package org.apache.maven.internal.impl;
   
   /*
    * 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.
   */
  
  import org.apache.maven.api.annotations.Nonnull;
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.List;
  
  import org.apache.maven.api.Node;
  import org.apache.maven.api.services.DependencyCollector;
  import org.apache.maven.api.services.DependencyCollectorException;
  import org.apache.maven.api.services.DependencyCollectorRequest;
  import org.apache.maven.api.services.DependencyCollectorResult;
  import org.eclipse.aether.DefaultRepositorySystemSession;
  import org.eclipse.aether.RepositorySystem;
  import org.eclipse.aether.RepositorySystemSession;
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.collection.CollectRequest;
  import org.eclipse.aether.collection.CollectResult;
  import org.eclipse.aether.collection.DependencyCollectionException;
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.util.graph.manager.DependencyManagerUtils;
  import org.eclipse.aether.util.graph.transformer.ConflictResolver;
  
  import static org.apache.maven.internal.impl.Utils.cast;
  import static org.apache.maven.internal.impl.Utils.nonNull;
  
  @Named
  @Singleton
  public class DefaultDependencyCollector implements DependencyCollector
  {
  
      private final RepositorySystem repositorySystem;
  
      @Inject
      DefaultDependencyCollector( @Nonnull RepositorySystem repositorySystem )
      {
          this.repositorySystem = repositorySystem;
      }
  
      @Nonnull
      @Override
      public DependencyCollectorResult collect( @Nonnull DependencyCollectorRequest request )
              throws DependencyCollectorException, IllegalArgumentException
      {
          nonNull( request, "request can not be null" );
          DefaultSession session = cast( DefaultSession.class, request.getSession(),
                  "request.session should be a " + DefaultSession.class );
  
          Artifact rootArtifact = request.getRootArtifact().map( session::toArtifact ).orElse( null );
          Dependency root = request.getRoot().map( session::toDependency ).orElse( null );
          CollectRequest collectRequest = new CollectRequest()
                  .setRootArtifact( rootArtifact )
                  .setRoot( root )
                  .setDependencies( session.toDependencies( request.getDependencies() ) )
                  .setManagedDependencies( session.toDependencies( request.getManagedDependencies() ) )
                  .setRepositories( session.toRepositories( session.getRemoteRepositories() ) );
  
          RepositorySystemSession systemSession = session.getSession();
          if ( request.getVerbose() )
          {
              systemSession = new DefaultRepositorySystemSession( systemSession )
                      .setConfigProperty( ConflictResolver.CONFIG_PROP_VERBOSE, true )
                      .setConfigProperty( DependencyManagerUtils.CONFIG_PROP_VERBOSE, true );
          }
  
          try
          {
              final CollectResult
                      result = repositorySystem.collectDependencies( systemSession, collectRequest );
              return new DependencyCollectorResult()
              {
                  @Override
                  public List<Exception> getExceptions()
                  {
                      return result.getExceptions();
                  }
  
                  @Override
                 public Node getRoot()
                 {
                     return session.getNode( result.getRoot(), request.getVerbose() );
                 }
             };
         }
         catch ( DependencyCollectionException e )
         {
             throw new DependencyCollectorException( "Unable to collect dependencies", e );
         }
     }
 
 }