/*
    *  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 Directory String according to RFC 4517.
   * 
   * From RFC 4517 :
   * 
   * <pre>
   * DirectoryString = 1*UTF8
   * </pre>
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  @SuppressWarnings("serial")
  public final class DirectoryStringSyntaxChecker extends SyntaxChecker
  {
      /**
       * A static instance of DirectoryStringSyntaxChecker
       */
      public static final DirectoryStringSyntaxChecker INSTANCE = 
          new DirectoryStringSyntaxChecker( SchemaConstants.DIRECTORY_STRING_SYNTAX );
      
      /**
       * A static Builder for this class
       */
      public static final class Builder extends SCBuilder<DirectoryStringSyntaxChecker>
      {
          /**
           * The Builder constructor
           */
          private Builder()
          {
              super( SchemaConstants.DIRECTORY_STRING_SYNTAX );
          }
          
          
          /**
           * Create a new instance of DirectoryStringSyntaxChecker
           * @return A new instance of DirectoryStringSyntaxChecker
           */
          @Override
          public DirectoryStringSyntaxChecker build()
          {
              return new DirectoryStringSyntaxChecker( oid );
          }
      }
  
      
      /**
       * Creates a new instance of DirectoryStringSyntaxChecker.
       * 
       * @param oid The OID to use for this SyntaxChecker
       */
      private DirectoryStringSyntaxChecker( 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 the value was an invalid UTF8 string, then it's length
         // will be 0 as the StringTools.utf8ToString() call will
         // return an empty string
         if ( strValue.length() == 0 )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, value ) );
             }
             
             return false;
         }
 
         // In any other case, we have to check that the
         // string does not contains the '0xFFFD' character
         for ( char c : strValue.toCharArray() )
         {
             if ( c == 0xFFFD )
             {
                 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;
     }
 }