/*
 * 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.analysis;

import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.elasticsearch.Version;
import org.elasticsearch.indices.analysis.PreBuiltCacheFactory;
import org.elasticsearch.indices.analysis.PreBuiltCacheFactory.CachingStrategy;

import java.util.function.BiFunction;
import java.util.function.Function;

/**
 * Provides pre-configured, shared {@link TokenFilter}s.
 */
public final class PreConfiguredTokenFilter extends PreConfiguredAnalysisComponent<TokenFilterFactory> {
    /**
     * Create a pre-configured token filter that may not vary at all.
     */
    public static PreConfiguredTokenFilter singleton(String name, boolean useFilterForMultitermQueries,
            Function<TokenStream, TokenStream> create) {
        return new PreConfiguredTokenFilter(name, useFilterForMultitermQueries, CachingStrategy.ONE,
                (tokenStream, version) -> create.apply(tokenStream));
    }

    /**
     * Create a pre-configured token filter that may not vary at all.
     */
    public static PreConfiguredTokenFilter singletonWithVersion(String name, boolean useFilterForMultitermQueries,
            BiFunction<TokenStream, Version, TokenStream> create) {
        return new PreConfiguredTokenFilter(name, useFilterForMultitermQueries, CachingStrategy.ONE,
                (tokenStream, version) -> create.apply(tokenStream, version));
    }

    /**
     * Create a pre-configured token filter that may vary based on the Lucene version.
     */
    public static PreConfiguredTokenFilter luceneVersion(String name, boolean useFilterForMultitermQueries,
            BiFunction<TokenStream, org.apache.lucene.util.Version, TokenStream> create) {
        return new PreConfiguredTokenFilter(name, useFilterForMultitermQueries, CachingStrategy.LUCENE,
                (tokenStream, version) -> create.apply(tokenStream, version.luceneVersion));
    }

    /**
     * Create a pre-configured token filter that may vary based on the Elasticsearch version.
     */
    public static PreConfiguredTokenFilter elasticsearchVersion(String name, boolean useFilterForMultitermQueries,
            BiFunction<TokenStream, org.elasticsearch.Version, TokenStream> create) {
        return new PreConfiguredTokenFilter(name, useFilterForMultitermQueries, CachingStrategy.ELASTICSEARCH, create);
    }

    private final boolean useFilterForMultitermQueries;
    private final BiFunction<TokenStream, Version, TokenStream> create;

    private PreConfiguredTokenFilter(String name, boolean useFilterForMultitermQueries,
            PreBuiltCacheFactory.CachingStrategy cache, BiFunction<TokenStream, Version, TokenStream> create) {
        super(name, cache);
        this.useFilterForMultitermQueries = useFilterForMultitermQueries;
        this.create = create;
    }

    /**
     * Can this {@link TokenFilter} be used in multi-term queries?
     */
    public boolean shouldUseFilterForMultitermQueries() {
        return useFilterForMultitermQueries;
    }

    @Override
    protected TokenFilterFactory create(Version version) {
        if (useFilterForMultitermQueries) {
            return new NormalizingTokenFilterFactory() {

                @Override
                public TokenStream normalize(TokenStream tokenStream) {
                    return create.apply(tokenStream, version);
                }

                @Override
                public String name() {
                    return getName();
                }

                @Override
                public TokenStream create(TokenStream tokenStream) {
                    return create.apply(tokenStream, version);
                }

            };
        }
        return new TokenFilterFactory() {
            @Override
            public String name() {
                return getName();
            }

            @Override
            public TokenStream create(TokenStream tokenStream) {
                return create.apply(tokenStream, version);
            }
        };
    }
}
