package org.apache.maven.cli.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.io.File;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Set;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  
  import org.apache.maven.RepositoryUtils;
  import org.apache.maven.cli.internal.extension.model.CoreExtension;
  import org.apache.maven.execution.MavenExecutionRequest;
  import org.apache.maven.extension.internal.CoreExports;
  import org.apache.maven.extension.internal.CoreExtensionEntry;
  import org.apache.maven.internal.aether.DefaultRepositorySystemSessionFactory;
  import org.apache.maven.api.model.Plugin;
  import org.apache.maven.plugin.PluginResolutionException;
  import org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver;
  import org.codehaus.plexus.DefaultPlexusContainer;
  import org.codehaus.plexus.PlexusContainer;
  import org.codehaus.plexus.classworlds.ClassWorld;
  import org.codehaus.plexus.classworlds.realm.ClassRealm;
  import org.codehaus.plexus.interpolation.InterpolationException;
  import org.codehaus.plexus.interpolation.Interpolator;
  import org.codehaus.plexus.interpolation.MapBasedValueSource;
  import org.codehaus.plexus.interpolation.StringSearchInterpolator;
  import org.eclipse.aether.RepositorySystemSession;
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.graph.DependencyFilter;
  import org.eclipse.aether.graph.DependencyNode;
  import org.eclipse.aether.repository.RemoteRepository;
  import org.eclipse.aether.util.filter.ExclusionsDependencyFilter;
  import org.eclipse.aether.util.graph.visitor.PreorderNodeListGenerator;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * BootstrapCoreExtensionManager
   */
  @Named
  public class BootstrapCoreExtensionManager
  {
      public static final String STRATEGY_PARENT_FIRST = "parent-first";
      public static final String STRATEGY_PLUGIN = "plugin";
      public static final String STRATEGY_SELF_FIRST = "self-first";
  
      private final Logger log = LoggerFactory.getLogger( getClass() );
  
      private final DefaultPluginDependenciesResolver pluginDependenciesResolver;
  
      private final DefaultRepositorySystemSessionFactory repositorySystemSessionFactory;
  
      private final CoreExports coreExports;
  
      private final ClassWorld classWorld;
  
      private final ClassRealm parentRealm;
  
      @Inject
      public BootstrapCoreExtensionManager( DefaultPluginDependenciesResolver pluginDependenciesResolver,
                                            DefaultRepositorySystemSessionFactory repositorySystemSessionFactory,
                                            CoreExports coreExports,
                                            PlexusContainer container )
      {
          this.pluginDependenciesResolver = pluginDependenciesResolver;
          this.repositorySystemSessionFactory = repositorySystemSessionFactory;
          this.coreExports = coreExports;
          this.classWorld = ( (DefaultPlexusContainer) container ).getClassWorld();
          this.parentRealm = container.getContainerRealm();
      }
  
      public List<CoreExtensionEntry> loadCoreExtensions( MavenExecutionRequest request, Set<String> providedArtifacts,
                                                          List<CoreExtension> extensions )
          throws Exception
      {
          RepositorySystemSession repoSession = repositorySystemSessionFactory.newRepositorySession( request );
          List<RemoteRepository> repositories = RepositoryUtils.toRepos( request.getPluginArtifactRepositories() );
          Interpolator interpolator = createInterpolator( request );
 
         return resolveCoreExtensions( repoSession, repositories, providedArtifacts, extensions, interpolator );
     }
 
     private List<CoreExtensionEntry> resolveCoreExtensions( RepositorySystemSession repoSession,
                                                             List<RemoteRepository> repositories,
                                                             Set<String> providedArtifacts,
                                                             List<CoreExtension> configuration,
                                                             Interpolator interpolator )
         throws Exception
     {
         List<CoreExtensionEntry> extensions = new ArrayList<>();
 
