package org.apache.maven.tools.plugin.generator;

 /*

  * 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.plugin.descriptor.MojoDescriptor;

 import org.apache.maven.plugin.descriptor.PluginDescriptor;

 import org.apache.maven.project.MavenProject;

 import org.apache.maven.tools.plugin.PluginToolsRequest;

 import org.apache.velocity.VelocityContext;

 import org.codehaus.plexus.logging.AbstractLogEnabled;

 import org.codehaus.plexus.logging.Logger;

 import org.codehaus.plexus.logging.console.ConsoleLogger;

 import org.codehaus.plexus.util.FileUtils;

 import org.codehaus.plexus.util.IOUtil;

 import org.codehaus.plexus.util.PropertyUtils;

 import org.codehaus.plexus.util.StringUtils;

 import org.codehaus.plexus.velocity.VelocityComponent;

 import org.objectweb.asm.ClassReader;

 import org.objectweb.asm.ClassVisitor;

 import org.objectweb.asm.ClassWriter;

 import org.objectweb.asm.commons.Remapper;

 import org.objectweb.asm.commons.RemappingClassAdapter;

 import org.objectweb.asm.commons.SimpleRemapper;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.StringWriter;

 import java.util.List;

 import java.util.Properties;

 /**

  * Generates an <code>HelpMojo</code> class.

  *

  * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>

  * @version $Id: PluginHelpGenerator.java 1354250 2012-06-26 21:36:53Z hboutemy $

  * @since 2.4

  */

 public class PluginHelpGenerator

     extends AbstractLogEnabled

     implements Generator

 {

     /**

      * Default generated class name

      */

     private static final String HELP_MOJO_CLASS_NAME = "HelpMojo";

     /**

      * Help properties file, to store data about generated source.

      */

     private static final String HELP_PROPERTIES_FILENAME = "maven-plugin-help.properties";

     /**

      * Default goal

      */

     private static final String HELP_GOAL = "help";

     private String helpPackageName;

     private VelocityComponent velocityComponent;

     /**

      * Default constructor

      */

     public PluginHelpGenerator()

     {

         this.enableLogging( new ConsoleLogger( Logger.LEVEL_INFO, "PluginHelpGenerator" ) );

     }

     // ----------------------------------------------------------------------

     // Public methods

     // ----------------------------------------------------------------------

     /**

      * {@inheritDoc}

      */

     public void execute( File destinationDirectory, PluginToolsRequest request )

         throws GeneratorException

     {

         PluginDescriptor pluginDescriptor = request.getPluginDescriptor();

         String helpImplementation = getImplementation( pluginDescriptor );

         @SuppressWarnings( "unchecked" )

         List<MojoDescriptor> mojoDescriptors = pluginDescriptor.getMojos();

         if ( mojoDescriptors != null )

         {

             // Verify that no help goal already exists

             MojoDescriptor descriptor = pluginDescriptor.getMojo( HELP_GOAL );

             if ( ( descriptor != null ) && !descriptor.getImplementation().equals( helpImplementation ) )

             {

                 if ( getLogger().isWarnEnabled() )

                 {

                     getLogger().warn( "\n\nA help goal (" + descriptor.getImplementation()

                                           + ") already exists in this plugin. SKIPPED THE " + helpImplementation

                                           + " GENERATION.\n" );

                 }

                 return;

             }

         }

         writeHelpPropertiesFile( request );

         try

         {

             String sourcePath = helpImplementation.replace( '.', File.separatorChar ) + ".java";

             File helpClass = new File( destinationDirectory, sourcePath );

             helpClass.getParentFile().mkdirs();

             MavenProject mavenProject = request.getProject();

             String pluginResourcesPath = "META-INF/maven/" + mavenProject.getGroupId() + "/" + mavenProject.getArtifactId();

             String helpClassSources = getHelpClassSources( pluginResourcesPath, pluginDescriptor );

             FileUtils.fileWrite( helpClass, request.getEncoding(), helpClassSources );

         }

         catch ( IOException e )

         {

             throw new GeneratorException( e.getMessage(), e );

         }

     }

     public PluginHelpGenerator setHelpPackageName( String helpPackageName )

     {

         this.helpPackageName = helpPackageName;

         return this;

     }

     public VelocityComponent getVelocityComponent()

     {

         return velocityComponent;

     }

     public PluginHelpGenerator setVelocityComponent( VelocityComponent velocityComponent )

     {

         this.velocityComponent = velocityComponent;

         return this;

     }

     // ----------------------------------------------------------------------

     // Private methods

     // ----------------------------------------------------------------------

     private String getHelpClassSources( String pluginResourcesPath, PluginDescriptor pluginDescriptor )

     {

         Properties properties = new Properties();

         VelocityContext context = new VelocityContext( properties );

         if ( this.helpPackageName != null )

         {

             properties.put( "helpPackageName", this.helpPackageName );

         }

         else

         {

             properties.put( "helpPackageName", "" );

         }

         properties.put( "pluginHelpPath", pluginResourcesPath + "/plugin-help.xml" );

         properties.put( "artifactId", pluginDescriptor.getArtifactId() );

         properties.put( "goalPrefix", pluginDescriptor.getGoalPrefix() );

         // FIXME encoding !

         StringWriter stringWriter = new StringWriter();

         InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream( "help-class-source.vm" );

         InputStreamReader isReader = new InputStreamReader( is );

         velocityComponent.getEngine().evaluate( context, stringWriter, "", isReader );

         return stringWriter.toString();

     }

     /**

      * @param pluginDescriptor The descriptor of the plugin for which to generate a help goal, must not be

      *                         <code>null</code>.

