/*
    *  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.i18n.I18n;
  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;
  
  
  /**
   * A SyntaxChecker which verifies that a value is a TeletexTerminalIdentifier according to 
   * RFC 4517 :
   * <pre>
   * 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
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  @SuppressWarnings("serial")
  public final class TeletexTerminalIdentifierSyntaxChecker extends SyntaxChecker
  {
      /**
       * A static instance of TeletexTerminalIdentifierSyntaxChecker
       */
      public static final TeletexTerminalIdentifierSyntaxChecker INSTANCE = 
          new TeletexTerminalIdentifierSyntaxChecker( SchemaConstants.TELETEX_TERMINAL_IDENTIFIER_SYNTAX );
      
      /**
       * A static Builder for this class
       */
      public static final class Builder extends SCBuilder<TeletexTerminalIdentifierSyntaxChecker>
      {
          /**
           * The Builder constructor
           */
          private Builder()
          {
              super( SchemaConstants.TELETEX_TERMINAL_IDENTIFIER_SYNTAX );
          }
          
          
          /**
           * Create a new instance of TeletexTerminalIdentifierSyntaxChecker
           * @return A new instance of TeletexTerminalIdentifierSyntaxChecker
           */
          @Override
          public TeletexTerminalIdentifierSyntaxChecker build()
          {
              return new TeletexTerminalIdentifierSyntaxChecker( oid );
          }
      }
  
      
      /**
       * Creates a new instance of TeletexTerminalIdentifier.
       * 
       * @param oid the child's OID
       */
      private TeletexTerminalIdentifierSyntaxChecker( String oid )
      {
          super( oid );
      }
  
      
      /**
       * @return An instance of the Builder for this class
       */
      public static Builder builder()
      {
          return new Builder();
      }
  
  
      /**
       * {@inheritDoc}
      */
     @Override
     public boolean isValidSyntax( Object value )
     {
         String strValue;
 
         if ( value == null )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, "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 )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, 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
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
             }
             
             return false;
         }
 
         if ( !Strings.isPrintableString( terminalIdentifier ) )
         {
             // It's not a valid PrintableString 
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
             }
             
             return false;
         }
 
         if ( dollar == -1 )
         {
             // No ttx-param : let's get out
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.msg( I18n.MSG_04489_SYNTAX_VALID, value ) );
             }
             
             return true;
         }
 
         // Ok, now let's deal with optional ttx-params
         String[] ttxParams = strValue.substring( dollar + 1 ).split( "\\$" );
 
         if ( ttxParams.length == 0 )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
             }
                 
             return false;
         }
 
         for ( String ttxParam : ttxParams )
         {
             int colon = ttxParam.indexOf( ':' );
 
             if ( colon == -1 )
             {
                 // we must have a ':' separator
                 if ( LOG.isDebugEnabled() )
                 {
                     LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, 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() )
                 {
                     if ( LOG.isDebugEnabled() )
                     {
                         LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
                     }
                     
                     return false;
                 }
 
                 boolean hasEsc = false;
 
                 for ( byte b : Strings.getBytesUtf8( ttxParam ) )
                 {
                     switch ( b )
                     {
                         case 0x24:
                             // '$' is not accepted
                             if ( LOG.isDebugEnabled() )
                             {
                                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
                             }
                             
                             return false;
 
                         case 0x5c:
                             if ( hasEsc )
                             {
                                 // two following \ are not accepted
                                 if ( LOG.isDebugEnabled() )
                                 {
                                     LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, 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
             {
                 if ( LOG.isDebugEnabled() )
                 {
                     LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
                 }
                 
                 return false;
             }
         }
 
         if ( LOG.isDebugEnabled() )
         {
             LOG.debug( I18n.msg( I18n.MSG_04489_SYNTAX_VALID, value ) );
         }
         
         return true;
     }
 }