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 static java.nio.charset.StandardCharsets.UTF_8;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.File;
  import java.io.IOException;
  import java.io.StringReader;
  import java.io.UnsupportedEncodingException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Stack;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import javax.swing.text.MutableAttributeSet;
  import javax.swing.text.html.HTML;
  import javax.swing.text.html.HTMLEditorKit;
  import javax.swing.text.html.parser.ParserDelegator;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.artifact.DependencyResolutionRequiredException;
  import org.apache.maven.plugin.descriptor.MojoDescriptor;
  import org.apache.maven.plugin.descriptor.PluginDescriptor;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.reporting.MavenReport;
  import org.codehaus.plexus.component.repository.ComponentDependency;
  import org.codehaus.plexus.util.StringUtils;
  import org.codehaus.plexus.util.xml.XMLWriter;
  import org.w3c.tidy.Tidy;
  
  /**
   * Convenience methods to play with Maven plugins.
   *
   * @author jdcasey
   */
  public final class GeneratorUtils
  {
      private GeneratorUtils()
      {
          // nop
      }
  
      /**
       * @param w not null writer
       * @param pluginDescriptor not null
       */
      public static void writeDependencies( XMLWriter w, PluginDescriptor pluginDescriptor )
      {
          w.startElement( "dependencies" );
  
          @SuppressWarnings( "unchecked" )
          List<ComponentDependency> deps = pluginDescriptor.getDependencies();
          for ( ComponentDependency dep : deps )
          {
              w.startElement( "dependency" );
  
              element( w, "groupId", dep.getGroupId() );
  
              element( w, "artifactId", dep.getArtifactId() );
  
              element( w, "type", dep.getType() );
  
              element( w, "version", dep.getVersion() );
  
              w.endElement();
          }
  
          w.endElement();
      }
  
      /**
      * @param w not null writer
      * @param name  not null
      * @param value could be null
      */
     public static void element( XMLWriter w, String name, String value )
     {
         w.startElement( name );
 
         if ( value == null )
         {
             value = "";
         }
 
         w.writeText( value );
 
         w.endElement();
     }
 
     public static void element( XMLWriter w, String name, String value, boolean asText )
     {
         element( w, name, asText ? GeneratorUtils.toText( value ) : value );
     }
     
     /**
      * @param artifacts not null collection of <code>Artifact</code>
      * @return list of component dependencies
      */
     public static List<ComponentDependency> toComponentDependencies( Collection<Artifact> artifacts )
     {
         List<ComponentDependency> componentDeps = new LinkedList<>();
 
         for ( Artifact artifact : artifacts )
         {
             ComponentDependency cd = new ComponentDependency();
 
             cd.setArtifactId( artifact.getArtifactId() );
             cd.setGroupId( artifact.getGroupId() );
             cd.setVersion( artifact.getVersion() );
             cd.setType( artifact.getType() );
 
             componentDeps.add( cd );
         }
 
         return componentDeps;
     }
 
     /**
      * Returns a literal replacement <code>String</code> for the specified <code>String</code>. This method
      * produces a <code>String</code> that will work as a literal replacement <code>s</code> in the
      * <code>appendReplacement</code> method of the {@link Matcher} class. The <code>String</code> produced will
      * match the sequence of characters in <code>s</code> treated as a literal sequence. Slashes ('\') and dollar
      * signs ('$') will be given no special meaning. TODO: copied from Matcher class of Java 1.5, remove once target
      * platform can be upgraded
      *
      * @see <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/regex/Matcher.html">java.util.regex.Matcher</a>
      * @param s The string to be literalized
      * @return A literal string replacement
      */
     private static String quoteReplacement( String s )
     {
         if ( ( s.indexOf( '\\' ) == -1 ) && ( s.indexOf( '$' ) == -1 ) )
         {
             return s;
         }
 