      * @return The implementation.

      */

     private String getImplementation( PluginDescriptor pluginDescriptor )

     {

         String packageName = helpPackageName;

         if ( StringUtils.isEmpty( packageName ) )

         {

             packageName = GeneratorUtils.discoverPackageName( pluginDescriptor );

         }

         return StringUtils.isEmpty( packageName ) ? HELP_MOJO_CLASS_NAME : packageName + '.' + HELP_MOJO_CLASS_NAME;

     }

     /**

      * Write help properties files for later use to eventually rewrite Help Mojo.

      *

      * @param request

      * @throws GeneratorException

      * @see {@link #rewriteHelpMojo(PluginToolsRequest)}

      */

     private void writeHelpPropertiesFile( PluginToolsRequest request )

         throws GeneratorException

     {

         Properties properties = new Properties();

         properties.put( "helpPackageName", helpPackageName == null ? "" : helpPackageName );

         File tmpPropertiesFile =

             new File( request.getProject().getBuild().getDirectory(), HELP_PROPERTIES_FILENAME );

         if ( tmpPropertiesFile.exists() )

         {

             tmpPropertiesFile.delete();

         }

         else if ( !tmpPropertiesFile.getParentFile().exists() )

         {

             tmpPropertiesFile.getParentFile().mkdirs();

         }

         FileOutputStream fos = null;

         try

         {

             fos = new FileOutputStream( tmpPropertiesFile );

             properties.store( fos, "maven plugin help mojo generation informations" );

         }

         catch ( IOException e )

         {

             throw new GeneratorException( e.getMessage(), e );

         }

         finally

         {

             IOUtil.close( fos );

         }

     }

     /**

      * Rewrite Help Mojo to match actual Mojos package name if it was not available at source generation

      * time. This is used at descriptor generation time.

      *

      * @param request

      * @throws GeneratorException

      */

     static void rewriteHelpMojo( PluginToolsRequest request )

         throws GeneratorException

     {

         File tmpPropertiesFile =

             new File( request.getProject().getBuild().getDirectory(), HELP_PROPERTIES_FILENAME );

         if ( !tmpPropertiesFile.exists() )

         {

             return;

         }

         Properties properties = PropertyUtils.loadProperties( tmpPropertiesFile );

         String helpPackageName = properties.getProperty( "helpPackageName" );

         // if helpPackageName property is empty, we have to rewrite the class with a better package name than empty

         if ( StringUtils.isEmpty( helpPackageName ) )

         {

             String helpMojoImplementation = rewriteHelpClassToMojoPackage( request );

             if ( helpMojoImplementation != null )

             {

                 // rewrite plugin descriptor with new HelpMojo implementation class

                 updateHelpMojoDescriptor( request.getPluginDescriptor(), helpMojoImplementation );

             }

         }

     }

     private static String rewriteHelpClassToMojoPackage( PluginToolsRequest request )

         throws GeneratorException

     {

         String destinationPackage = GeneratorUtils.discoverPackageName( request.getPluginDescriptor() );

         if ( StringUtils.isEmpty( destinationPackage ) )

         {

             return null;

         }

         String packageAsDirectory = StringUtils.replace( destinationPackage, '.', '/' );

         String outputDirectory = request.getProject().getBuild().getOutputDirectory();

         File helpClassFile = new File( outputDirectory, HELP_MOJO_CLASS_NAME + ".class" );

         if ( !helpClassFile.exists() )

         {

             return null;

         }

         File rewriteHelpClassFile =

             new File( outputDirectory + '/' + packageAsDirectory, HELP_MOJO_CLASS_NAME + ".class" );

         if ( !rewriteHelpClassFile.getParentFile().exists() )

         {

             rewriteHelpClassFile.getParentFile().mkdirs();

         }

         FileInputStream fileInputStream = null;

         ClassReader cr = null;

         try

         {

             fileInputStream = new FileInputStream( helpClassFile );

             cr = new ClassReader( fileInputStream );

         }

         catch ( IOException e )

         {

             throw new GeneratorException( e.getMessage(), e );

         }

         finally

         {

             IOUtil.close( fileInputStream );

         }

         ClassWriter cw = new ClassWriter( 0 );

         Remapper packageRemapper =

             new SimpleRemapper( HELP_MOJO_CLASS_NAME, packageAsDirectory + '/' + HELP_MOJO_CLASS_NAME );

         ClassVisitor cv = new RemappingClassAdapter( cw, packageRemapper );

         try

         {

             cr.accept( cv, ClassReader.EXPAND_FRAMES );

         }

         catch ( Throwable e )

         {

             throw new GeneratorException( "ASM issue processing class-file " + helpClassFile.getPath(), e );

         }

         byte[] renamedClass = cw.toByteArray();

         FileOutputStream fos = null;

         try

         {

             fos = new FileOutputStream( rewriteHelpClassFile );

             fos.write( renamedClass );

         }

         catch ( IOException e )

         {

             throw new GeneratorException( "Error rewriting help class: " + e.getMessage(), e );

         }

         finally

         {

             IOUtil.close( fos );

         }

         helpClassFile.delete();

         return destinationPackage + ".HelpMojo";

     }

     private static void updateHelpMojoDescriptor( PluginDescriptor pluginDescriptor, String helpMojoImplementation )

     {

         MojoDescriptor mojoDescriptor = pluginDescriptor.getMojo( HELP_GOAL );

         if ( mojoDescriptor != null )

         {

             mojoDescriptor.setImplementation( helpMojoImplementation );

         }

     }

 }