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.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringWriter;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Properties;
  import java.util.TreeMap;
  import java.util.jar.JarEntry;
  import java.util.jar.JarInputStream;
  
  import org.apache.commons.lang3.ClassUtils;
  import org.apache.maven.lifecycle.internal.MojoDescriptorCreator;
  import org.apache.maven.model.Dependency;
  import org.apache.maven.model.Model;
  import org.apache.maven.model.io.xpp3.MavenXpp3Writer;
  import org.apache.maven.plugin.MojoExecution;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.MojoFailureException;
  import org.apache.maven.plugin.PluginParameterExpressionEvaluator;
  import org.apache.maven.plugin.descriptor.MojoDescriptor;
  import org.apache.maven.plugins.annotations.Component;
  import org.apache.maven.plugins.annotations.Mojo;
  import org.apache.maven.plugins.annotations.Parameter;
  import org.apache.maven.project.DefaultProjectBuildingRequest;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.project.ProjectBuildingException;
  import org.apache.maven.project.ProjectBuildingRequest;
  import org.apache.maven.settings.Settings;
  import org.apache.maven.settings.io.xpp3.SettingsXpp3Writer;
  import org.apache.maven.shared.artifact.ArtifactCoordinate;
  import org.apache.maven.shared.artifact.resolve.ArtifactResolverException;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
  import org.codehaus.plexus.components.interactivity.InputHandler;
  import org.codehaus.plexus.util.IOUtil;
  import org.codehaus.plexus.util.StringUtils;
  
  import com.thoughtworks.xstream.XStream;
  import com.thoughtworks.xstream.converters.MarshallingContext;
  import com.thoughtworks.xstream.converters.collections.PropertiesConverter;
  import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
  
  /**
   * Evaluates Maven expressions given by the user in an interactive mode.
   *
   * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
   * @version $Id$
   * @since 2.1
   */
  @Mojo( name = "evaluate", requiresProject = false )
  public class EvaluateMojo
      extends AbstractHelpMojo
  {
      // ----------------------------------------------------------------------
      // Mojo components
      // ----------------------------------------------------------------------
  
      /**
       * Input handler, needed for command line handling.
       */
      @Component
      private InputHandler inputHandler;
  
      /**
       * Component used to get mojo descriptors.
       */
      @Component
      private MojoDescriptorCreator mojoDescriptorCreator;
  
      // ----------------------------------------------------------------------
      // Mojo parameters
      // ----------------------------------------------------------------------
      
      // we need to hide the 'output' defined in AbstractHelpMojo to have a correct "since".
      /**
       * Optional parameter to write the output of this help in a given file, instead of writing to the console.
      * This parameter will be ignored if no <code>expression</code> is specified.
      * <br/>
      * <b>Note</b>: Could be a relative path.
      * 
      * @since 3.0.0
      */
     @Parameter( property = "output" )
     private File output;
 
     /**
      * An artifact for evaluating Maven expressions.
      * <br/>
      * <b>Note</b>: Should respect the Maven format, i.e. <code>groupId:artifactId[:version]</code>. The
      * latest version of the artifact will be used when no version is specified.
      */
     @Parameter( property = "artifact" )
     private String artifact;
 
     /**
      * An expression to evaluate instead of prompting. Note that this <i>must not</i> include the surrounding ${...}.
      */
     @Parameter( property = "expression" )
     private String expression;
 
     /**
      * Maven project built from the given {@link #artifact}. Otherwise, the current Maven project or the super pom.
      */
     @Parameter( defaultValue = "${project}", readonly = true, required = true )
     private MavenProject project;
 
     /**
      * The system settings for Maven.
      */
     @Parameter( defaultValue = "${settings}", readonly = true, required = true )
     private Settings settings;
 
     // ----------------------------------------------------------------------
     // Instance variables
     // ----------------------------------------------------------------------
 
     /** lazy loading evaluator variable */
     private PluginParameterExpressionEvaluator evaluator;
 
     /** lazy loading xstream variable */
     private XStream xstream;
 
     // ----------------------------------------------------------------------
     // Public methods
     // ----------------------------------------------------------------------
 
