package org.apache.maven.plugins.help;

 /*

  * 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.IOException;

 import java.lang.reflect.Field;

 import java.util.Arrays;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Map;

 import org.apache.maven.plugin.MojoExecutionException;

 import org.apache.maven.plugin.MojoFailureException;

 import org.apache.maven.usability.plugin.Expression;

 import org.apache.maven.usability.plugin.ExpressionDocumentationException;

 import org.apache.maven.usability.plugin.ExpressionDocumenter;

 import org.codehaus.plexus.util.StringUtils;

 /**

  * Displays the supported Plugin expressions used by Maven.

  *

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

  * @version $Id: ExpressionsMojo.java 689770 2008-08-28 09:47:18Z vsiveton $

  * @since 2.1

  * @goal expressions

  * @requiresProject false

  */

 public class ExpressionsMojo

     extends AbstractHelpMojo

 {

     /** English sentence when no description exists */

     private static final String NO_DESCRIPTION_AVAILABLE = "No description available.";

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

     // Public methods

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

     /** {@inheritDoc} */

     public void execute()

         throws MojoExecutionException, MojoFailureException

     {

         Map m;

         try

         {

             m = ExpressionDocumenter.load();

         }

         catch ( ExpressionDocumentationException e )

         {

             throw new MojoExecutionException( "ExpressionDocumentationException: " + e.getMessage(), e );

         }

         StringBuffer sb = new StringBuffer();

         sb.append( "Maven supports the following Plugin expressions:\n\n" );

         for ( Iterator it = getExpressionsRoot().iterator(); it.hasNext(); )

         {

             String expression = (String) it.next();

             sb.append( "${" ).append( expression ).append( "}: " );

             sb.append( NO_DESCRIPTION_AVAILABLE );

             sb.append( "\n\n" );

         }

         for ( Iterator it = m.keySet().iterator(); it.hasNext(); )

         {

             String key = (String) it.next();

             Expression expression = (Expression) m.get( key );

             sb.append( "${" ).append( key ).append( "}: " );

             sb.append( trimCDATA( expression.getDescription() ) );

             sb.append( "\n\n" );

         }

         if ( output != null )

         {

             try

             {

                 writeFile( output, sb );

             }

             catch ( IOException e )

             {

                 throw new MojoExecutionException( "Cannot write plugins expressions description to output: "

                     + output, e );

             }

             if ( getLog().isInfoEnabled() )

             {

                 getLog().info( "Wrote descriptions to: " + output );

             }

         }

         else

         {

             if ( getLog().isInfoEnabled() )

             {

                 getLog().info( sb.toString() );

             }

         }

     }

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

     // Private methods

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

     /**

      * @return the value of the private static field <code>ExpressionDocumenter#EXPRESSION_ROOTS</code>.

      * @throws MojoFailureException if any reflection exceptions occur

      * @throws MojoExecutionException if no value exists for <code>ExpressionDocumenter#EXPRESSION_ROOTS</code>

      */

     private static List getExpressionsRoot()

         throws MojoFailureException, MojoExecutionException

     {

         try

         {

             Field f = ExpressionDocumenter.class.getDeclaredField( "EXPRESSION_ROOTS" );

             f.setAccessible( true );

             String[] value = (String[]) f.get( new ExpressionDocumenter() );

             if ( value == null )

             {

                 throw new MojoExecutionException( "org.apache.maven.usability.plugin.ExpressionDocumenter#"

                     + "EXPRESSION_ROOTS has no value." );

             }

             return Arrays.asList( value );

         }

         catch ( SecurityException e )

         {

             throw new MojoFailureException( "SecurityException: " + e.getMessage() );

         }

         catch ( IllegalArgumentException e )

         {

             throw new MojoFailureException( "IllegalArgumentException: " + e.getMessage() );

         }

         catch ( NoSuchFieldException e )

         {

             throw new MojoFailureException( "NoSuchFieldException: " + e.getMessage() );

         }

         catch ( IllegalAccessException e )

         {

             throw new MojoFailureException( "IllegalAccessException: " + e.getMessage() );

         }

     }

     /**

      * @param description could be null

      * @return the given description without any new line, or <code>NO_DESCRIPTION_AVAILABLE</code> value if

      * <code>description</code> is null.

      * @see #NO_DESCRIPTION_AVAILABLE

      */

     private static String trimCDATA( String description )

     {

         if ( StringUtils.isEmpty( description ) )

         {

             return NO_DESCRIPTION_AVAILABLE;

         }

         StringBuffer sb = new StringBuffer();

         String[] lines = StringUtils.split( description, "\r\n" );

         for ( int i = 0; i < lines.length; i++ )

         {

             sb.append( StringUtils.trim( lines[i] ) ).append( " " );

         }

         return sb.toString();

     }

 }