/*
    * 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.normalization;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.function.Function;
  import javax.inject.Named;
  import javax.inject.Singleton;
  import org.apache.maven.api.model.Build;
  import org.apache.maven.api.model.Dependency;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.api.model.Plugin;
  import org.apache.maven.model.building.ModelBuildingRequest;
  import org.apache.maven.model.building.ModelProblemCollector;
  import org.apache.maven.model.merge.MavenModelMerger;
  import org.codehaus.plexus.util.StringUtils;
  
  /**
   * Handles normalization of a model.
   *
   * @author Benjamin Bentmann
   */
  @Named
  @Singleton
  public class DefaultModelNormalizer implements ModelNormalizer {
  
      private DuplicateMerger merger = new DuplicateMerger();
  
      @Override
      public Model mergeDuplicates(Model model, ModelBuildingRequest request, ModelProblemCollector problems) {
          Model.Builder builder = Model.newBuilder(model);
  
          Build build = model.getBuild();
          if (build != null) {
              List<Plugin> plugins = build.getPlugins();
              Map<Object, Plugin> normalized = new LinkedHashMap<>(plugins.size() * 2);
  
              for (Plugin plugin : plugins) {
                  Object key = plugin.getKey();
                  Plugin first = normalized.get(key);
                  if (first != null) {
                      plugin = merger.mergePlugin(plugin, first);
                  }
                  normalized.put(key, plugin);
              }
  
              if (plugins.size() != normalized.size()) {
                  builder.build(
                          Build.newBuilder(build).plugins(normalized.values()).build());
              }
          }
  
          /*
           * NOTE: This is primarily to keep backward-compat with Maven 2.x which did not validate that dependencies are
           * unique within a single POM. Upon multiple declarations, 2.x just kept the last one but retained the order of
           * the first occurrence. So when we're in lenient/compat mode, we have to deal with such broken POMs and mimic
           * the way 2.x works. When we're in strict mode, the removal of duplicates just saves other merging steps from
           * aftereffects and bogus error messages.
           */
          List<Dependency> dependencies = model.getDependencies();
          Map<String, Dependency> normalized = new LinkedHashMap<>(dependencies.size() * 2);
  
          for (Dependency dependency : dependencies) {
              normalized.put(dependency.getManagementKey(), dependency);
          }
  
          if (dependencies.size() != normalized.size()) {
              builder.dependencies(normalized.values());
          }
  
          return builder.build();
      }
  
      /**
       * DuplicateMerger
       */
      protected static class DuplicateMerger extends MavenModelMerger {
  
          public Plugin mergePlugin(Plugin target, Plugin source) {
             return super.mergePlugin(target, source, false, Collections.emptyMap());
         }
     }
 
     @Override
     public Model injectDefaultValues(Model model, ModelBuildingRequest request, ModelProblemCollector problems) {
         Model.Builder builder = Model.newBuilder(model);
 
         builder.dependencies(injectList(model.getDependencies(), this::injectDependency));
         Build build = model.getBuild();
         if (build != null) {
             Build newBuild = Build.newBuilder(build)
                     .plugins(injectList(build.getPlugins(), this::injectPlugin))
                     .build();
             builder.build(newBuild != build ? newBuild : null);
         }
 
         return builder.build();
     }
 
     private Plugin injectPlugin(Plugin p) {
         return Plugin.newBuilder(p)
                 .dependencies(injectList(p.getDependencies(), this::injectDependency))
                 .build();
     }
 
     private Dependency injectDependency(Dependency d) {
         // we cannot set this directly in the MDO due to the interactions with dependency management
         return StringUtils.isEmpty(d.getScope())
                 ? Dependency.newBuilder(d).scope("compile").build()
                 : d;
     }
 
     /**
      * Returns a list suited for the builders, i.e. null if not modified
      */
     private <T> List<T> injectList(List<T> list, Function<T, T> modifer) {
         List<T> newList = null;
         for (int i = 0; i < list.size(); i++) {
             T oldT = list.get(i);
             T newT = modifer.apply(oldT);
             if (newT != oldT) {
                 if (newList == null) {
                     newList = new ArrayList<>(list);
                 }
                 newList.set(i, newT);
             }
         }
         return newList;
     }
 }