     /** {@inheritDoc} */
     public void execute()
         throws MojoExecutionException, MojoFailureException
     {
         if ( expression == null && !settings.isInteractiveMode() )
         {
 
             getLog().error( "Maven is configured to NOT interact with the user for input. "
                             + "This Mojo requires that 'interactiveMode' in your settings file is flag to 'true'." );
             return;
         }
 
         validateParameters();
 
         if ( StringUtils.isNotEmpty( artifact ) )
         {
             project = getMavenProject( artifact );
         }
 
         if ( expression == null )
         {
             if ( output != null )
             {
                 getLog().warn( "When prompting for input, the result will be written to the console, "
                     + "ignoring 'output'." );
             }
             while ( true )
             {
                 getLog().info( "Enter the Maven expression i.e. ${project.groupId} or 0 to exit?:" );
 
                 try
                 {
                     String userExpression = inputHandler.readLine();
                     if ( userExpression == null || userExpression.toLowerCase( Locale.ENGLISH ).equals( "0" ) )
                     {
                         break;
                     }
 
                     handleResponse( userExpression, null );
                 }
                 catch ( IOException e )
                 {
                     throw new MojoExecutionException( "Unable to read from standard input.", e );
                 }
             }
         }
         else
         {
             handleResponse( "${" + expression + "}", output );
         }
     }
 
     // ----------------------------------------------------------------------
     // Private methods
     // ----------------------------------------------------------------------
 
     /**
      * Validate Mojo parameters.
      */
     private void validateParameters()
     {
         if ( artifact == null )
         {
             // using project if found or super-pom
             getLog().info( "No artifact parameter specified, using '" + project.getId() + "' as project." );
         }
     }
 
     /**
      * @return a lazy loading evaluator object.
      * @throws MojoExecutionException if any
      * @throws MojoFailureException if any reflection exceptions occur or missing components.
      */
     private PluginParameterExpressionEvaluator getEvaluator()
         throws MojoExecutionException, MojoFailureException
     {
         if ( evaluator == null )
         {
             MojoDescriptor mojoDescriptor;
             try
             {
                 mojoDescriptor = mojoDescriptorCreator.getMojoDescriptor( "help:evaluate", session, project );
             }
             catch ( Exception e )
             {
                 throw new MojoFailureException( "Failure while evaluating.", e );
             }
             MojoExecution mojoExecution = new MojoExecution( mojoDescriptor );
 
             MavenProject currentProject = session.getCurrentProject();
             // Maven 3: PluginParameterExpressionEvaluator gets the current project from the session:
             // synchronize in case another thread wants to fetch the real current project in between
             synchronized ( session )
             {
                 session.setCurrentProject( project );
                 evaluator = new PluginParameterExpressionEvaluator( session, mojoExecution );
                 session.setCurrentProject( currentProject );
             }
         }
 
         return evaluator;
     }
 
     /**
      * @param expr the user expression asked.
      * @param output the file where to write the result, or <code>null</code> to print in standard output.
      * @throws MojoExecutionException if any
      * @throws MojoFailureException if any reflection exceptions occur or missing components.
      */
     private void handleResponse( String expr, File output )
         throws MojoExecutionException, MojoFailureException
     {
         StringBuilder response = new StringBuilder();
 
         Object obj;
         try
         {
             obj = getEvaluator().evaluate( expr );
         }
         catch ( ExpressionEvaluationException e )
         {
             throw new MojoExecutionException( "Error when evaluating the Maven expression", e );
         }
 
         if ( obj != null && expr.equals( obj.toString() ) )
         {
             getLog().warn( "The Maven expression was invalid. Please use a valid expression." );
             return;
         }
 
         // handle null
         if ( obj == null )
         {
             response.append( "null object or invalid expression" );
         }
         // handle primitives objects
         else if ( obj instanceof String )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Boolean )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Byte )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Character )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Double )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Float )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Integer )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Long )
         {
             response.append( obj.toString() );
         }
         else if ( obj instanceof Short )
         {
             response.append( obj.toString() );
         }
         // handle specific objects
         else if ( obj instanceof File )
         {
             File f = (File) obj;
             response.append( f.getAbsolutePath() );
         }
         // handle Maven pom object
         else if ( obj instanceof MavenProject )
         {
             MavenProject projectAsked = (MavenProject) obj;
             StringWriter sWriter = new StringWriter();
             MavenXpp3Writer pomWriter = new MavenXpp3Writer();
             try
             {
                 pomWriter.write( sWriter, projectAsked.getModel() );
             }
             catch ( IOException e )
             {
                 throw new MojoExecutionException( "Error when writing pom", e );
             }
 
             response.append( sWriter.toString() );
         }
         // handle Maven Settings object
         else if ( obj instanceof Settings )
         {
             Settings settingsAsked = (Settings) obj;
             StringWriter sWriter = new StringWriter();
             SettingsXpp3Writer settingsWriter = new SettingsXpp3Writer();
             try
             {
                 settingsWriter.write( sWriter, settingsAsked );
             }
             catch ( IOException e )
             {
                 throw new MojoExecutionException( "Error when writing settings", e );
             }
 
             response.append( sWriter.toString() );
         }
         else
         {
             // others Maven objects
             response.append( toXML( expr, obj ) );
         }
 
         if ( output != null )
         {
             try
             {
                 writeFile( output, response );
             }
             catch ( IOException e )
             {
                 throw new MojoExecutionException( "Cannot write evaluation of expression to output: " + output, e );
             }
             getLog().info( "Result of evaluation written to: " + output );
         }
         else
         {
             getLog().info( LS + response.toString() );
         }
     }
 