         DependencyFilter dependencyFilter = new ExclusionsDependencyFilter( providedArtifacts );
 
         for ( CoreExtension extension : configuration )
         {
             List<Artifact> artifacts = resolveExtension( extension, repoSession, repositories,
                                                          dependencyFilter, interpolator );
             if ( !artifacts.isEmpty() )
             {
                 extensions.add( createExtension( extension, artifacts ) );
             }
         }
 
         return Collections.unmodifiableList( extensions );
     }
 
     private CoreExtensionEntry createExtension( CoreExtension extension, List<Artifact> artifacts )
         throws Exception
     {
         String realmId =
             "coreExtension>" + extension.getGroupId() + ":" + extension.getArtifactId() + ":" + extension.getVersion();
         final ClassRealm realm = classWorld.newRealm( realmId, null );
         Set<String> providedArtifacts = Collections.emptySet();
         String classLoadingStrategy = extension.getClassLoadingStrategy();
         if ( STRATEGY_PARENT_FIRST.equals( classLoadingStrategy ) )
         {
             realm.importFrom( parentRealm, "" );
         }
         else if ( STRATEGY_PLUGIN.equals( classLoadingStrategy ) )
         {
             coreExports.getExportedPackages().forEach( ( p, cl ) -> realm.importFrom( cl, p ) );
             providedArtifacts = coreExports.getExportedArtifacts();
         }
         else if ( STRATEGY_SELF_FIRST.equals( classLoadingStrategy ) )
         {
             realm.setParentRealm( parentRealm );
         }
         else
         {
             throw new IllegalArgumentException( "Unsupported class-loading strategy '"
                     + classLoadingStrategy + "'. Supported values are: " + STRATEGY_PARENT_FIRST
                     + ", " + STRATEGY_PLUGIN + " and " + STRATEGY_SELF_FIRST );
         }
         log.debug( "Populating class realm {}", realm.getId() );
         for ( Artifact artifact : artifacts )
         {
             String id = artifact.getGroupId() + ":" + artifact.getArtifactId();
             if ( providedArtifacts.contains( id ) )
             {
                 log.debug( "  Excluded {}", id );
             }
             else
             {
                 File file = artifact.getFile();
                 log.debug( "  Included {} located at {}", id, file );
                 realm.addURL( file.toURI().toURL() );
             }
         }
         return CoreExtensionEntry.discoverFrom( realm, Collections.singleton( artifacts.get( 0 ).getFile() ) );
     }
 
     private List<Artifact> resolveExtension( CoreExtension extension, RepositorySystemSession repoSession,
                                              List<RemoteRepository> repositories, DependencyFilter dependencyFilter,
                                              Interpolator interpolator )
         throws ExtensionResolutionException
     {
         try
         {
             /* TODO: Enhance the PluginDependenciesResolver to provide a
              * resolveCoreExtension method which uses a CoreExtension
              * object instead of a Plugin as this makes no sense.
              */
             Plugin plugin = Plugin.newBuilder()
                     .groupId( interpolator.interpolate( extension.getGroupId() ) )
                     .artifactId( interpolator.interpolate( extension.getArtifactId() ) )
                     .version( interpolator.interpolate( extension.getVersion() ) )
                     .build();
 
             DependencyNode root = pluginDependenciesResolver
                     .resolveCoreExtension( new org.apache.maven.model.Plugin( plugin ),
                             dependencyFilter, repositories, repoSession );
             PreorderNodeListGenerator nlg = new PreorderNodeListGenerator();
             root.accept( nlg );
 
             return nlg.getArtifacts( false );
         }
         catch ( PluginResolutionException e )
         {
             throw new ExtensionResolutionException( extension, e.getCause() );
         }
         catch ( InterpolationException e )
         {
             throw new ExtensionResolutionException( extension, e );
         }
     }
 
     private static Interpolator createInterpolator( MavenExecutionRequest request )
     {
         StringSearchInterpolator interpolator = new StringSearchInterpolator();
         interpolator.addValueSource( new MapBasedValueSource( request.getUserProperties() ) );
         interpolator.addValueSource( new MapBasedValueSource( request.getSystemProperties() ) );
         return interpolator;
     }
 
 }