/*
    * 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.eclipse.aether.internal.impl.transport.http;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.Collections;
  import java.util.Map;
  import java.util.function.Function;
  
  import org.eclipse.aether.internal.impl.checksum.Sha1ChecksumAlgorithmFactory;
  import org.eclipse.aether.spi.connector.transport.http.ChecksumExtractorStrategy;
  import org.eclipse.aether.spi.connector.transport.http.HttpConstants;
  
  /**
   * Sonatype Nexus2 checksum extractor.
   */
  @Singleton
  @Named(Nx2ChecksumExtractor.NAME)
  public final class Nx2ChecksumExtractor extends ChecksumExtractorStrategy {
      public static final String NAME = "nx2";
  
      @Override
      public Map<String, String> extractChecksums(Function<String, String> headerGetter) {
          // Nexus-style, ETag: "{SHA1{d40d68ba1f88d8e9b0040f175a6ff41928abd5e7}}"
          String etag = headerGetter.apply(HttpConstants.ETAG);
          if (etag != null) {
              int start = etag.indexOf("SHA1{"), end = etag.indexOf("}", start + 5);
              if (start >= 0 && end > start) {
                  return Collections.singletonMap(Sha1ChecksumAlgorithmFactory.NAME, etag.substring(start + 5, end));
              }
          }
          return null;
      }
  }