     /**
      * @param expr the user expression.
      * @param obj a not null.
      * @return the XML for the given object.
      */
     private String toXML( String expr, Object obj )
     {
         XStream currentXStream = getXStream();
 
         // beautify list
         if ( obj instanceof List )
         {
             List<?> list = (List<?>) obj;
             if ( list.size() > 0 )
             {
                 Object elt = list.iterator().next();
 
                 String name = StringUtils.lowercaseFirstLetter( elt.getClass().getSimpleName() );
                 currentXStream.alias( pluralize( name ), List.class );
             }
             else
             {
                 // try to detect the alias from question
                 if ( expr.indexOf( '.' ) != -1 )
                 {
                     String name = expr.substring( expr.indexOf( '.' ) + 1, expr.indexOf( '}' ) );
                     currentXStream.alias( name, List.class );
                 }
             }
         }
 
         return currentXStream.toXML( obj );
     }
 
     /**
      * @return lazy loading xstream object.
      */
     private XStream getXStream()
     {
         if ( xstream == null )
         {
             xstream = new XStream();
             addAlias( xstream );
 
             // handle Properties a la Maven
             xstream.registerConverter( new PropertiesConverter()
             {
                 /** {@inheritDoc} */
                 public boolean canConvert( @SuppressWarnings( "rawtypes" ) Class type )
                 {
                     return Properties.class == type;
                 }
 
                 /** {@inheritDoc} */
                 public void marshal( Object source, HierarchicalStreamWriter writer, MarshallingContext context )
                 {
                     Properties properties = (Properties) source;
                     Map<?, ?> map = new TreeMap<Object, Object>( properties ); // sort
                     for ( Map.Entry<?, ?> entry : map.entrySet() )
                     {
                         writer.startNode( entry.getKey().toString() );
                         writer.setValue( entry.getValue().toString() );
                         writer.endNode();
                     }
                 }
             } );
         }
 
         return xstream;
     }
 
     /**
      * @param xstreamObject not null
      */
     private void addAlias( XStream xstreamObject )
     {
         try
         {
             addAlias( xstreamObject, getMavenModelJarFile(), "org.apache.maven.model" );
             addAlias( xstreamObject, getMavenSettingsJarFile(), "org.apache.maven.settings" );
         }
         catch ( MojoExecutionException e )
         {
             if ( getLog().isDebugEnabled() )
             {
                 getLog().debug( "MojoExecutionException: " + e.getMessage(), e );
             }
         }
         catch ( ArtifactResolverException e )
         {
             if ( getLog().isDebugEnabled() )
             {
                 getLog().debug( "ArtifactResolverException: " + e.getMessage(), e );
             }
         }
         catch ( ProjectBuildingException e )
         {
             if ( getLog().isDebugEnabled() )
             {
                 getLog().debug( "ProjectBuildingException: " + e.getMessage(), e );
             }
         }
 
         // TODO need to handle specific Maven objects like DefaultArtifact?
     }
 
     /**
      * @param xstreamObject not null
      * @param jarFile not null
      * @param packageFilter a package name to filter.
      */
     private void addAlias( XStream xstreamObject, File jarFile, String packageFilter )
     {
         JarInputStream jarStream = null;
         try
         {
             jarStream = new JarInputStream( new FileInputStream( jarFile ) );
             for ( JarEntry jarEntry = jarStream.getNextJarEntry(); jarEntry != null;
                   jarEntry = jarStream.getNextJarEntry() )
             {
                 if ( jarEntry.getName().toLowerCase( Locale.ENGLISH ).endsWith( ".class" ) )
                 {
                     String name = jarEntry.getName().substring( 0, jarEntry.getName().indexOf( "." ) );
                     name = name.replaceAll( "/", "\\." );
 
                     if ( name.contains( packageFilter ) )
                     {
                         try
                         {
                             Class<?> clazz = ClassUtils.getClass( name );
                             String alias = StringUtils.lowercaseFirstLetter( clazz.getSimpleName() );
                             xstreamObject.alias( alias, clazz );
                             if ( !clazz.equals( Model.class ) )
                             {
                                 xstreamObject.omitField( clazz, "modelEncoding" ); // unnecessary field
                             }
                         }
                         catch ( ClassNotFoundException e )
                         {
                             getLog().error( e );
                         }
                     }
                 }
 
                 jarStream.closeEntry();
             }
 
             jarStream.close();
             jarStream = null;
         }
         catch ( IOException e )
         {
             if ( getLog().isDebugEnabled() )
             {
                 getLog().debug( "IOException: " + e.getMessage(), e );
             }
         }
         finally
         {
             IOUtil.close( jarStream );
         }
     }
 
