/*
    *  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.Chars;
  import org.apache.directory.api.util.Strings;
  
  
  /**
   * A SyntaxChecker which verifies that a value is a Boolean according to RFC 4517.
   * <br>
   * From RFC 4512 &amp; RFC 4517 :
   * <pre>
   * BitString    = SQUOTE *binary-digit SQUOTE "B"
   * binary-digit = "0" / "1"
   * SQUOTE       = %x27                           ; hyphen ("'")
   * </pre>
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  @SuppressWarnings("serial")
  public final class BitStringSyntaxChecker extends SyntaxChecker
  {
      /**
       * A static instance of BitStringSyntaxChecker
       */
      public static final BitStringSyntaxChecker INSTANCE = new BitStringSyntaxChecker( SchemaConstants.BIT_STRING_SYNTAX );
  
      /**
       * A static Builder for this class
       */
      public static final class Builder extends SCBuilder<BitStringSyntaxChecker>
      {
          /**
           * The Builder constructor
           */
          private Builder()
          {
              super( SchemaConstants.BIT_STRING_SYNTAX );
          }
          
          
          /**
           * Create a new instance of BitStringSyntaxChecker
           * @return A new instance of BitStringSyntaxChecker
           */
          @Override
          public BitStringSyntaxChecker build()
          {
              return new BitStringSyntaxChecker( oid );
          }
      }
  
      
      /**
       * Creates a new instance of BitStringSyntaxChecker.
       *
       * @param oid The OID to use for this SyntaxChecker
       */
      private BitStringSyntaxChecker( String oid )
      {
          super( oid );
      }
  
  
      /**
       * @return An instance of the Builder for this class
       */
      public static Builder builder()
      {
          return new Builder();
      }
  
  
      /**
       * A shared and static method used to check that the string is a BitString.
       * A BitString is a string of bits, between quotes and followed by a 'B' :
       * 
      * '01010110'B for instance
      * 
      * @param strValue The string to check
      * @return <code>true</code> if the string is a BitString
      */
     public static boolean isValid( String strValue )
     {
         if ( strValue.length() == 0 )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, strValue ) );
             }
             
             return false;
         }
 
         int pos = 0;
 
         // Check that the String respect the syntax : ' ([01]+) ' B
         if ( !Strings.isCharASCII( strValue, pos++, '\'' ) )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, strValue ) );
             }
             
             return false;
         }
 
         // We must have at least one bit
         if ( !Chars.isBit( strValue, pos++ ) )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, strValue ) );
             }
             
             return false;
         }
 
         while ( Chars.isBit( strValue, pos ) )
         {
             // Loop until we get a char which is not a 0 or a 1
             pos++;
         }
 
         // Now, we must have a simple quote 
         if ( !Strings.isCharASCII( strValue, pos++, '\'' ) )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, strValue ) );
             }
             
             return false;
         }
 
         // followed by a 'B'
         if ( !Strings.isCharASCII( strValue, pos, 'B' ) )
         {
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.err( I18n.ERR_04488_SYNTAX_INVALID, strValue ) );
             }
             
             return false;
         }
 
         if ( LOG.isDebugEnabled() )
         {
             LOG.debug( I18n.msg( I18n.MSG_04489_SYNTAX_VALID, strValue ) );
         }
         
         return true;
     }
 
 
     /**
      * {@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();
         }
 
         return isValid( strValue );
     }
 }