package org.apache.maven.plugins.dependency.analyze;
   
   /*
    * 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.IOException;
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.commons.collections4.CollectionUtils;
  import org.apache.maven.model.Dependency;
  import org.apache.maven.model.Model;
  import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.MojoFailureException;
  import org.apache.maven.plugins.annotations.Mojo;
  import org.apache.maven.plugins.annotations.Parameter;
  import org.apache.maven.project.MavenProject;
  import org.codehaus.plexus.util.ReaderFactory;
  import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
  
  /**
   * Analyzes the <code>&lt;dependencies/&gt;</code> and <code>&lt;dependencyManagement/&gt;</code> tags in the
   * <code>pom.xml</code> and determines the duplicate declared dependencies.
   *
   * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
   */
  @Mojo( name = "analyze-duplicate", aggregator = false, threadSafe = true )
  public class AnalyzeDuplicateMojo
      extends AbstractMojo
  {
      public static final String MESSAGE_DUPLICATE_DEP_IN_DEPENDENCIES =
          "List of duplicate dependencies defined in <dependencies/> in your pom.xml:\n";
  
      public static final String MESSAGE_DUPLICATE_DEP_IN_DEPMGMT =
          "List of duplicate dependencies defined in <dependencyManagement/> in your pom.xml:\n";
  
      /**
       * Skip plugin execution completely.
       *
       * @since 2.7
       */
      @Parameter( property = "mdep.analyze.skip", defaultValue = "false" )
      private boolean skip;
  
      /**
       * The Maven project to analyze.
       */
      @Parameter( defaultValue = "${project}", readonly = true, required = true )
      private MavenProject project;
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void execute()
          throws MojoExecutionException, MojoFailureException
      {
          if ( skip )
          {
              getLog().info( "Skipping plugin execution" );
              return;
          }
  
          MavenXpp3Reader pomReader = new MavenXpp3Reader();
          Model model = null;
          try ( Reader reader = ReaderFactory.newXmlReader( project.getFile() ) )
          {
              model = pomReader.read( reader );
          }
          catch ( IOException | XmlPullParserException e )
          {
              throw new MojoExecutionException( "Exception: " + e.getMessage(), e );
          }
  
          Set<String> duplicateDependencies = Collections.emptySet();
          if ( model.getDependencies() != null )
         {
             duplicateDependencies = findDuplicateDependencies( model.getDependencies() );
         }
 
         Set<String> duplicateDependenciesManagement = Collections.emptySet();
         if ( model.getDependencyManagement() != null && model.getDependencyManagement().getDependencies() != null )
         {
             duplicateDependenciesManagement =
                 findDuplicateDependencies( model.getDependencyManagement().getDependencies() );
         }
 
         if ( getLog().isInfoEnabled() )
         {
             StringBuilder sb = new StringBuilder();
 
             createMessage( duplicateDependencies, sb, MESSAGE_DUPLICATE_DEP_IN_DEPENDENCIES );
             createMessage( duplicateDependenciesManagement, sb, MESSAGE_DUPLICATE_DEP_IN_DEPMGMT );
 
             if ( sb.length() > 0 )
             {
                 getLog().info( sb.toString() );
             }
             else
             {
                 getLog().info( "No duplicate dependencies found in <dependencies/> or in <dependencyManagement/>" );
             }
         }
     }
 
     private void createMessage( Set<String> duplicateDependencies, StringBuilder sb,
                                 String messageDuplicateDepInDependencies )
     {
         if ( !duplicateDependencies.isEmpty() )
         {
             if ( sb.length() > 0 )
             {
                 sb.append( "\n" );
             }
             sb.append( messageDuplicateDepInDependencies );
             for ( Iterator<String> it = duplicateDependencies.iterator(); it.hasNext(); )
             {
                 String dup = it.next();
 
                 sb.append( "\to " ).append( dup );
                 if ( it.hasNext() )
                 {
                     sb.append( "\n" );
                 }
             }
         }
     }
 
     private Set<String> findDuplicateDependencies( List<Dependency> modelDependencies )
     {
         List<String> modelDependencies2 = new ArrayList<>();
         for ( Dependency dep : modelDependencies )
         {
             modelDependencies2.add( dep.getManagementKey() );
         }
 
         // @formatter:off
         return new LinkedHashSet<String>( 
                 CollectionUtils.disjunction( modelDependencies2, new LinkedHashSet<>( modelDependencies2 ) ) );
         // @formatter:on
     }
 }