/*
    * 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.transformer;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Set;
  
  import org.eclipse.aether.RepositoryException;
  import org.eclipse.aether.util.artifact.JavaScopes;
  import org.eclipse.aether.util.graph.transformer.ConflictResolver.ConflictContext;
  import org.eclipse.aether.util.graph.transformer.ConflictResolver.ConflictItem;
  import org.eclipse.aether.util.graph.transformer.ConflictResolver.ScopeSelector;
  
  /**
   * A scope selector for use with {@link ConflictResolver} that supports the scopes from {@link JavaScopes}. In general,
   * this selector picks the widest scope present among conflicting dependencies where e.g. "compile" is wider than
   * "runtime" which is wider than "test". If however a direct dependency is involved, its scope is selected.
   */
  public final class JavaScopeSelector extends ScopeSelector {
  
      /**
       * Creates a new instance of this scope selector.
       */
      public JavaScopeSelector() {}
  
      @Override
      public void selectScope(ConflictContext context) throws RepositoryException {
          String scope = context.getWinner().getDependency().getScope();
          if (!JavaScopes.SYSTEM.equals(scope)) {
              scope = chooseEffectiveScope(context.getItems());
          }
          context.setScope(scope);
      }
  
      private String chooseEffectiveScope(Collection<ConflictItem> items) {
          Set<String> scopes = new HashSet<>();
          for (ConflictItem item : items) {
              if (item.getDepth() <= 1) {
                  return item.getDependency().getScope();
              }
              scopes.addAll(item.getScopes());
          }
          return chooseEffectiveScope(scopes);
      }
  
      private String chooseEffectiveScope(Set<String> scopes) {
          if (scopes.size() > 1) {
              scopes.remove(JavaScopes.SYSTEM);
          }
  
          String effectiveScope = "";
  
          if (scopes.size() == 1) {
              effectiveScope = scopes.iterator().next();
          } else if (scopes.contains(JavaScopes.COMPILE)) {
              effectiveScope = JavaScopes.COMPILE;
          } else if (scopes.contains(JavaScopes.RUNTIME)) {
              effectiveScope = JavaScopes.RUNTIME;
          } else if (scopes.contains(JavaScopes.PROVIDED)) {
              effectiveScope = JavaScopes.PROVIDED;
          } else if (scopes.contains(JavaScopes.TEST)) {
              effectiveScope = JavaScopes.TEST;
          }
  
          return effectiveScope;
      }
  }