/*
    * 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.cli.internal;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Set;
  
  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.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.codehaus.plexus.logging.Logger;
  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;
  
  /**
   * 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;
  
      private final DefaultPluginDependenciesResolver pluginDependenciesResolver;
  
      private final DefaultRepositorySystemSessionFactory repositorySystemSessionFactory;
  
      private final CoreExports coreExports;
  
      private final ClassWorld classWorld;
  
      private final ClassRealm parentRealm;
  
      @Inject
      public BootstrapCoreExtensionManager(
              Logger log,
              DefaultPluginDependenciesResolver pluginDependenciesResolver,
              DefaultRepositorySystemSessionFactory repositorySystemSessionFactory,
              CoreExports coreExports,
              PlexusContainer container) {
          this.log = log;
          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 " + id + " located at " + 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 = new Plugin();
             plugin.setGroupId(interpolator.interpolate(extension.getGroupId()));
             plugin.setArtifactId(interpolator.interpolate(extension.getArtifactId()));
             plugin.setVersion(interpolator.interpolate(extension.getVersion()));
 
             DependencyNode root = pluginDependenciesResolver.resolveCoreExtension(
                     plugin, dependencyFilter, repositories, repoSession);
             PreorderNodeListGenerator nlg = new PreorderNodeListGenerator();
             root.accept(nlg);
             List<Artifact> artifacts = nlg.getArtifacts(false);
 
             return artifacts;
         } 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;
     }
 }