package org.apache.maven.plugin.compiler.module;
   
   /*
    * 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 java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  
  import org.codehaus.plexus.component.annotations.Component;
  import org.objectweb.asm.ClassReader;
  import org.objectweb.asm.ClassVisitor;
  //import org.objectweb.asm.ModuleVisitor;
  import org.objectweb.asm.Opcodes;
  
  /**
   * Extract information from module with ASM
   * 
   * @author Robert Scholte
   * @since 3.6
   */
  @Component( role = ModuleInfoParser.class, hint = "asm" )
  public class AsmModuleInfoParser
      implements ModuleInfoParser
  {
      @Override
      public Type getType()
      {
          return Type.CLASS;
      }
  
      
      @Override
      public JavaModuleDescriptor getModuleDescriptor( File modulePath )
          throws IOException
      {
          final JavaModuleDescriptorWrapper wrapper = new JavaModuleDescriptorWrapper();
  
          InputStream in = getModuleInfoClass( modulePath );
  
          if ( in != null )
          {
              ClassReader reader = new ClassReader( in );
              reader.accept( new ClassVisitor( Opcodes.ASM6 )
              {
  //  REQUIRES ASM 6.0_ALPHA2
                  
  //                @Override
  //                public ModuleVisitor visitModule( String name, int arg1, String arg2 )
  //                {
  //                    wrapper.builder = JavaModuleDescriptor.newModule( name );
  //
  //                    return new ModuleVisitor( Opcodes.ASM6 )
  //                    {
  //                        @Override
  //                        public void visitRequire( String module, int access, String version )
  //                        {
  //                            wrapper.builder.requires( module );
  //                        }
  //                    };
  //                }
              }, 0 );
  
              in.close();
          }
          else
          {
              wrapper.builder = JavaModuleDescriptor.newAutomaticModule( null );
          }
  
          return wrapper.builder.build();
      }
  
      private InputStream getModuleInfoClass( File modulePath )
          throws FileNotFoundException, IOException
      {
          InputStream in;
          if ( modulePath.isDirectory() )
          {
             in = new FileInputStream( new File( modulePath, "module-info.class" ) );
         }
         else
         {
             // 
             JarFile jarFile = new JarFile( modulePath );
             JarEntry moduleInfo = jarFile.getJarEntry( "/module-info.class" );
             
             if ( moduleInfo != null )
             {
                 in = jarFile.getInputStream( moduleInfo );
             }
             else
             {
                 in = null;
             }
         }
         return in;
     }
     
     private static class JavaModuleDescriptorWrapper 
     {
         private JavaModuleDescriptor.Builder builder;
     }
 }