/*
    * 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.
   */
  package org.eclipse.aether.util.graph.selector;
  
  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);
     }
 }