package org.apache.maven.model.normalization;
   
   /*
    * 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.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.function.Function;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import org.apache.maven.api.model.Build;
  import org.apache.maven.api.model.Dependency;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.api.model.Plugin;
  import org.apache.maven.model.building.ModelBuildingRequest;
  import org.apache.maven.model.building.ModelProblemCollector;
  import org.apache.maven.model.merge.MavenModelMerger;
  import org.codehaus.plexus.util.StringUtils;
  
  /**
   * Handles normalization of a model.
   *
   * @author Benjamin Bentmann
   */
  @Named
  @Singleton
  public class DefaultModelNormalizer
      implements ModelNormalizer
  {
  
      private DuplicateMerger merger = new DuplicateMerger();
  
      @Override
      public Model mergeDuplicates( Model model, ModelBuildingRequest request, ModelProblemCollector problems )
      {
          Model.Builder builder = Model.newBuilder( model );
  
          Build build = model.getBuild();
          if ( build != null )
          {
              List<Plugin> plugins = build.getPlugins();
              Map<Object, Plugin> normalized = new LinkedHashMap<>( plugins.size() * 2 );
  
              for ( Plugin plugin : plugins )
              {
                  Object key = plugin.getKey();
                  Plugin first = normalized.get( key );
                  if ( first != null )
                  {
                      plugin = merger.mergePlugin( plugin, first );
                  }
                  normalized.put( key, plugin );
              }
  
              if ( plugins.size() != normalized.size() )
              {
                  builder.build( Build.newBuilder( build )
                              .plugins( normalized.values() )
                              .build() );
              }
          }
  
          /*
           * NOTE: This is primarily to keep backward-compat with Maven 2.x which did not validate that dependencies are
           * unique within a single POM. Upon multiple declarations, 2.x just kept the last one but retained the order of
           * the first occurrence. So when we're in lenient/compat mode, we have to deal with such broken POMs and mimic
           * the way 2.x works. When we're in strict mode, the removal of duplicates just saves other merging steps from
           * aftereffects and bogus error messages.
           */
          List<Dependency> dependencies = model.getDependencies();
          Map<String, Dependency> normalized = new LinkedHashMap<>( dependencies.size() * 2 );
  
          for ( Dependency dependency : dependencies )
          {
              normalized.put( dependency.getManagementKey(), dependency );
          }
  
          if ( dependencies.size() != normalized.size() )
         {
             builder.dependencies( normalized.values() );
         }
 
         return builder.build();
     }
 
     /**
      * DuplicateMerger
      */
     protected static class DuplicateMerger
         extends MavenModelMerger
     {
 
         public Plugin mergePlugin( Plugin target, Plugin source )
         {
             return super.mergePlugin( target, source, false, Collections.emptyMap() );
         }
 
     }
 
     @Override
     public Model injectDefaultValues( Model model, ModelBuildingRequest request, ModelProblemCollector problems )
     {
         Model.Builder builder = Model.newBuilder( model );
 
         builder.dependencies( injectList( model.getDependencies(), this::injectDependency ) );
         Build build = model.getBuild();
         if ( build != null )
         {
             Build newBuild = Build.newBuilder( build )
                     .plugins( injectList( build.getPlugins(), this::injectPlugin ) )
                     .build();
             builder.build( newBuild != build ? newBuild : null );
         }
 
         return builder.build();
     }
 
     private Plugin injectPlugin( Plugin p )
     {
         return Plugin.newBuilder( p )
                 .dependencies( injectList( p.getDependencies(), this::injectDependency ) )
                 .build();
     }
 
     private Dependency injectDependency( Dependency d )
     {
         // we cannot set this directly in the MDO due to the interactions with dependency management
         return StringUtils.isEmpty( d.getScope() ) ? Dependency.newBuilder( d ).scope( "compile" ).build() : d;
     }
 
     /**
      * Returns a list suited for the builders, i.e. null if not modified
      */
     private <T> List<T> injectList( List<T> list, Function<T, T> modifer )
     {
         List<T> newList = null;
         for ( int i = 0; i < list.size(); i++ )
         {
             T oldT = list.get( i );
             T newT = modifer.apply( oldT );
             if ( newT != oldT )
             {
                 if ( newList == null )
                 {
                     newList = new ArrayList<>( list );
                 }
                 newList.set( i, newT );
             }
        }
         return newList;
     }
 
 }