         StringBuilder sb = new StringBuilder();
         for ( int i = 0; i < s.length(); i++ )
         {
             char c = s.charAt( i );
             if ( c == '\\' )
             {
                 sb.append( '\\' );
                 sb.append( '\\' );
             }
             else if ( c == '$' )
             {
                 sb.append( '\\' );
                 sb.append( '$' );
             }
             else
             {
                 sb.append( c );
             }
         }
 
         return sb.toString();
     }
 
     /**
      * Decodes javadoc inline tags into equivalent HTML tags. For instance, the inline tag "{@code <A&B>}" should be
      * rendered as "<code>&lt;A&amp;B&gt;</code>".
      *
      * @param description The javadoc description to decode, may be <code>null</code>.
      * @return The decoded description, never <code>null</code>.
      */
     static String decodeJavadocTags( String description )
     {
         if ( StringUtils.isEmpty( description ) )
         {
             return "";
         }
 
         StringBuffer decoded = new StringBuffer( description.length() + 1024 );
 
         Matcher matcher = Pattern.compile( "\\{@(\\w+)\\s*([^\\}]*)\\}" ).matcher( description );
         while ( matcher.find() )
         {
             String tag = matcher.group( 1 );
             String text = matcher.group( 2 );
             text = StringUtils.replace( text, "&", "&amp;" );
             text = StringUtils.replace( text, "<", "&lt;" );
             text = StringUtils.replace( text, ">", "&gt;" );
             if ( "code".equals( tag ) )
             {
                 text = "<code>" + text + "</code>";
             }
             else if ( "link".equals( tag ) || "linkplain".equals( tag ) || "value".equals( tag ) )
             {
                 String pattern = "(([^#\\.\\s]+\\.)*([^#\\.\\s]+))?" + "(#([^\\(\\s]*)(\\([^\\)]*\\))?\\s*(\\S.*)?)?";
                 final int label = 7;
                 final int clazz = 3;
                 final int member = 5;
                 final int args = 6;
                 Matcher link = Pattern.compile( pattern ).matcher( text );
                 if ( link.matches() )
                 {
                     text = link.group( label );
                     if ( StringUtils.isEmpty( text ) )
                     {
                         text = link.group( clazz );
                         if ( StringUtils.isEmpty( text ) )
                         {
                             text = "";
                         }
                         if ( StringUtils.isNotEmpty( link.group( member ) ) )
                         {
                             if ( StringUtils.isNotEmpty( text ) )
                             {
                                 text += '.';
                             }
                             text += link.group( member );
                             if ( StringUtils.isNotEmpty( link.group( args ) ) )
                             {
                                 text += "()";
                             }
                         }
                     }
                 }
                 if ( !"linkplain".equals( tag ) )
                 {
                     text = "<code>" + text + "</code>";
                 }
             }
             matcher.appendReplacement( decoded, ( text != null ) ? quoteReplacement( text ) : "" );
         }
         matcher.appendTail( decoded );
 
         return decoded.toString();
     }
 
     /**
      * Fixes some javadoc comment to become a valid XHTML snippet.
      *
      * @param description Javadoc description with HTML tags, may be <code>null</code>.
      * @return The description with valid XHTML tags, never <code>null</code>.
      */
     public static String makeHtmlValid( String description )
     {
         if ( StringUtils.isEmpty( description ) )
         {
             return "";
         }
 
         String commentCleaned = decodeJavadocTags( description );
 
         // Using jTidy to clean comment
         Tidy tidy = new Tidy();
         tidy.setDocType( "loose" );
         tidy.setXHTML( true );
         tidy.setXmlOut( true );
         tidy.setInputEncoding( "UTF-8" );
         tidy.setOutputEncoding( "UTF-8" );
         tidy.setMakeClean( true );
         tidy.setNumEntities( true );
         tidy.setQuoteNbsp( false );
         tidy.setQuiet( true );
         tidy.setShowWarnings( false );
         try
         {
             ByteArrayOutputStream out = new ByteArrayOutputStream( commentCleaned.length() + 256 );
             tidy.parse( new ByteArrayInputStream( commentCleaned.getBytes( UTF_8 ) ), out );
             commentCleaned = out.toString( "UTF-8" );
         }
         catch ( UnsupportedEncodingException e )
         {
             // cannot happen as every JVM must support UTF-8, see also class javadoc for java.nio.charset.Charset
         }
 
         if ( StringUtils.isEmpty( commentCleaned ) )
         {
             return "";
         }
 
