package org.apache.maven.doxia.module.fo;
   
   /*
    * 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.IOException;
  import java.util.List;
  
  import javax.swing.text.MutableAttributeSet;
  import javax.swing.text.SimpleAttributeSet;
  
  import org.apache.commons.configuration.ConfigurationException;
  import org.apache.commons.configuration.XMLConfiguration;
  import org.apache.maven.doxia.sink.impl.SinkUtils;
  import org.codehaus.plexus.util.ReaderFactory;
  
  /**
   * A utility class to construct FO configuration parameters.
   *
   * @author ltheussl
   * @since 1.1
   */
  public class FoConfiguration
  {
      /** Holds the single attributes. */
      private MutableAttributeSet attributeSet;
  
      /** The configuration instance. */
      private final XMLConfiguration config;
  
      /** The list of attribute sets. */
      private List<?> sets;
  
      /**
       * Constructor.
       */
      public FoConfiguration()
      {
          this.config = new XMLConfiguration();
  
          // necessary because some attributes contain commas:
          config.setDelimiterParsingDisabled( true );
  
          loadDefaultConfig();
      }
  
      /**
       * Load configuration parameters from a File.
       *
       * @param configFile the configuration file.
       *
       * @throws java.io.IOException if the File cannot be read
       *  or some error occurs when initializing the configuration parameters.
       *
       * @since 1.1.1
       */
      public void load( File configFile )
              throws IOException
      {
          config.clear();
  
          try
          {
              config.load( configFile );
          }
          catch ( ConfigurationException cex )
          {
              throw new IOException( cex );
          }
  
          loadDefaultConfig(); // this adds default values that are missing from above
      }
  
      /**
       * Builds a list of attributes.
       *
       * @param attributeId A unique id to identify the set of attributes.
       * This should correspond to the name of an attribute-set
       * defined in the configuration file.
       * @return A string that contains a list of attributes with
       * the values configured for the current builder. Returns the
       * empty string if attributeId is null or if attributeId
      * is not a valid identifier.
      */
     public String getAttributeString( String attributeId )
     {
         if ( attributeId == null )
         {
             return "";
         }
 
         reset();
         addAttributes( attributeId );
 
         return SinkUtils.getAttributeString( attributeSet );
     }
 
     /**
      * Builds a set of attributes.
      *
      * @param attributeId A unique id to identify the set of attributes.
      * This should correspond to the name of an attribute-set
      * defined in the configuration file.
      * @return A MutableAttributeSet that contains the attributes with
      * the values configured for the current builder. Returns null
      * if attributeId is null or empty, or if attributeId is not a valid identifier.
      */
     public MutableAttributeSet getAttributeSet( String attributeId )
     {
         if ( attributeId == null || attributeId.length() == 0 )
         {
             return null;
         }
 
         reset();
         addAttributes( attributeId );
 
         if ( attributeSet.getAttributeCount() == 0 )
         {
             return null;
         }
 
         return attributeSet;
     }
 
     /**
      * Adds an attribute to the current StringBuilder.
      *
      * @param attributeId A unique id to identify the set of attributes.
      * This should correspond to the name of an attribute-set
      * defined in the configuration file.
      */
     private void addAttributes( String attributeId )
     {
         int index = sets.indexOf( attributeId );
         String keybase = "xsl:attribute-set(" + index + ")";
 
         Object prop = config.getProperty( keybase + ".xsl:attribute" );
 
         if ( prop instanceof List<?> )
         {
             List<?> values = (List<?>) prop;
             List<?> keys = config.getList( keybase + ".xsl:attribute[@name]" );
 
             for ( int i = 0; i < values.size(); i++ )
             {
                 attributeSet.addAttribute( keys.get( i ), values.get( i ) );
             }
         }
         else if ( prop instanceof String )
         {
             String value = config.getString( keybase + ".xsl:attribute" );
             String key = config.getString( keybase + ".xsl:attribute[@name]" );
             attributeSet.addAttribute( key, value );
         }
 
         String extend = config.getString( keybase + "[@use-attribute-sets]" );
 
         if ( extend != null )
         {
             addAttributes( extend );
         }
     }
 
     /** Load the default fo configuration file. */
     private void loadDefaultConfig()
     {
         try
         {
             config.load( ReaderFactory.newXmlReader( getClass().getResourceAsStream( "/fo-styles.xslt" ) ) );
         }
         catch ( ConfigurationException | IOException cex )
         {
             // this should not happen
             throw new RuntimeException( cex );
         }
 
         this.sets = config.getList( "xsl:attribute-set[@name]" );
         reset();
     }
 
     /**
      * (Re-)initialize the AttributeSet.
      */
     private void reset()
     {
         this.attributeSet = new SimpleAttributeSet();
     }
 
 }