/*
 * 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.similarity;

import org.apache.lucene.search.similarities.Similarity;
import org.opensearch.common.annotation.PublicApi;

import java.util.Objects;

/**
 * Wrapper around a {@link Similarity} and its name.
 *
 * @opensearch.api
 */
@PublicApi(since = "1.0.0")
public final class SimilarityProvider {

    private final String name;
    private final Similarity similarity;

    public SimilarityProvider(String name, Similarity similarity) {
        this.name = name;
        this.similarity = similarity;
    }

    /**
     * Return the name of this {@link Similarity}.
     */
    public String name() {
        return name;
    }

    /**
     * Return the wrapped {@link Similarity}.
     */
    public Similarity get() {
        return similarity;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        SimilarityProvider that = (SimilarityProvider) o;
        /*
          We check <code>name</code> only because the <code>similarity</code> is
          re-created for each new instance and they don't implement equals.
          This is not entirely correct though but we only use equality checks
          for similarities inside the same index and names are unique in this case.
         */
        return Objects.equals(name, that.name);
    }

    @Override
    public int hashCode() {
        /*
          We use <code>name</code> only because the <code>similarity</code> is
          re-created for each new instance and they don't implement equals.
          This is not entirely correct though but we only use equality checks
          for similarities a single index and names are unique in this case.
         */
        return Objects.hash(name);
    }
}
