package org.eclipse.aether.util.graph.selector;
   
   /*
    * 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.Arrays;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Objects;
  import java.util.TreeSet;
  
  import org.eclipse.aether.collection.DependencyCollectionContext;
  import org.eclipse.aether.collection.DependencySelector;
  import org.eclipse.aether.graph.Dependency;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A dependency selector that filters transitive dependencies based on their scope. Direct dependencies are always
   * included regardless of their scope. <em>Note:</em> This filter does not assume any relationships between the scopes.
   * In particular, the filter is not aware of scopes that logically include other scopes.
   * 
   * @see Dependency#getScope()
   */
  public final class ScopeDependencySelector
      implements DependencySelector
  {
  
      private final boolean transitive;
  
      private final Collection<String> included;
  
      private final Collection<String> excluded;
  
      /**
       * Creates a new selector using the specified includes and excludes.
       * 
       * @param included The set of scopes to include, may be {@code null} or empty to include any scope.
       * @param excluded The set of scopes to exclude, may be {@code null} or empty to exclude no scope.
       */
      public ScopeDependencySelector( Collection<String> included, Collection<String> excluded )
      {
          transitive = false;
          this.included = clone( included );
          this.excluded = clone( excluded );
      }
  
      private static Collection<String> clone( Collection<String> scopes )
      {
          Collection<String> copy;
          if ( scopes == null || scopes.isEmpty() )
          {
              // checking for null is faster than isEmpty()
              copy = null;
          }
          else
          {
              copy = new HashSet<>( scopes );
              if ( copy.size() <= 2 )
              {
                  // contains() is faster for smallish array (sorted for equals()!)
                  copy = new ArrayList<>( new TreeSet<>( copy ) );
              }
          }
          return copy;
      }
  
      /**
       * Creates a new selector using the specified excludes.
       * 
       * @param excluded The set of scopes to exclude, may be {@code null} or empty to exclude no scope.
       */
      public ScopeDependencySelector( String... excluded )
      {
          this( null, ( excluded != null ) ? Arrays.asList( excluded ) : null );
      }
  
      private ScopeDependencySelector( boolean transitive, Collection<String> included, Collection<String> excluded )
      {
          this.transitive = transitive;
          this.included = included;
          this.excluded = excluded;
     }
 
     public boolean selectDependency( Dependency dependency )
     {
         requireNonNull( dependency, "dependency cannot be null" );
         if ( !transitive )
         {
             return true;
         }
 
         String scope = dependency.getScope();
         return ( included == null || included.contains( scope ) )
                 && ( excluded == null || !excluded.contains( scope ) );
     }
 
     public DependencySelector deriveChildSelector( DependencyCollectionContext context )
     {
         requireNonNull( context, "context cannot be null" );
         if ( this.transitive || context.getDependency() == null )
         {
             return this;
         }
 
         return new ScopeDependencySelector( true, included, excluded );
     }
 
     @Override
     public boolean equals( Object obj )
     {
         if ( this == obj )
         {
             return true;
         }
         else if ( null == obj || !getClass().equals( obj.getClass() ) )
         {
             return false;
         }
 
         ScopeDependencySelector that = (ScopeDependencySelector) obj;
         return transitive == that.transitive && Objects.equals( included, that.included )
                 && Objects.equals( excluded, that.excluded );
     }
 
     @Override
     public int hashCode()
     {
         int hash = 17;
         hash = hash * 31 + ( transitive ? 1 : 0 );
         hash = hash * 31 + ( included != null ? included.hashCode() : 0 );
         hash = hash * 31 + ( excluded != null ? excluded.hashCode() : 0 );
         return hash;
     }
 
     @Override
     public String toString()
     {
         return String.format(
             "%s(included: %s, excluded: %s, transitive: %s)", getClass().getSimpleName(), included, excluded, transitive
         );
     }
 
 }