/*
    * 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.internal;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import org.apache.maven.plugin.MavenPluginPrerequisitesChecker;
  import org.apache.maven.plugin.descriptor.PluginDescriptor;
  import org.eclipse.aether.util.version.GenericVersionScheme;
  import org.eclipse.aether.version.InvalidVersionSpecificationException;
  import org.eclipse.aether.version.Version;
  import org.eclipse.aether.version.VersionConstraint;
  import org.eclipse.aether.version.VersionScheme;
  
  @Named
  @Singleton
  public class MavenPluginJavaPrerequisiteChecker implements MavenPluginPrerequisitesChecker {
      private final VersionScheme versionScheme = new GenericVersionScheme();
  
      @Override
      public void accept(PluginDescriptor pluginDescriptor) {
          String requiredJavaVersion = pluginDescriptor.getRequiredJavaVersion();
          if (requiredJavaVersion != null && !requiredJavaVersion.isEmpty()) {
              String currentJavaVersion = System.getProperty("java.version");
              if (!matchesVersion(requiredJavaVersion, currentJavaVersion)) {
                  throw new IllegalStateException("Required Java version " + requiredJavaVersion
                          + " is not met by current version: " + currentJavaVersion);
              }
          }
      }
  
      boolean matchesVersion(String requiredVersion, String currentVersion) {
          // Java 8 is consistent: it will always say "1.8...". Users are not consistent.
          if (!requiredVersion.contains("1.8") && currentVersion.startsWith("1.8")) {
              currentVersion = currentVersion.substring(2);
          }
          VersionConstraint constraint;
          try {
              constraint = versionScheme.parseVersionConstraint(requiredVersion);
          } catch (InvalidVersionSpecificationException e) {
              throw new IllegalArgumentException("Invalid 'requiredJavaVersion' given in plugin descriptor", e);
          }
          Version current;
          try {
              current = versionScheme.parseVersion(currentVersion);
          } catch (InvalidVersionSpecificationException e) {
              throw new IllegalStateException("Could not parse current Java version", e);
          }
          if (constraint.getRange() == null) {
              return constraint.getVersion().compareTo(current) <= 0;
          }
          return constraint.containsVersion(current);
      }
  }