryParserSettings == null) {
                    queryParserSettings = EMPTY_SETTINGS;
                }
                queryParsers.add(queryParserFactory.create(queryParserName, queryParserSettings));
            }
        }

        Map<String, QueryParser> queryParsersMap = newHashMap();
        queryParsersMap.putAll(indicesQueriesRegistry.queryParsers());
        if (queryParsers != null) {
            for (QueryParser queryParser : queryParsers) {
                add(queryParsersMap, queryParser);
            }
        }
        this.queryParsers = ImmutableMap.copyOf(queryParsersMap);

        List<FilterParser> filterParsers = newArrayList();
        if (namedFilterParsers != null) {
            Map<String, Settings> filterParserGroups = indexSettings.getGroups(IndexQueryParserService.Defaults.FILTER_PREFIX);
            for (Map.Entry<String, FilterParserFactory> entry : namedFilterParsers.entrySet()) {
                String filterParserName = entry.getKey();
                FilterParserFactory filterParserFactory = entry.getValue();
                Settings filterParserSettings = filterParserGroups.get(filterParserName);
                if (filterParserSettings == null) {
                    filterParserSettings = EMPTY_SETTINGS;
                }
                filterParsers.add(filterParserFactory.create(filterParserName, filterParserSettings));
            }
        }

        Map<String, FilterParser> filterParsersMap = newHashMap();
        filterParsersMap.putAll(indicesQueriesRegistry.filterParsers());
        if (filterParsers != null) {
            for (FilterParser filterParser : filterParsers) {
                add(filterParsersMap, filterParser);
            }
        }
        this.filterParsers = ImmutableMap.copyOf(filterParsersMap);
    }

    public void close() {
        cache.close();
    }

    public String defaultField() {
        return this.defaultField;
    }

    public boolean queryStringLenient() {
        return this.queryStringLenient;
    }

    public QueryParser queryParser(String name) {
        return queryParsers.get(name);
    }

    public FilterParser filterParser(String name) {
        return filterParsers.get(name);
    }

    public ParsedQuery parse(QueryBuilder queryBuilder) throws ElasticsearchException {
        XContentParser parser = null;
        try {
            BytesReference bytes = queryBuilder.buildAsBytes();
            parser = XContentFactory.xContent(bytes).createParser(bytes);
            return parse(cache.get(), parser);
        } catch (QueryParsingException e) {
            throw e;
        } catch (Exception e) {
            throw new QueryParsingException(index, "Failed to parse", e);
        } finally {
            if (parser != null) {
                parser.close();
            }
        }
    }

    public ParsedQuery parse(byte[] source) throws ElasticsearchException {
        return parse(source, 0, source.length);
    }

    public ParsedQuery parse(byte[] source, int offset, int length) throws ElasticsearchException {
        XContentParser parser = null;
        try {
            parser = XContentFactory.xContent(source, offset, length).createParser(source, offset, length);
            return parse(cache.get(), parser);
        } catch (QueryParsingException e) {
            throw e;
        } catch (Exception e) {
            throw new QueryParsingException(index, "Failed to parse", e);
        } finally {
            if (parser != null) {
                parser.close();
            }
        }
    }

    public ParsedQuery parse(BytesReference source) throws ElasticsearchException {
        return parse(cache.get(), source);
    }

    public ParsedQuery parse(QueryParseContext context, BytesReference source) throws ElasticsearchException {
        XContentParser parser = null;
        try {
            parser = XContentFactory.xContent(source).createParser(source);
            return innerParse(context, parser);
        } catch (QueryParsingException e) {
            throw e;
        } catch (Exception e) {
            throw new QueryParsingException(index, "Failed to parse", e);
        } finally {
            if (parser != null) {
                parser.close();
            }
        }
    }

    public ParsedQuery parse(String source) throws QueryParsingException {
        XContentParser parser = null;
        try {
            parser = XContentFactory.xContent(source).createParser(source);
            return innerParse(cache.get(), parser);
        } catch (QueryParsingException e) {
            throw e;
        } catch (Exception e) {
            throw new QueryParsingException(index, "Failed to parse [" + source + "]", e);
        } finally {
            if (parser != null) {
                parser.close();
            }
        }
    }

    public ParsedQuery parse(XContentParser parser) {
        return parse(cache.get(), parser);
    }

    public ParsedQuery parse(QueryParseContext context, XContentParser parser) {
        try {
            return innerParse(context, parser);
        } catch (IOException e) {
            throw new QueryParsingException(index, "Failed to parse", e);
        }
    }