         // strip the header/body stuff
         String ls = System.getProperty( "line.separator" );
         int startPos = commentCleaned.indexOf( "<body>" + ls ) + 6 + ls.length();
         int endPos = commentCleaned.indexOf( ls + "</body>" );
         commentCleaned = commentCleaned.substring( startPos, endPos );
 
         return commentCleaned;
     }
 
     /**
      * Converts a HTML fragment as extracted from a javadoc comment to a plain text string. This method tries to retain
      * as much of the text formatting as possible by means of the following transformations:
      * <ul>
      * <li>List items are converted to leading tabs (U+0009), followed by the item number/bullet, another tab and
      * finally the item contents. Each tab denotes an increase of indentation.</li>
      * <li>Flow breaking elements as well as literal line terminators in preformatted text are converted to a newline
      * (U+000A) to denote a mandatory line break.</li>
      * <li>Consecutive spaces and line terminators from character data outside of preformatted text will be normalized
      * to a single space. The resulting space denotes a possible point for line wrapping.</li>
      * <li>Each space in preformatted text will be converted to a non-breaking space (U+00A0).</li>
      * </ul>
      *
      * @param html The HTML fragment to convert to plain text, may be <code>null</code>.
      * @return A string with HTML tags converted into pure text, never <code>null</code>.
      * @since 2.4.3
      */
     public static String toText( String html )
     {
         if ( StringUtils.isEmpty( html ) )
         {
             return "";
         }
 
         final StringBuilder sb = new StringBuilder();
 
         HTMLEditorKit.Parser parser = new ParserDelegator();
         HTMLEditorKit.ParserCallback htmlCallback = new MojoParserCallback( sb );
 
         try
         {
             parser.parse( new StringReader( makeHtmlValid( html ) ), htmlCallback, true );
         }
         catch ( IOException e )
         {
             throw new RuntimeException( e );
         }
 
         return sb.toString().replace( '\"', '\'' ); // for CDATA
     }
 
     /**
      * ParserCallback implementation.
      */
     private static class MojoParserCallback
         extends HTMLEditorKit.ParserCallback
     {
         /**
          * Holds the index of the current item in a numbered list.
          */
         class Counter
         {
             int value;
         }
 
         /**
          * A flag whether the parser is currently in the body element.
          */
         private boolean body;
 
         /**
          * A flag whether the parser is currently processing preformatted text, actually a counter to track nesting.
          */
         private int preformatted;
 
         /**
          * The current indentation depth for the output.
          */
         private int depth;
 
         /**
          * A stack of {@link Counter} objects corresponding to the nesting of (un-)ordered lists. A
          * <code>null</code> element denotes an unordered list.
          */
         private Stack<Counter> numbering = new Stack<>();
 
         /**
          * A flag whether an implicit line break is pending in the output buffer. This flag is used to postpone the
          * output of implicit line breaks until we are sure that are not to be merged with other implicit line
          * breaks.
          */
         private boolean pendingNewline;
 
         /**
          * A flag whether we have just parsed a simple tag.
          */
         private boolean simpleTag;
 
         /**
          * The current buffer.
          */
         private final StringBuilder sb;
 
         /**
          * @param sb not null
          */
         MojoParserCallback( StringBuilder sb )
         {
             this.sb = sb;
         }
 
         /** {@inheritDoc} */
         @Override
         public void handleSimpleTag( HTML.Tag t, MutableAttributeSet a, int pos )
         {
             simpleTag = true;
             if ( body && HTML.Tag.BR.equals( t ) )
             {
                 newline( false );
             }
         }
 