     /**
      * @return the <code>org.apache.maven:maven-model</code> artifact jar file in the local repository.
      * @throws MojoExecutionException if any
      * @throws ProjectBuildingException if any
      * @throws ArtifactResolverException if any
      */
     private File getMavenModelJarFile()
         throws MojoExecutionException, ProjectBuildingException, ArtifactResolverException
     {
         return getArtifactFile( true );
     }
 
     /**
      * @return the <code>org.apache.maven:maven-settings</code> artifact jar file in the local repository.
      * @throws MojoExecutionException if any
      * @throws ProjectBuildingException if any
      * @throws ArtifactResolverException if any
      */
     private File getMavenSettingsJarFile()
         throws MojoExecutionException, ProjectBuildingException, ArtifactResolverException
     {
         return getArtifactFile( false );
     }
 
     /**
      * @param isPom <code>true</code> to lookup the <code>maven-model</code> artifact jar, <code>false</code> to lookup
      *            the <code>maven-settings</code> artifact jar.
      * @return the <code>org.apache.maven:maven-model|maven-settings</code> artifact jar file for this current
      *         HelpPlugin pom.
      * @throws MojoExecutionException if any
      * @throws ProjectBuildingException if any
      * @throws ArtifactResolverException if any
      */
     private File getArtifactFile( boolean isPom )
         throws MojoExecutionException, ProjectBuildingException, ArtifactResolverException
     {
         List<Dependency> dependencies = getHelpPluginPom().getDependencies();
         for ( Dependency depependency : dependencies )
         {
             if ( !( depependency.getGroupId().equals( "org.apache.maven" ) ) )
             {
                 continue;
             }
 
             if ( isPom )
             {
                 if ( !( depependency.getArtifactId().equals( "maven-model" ) ) )
                 {
                     continue;
                 }
             }
             else
             {
                 if ( !( depependency.getArtifactId().equals( "maven-settings" ) ) )
                 {
                     continue;
                 }
             }
 
             ArtifactCoordinate coordinate =
                 getArtifactCoordinate( depependency.getGroupId(), depependency.getArtifactId(),
                                        depependency.getVersion(), "jar" );
             ProjectBuildingRequest pbr = new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
             pbr.setRemoteRepositories( remoteRepositories );
             return artifactResolver.resolveArtifact( pbr, coordinate ).getArtifact().getFile();
         }
 
         throw new MojoExecutionException( "Unable to find the 'org.apache.maven:"
             + ( isPom ? "maven-model" : "maven-settings" ) + "' artifact" );
     }
 
     /**
      * @return the Maven POM for the current help plugin
      * @throws MojoExecutionException if any
      * @throws ProjectBuildingException if any
      */
     private MavenProject getHelpPluginPom()
         throws MojoExecutionException, ProjectBuildingException
     {
         String resource = "META-INF/maven/org.apache.maven.plugins/maven-help-plugin/pom.properties";
 
         InputStream resourceAsStream = EvaluateMojo.class.getClassLoader().getResourceAsStream( resource );
         if ( resourceAsStream == null )
         {
             throw new MojoExecutionException( "The help plugin artifact was not found." );
         }
         Properties properties = new Properties();
         try
         {
             properties.load( resourceAsStream );
         }
         catch ( IOException e )
         {
             if ( getLog().isDebugEnabled() )
             {
                 getLog().debug( "IOException: " + e.getMessage(), e );
             }
         }
         finally
         {
             IOUtil.close( resourceAsStream );
         }
 
         String artifactString =
             properties.getProperty( "groupId", "unknown" ) + ":"
                 + properties.getProperty( "artifactId", "unknown" ) + ":"
                 + properties.getProperty( "version", "unknown" );
 
         return getMavenProject( artifactString );
     }
 
     /**
      * @param name not null
      * @return the plural of the name
      */
     private static String pluralize( String name )
     {
         if ( StringUtils.isEmpty( name ) )
         {
             throw new IllegalArgumentException( "name is required" );
         }
 
         if ( name.endsWith( "y" ) )
         {
             return name.substring( 0, name.length() - 1 ) + "ies";
         }
         else if ( name.endsWith( "s" ) )
         {
             return name;
         }
         else
         {
             return name + "s";
         }
     }
 }