/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * 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.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.index.mapper;

import org.apache.lucene.document.FieldType;
import org.apache.lucene.index.IndexOptions;
import org.opensearch.common.lucene.Lucene;
import org.opensearch.index.analysis.NamedAnalyzer;
import org.opensearch.index.similarity.SimilarityProvider;

/**
 * Encapsulates information about how to perform text searches over a field
 *
 * @opensearch.internal
 */
public class TextSearchInfo {

    private static final FieldType SIMPLE_MATCH_ONLY_FIELD_TYPE = new FieldType();
    static {
        SIMPLE_MATCH_ONLY_FIELD_TYPE.setTokenized(false);
        SIMPLE_MATCH_ONLY_FIELD_TYPE.setOmitNorms(true);
        SIMPLE_MATCH_ONLY_FIELD_TYPE.freeze();
    }

    /**
     * Defines indexing information for fields that support only simple match text queries
     */
    public static final TextSearchInfo SIMPLE_MATCH_ONLY = new TextSearchInfo(
        SIMPLE_MATCH_ONLY_FIELD_TYPE,
        null,
        Lucene.KEYWORD_ANALYZER,
        Lucene.KEYWORD_ANALYZER
    );

    /**
     * Defines indexing information for fields that index as keywords, but split query input
     * on whitespace to build disjunctions.
     */
    public static final TextSearchInfo WHITESPACE_MATCH_ONLY = new TextSearchInfo(
        SIMPLE_MATCH_ONLY_FIELD_TYPE,
        null,
        Lucene.WHITESPACE_ANALYZER,
        Lucene.WHITESPACE_ANALYZER
    );

    /**
     * Specifies that this field does not support text searching of any kind
     */
    public static final TextSearchInfo NONE = new TextSearchInfo(SIMPLE_MATCH_ONLY_FIELD_TYPE, null, null, null);

    private final FieldType luceneFieldType;
    private final SimilarityProvider similarity;
    private final NamedAnalyzer searchAnalyzer;
    private final NamedAnalyzer searchQuoteAnalyzer;

    /**
     * Create a new TextSearchInfo
     *
     * @param luceneFieldType   the lucene {@link FieldType} of the field to be searched
     * @param similarity        defines which Similarity to use when searching.  If set to {@code null}
     *                          then the default Similarity will be used.
     */
    public TextSearchInfo(
        FieldType luceneFieldType,
        SimilarityProvider similarity,
        NamedAnalyzer searchAnalyzer,
        NamedAnalyzer searchQuoteAnalyzer
    ) {
        this.luceneFieldType = luceneFieldType;
        this.similarity = similarity;
        this.searchAnalyzer = searchAnalyzer;
        this.searchQuoteAnalyzer = searchQuoteAnalyzer;
    }

    public SimilarityProvider getSimilarity() {
        return similarity;
    }

    public NamedAnalyzer getSearchAnalyzer() {
        return searchAnalyzer;
    }

    public NamedAnalyzer getSearchQuoteAnalyzer() {
        return searchQuoteAnalyzer;
    }

    /**
     * @return whether or not this field supports positional queries
     */
    public boolean hasPositions() {
        return luceneFieldType.indexOptions().compareTo(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS) >= 0;
    }

    /**
     * @return whether or not this field has indexed offsets for highlighting
     */
    public boolean hasOffsets() {
        return luceneFieldType.indexOptions().compareTo(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS) >= 0;
    }

    /**
     * @return whether or not this field has indexed norms
     */
    public boolean hasNorms() {
        return luceneFieldType.omitNorms() == false;
    }

    /**
     * @return whether or not this field is tokenized
     */
    public boolean isTokenized() {
        return luceneFieldType.tokenized();
    }

    /**
     * What sort of term vectors are available
     *
     * @opensearch.internal
     */
    public enum TermVector {
        NONE,
        DOCS,
        POSITIONS,
        OFFSETS
    }

    /**
     * @return the type of term vectors available for this field
     */
    public TermVector termVectors() {
        if (luceneFieldType.storeTermVectors() == false) {
            return TermVector.NONE;
        }
        if (luceneFieldType.storeTermVectorOffsets()) {
            return TermVector.OFFSETS;
        }
        if (luceneFieldType.storeTermVectorPositions()) {
            return TermVector.POSITIONS;
        }
        return TermVector.DOCS;
    }

}