/*
    * 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.internal.impl.collect;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.Map;
  
  import org.eclipse.aether.ConfigurationProperties;
  import org.eclipse.aether.RepositorySystemSession;
  import org.eclipse.aether.collection.CollectRequest;
  import org.eclipse.aether.collection.CollectResult;
  import org.eclipse.aether.collection.DependencyCollectionException;
  import org.eclipse.aether.impl.DependencyCollector;
  import org.eclipse.aether.util.ConfigUtils;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Default implementation of {@link DependencyCollector} that merely indirect to selected delegate.
   */
  @Singleton
  @Named
  public class DefaultDependencyCollector implements DependencyCollector {
  
      public static final String CONFIG_PROPS_PREFIX = ConfigurationProperties.PREFIX_AETHER + "dependencyCollector.";
  
      /**
       * The name of the dependency collector implementation to use: depth-first (original) named "df", and
       * breadth-first (new in 1.8.0) named "bf". Both collectors produce equivalent results, but they may differ
       * performance wise, depending on project being applied to. Our experience shows that existing "df" is well
       * suited for smaller to medium size projects, while "bf" may perform better on huge projects with many
       * dependencies. Experiment (and come back to us!) to figure out which one suits you the better.
       *
       * @since 1.8.0
       * @configurationSource {@link RepositorySystemSession#getConfigProperties()}
       * @configurationType {@link java.lang.String}
       * @configurationDefaultValue {@link #DEFAULT_COLLECTOR_IMPL}
       */
      public static final String CONFIG_PROP_COLLECTOR_IMPL = CONFIG_PROPS_PREFIX + "impl";
  
      public static final String DEFAULT_COLLECTOR_IMPL =
              org.eclipse.aether.internal.impl.collect.bf.BfDependencyCollector.NAME;
  
      private final Map<String, DependencyCollectorDelegate> delegates;
  
      @Inject
      public DefaultDependencyCollector(Map<String, DependencyCollectorDelegate> delegates) {
          this.delegates = requireNonNull(delegates);
      }
  
      @Override
      public CollectResult collectDependencies(RepositorySystemSession session, CollectRequest request)
              throws DependencyCollectionException {
          String delegateName = ConfigUtils.getString(session, DEFAULT_COLLECTOR_IMPL, CONFIG_PROP_COLLECTOR_IMPL);
          DependencyCollectorDelegate delegate = delegates.get(delegateName);
          if (delegate == null) {
              throw new IllegalArgumentException(
                      "Unknown collector impl: '" + delegateName + "', known implementations are " + delegates.keySet());
          }
          return delegate.collectDependencies(session, request);
      }
  }