package org.apache.maven.plugins.shade.resource;
   
   /*
    * 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.
   */
  
  import org.apache.maven.plugins.shade.relocation.Relocator;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Properties;
  import java.util.jar.JarEntry;
  import java.util.jar.JarOutputStream;
  
  /**
   * Aggregate Apache Groovy extension modules descriptors
   */
  public class GroovyResourceTransformer
      extends AbstractCompatibilityTransformer
  {
  
      static final String EXT_MODULE_NAME_LEGACY = "META-INF/services/org.codehaus.groovy.runtime.ExtensionModule";
  
      // Since Groovy 2.5.x/Java 9 META-INF/services may only be used by Service Providers
      static final String EXT_MODULE_NAME = "META-INF/groovy/org.codehaus.groovy.runtime.ExtensionModule";
  
      private List<String> extensionClassesList = new ArrayList<>();
  
      private List<String> staticExtensionClassesList = new ArrayList<>();
  
      private String extModuleName = "no-module-name";
  
      private String extModuleVersion = "1.0";
  
      private long time = Long.MIN_VALUE;
  
      @Override
      public boolean canTransformResource( String resource )
      {
          return EXT_MODULE_NAME.equals( resource ) || EXT_MODULE_NAME_LEGACY.equals( resource );
      }
  
      @Override
      public void processResource( String resource, InputStream is, List<Relocator> relocators, long time )
          throws IOException
      {
          Properties out = new Properties();
          try ( InputStream props = is )
          {
              out.load( props );
          }
          String extensionClasses = out.getProperty( "extensionClasses", "" ).trim();
          if ( extensionClasses.length() > 0 )
          {
              append( extensionClasses, extensionClassesList );
          }
          String staticExtensionClasses = out.getProperty( "staticExtensionClasses", "" ).trim();
          if ( staticExtensionClasses.length() > 0 )
          {
              append( staticExtensionClasses, staticExtensionClassesList );
          }
          if ( time > this.time )
          {
              this.time = time;        
          }
      }
  
      private void append( String entry, List<String> list )
      {
          if ( entry != null )
          {
              Collections.addAll( list, entry.split( "\\s*,\\s*" ) );
          }
      }
  
      @Override
      public boolean hasTransformedResource()
      {
          return extensionClassesList.size() > 0 && staticExtensionClassesList.size() > 0;
     }
 
     @Override
     public void modifyOutputStream( JarOutputStream os )
         throws IOException
     {
         if ( hasTransformedResource() )
         {
             JarEntry jarEntry = new JarEntry( EXT_MODULE_NAME );
             jarEntry.setTime( time );
             os.putNextEntry( jarEntry );
 
             Properties desc = new Properties();
             desc.put( "moduleName", extModuleName );
             desc.put( "moduleVersion", extModuleVersion );
             if ( extensionClassesList.size() > 0 )
             {
                 desc.put( "extensionClasses", join( extensionClassesList ) );
             }
             if ( staticExtensionClassesList.size() > 0 )
             {
                 desc.put( "staticExtensionClasses", join( staticExtensionClassesList ) );
             }
             desc.store( os, null );
         }
     }
 
     private String join( Collection<String> strings )
     {
         Iterator<String> it = strings.iterator();
         switch ( strings.size() )
         {
             case 0:
                 return "";
             case 1:
                 return it.next();
             default:
                 StringBuilder buff = new StringBuilder( it.next() );
                 while ( it.hasNext() )
                 {
                     buff.append( "," ).append( it.next() );
                 }
                 return buff.toString();
         }
     }
 
     public void setExtModuleName( String extModuleName )
     {
         this.extModuleName = extModuleName;
     }
 
     public void setExtModuleVersion( String extModuleVersion )
     {
         this.extModuleVersion = extModuleVersion;
     }
 }