package org.apache.maven.plugins.checkstyle;
   
   /*
    * 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.util.ArrayList;
  import java.util.List;
  
  import org.codehaus.plexus.util.StringUtils;
  
  import com.puppycrawl.tools.checkstyle.api.AuditEvent;
  
  /**
   * Tooling for Checkstyle rules conventions: names, categories.
   *
   * @author Hervé Boutemy
   * @since 2.13
   */
  public final class RuleUtil
  {
      private RuleUtil()
      {
          // hide utility class constructor
      }
      
      private static final String CHECKSTYLE_PACKAGE = "com.puppycrawl.tools.checkstyle.checks";
  
      /**
       * Get the rule name from an audit event.
       *
       * @param event the audit event
       * @return the rule name, which is the class name without package and removed eventual "Check" suffix
       */
      public static String getName( AuditEvent event )
      {
          return getName( event.getSourceName() );
      }
      /**
       * Get the rule name from an audit event source name.
       *
       * @param eventSrcName the audit event source name
       * @return the rule name, which is the class name without package and removed eventual "Check" suffix
       */
      public static String getName( String eventSrcName )
      {
          if ( eventSrcName == null )
          {
              return null;
          }
  
          if ( eventSrcName.endsWith( "Check" ) )
          {
              eventSrcName = eventSrcName.substring( 0, eventSrcName.length() - 5 );
          }
  
          return eventSrcName.substring( eventSrcName.lastIndexOf( '.' ) + 1 );
      }
  
      /**
       * Get the rule category from an audit event.
       *
       * @param event the audit event
       * @return the rule category, which is the last package name or "misc" or "extension"
       */
      public static String getCategory( AuditEvent event )
      {
          return getCategory( event.getSourceName() );
      }
  
      /**
       * Get the rule category from an audit event source name.
       *
       * @param eventSrcName the audit event source name
       * @return the rule category, which is the last package name or "misc" or "extension"
       */
      public static String getCategory( String eventSrcName )
      {
          if ( eventSrcName == null )
          {
              return null;
          }
  
          int end = eventSrcName.lastIndexOf( '.' );
         eventSrcName = end == -1 ? eventSrcName : eventSrcName.substring( 0,  end );
 
         if ( CHECKSTYLE_PACKAGE.equals( eventSrcName ) )
         {
             return "misc";
         }
         else if ( !eventSrcName.startsWith( CHECKSTYLE_PACKAGE ) )
         {
             return "extension";
         }
 
         return eventSrcName.substring( eventSrcName.lastIndexOf( '.' ) + 1 );
     }
 
     public static List<Matcher> parseMatchers( String[] specs )
     {
         List<Matcher> matchers = new ArrayList<>();
         for ( String spec : specs )
         {
             if ( StringUtils.isBlank( spec ) )
             {
                 continue;
             }
             spec = spec.trim();
             Matcher matcher;
             if ( Character.isUpperCase( spec.charAt( 0 ) ) )
             {
                 // spec starting with uppercase is a rule name
                 matcher = new RuleMatcher( spec );
             }
             else if ( "misc".equals( spec ) )
             {
                 // "misc" is a special case
                 matcher = new PackageMatcher( CHECKSTYLE_PACKAGE );
             }
             else if ( "extension".equals( spec ) )
             {
                 // "extension" is a special case
                 matcher = new ExtensionMatcher();
             }
             else if ( !spec.contains( "." ) )
             {
                 matcher = new PackageMatcher( CHECKSTYLE_PACKAGE + '.' + spec );
             }
             else
             {
                 // by default, spec is a package name
                 matcher = new PackageMatcher( spec );
             }
             matchers.add( matcher );
         }
         return matchers;
     }
 
     /**
      * Audit event source name matcher.
      */
     public interface Matcher
     {
         /**
          * Does the event source name match?
          * @param eventSrcName the event source name
          * @return boolean
          */
         boolean match( String eventSrcName );
     }
 
     private static class RuleMatcher
         implements Matcher
     {
         private final String rule;
 
         RuleMatcher( String rule )
         {
             this.rule = rule;
         }
 
         public boolean match( String eventSrcName )
         {
             return rule.equals( getName( eventSrcName ) );
         }
     }
 
     private static class PackageMatcher
         implements Matcher
     {
         private final String packageName;
 
         PackageMatcher( String packageName )
         {
             this.packageName = packageName;
         }
 
         public boolean match( String eventSrcName )
         {
             return eventSrcName.startsWith( packageName )
                 && !eventSrcName.substring( packageName.length() + 1 ).contains( "." );
         }
     }
 
     /**
      * An extension does not start with Checkstyle package.
      */
     private static class ExtensionMatcher
         implements Matcher
     {
         public boolean match( String eventSrcName )
         {
             return !eventSrcName.startsWith( CHECKSTYLE_PACKAGE );
         }
     }
 }