         /** {@inheritDoc} */
         @Override
         public void handleStartTag( HTML.Tag t, MutableAttributeSet a, int pos )
         {
             simpleTag = false;
             if ( body && ( t.breaksFlow() || t.isBlock() ) )
             {
                 newline( true );
             }
             if ( HTML.Tag.OL.equals( t ) )
             {
                 numbering.push( new Counter() );
             }
             else if ( HTML.Tag.UL.equals( t ) )
             {
                 numbering.push( null );
             }
             else if ( HTML.Tag.LI.equals( t ) )
             {
                 Counter counter = numbering.peek();
                 if ( counter == null )
                 {
                     text( "-\t" );
                 }
                 else
                 {
                     text( ++counter.value + ".\t" );
                 }
                 depth++;
             }
             else if ( HTML.Tag.DD.equals( t ) )
             {
                 depth++;
             }
             else if ( t.isPreformatted() )
             {
                 preformatted++;
             }
             else if ( HTML.Tag.BODY.equals( t ) )
             {
                 body = true;
             }
         }
 
         /** {@inheritDoc} */
         @Override
         public void handleEndTag( HTML.Tag t, int pos )
         {
             if ( HTML.Tag.OL.equals( t ) || HTML.Tag.UL.equals( t ) )
             {
                 numbering.pop();
             }
             else if ( HTML.Tag.LI.equals( t ) || HTML.Tag.DD.equals( t ) )
             {
                 depth--;
             }
             else if ( t.isPreformatted() )
             {
                 preformatted--;
             }
             else if ( HTML.Tag.BODY.equals( t ) )
             {
                 body = false;
             }
             if ( body && ( t.breaksFlow() || t.isBlock() ) && !HTML.Tag.LI.equals( t ) )
             {
                 if ( ( HTML.Tag.P.equals( t ) || HTML.Tag.PRE.equals( t ) || HTML.Tag.OL.equals( t )
                     || HTML.Tag.UL.equals( t ) || HTML.Tag.DL.equals( t ) )
                     && numbering.isEmpty() )
                 {
                     pendingNewline = false;
                     newline( pendingNewline );
                 }
                 else
                 {
                     newline( true );
                 }
             }
         }
 
         /** {@inheritDoc} */
         @Override
         public void handleText( char[] data, int pos )
         {
             /*
              * NOTE: Parsers before JRE 1.6 will parse XML-conform simple tags like <br/> as "<br>" followed by
              * the text event ">..." so we need to watch out for the closing angle bracket.
              */
             int offset = 0;
             if ( simpleTag && data[0] == '>' )
             {
                 simpleTag = false;
                 for ( ++offset; offset < data.length && data[offset] <= ' '; )
                 {
                     offset++;
                 }
             }
             if ( offset < data.length )
             {
                 String text = new String( data, offset, data.length - offset );
                 text( text );
             }
         }
 
         /** {@inheritDoc} */
         @Override
         public void flush()
         {
             flushPendingNewline();
         }
 
         /**
          * Writes a line break to the plain text output.
          *
          * @param implicit A flag whether this is an explicit or implicit line break. Explicit line breaks are
          *            always written to the output whereas consecutive implicit line breaks are merged into a single
          *            line break.
          */
         private void newline( boolean implicit )
         {
             if ( implicit )
             {
                 pendingNewline = true;
             }
             else
             {
                 flushPendingNewline();
                 sb.append( '\n' );
             }
         }
 
         /**
          * Flushes a pending newline (if any).
          */
         private void flushPendingNewline()
         {
             if ( pendingNewline )
             {
                 pendingNewline = false;
                 if ( sb.length() > 0 )
                 {
                     sb.append( '\n' );
                 }
             }
         }
 
