/*
    * 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.internal.impl;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.function.Function;
  
  import org.apache.maven.api.di.Named;
  import org.apache.maven.api.di.Singleton;
  import org.apache.maven.api.model.Build;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.api.model.Plugin;
  import org.apache.maven.api.model.PluginManagement;
  import org.apache.maven.api.model.ReportPlugin;
  import org.apache.maven.api.model.Reporting;
  import org.apache.maven.api.services.ModelBuilderRequest;
  import org.apache.maven.api.services.ModelProblemCollector;
  import org.apache.maven.api.services.model.PluginConfigurationExpander;
  import org.apache.maven.api.xml.XmlNode;
  
  /**
   * Handles expansion of general build plugin configuration into individual executions.
   *
   */
  @Named
  @Singleton
  public class DefaultPluginConfigurationExpander implements PluginConfigurationExpander {
  
      @Override
      public Model expandPluginConfiguration(Model model, ModelBuilderRequest request, ModelProblemCollector problems) {
          Build build = model.getBuild();
          if (build != null) {
              build = build.withPlugins(expandPlugin(build.getPlugins()));
              PluginManagement pluginManagement = build.getPluginManagement();
              if (pluginManagement != null) {
                  build = build.withPluginManagement(
                          pluginManagement.withPlugins(expandPlugin(pluginManagement.getPlugins())));
              }
              model = model.withBuild(build);
          }
          Reporting reporting = model.getReporting();
          if (reporting != null) {
              expandReport(reporting.getPlugins());
          }
          return model.withBuild(build);
      }
  
      private List<Plugin> expandPlugin(List<Plugin> oldPlugins) {
          return map(oldPlugins, plugin -> {
              XmlNode pluginConfiguration = plugin.getConfiguration();
              if (pluginConfiguration != null) {
                  return plugin.withExecutions(map(
                          plugin.getExecutions(),
                          execution -> execution.withConfiguration(
                                  XmlNode.merge(execution.getConfiguration(), pluginConfiguration))));
              } else {
                  return plugin;
              }
          });
      }
  
      private List<ReportPlugin> expandReport(List<ReportPlugin> oldPlugins) {
          return map(oldPlugins, plugin -> {
              XmlNode pluginConfiguration = plugin.getConfiguration();
              if (pluginConfiguration != null) {
                  return plugin.withReportSets(map(
                          plugin.getReportSets(),
                          report -> report.withConfiguration(
                                  XmlNode.merge(report.getConfiguration(), pluginConfiguration))));
              } else {
                  return plugin;
              }
          });
      }
  
      static <T> List<T> map(List<T> list, Function<T, T> mapper) {
          List<T> newList = list;
          for (int i = 0; i < newList.size(); i++) {
              T oldT = newList.get(i);
              T newT = mapper.apply(oldT);
              if (newT != oldT) {
                  if (newList == list) {
                     newList = new ArrayList<>(list);
                 }
                 newList.set(i, newT);
             }
         }
         return newList;
     }
 }