/*
    * 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.apache.maven.model.management;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.api.model.Dependency;
  import org.apache.maven.api.model.DependencyManagement;
  import org.apache.maven.api.model.Exclusion;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.model.building.ModelBuildingRequest;
  import org.apache.maven.model.building.ModelProblemCollector;
  import org.apache.maven.model.merge.MavenModelMerger;
  
  /**
   * Handles injection of dependency management into the model.
   *
   * @author Benjamin Bentmann
   */
  @SuppressWarnings({"checkstyle:methodname"})
  @Named
  @Singleton
  public class DefaultDependencyManagementInjector implements DependencyManagementInjector {
  
      private ManagementModelMerger merger = new ManagementModelMerger();
  
      @Override
      public void injectManagement(
              org.apache.maven.model.Model model, ModelBuildingRequest request, ModelProblemCollector problems) {
          model.update(merger.mergeManagedDependencies(model.getDelegate()));
      }
  
      /**
       * ManagementModelMerger
       */
      protected static class ManagementModelMerger extends MavenModelMerger {
  
          public Model mergeManagedDependencies(Model model) {
              DependencyManagement dependencyManagement = model.getDependencyManagement();
              if (dependencyManagement != null) {
                  Map<Object, Dependency> dependencies = new HashMap<>();
                  Map<Object, Object> context = Collections.emptyMap();
  
                  for (Dependency dependency : model.getDependencies()) {
                      Object key = getDependencyKey().apply(dependency);
                      dependencies.put(key, dependency);
                  }
  
                  boolean modified = false;
                  for (Dependency managedDependency : dependencyManagement.getDependencies()) {
                      Object key = getDependencyKey().apply(managedDependency);
                      Dependency dependency = dependencies.get(key);
                      if (dependency != null) {
                          Dependency merged = mergeDependency(dependency, managedDependency, false, context);
                          if (merged != dependency) {
                              dependencies.put(key, merged);
                              modified = true;
                          }
                      }
                  }
  
                  if (modified) {
                      List<Dependency> newDeps = new ArrayList<>(dependencies.size());
                      for (Dependency dep : model.getDependencies()) {
                          Object key = getDependencyKey().apply(dep);
                          Dependency dependency = dependencies.get(key);
                          newDeps.add(dependency);
                      }
                      return Model.newBuilder(model).dependencies(newDeps).build();
                  }
              }
              return model;
          }
  
          @Override
          protected void mergeDependency_Optional(
                 Dependency.Builder builder,
                 Dependency target,
                 Dependency source,
                 boolean sourceDominant,
                 Map<Object, Object> context) {
             // optional flag is not managed
         }
 
         @Override
         protected void mergeDependency_Exclusions(
                 Dependency.Builder builder,
                 Dependency target,
                 Dependency source,
                 boolean sourceDominant,
                 Map<Object, Object> context) {
             List<Exclusion> tgt = target.getExclusions();
             if (tgt.isEmpty()) {
                 List<Exclusion> src = source.getExclusions();
                 builder.exclusions(src);
             }
         }
     }
 }