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.IOUtil;
  import org.codehaus.plexus.util.StringUtils;
  import org.codehaus.plexus.velocity.VelocityComponent;
  
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.io.StringWriter;
  import java.io.Writer;
  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 1342957 2012-05-26 20:29:09Z hboutemy $
   * @since 2.4
   */
  public class PluginHelpGenerator
      extends AbstractLogEnabled
      implements Generator
  {
      /**
       * Default generated class name
       */
      private static final String HELP_MOJO_CLASS_NAME = "HelpMojo";
  
      /**
       * 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
              for ( MojoDescriptor descriptor : mojoDescriptors )
             {
                 if ( HELP_GOAL.equals( descriptor.getGoal() )
                     && !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;
                 }
             }
         }
         Properties properties = new Properties();
         properties.put( "helpPackageName", helpPackageName == null ? "" : helpPackageName );
 
         MavenProject mavenProject = request.getProject();
 
         String propertiesFilePath = "META-INF/maven/" + mavenProject.getGroupId() + "/" + mavenProject.getArtifactId();
 
         File tmpPropertiesFile =
             new File( request.getProject().getBuild().getDirectory(), "maven-plugin-help.properties" );
         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 generation informations" );
         }
         catch ( IOException e )
         {
             throw new GeneratorException( e.getMessage(), e );
         }
         finally
         {
             IOUtil.close( fos );
         }
 
         String sourcePath = helpImplementation.replace( '.', File.separatorChar ) + ".java";
         File helpClass = new File( destinationDirectory, sourcePath );
         helpClass.getParentFile().mkdirs();
 
         Writer writer = null;
         try
         {
             writer = new OutputStreamWriter( new FileOutputStream( helpClass ), request.getEncoding() );
             writer.write( getHelpClassSources( propertiesFilePath ) );
             writer.flush();
         }
         catch ( IOException e )
         {
             throw new GeneratorException( e.getMessage(), e );
         }
         finally
         {
             IOUtil.close( writer );
         }
     }
 
     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
     // ----------------------------------------------------------------------
 
     protected String getHelpClassSources( String propertiesFilePath )
     {
         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", propertiesFilePath + "/plugin-help.xml" );
         // 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;
     }
 }