package org.apache.maven.model.management;
   
   /*
    * 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.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import org.apache.maven.api.model.Dependency;
  import org.apache.maven.api.model.DependencyManagement;
  import org.apache.maven.api.model.Exclusion;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.model.building.ModelBuildingRequest;
  import org.apache.maven.model.building.ModelProblemCollector;
  import org.apache.maven.model.merge.MavenModelMerger;
  
  /**
   * Handles injection of dependency management into the model.
   *
   * @author Benjamin Bentmann
   */
  @SuppressWarnings( { "checkstyle:methodname" } )
  @Named
  @Singleton
  public class DefaultDependencyManagementInjector
      implements DependencyManagementInjector
  {
  
      private ManagementModelMerger merger = new ManagementModelMerger();
  
      @Override
      public void injectManagement( org.apache.maven.model.Model model, ModelBuildingRequest request,
                                    ModelProblemCollector problems )
      {
          model.update( merger.mergeManagedDependencies( model.getDelegate() ) );
      }
  
      /**
       * ManagementModelMerger
       */
      protected static class ManagementModelMerger
          extends MavenModelMerger
      {
  
          public Model mergeManagedDependencies( Model model )
          {
              DependencyManagement dependencyManagement = model.getDependencyManagement();
              if ( dependencyManagement != null )
              {
                  Map<Object, Dependency> dependencies = new HashMap<>();
                  Map<Object, Object> context = Collections.emptyMap();
  
                  for ( Dependency dependency : model.getDependencies() )
                  {
                      Object key = getDependencyKey().apply( dependency );
                      dependencies.put( key, dependency );
                  }
  
                  boolean modified = false;
                  for ( Dependency managedDependency : dependencyManagement.getDependencies() )
                  {
                      Object key = getDependencyKey().apply( managedDependency );
                      Dependency dependency = dependencies.get( key );
                      if ( dependency != null )
                      {
                          Dependency merged = mergeDependency( dependency, managedDependency, false, context );
                          if ( merged != dependency )
                          {
                              dependencies.put( key, merged );
                              modified = true;
                          }
                      }
                  }
  
                  if ( modified )
                  {
                      List<Dependency> newDeps = new ArrayList<>( dependencies.size() );
                     for ( Dependency dep : model.getDependencies() )
                     {
                         Object key = getDependencyKey().apply( dep );
                         Dependency dependency = dependencies.get( key );
                         newDeps.add( dependency );
                     }
                     return Model.newBuilder( model ).dependencies( newDeps ).build();
                 }
             }
             return model;
         }
 
         @Override
         protected void mergeDependency_Optional( Dependency.Builder builder,
                                                  Dependency target, Dependency source, boolean sourceDominant,
                                                  Map<Object, Object> context )
         {
             // optional flag is not managed
         }
 
         @Override
         protected void mergeDependency_Exclusions( Dependency.Builder builder,
                                                    Dependency target, Dependency source, boolean sourceDominant,
                                                    Map<Object, Object> context )
         {
             List<Exclusion> tgt = target.getExclusions();
             if ( tgt.isEmpty() )
             {
                 List<Exclusion> src = source.getExclusions();
                 builder.exclusions( src );
             }
         }
 
     }
 
 }