package org.apache.maven.doxia.module.twiki.parser;
   
   /*
    * 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.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.maven.doxia.util.ByLineSource;
  import org.apache.maven.doxia.parser.ParseException;
  
  /**
   * Parse looking for sections
   *
   * @author Juan F. Codagnone
   */
  public class SectionBlockParser
      implements BlockParser
  {
      /**
       * '---++ Header', '---## Header'
       */
      private static final Pattern HEADER_DA = Pattern.compile( "^---([+]+)\\s*(.+)\\s*$" );
  
      /**
       * {@link ParagraphBlockParser} to use. injected
       */
      private ParagraphBlockParser paraParser;
  
      /**
       * {@link ParagraphBlockParser} to use. injected
       */
      private HRuleBlockParser hrulerParser;
  
      /** {@link VerbatimBlockParser} */
      private VerbatimBlockParser verbatimBlockParser;
  
      /** {@inheritDoc} */
      public final boolean accept( final String line )
      {
          return HEADER_DA.matcher( line ).lookingAt();
      }
  
      /** {@inheritDoc} */
      public final Block visit( final String line, final ByLineSource source )
          throws ParseException
      {
          final Matcher m = HEADER_DA.matcher( line );
  
          if ( !m.lookingAt() )
          {
              throw new IllegalArgumentException( "don't know how to handle: " + line );
          }
  
          String newLine;
          final ArrayList<Block> blocks = new ArrayList<>();
  
          while ( ( newLine = source.getNextLine() ) != null && !accept( newLine ) )
          {
              if ( hrulerParser.accept( newLine ) )
              {
                  blocks.add( hrulerParser.visit( newLine, source ) );
              }
              else
              {
                  if ( verbatimBlockParser.accept( newLine ) )
                  {
                      blocks.add( verbatimBlockParser.visit( newLine, source ) );
                  }
                  else
                  {
                      blocks.add( paraParser.visit( newLine, source ) );
                  }
              }
          }
  
          if ( newLine != null )
          {
              source.ungetLine();
          }
  
          return new SectionBlock( m.group( 2 ), getLevel( m.group( 1 ) ), blocks.toArray( new Block[] {} ) );
     }
 
     /**
      * @param s "++"
      * @return tha level of the section
      * @throws IllegalArgumentException on error
      */
     static int getLevel( final String s )
         throws IllegalArgumentException
     {
         for ( int i = 0, n = s.length(); i < n; i++ )
         {
             if ( s.charAt( i ) != '+' )
             {
                 throw new IllegalArgumentException( "the argument must have only" + " '+' characters" );
             }
         }
         return s.length();
     }
 
     /**
      * Sets the paraParser.
      *
      * @param paraParser <code>ParagraphBlockParser</code> with the paraParser.
      */
     public final void setParaParser( final ParagraphBlockParser paraParser )
     {
         if ( paraParser == null )
         {
             throw new IllegalArgumentException( "argument can't be null" );
         }
         this.paraParser = paraParser;
     }
 
     /**
      * Sets the hrulerParser.
      *
      * @param hrulerParser <code>HRuleBlockParser</code> with the hrulerParser.
      */
     public final void setHrulerParser( final HRuleBlockParser hrulerParser )
     {
         if ( hrulerParser == null )
         {
             throw new IllegalArgumentException( "argument can't be null" );
         }
         this.hrulerParser = hrulerParser;
     }
 
     /**
      * Sets the verbatimBlockParser.
      *
      * @param verbatimBlockParser <code>VerbatimBlockParser</code> with the verbatimBlockParser.
      * @since 1.1
      */
     public final void setVerbatimBlockParser( VerbatimBlockParser verbatimBlockParser )
     {
         if ( verbatimBlockParser == null )
         {
             throw new IllegalArgumentException( "argument can't be null" );
         }
         this.verbatimBlockParser = verbatimBlockParser;
     }
 }