    /**
     * Parses an inner filter, returning null if the filter should be ignored.
     */
    @Nullable
    public ParsedFilter parseInnerFilter(XContentParser parser) throws IOException {
        QueryParseContext context = cache.get();
        context.reset(parser);
        try {
            Filter filter = context.parseInnerFilter();
            if (filter == null) {
                return null;
            }
            return new ParsedFilter(filter, context.copyNamedFilters());
        } finally {
            context.reset(null);
        }
    }

    @Nullable
    public Query parseInnerQuery(XContentParser parser) throws IOException {
        QueryParseContext context = cache.get();
        context.reset(parser);
        try {
            return context.parseInnerQuery();
        } finally {
            context.reset(null);
        }
    }

    @Nullable
    public Query parseInnerQuery(QueryParseContext parseContext) throws IOException {
        if (strict) {
            parseContext.parseFlags(EnumSet.of(ParseField.Flag.STRICT));
        }
        Query query = parseContext.parseInnerQuery();
        if (query == null) {
            query = Queries.newMatchNoDocsQuery();
        }
        return query;
    }

    public QueryParseContext getParseContext() {
        return cache.get();
    }

    public boolean defaultAllowUnmappedFields() {
        return defaultAllowUnmappedFields;
    }

    /**
     * @return The lowest node version in the cluster when the index was created or <code>null</code> if that was unknown
     */
    public Version getIndexCreatedVersion() {
        return Version.indexCreated(indexSettings);
    }

    /**
     * Selectively parses a query from a top level query or query_binary json field from the specified source.
     */
    public ParsedQuery parseQuery(BytesReference source) {
        try {
            ParsedQuery parsedQuery = null;
            XContentParser parser = XContentHelper.createParser(source);
            for (XContentParser.Token token = parser.nextToken(); token != XContentParser.Token.END_OBJECT; token = parser.nextToken()) {
                if (token == XContentParser.Token.FIELD_NAME) {
                    String fieldName = parser.currentName();
                    if ("query".equals(fieldName)) {
                        parsedQuery = parse(parser);
                    } else if ("query_binary".equals(fieldName) || "queryBinary".equals(fieldName)) {
                        byte[] querySource = parser.binaryValue();
                        XContentParser qSourceParser = XContentFactory.xContent(querySource).createParser(querySource);
                        parsedQuery = parse(qSourceParser);
                    } else {
                        throw new QueryParsingException(index(), "request does not support [" + fieldName + "]");
                    }
                }
            }
            if (parsedQuery != null) {
                return parsedQuery;
            }
        } catch (QueryParsingException e) {
            throw e;
        } catch (Throwable e) {
            throw new QueryParsingException(index, "Failed to parse", e);
        }

        throw new QueryParsingException(index(), "Required query is missing");
    }

    private ParsedQuery innerParse(QueryParseContext parseContext, XContentParser parser) throws IOException, QueryParsingException {
        parseContext.reset(parser);
        try {
            if (strict) {
                parseContext.parseFlags(EnumSet.of(ParseField.Flag.STRICT));
            }
            Query query = parseContext.parseInnerQuery();
            if (query == null) {
                query = Queries.newMatchNoDocsQuery();
            }
            return new ParsedQuery(query, parseContext.copyNamedFilters());
        } finally {
            parseContext.reset(null);
        }
    }

    private void add(Map<String, FilterParser> map, FilterParser filterParser) {
        for (String name : filterParser.names()) {
            map.put(name.intern(), filterParser);
        }
    }

    private void add(Map<String, QueryParser> map, QueryParser queryParser) {
        for (String name : queryParser.names()) {
            map.put(name.intern(), queryParser);
        }
    }
}
