code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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.apache.skywalking.library.elasticsearch;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import org.apache.skywalking.library.elasticsearch.requests.factory.Codec;
  import org.apache.skywalking.library.elasticsearch.requests.factory.RequestFactory;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v6.V6RequestFactory;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v6.codec.V6Codec;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v7plus.V78RequestFactory;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v7plus.V7RequestFactory;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v7plus.V81RequestFactory;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v7plus.codec.V78Codec;
  import org.apache.skywalking.library.elasticsearch.requests.factory.v7plus.codec.V7Codec;
  
  public final class ElasticSearchVersion {
      private final String distribution;
      private final int major;
      private final int minor;
  
      private final RequestFactory requestFactory;
      private final Codec codec;
  
      private ElasticSearchVersion(final String distribution, final int major, final int minor) {
          this.distribution = distribution;
          this.major = major;
          this.minor = minor;
  
          if (distribution.equalsIgnoreCase("OpenSearch")) {
              requestFactory = new V81RequestFactory(this);
              codec = V78Codec.INSTANCE;
              return;
          }
  
          if (distribution.equalsIgnoreCase("ElasticSearch")) {
              if (major == 6) { // 6.x
                  requestFactory = new V6RequestFactory(this);
                  codec = V6Codec.INSTANCE;
                  return;
              }
              if (major == 7) {
                  if (minor < 8) { // [7.0, 7.8)
                      requestFactory = new V7RequestFactory(this);
                      codec = V7Codec.INSTANCE;
                  } else { // [7.8, 8.0)
                      requestFactory = new V78RequestFactory(this);
                      codec = V78Codec.INSTANCE;
                  }
                  return;
              }
              if (major == 8) {
                  requestFactory = new V81RequestFactory(this);
                  codec = V78Codec.INSTANCE;
                  return;
              }
          }
          throw new UnsupportedOperationException("Unsupported version: " + this);
      }
  
      @Override
      public String toString() {
          return distribution + " " + major + "." + minor;
      }
  
      private static final Pattern REGEX = Pattern.compile("(\\d+)\\.(\\d+).*");
  
      public static ElasticSearchVersion of(String distribution, String version) {
          final Matcher matcher = REGEX.matcher(version);
          if (!matcher.matches()) {
              throw new IllegalArgumentException("Failed to parse version: " + version);
          }
          final int major = Integer.parseInt(matcher.group(1));
          final int minor = Integer.parseInt(matcher.group(2));
          return new ElasticSearchVersion(distribution, major, minor);
      }
  
      /**
       * Returns a {@link RequestFactory} that is responsible to compose correct requests according to
       * the syntax of specific {@link ElasticSearchVersion}.
       */
      public RequestFactory requestFactory() {
          return requestFactory;
      }
  
      /**
       * Returns a {@link Codec} to encode the requests and decode the response.
       */
      public Codec codec() {
          return codec;
      }
  }
  