         /**
          * Writes the specified character data to the plain text output. If the last output was a line break, the
          * character data will automatically be prefixed with the current indent.
          *
          * @param data The character data, must not be <code>null</code>.
          */
         private void text( String data )
         {
             flushPendingNewline();
             if ( sb.length() <= 0 || sb.charAt( sb.length() - 1 ) == '\n' )
             {
                 for ( int i = 0; i < depth; i++ )
                 {
                     sb.append( '\t' );
                 }
             }
             String text;
             if ( preformatted > 0 )
             {
                 text = data;
             }
             else
             {
                 text = data.replace( '\n', ' ' );
             }
             sb.append( text );
         }
     }
 
     /**
      * Find the best package name, based on the number of hits of actual Mojo classes.
      *
      * @param pluginDescriptor not null
      * @return the best name of the package for the generated mojo
      */
     public static String discoverPackageName( PluginDescriptor pluginDescriptor )
     {
         Map<String, Integer> packageNames = new HashMap<>();
 
         List<MojoDescriptor> mojoDescriptors = pluginDescriptor.getMojos();
         if ( mojoDescriptors == null )
         {
             return "";
         }
         for ( MojoDescriptor descriptor : mojoDescriptors )
         {
 
             String impl = descriptor.getImplementation();
             if ( StringUtils.equals( descriptor.getGoal(), "help" ) && StringUtils.equals( "HelpMojo", impl ) )
             {
                 continue;
             }
             if ( impl.lastIndexOf( '.' ) != -1 )
             {
                 String name = impl.substring( 0, impl.lastIndexOf( '.' ) );
                 if ( packageNames.get( name ) != null )
                 {
                     int next = ( packageNames.get( name ) ).intValue() + 1;
                     packageNames.put( name,  Integer.valueOf( next ) );
                 }
                 else
                 {
                     packageNames.put( name, Integer.valueOf( 1 ) );
                 }
             }
             else
             {
                 packageNames.put( "", Integer.valueOf( 1 ) );
             }
         }
 
         String packageName = "";
         int max = 0;
         for ( Map.Entry<String, Integer> entry : packageNames.entrySet() )
         {
             int value = entry.getValue().intValue();
             if ( value > max )
             {
                 max = value;
                 packageName = entry.getKey();
             }
         }
 
         return packageName;
     }
 
     /**
      * @param impl a Mojo implementation, not null
      * @param project a MavenProject instance, could be null
      * @return <code>true</code> is the Mojo implementation implements <code>MavenReport</code>,
      * <code>false</code> otherwise.
      * @throws IllegalArgumentException if any
      */
     @SuppressWarnings( "unchecked" )
     public static boolean isMavenReport( String impl, MavenProject project )
         throws IllegalArgumentException
     {
         if ( impl == null )
         {
             throw new IllegalArgumentException( "mojo implementation should be declared" );
         }
 
         ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
         if ( project != null )
         {
             List<String> classPathStrings;
             try
             {
                 classPathStrings = project.getCompileClasspathElements();
                 if ( project.getExecutionProject() != null )
                 {
                     classPathStrings.addAll( project.getExecutionProject().getCompileClasspathElements() );
                 }
             }
             catch ( DependencyResolutionRequiredException e )
             {
                 throw new IllegalArgumentException( e );
             }
 
             List<URL> urls = new ArrayList<>( classPathStrings.size() );
             for ( String classPathString : classPathStrings )
             {
                 try
                 {
                     urls.add( new File( classPathString ).toURL() );
                 }
                 catch ( MalformedURLException e )
                 {
                     throw new IllegalArgumentException( e );
                 }
             }
 
             classLoader = new URLClassLoader( urls.toArray( new URL[urls.size()] ), classLoader );
         }
 
         try
         {
             Class<?> clazz = Class.forName( impl, false, classLoader );
 
             return MavenReport.class.isAssignableFrom( clazz );
         }
         catch ( ClassNotFoundException e )
         {
             return false;
         }
     }
 
 }