/*
    * 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.maven.internal.impl;
  
  import java.io.BufferedInputStream;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.UncheckedIOException;
  import java.nio.ByteBuffer;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.stream.Collectors;
  
  import org.apache.maven.api.di.Inject;
  import org.apache.maven.api.di.Named;
  import org.apache.maven.api.di.Singleton;
  import org.apache.maven.api.services.ChecksumAlgorithmService;
  import org.apache.maven.api.services.ChecksumAlgorithmServiceException;
  import org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithmFactory;
  import org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithmFactorySelector;
  
  import static org.apache.maven.internal.impl.Utils.nonNull;
  
  @Named
  @Singleton
  public class DefaultChecksumAlgorithmService implements ChecksumAlgorithmService {
      private final ChecksumAlgorithmFactorySelector checksumAlgorithmFactorySelector;
  
      @Inject
      public DefaultChecksumAlgorithmService(ChecksumAlgorithmFactorySelector checksumAlgorithmFactorySelector) {
          this.checksumAlgorithmFactorySelector =
                  nonNull(checksumAlgorithmFactorySelector, "checksumAlgorithmFactorySelector");
      }
  
      @Override
      public Collection<String> getChecksumAlgorithmNames() {
          return checksumAlgorithmFactorySelector.getChecksumAlgorithmFactories().stream()
                  .map(ChecksumAlgorithmFactory::getName)
                  .collect(Collectors.toList());
      }
  
      @Override
      public ChecksumAlgorithm select(String algorithmName) {
          nonNull(algorithmName, "algorithmName");
          try {
              return new DefaultChecksumAlgorithm(checksumAlgorithmFactorySelector.select(algorithmName));
          } catch (IllegalArgumentException e) {
              throw new ChecksumAlgorithmServiceException("unsupported algorithm", e);
          }
      }
  
      @Override
      public Collection<ChecksumAlgorithm> select(Collection<String> algorithmNames) {
          nonNull(algorithmNames, "algorithmNames");
          try {
              return checksumAlgorithmFactorySelector.selectList(new ArrayList<>(algorithmNames)).stream()
                      .map(DefaultChecksumAlgorithm::new)
                      .collect(Collectors.toList());
          } catch (IllegalArgumentException e) {
              throw new ChecksumAlgorithmServiceException("unsupported algorithm", e);
          }
      }
  
      @Override
      public Map<ChecksumAlgorithm, String> calculate(byte[] data, Collection<ChecksumAlgorithm> algorithms) {
          nonNull(data, "data");
          nonNull(algorithms, "algorithms");
          try {
              return calculate(new ByteArrayInputStream(data), algorithms);
          } catch (IOException e) {
              throw new UncheckedIOException(e); // really unexpected
          }
      }
  
      @Override
      public Map<ChecksumAlgorithm, String> calculate(ByteBuffer data, Collection<ChecksumAlgorithm> algorithms) {
          nonNull(data, "data");
         nonNull(algorithms, "algorithms");
         LinkedHashMap<ChecksumAlgorithm, ChecksumCalculator> algMap = new LinkedHashMap<>();
         algorithms.forEach(f -> algMap.put(f, f.getCalculator()));
         data.mark();
         for (ChecksumCalculator checksumCalculator : algMap.values()) {
             checksumCalculator.update(data);
             data.reset();
         }
         LinkedHashMap<ChecksumAlgorithm, String> result = new LinkedHashMap<>();
         algMap.forEach((k, v) -> result.put(k, v.checksum()));
         return result;
     }
 
     @Override
     public Map<ChecksumAlgorithm, String> calculate(Path file, Collection<ChecksumAlgorithm> algorithms)
             throws IOException {
         nonNull(file, "file");
         nonNull(algorithms, "algorithms");
         try (InputStream inputStream = new BufferedInputStream(Files.newInputStream(file))) {
             return calculate(inputStream, algorithms);
         }
     }
 
     @Override
     public Map<ChecksumAlgorithm, String> calculate(InputStream stream, Collection<ChecksumAlgorithm> algorithms)
             throws IOException {
         nonNull(stream, "stream");
         nonNull(algorithms, "algorithms");
         LinkedHashMap<ChecksumAlgorithm, ChecksumCalculator> algMap = new LinkedHashMap<>();
         algorithms.forEach(f -> algMap.put(f, f.getCalculator()));
         final byte[] buffer = new byte[1024 * 32];
         for (; ; ) {
             int read = stream.read(buffer);
             if (read < 0) {
                 break;
             }
             for (ChecksumCalculator checksumCalculator : algMap.values()) {
                 checksumCalculator.update(ByteBuffer.wrap(buffer, 0, read));
             }
         }
         LinkedHashMap<ChecksumAlgorithm, String> result = new LinkedHashMap<>();
         algMap.forEach((k, v) -> result.put(k, v.checksum()));
         return result;
     }
 
     private static class DefaultChecksumAlgorithm implements ChecksumAlgorithm {
         private final ChecksumAlgorithmFactory factory;
 
         DefaultChecksumAlgorithm(ChecksumAlgorithmFactory factory) {
             this.factory = factory;
         }
 
         @Override
         public String getName() {
             return factory.getName();
         }
 
         @Override
         public String getFileExtension() {
             return factory.getFileExtension();
         }
 
         @Override
         public ChecksumCalculator getCalculator() {
             return new DefaultChecksumCalculator(factory.getAlgorithm());
         }
 
         @Override
         public boolean equals(Object o) {
             if (this == o) {
                 return true;
             }
             if (o == null || getClass() != o.getClass()) {
                 return false;
             }
             DefaultChecksumAlgorithm that = (DefaultChecksumAlgorithm) o;
             return Objects.equals(factory.getName(), that.factory.getName());
         }
 
         @Override
         public int hashCode() {
             return Objects.hash(factory.getName());
         }
     }
 
     private static class DefaultChecksumCalculator implements ChecksumCalculator {
         private final org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithm algorithm;
 
         DefaultChecksumCalculator(org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithm algorithm) {
             this.algorithm = algorithm;
         }
 
         @Override
         public void update(ByteBuffer input) {
             algorithm.update(input);
         }
 
         @Override
         public String checksum() {
             return algorithm.checksum();
         }
     }
 }