package org.apache.maven.shared.dependency.graph.internal;
   
   /*
    * 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 java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.maven.RepositoryUtils;
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
  import org.apache.maven.project.DefaultDependencyResolutionRequest;
  import org.apache.maven.project.DependencyResolutionException;
  import org.apache.maven.project.DependencyResolutionRequest;
  import org.apache.maven.project.DependencyResolutionResult;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.project.ProjectBuildingRequest;
  import org.apache.maven.project.ProjectDependenciesResolver;
  import org.apache.maven.shared.dependency.graph.DependencyGraphBuilder;
  import org.apache.maven.shared.dependency.graph.DependencyGraphBuilderException;
  import org.apache.maven.shared.dependency.graph.DependencyNode;
  import org.codehaus.plexus.component.annotations.Component;
  import org.codehaus.plexus.component.annotations.Requirement;
  import org.codehaus.plexus.logging.AbstractLogEnabled;
  import org.sonatype.aether.graph.DependencyFilter;
  import org.sonatype.aether.graph.Dependency;
  import org.sonatype.aether.version.VersionConstraint;
  
  /**
   * Wrapper around Maven 3 dependency resolver.
   *
   * @see ProjectDependenciesResolver
   * @author Hervé Boutemy
   * @since 2.0
   */
  @Component( role = DependencyGraphBuilder.class, hint = "maven3" )
  public class Maven3DependencyGraphBuilder
      extends AbstractLogEnabled
      implements DependencyGraphBuilder
  {
      @Requirement
      private ProjectDependenciesResolver resolver;
  
      /**
       * Builds the dependency graph for Maven 3.
       *
       * @param buildingRequest the buildingRequest
       * @param filter artifact filter (can be <code>null</code>)
       * @return DependencyNode containing the dependency graph.
       * @throws DependencyGraphBuilderException if some of the dependencies could not be resolved.
       */
      @Override
      public DependencyNode buildDependencyGraph( ProjectBuildingRequest buildingRequest, ArtifactFilter filter )
          throws DependencyGraphBuilderException
      {
          MavenProject project = buildingRequest.getProject();
  
          DependencyResolutionRequest request =
              new DefaultDependencyResolutionRequest( project, buildingRequest.getRepositorySession() );
  
          // only download the poms, not the artifacts
          DependencyFilter collectFilter = ( node, parents ) -> false;
          request.setResolutionFilter( collectFilter );
  
          DependencyResolutionResult result = resolveDependencies( request );
  
          return buildDependencyNode( null, result.getDependencyGraph(), project.getArtifact(), filter );
      }
  
      private DependencyResolutionResult resolveDependencies( DependencyResolutionRequest request )
          throws DependencyGraphBuilderException
      {
          try
          {
              return resolver.resolve( request );
          }
          catch ( DependencyResolutionException e )
          {
              throw new DependencyGraphBuilderException( "Could not resolve following dependencies: "
                  + e.getResult().getUnresolvedDependencies(), e );
          }
      }
 
     private Artifact getDependencyArtifact( Dependency dep )
     {
         Artifact mavenArtifact = RepositoryUtils.toArtifact( dep.getArtifact() );
 
         mavenArtifact.setScope( dep.getScope() );
         mavenArtifact.setOptional( dep.isOptional() );
 
         return mavenArtifact;
     }
 
     private DependencyNode buildDependencyNode( DependencyNode parent, org.sonatype.aether.graph.DependencyNode node,
                                                 Artifact artifact, ArtifactFilter filter )
     {
         DefaultDependencyNode current =
             new DefaultDependencyNode( parent, artifact,
                                        null /* node.getPremanagedVersion() */,
                                        null /* node.getPremanagedScope() */,
                                        getVersionSelectedFromRange( node.getVersionConstraint() ) );
 
         List<DependencyNode> nodes = new ArrayList<>( node.getChildren().size() );
         for ( org.sonatype.aether.graph.DependencyNode child : node.getChildren() )
         {
             Artifact childArtifact = getDependencyArtifact( child.getDependency() );
 
             if ( ( filter == null ) || filter.include( childArtifact ) )
             {
                 nodes.add( buildDependencyNode( current, child, childArtifact, filter ) );
             }
         }
 
         current.setChildren( Collections.unmodifiableList( nodes ) );
 
         return current;
     }
 
     private String getVersionSelectedFromRange( VersionConstraint constraint )
     {
         if ( ( constraint == null ) || ( constraint.getVersion() != null ) )
         {
             return null;
         }
 
         StringBuilder sb = new StringBuilder();
         for ( org.sonatype.aether.version.VersionRange range : constraint.getRanges() )
         {
             if ( sb.length() > 0 )
             {
                 sb.append( ',' );
             }
             sb.append( range );
         }
 
         return sb.toString();
     }
 }