/*
    *  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. 
   *  
   */
  package org.apache.directory.api.ldap.model.schema.syntaxCheckers;
  
  
  import org.apache.directory.api.ldap.model.constants.SchemaConstants;
  import org.apache.directory.api.ldap.model.schema.SyntaxChecker;
  import org.apache.directory.api.util.Strings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * A SyntaxChecker which verifies that a value is a TeletexTerminalIdentifier according to 
   * RFC 4517 :
   * 
   * teletex-id = ttx-term *(DOLLAR ttx-param)
   * ttx-term   = PrintableString          ; terminal identifier
   * ttx-param  = ttx-key COLON ttx-value  ; parameter
   * ttx-key    = "graphic" | "control" | "misc" | "page" | "private"
   * ttx-value  = *ttx-value-octet
   *
   * ttx-value-octet = %x00-23 | (%x5C "24") | %x25-5B | (%x5C "5C") | %x5D-FF
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  @SuppressWarnings("serial")
  public class TeletexTerminalIdentifierSyntaxChecker extends SyntaxChecker
  {
      /** A logger for this class */
      private static final Logger LOG = LoggerFactory.getLogger( TeletexTerminalIdentifierSyntaxChecker.class );
  
  
      /**
       * Creates a new instance of TeletexTerminalIdentifier.
       */
      public TeletexTerminalIdentifierSyntaxChecker()
      {
          super( SchemaConstants.TELETEX_TERMINAL_IDENTIFIER_SYNTAX );
      }
  
  
      /**
       * {@inheritDoc}
       */
      public boolean isValidSyntax( Object value )
      {
          String strValue = null;
  
          if ( value == null )
          {
              LOG.debug( "Syntax invalid for 'null'" );
              return false;
          }
  
          if ( value instanceof String )
          {
              strValue = ( String ) value;
          }
          else if ( value instanceof byte[] )
          {
              strValue = Strings.utf8ToString( ( byte[] ) value );
          }
          else
          {
              strValue = value.toString();
          }
  
          if ( strValue.length() == 0 )
          {
              LOG.debug( "Syntax invalid for '{}'", value );
              return false;
          }
  
          // Search for the first '$' separator
          int dollar = strValue.indexOf( '$' );
  
          String terminalIdentifier = ( ( dollar == -1 ) ? strValue : strValue.substring( 0, dollar ) );
  
          if ( terminalIdentifier.length() == 0 )
          {
              // It should not be null
             LOG.debug( "Syntax invalid for '{}'", value );
             return false;
         }
 
         if ( !Strings.isPrintableString( terminalIdentifier ) )
         {
             // It's not a valid PrintableString 
             LOG.debug( "Syntax invalid for '{}'", value );
             return false;
         }
 
         if ( dollar == -1 )
         {
             // No ttx-param : let's get out
             LOG.debug( "Syntax valid for '{}'", value );
             return true;
         }
 
         // Ok, now let's deal withh optional ttx-params
         String[] ttxParams = strValue.substring( dollar + 1 ).split( "\\$" );
 
         if ( ttxParams.length == 0 )
         {
             LOG.debug( "Syntax invalid for '{}'", value );
             return false;
         }
 
         for ( String ttxParam : ttxParams )
         {
             int colon = ttxParam.indexOf( ':' );
 
             if ( colon == -1 )
             {
                 // we must have a ':' separator
                 LOG.debug( "Syntax invalid for '{}'", value );
                 return false;
             }
 
             String key = ttxParam.substring( 0, colon );
 
             if ( key.startsWith( "graphic" )
                 || key.startsWith( "control" )
                 || key.startsWith( "misc" )
                 || key.startsWith( "page" )
                 || key.startsWith( "private" ) )
             {
                 if ( colon + 1 == ttxParam.length() )
                 {
                     LOG.debug( "Syntax invalid for '{}'", value );
                     return false;
                 }
 
                 boolean hasEsc = false;
 
                 for ( byte b : Strings.getBytesUtf8( ttxParam ) )
                 {
                     switch ( b )
                     {
                         case 0x24:
                             // '$' is not accepted
                             LOG.debug( "Syntax invalid for '{}'", value );
                             return false;
 
                         case 0x5c:
                             if ( hasEsc )
                             {
                                 // two following \ are not accepted
                                 LOG.debug( "Syntax invalid for '{}'", value );
                                 return false;
                             }
                             else
                             {
                                 hasEsc = true;
                             }
 
                             continue;
 
                         case '2':
                             continue;
 
                         case '4':
                             // We have found a "\24"
                             hasEsc = false;
                             continue;
 
                         case '5':
                             continue;
 
                         case 'c':
                         case 'C':
                             // We have found a "\5c" or a "\5C"
                             hasEsc = false;
                             continue;
 
                         default:
                             if ( hasEsc )
                             {
                                 // A \ should be followed by "24" or "5c" or "5C"
                                 return false;
                             }
 
                             continue;
                     }
                 }
             }
             else
             {
                 LOG.debug( "Syntax invalid for '{}'", value );
                 return false;
             }
         }
 
         LOG.debug( "Syntax valid for '{}'", value );
         return true;
     }
 }