/*
    * 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.plugin.plugin.report;
  
  import java.util.Arrays;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.maven.model.Plugin;
  import org.apache.maven.model.Prerequisites;
  import org.apache.maven.plugin.descriptor.PluginDescriptor;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.tools.plugin.ExtendedPluginDescriptor;
  import org.codehaus.plexus.util.xml.Xpp3Dom;
  
  /**
   * Plugin requirements history.
   *
   * @author Slawomir Jaranowski
   */
  public class RequirementsHistory {
      /**
       * The plugin version.
       */
      private String version;
  
      /**
       * The minimum version of Maven to run this plugin.
       */
      private String maven;
  
      /**
       * The minimum version of the JDK to run this plugin.
       */
      private String jdk;
  
      public String getVersion() {
          return version;
      }
  
      public String getMaven() {
          return maven;
      }
  
      public String getJdk() {
          return jdk;
      }
  
      @Override
      public String toString() {
          final StringBuilder sb = new StringBuilder("RequirementsHistory{");
          sb.append("version='").append(version).append('\'');
          sb.append(", maven='").append(maven).append('\'');
          sb.append(", jdk='").append(jdk).append('\'');
          sb.append('}');
          return sb.toString();
      }
  
      public static RequirementsHistory discoverRequirements(MavenProject project) {
          RequirementsHistory req = new RequirementsHistory();
          req.version = project.getVersion();
          req.jdk = discoverJdkRequirement(project, null);
          req.maven = discoverMavenRequirement(project, null);
          return req;
      }
      /**
       * Tries to determine the Maven requirement from either the plugin descriptor or (if not set) from the
       * Maven prerequisites element in the POM.
       *
       * @param project      not null
       * @param pluginDescriptor the plugin descriptor (can be null)
       * @return the Maven version or null if not specified
       */
      public static String discoverMavenRequirement(MavenProject project, PluginDescriptor pluginDescriptor) {
          if (pluginDescriptor != null && StringUtils.isNotBlank(pluginDescriptor.getRequiredMavenVersion())) {
              return pluginDescriptor.getRequiredMavenVersion();
          }
          return Optional.ofNullable(project.getPrerequisites())
                  .map(Prerequisites::getMaven)
                  .orElse(null);
      }
 
     /**
      * Tries to determine the JDK requirement from the following sources (until one is found)
      * <ol>
      * <li>use JDK requirement from plugin descriptor</li>
      * <li>use {@code release} configuration of {@code org.apache.maven.plugins:maven-compiler-plugin}</li>
      * <li>use {@code maven.compiler.release<} property</li>
      * <li>use {@code target} configuration of {@code org.apache.maven.plugins:maven-compiler-plugin}</li>
      * <li>use {@code maven.compiler.target} property</li>
      * </ol>
      *
      * @param project      not null
      * @param pluginDescriptor the plugin descriptor (can be null)
      * @return the JDK version
      */
     public static String discoverJdkRequirement(MavenProject project, PluginDescriptor pluginDescriptor) {
         String jdk = null;
         if (pluginDescriptor instanceof ExtendedPluginDescriptor) {
             ExtendedPluginDescriptor extPluginDescriptor = (ExtendedPluginDescriptor) pluginDescriptor;
             jdk = extPluginDescriptor.getRequiredJavaVersion();
         }
         if (jdk != null) {
             return jdk;
         }
         Plugin compiler = getCompilerPlugin(project.getBuild().getPluginsAsMap());
         if (compiler == null) {
             compiler = getCompilerPlugin(project.getPluginManagement().getPluginsAsMap());
         }
 
         jdk = getPluginParameter(compiler, "release");
         if (jdk == null) {
             jdk = project.getProperties().getProperty("maven.compiler.release");
         }
 
         if (jdk == null) {
             jdk = getPluginParameter(compiler, "target");
         }
 
         if (jdk == null) {
             // default value
             jdk = project.getProperties().getProperty("maven.compiler.target");
         }
 
         if (jdk == null) {
             String version = (compiler == null) ? null : compiler.getVersion();
 
             if (version != null) {
                 return "Default target for maven-compiler-plugin version " + version;
             }
         } else {
             if (Arrays.asList("1.5", "1.6", "1.7", "1.8").contains(jdk)) {
                 jdk = jdk.substring(2);
             }
         }
 
         return jdk;
     }
 
     private static Plugin getCompilerPlugin(Map<String, Plugin> pluginsAsMap) {
         return pluginsAsMap.get("org.apache.maven.plugins:maven-compiler-plugin");
     }
 
     private static String getPluginParameter(Plugin plugin, String parameter) {
         if (plugin != null) {
             Xpp3Dom pluginConf = (Xpp3Dom) plugin.getConfiguration();
 
             if (pluginConf != null) {
                 Xpp3Dom target = pluginConf.getChild(parameter);
 
                 if (target != null) {
                     return target.getValue();
                 }
             }
         }
 
         return null;
     }
 
     public boolean hasSameRequirements(RequirementsHistory other) {
         return Objects.equals(this.maven, other.getMaven()) && Objects.equals(this.jdk, other.getJdk());
     }
 }