/*
    * 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.plugins.dependency;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import org.apache.maven.RepositoryUtils;
  import org.apache.maven.model.DependencyManagement;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugins.annotations.Component;
  import org.apache.maven.plugins.annotations.Mojo;
  import org.eclipse.aether.RepositorySystem;
  import org.eclipse.aether.artifact.ArtifactTypeRegistry;
  import org.eclipse.aether.collection.CollectRequest;
  import org.eclipse.aether.collection.CollectResult;
  import org.eclipse.aether.collection.DependencyCollectionException;
  import org.eclipse.aether.graph.DependencyNode;
  import org.eclipse.aether.graph.DependencyVisitor;
  import org.eclipse.aether.repository.RemoteRepository;
  import org.eclipse.aether.util.graph.visitor.TreeDependencyVisitor;
  
  /**
   * Goal that collect all project dependencies and then lists the repositories used by the build and by the transitive
   * dependencies
   *
   * @author <a href="mailto:brianf@apache.org">Brian Fox</a>
   * @since 2.2
   */
  @Mojo(name = "list-repositories", threadSafe = true)
  public class ListRepositoriesMojo extends AbstractDependencyMojo {
  
      @Component
      private RepositorySystem repositorySystem;
  
      /**
       * Displays a list of the repositories used by this build.
       *
       * @throws MojoExecutionException with a message if an error occurs.
       */
      @Override
      protected void doExecute() throws MojoExecutionException {
  
          CollectRequest request = new CollectRequest();
          request.setRepositories(getProject().getRemoteProjectRepositories());
          request.setRootArtifact(RepositoryUtils.toArtifact(getProject().getArtifact()));
  
          ArtifactTypeRegistry artifactTypeRegistry =
                  session.getRepositorySession().getArtifactTypeRegistry();
  
          request.setDependencies(getProject().getDependencies().stream()
                  .map(d -> RepositoryUtils.toDependency(d, artifactTypeRegistry))
                  .collect(Collectors.toList()));
  
          request.setManagedDependencies(Optional.ofNullable(getProject().getDependencyManagement())
                  .map(DependencyManagement::getDependencies)
                  .orElseGet(Collections::emptyList)
                  .stream()
                  .map(d -> RepositoryUtils.toDependency(d, artifactTypeRegistry))
                  .collect(Collectors.toList()));
  
          try {
              CollectResult collectResult = repositorySystem.collectDependencies(session.getRepositorySession(), request);
              Set<RemoteRepository> repositories = new HashSet<>();
              collectResult.getRoot().accept(new TreeDependencyVisitor(new DependencyVisitor() {
                  @Override
                  public boolean visitEnter(DependencyNode node) {
                      repositories.addAll(node.getRepositories());
                      return true;
                  }
  
                  @Override
                  public boolean visitLeave(DependencyNode node) {
                      return true;
                  }
              }));
 
             if (repositories.isEmpty()) {
                 getLog().info("No remote repository is used by this build." + System.lineSeparator());
                 return;
             }
 
             StringBuilder message = new StringBuilder();
 
             Map<Boolean, List<RemoteRepository>> repoGroupByMirrors = repositories.stream()
                     .collect(Collectors.groupingBy(
                             repo -> repo.getMirroredRepositories().isEmpty()));
 
             prepareRemoteRepositoriesList(
                     message, repoGroupByMirrors.getOrDefault(Boolean.TRUE, Collections.emptyList()));
             prepareRemoteMirrorRepositoriesList(
                     message, repoGroupByMirrors.getOrDefault(Boolean.FALSE, Collections.emptyList()));
 
             getLog().info(message);
 
         } catch (DependencyCollectionException e) {
             throw new MojoExecutionException(e.getMessage(), e);
         }
     }
 
     private void prepareRemoteMirrorRepositoriesList(
             StringBuilder message, Collection<RemoteRepository> remoteProjectRepositories) {
 
         Map<RemoteRepository, RemoteRepository> mirrorMap = new HashMap<>();
         remoteProjectRepositories.forEach(
                 repo -> repo.getMirroredRepositories().forEach(mrepo -> mirrorMap.put(mrepo, repo)));
 
         mirrorMap.forEach((repo, mirror) -> message.append(" * ")
                 .append(repo)
                 .append(" mirrored by ")
                 .append(mirror)
                 .append(System.lineSeparator()));
     }
 
     private void prepareRemoteRepositoriesList(
             StringBuilder message, Collection<RemoteRepository> remoteProjectRepositories) {
 
         message.append("Project remote repositories used by this build:").append(System.lineSeparator());
 
         remoteProjectRepositories.forEach(
                 repo -> message.append(" * ").append(repo).append(System.lineSeparator()));
     }
 
     private Map<RemoteRepository, RemoteRepository> getMirroredRepo(Set<RemoteRepository> repositories) {
         Map<RemoteRepository, RemoteRepository> mirrorMap = new HashMap<>();
 
         repositories.stream()
                 .filter(repo -> !repo.getMirroredRepositories().isEmpty())
                 .forEach(repo -> repo.getMirroredRepositories().forEach(mrepo -> mirrorMap.put(mrepo, repo)));
 
         return mirrorMap;
     }
 }