/*
    * 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 javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.api.Artifact;
  import org.apache.maven.api.ArtifactCoordinate;
  import org.apache.maven.api.annotations.Nonnull;
  import org.apache.maven.api.services.ArtifactManager;
  import org.apache.maven.api.services.ArtifactResolver;
  import org.apache.maven.api.services.ArtifactResolverException;
  import org.apache.maven.api.services.ArtifactResolverRequest;
  import org.apache.maven.api.services.ArtifactResolverResult;
  import org.eclipse.aether.RepositorySystem;
  import org.eclipse.aether.repository.RemoteRepository;
  import org.eclipse.aether.resolution.ArtifactRequest;
  import org.eclipse.aether.resolution.ArtifactResolutionException;
  import org.eclipse.aether.resolution.ArtifactResult;
  
  import static org.apache.maven.internal.impl.Utils.nonNull;
  
  @Named
  @Singleton
  public class DefaultArtifactResolver implements ArtifactResolver {
      private final RepositorySystem repositorySystem;
  
      @Inject
      DefaultArtifactResolver(@Nonnull RepositorySystem repositorySystem) {
          this.repositorySystem = nonNull(repositorySystem, "repositorySystem");
      }
  
      @Override
      public ArtifactResolverResult resolve(ArtifactResolverRequest request)
              throws ArtifactResolverException, IllegalArgumentException {
          nonNull(request, "request");
          InternalSession session = InternalSession.from(request.getSession());
          try {
              Map<Artifact, Path> paths = new HashMap<>();
              ArtifactManager artifactManager = session.getService(ArtifactManager.class);
              List<RemoteRepository> repositories = session.toRepositories(session.getRemoteRepositories());
              List<ArtifactRequest> requests = new ArrayList<>();
              for (ArtifactCoordinate coord : request.getCoordinates()) {
                  org.eclipse.aether.artifact.Artifact aetherArtifact = session.toArtifact(coord);
                  Artifact artifact = session.getArtifact(aetherArtifact);
                  Path path = artifactManager.getPath(artifact).orElse(null);
                  if (path != null) {
                      paths.put(artifact, path);
                  } else {
                      requests.add(new ArtifactRequest(aetherArtifact, repositories, null));
                  }
              }
              if (!requests.isEmpty()) {
                  List<ArtifactResult> results = repositorySystem.resolveArtifacts(session.getSession(), requests);
                  for (ArtifactResult result : results) {
                      Artifact artifact = session.getArtifact(result.getArtifact());
                      Path path = result.getArtifact().getFile().toPath();
                      artifactManager.setPath(artifact, path);
                      paths.put(artifact, path);
                  }
              }
              return () -> paths;
          } catch (ArtifactResolutionException e) {
              throw new ArtifactResolverException("Unable to resolve artifact", e);
          }
      }
  }