package org.apache.maven.report.projectinfo.dependencies;
   
   /*
    * 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.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.shared.dependency.tree.DependencyNode;
  import org.apache.maven.shared.dependency.tree.traversal.DependencyNodeVisitor;
  
  /**
   * @author Simon Wang
   * @since 2.8
   */
  public class DependencyVersionMap
      implements DependencyNodeVisitor
  {
      private boolean uniqueVersions;
  
      private Map<String, List<DependencyNode>> idsToNode;
  
      // ----------------------------------------------------------------------
      // Public methods
      // ----------------------------------------------------------------------
  
      /**
       * Create an instance.
       */
      public DependencyVersionMap()
      {
          idsToNode = new HashMap<>();
      }
  
      /**
       * @param uniqueVersions {@link #uniqueVersions}
       */
      public void setUniqueVersions( boolean uniqueVersions )
      {
          this.uniqueVersions = uniqueVersions;
      }
  
      /**
       * {@inheritDoc}
       */
      public boolean visit( DependencyNode node )
      {
          addDependency( node );
          return !containsConflicts( node );
      }
  
      /**
       * {@inheritDoc}
       */
      public boolean endVisit( DependencyNode node )
      {
          return true;
      }
  
      /**
       * Get conflicting nodes groups
       *
       * @return conflicting nodes groups
       */
      public List<List<DependencyNode>> getConflictedVersionNumbers()
      {
          List<List<DependencyNode>> output = new ArrayList<>();
          for ( List<DependencyNode> nodes : idsToNode.values() )
          {
              if ( containsConflicts( nodes ) )
              {
                  output.add( nodes );
              }
          }
          return output;
      }
  
      // ----------------------------------------------------------------------
      // Private methods
      // ----------------------------------------------------------------------
 
     private void addDependency( DependencyNode node )
     {
         String key = constructKey( node );
         List<DependencyNode> nodes = idsToNode.get( key );
         if ( nodes == null )
         {
             nodes = new ArrayList<>();
             idsToNode.put( key, nodes );
         }
         nodes.add( node );
     }
 
     private String constructKey( DependencyNode node )
     {
         return constructKey( node.getArtifact() );
     }
 
     private String constructKey( Artifact artifact )
     {
         return artifact.getGroupId() + ":" + artifact.getArtifactId();
     }
 
     private String getVersion( Artifact artifact )
     {
         return uniqueVersions ? artifact.getVersion() : artifact.getBaseVersion();
     }
 
     private boolean containsConflicts( DependencyNode node )
     {
         return containsConflicts( node.getArtifact() );
     }
 
     private boolean containsConflicts( Artifact artifact )
     {
         return containsConflicts( idsToNode.get( constructKey( artifact ) ) );
     }
 
     /**
      * Check whether given dependency nodes contains conflicts
      *
      * @param nodes
      * @return contains:true; not contains:false;
      */
     private boolean containsConflicts( List<DependencyNode> nodes )
     {
         String version = null;
         for ( DependencyNode node : nodes )
         {
             if ( version == null )
             {
                 version = getVersion( node.getArtifact() );
             }
             else
             {
                 if ( version.compareTo( getVersion( node.getArtifact() ) ) != 0 )
                 {
                     return true;
                 }
             }
         }
         return false;
     }
 
 }