/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2009 Sun Microsystems, Inc.
 */
package org.opends.sdk.schema;



import static com.sun.opends.sdk.util.StringPrepProfile.*;

import org.opends.sdk.*;



/**
 * This class implements the keywordMatch matching rule defined in
 * X.520. That document defines "keyword" as implementation-specific,
 * but in this case we will consider it a match if the assertion value
 * is contained within the attribute value and is bounded by the edge of
 * the value or any of the following characters: <BR>
 * <UL>
 * <LI>A space</LI>
 * <LI>A period</LI>
 * <LI>A comma</LI>
 * <LI>A slash</LI>
 * <LI>A dollar sign</LI>
 * <LI>A plus sign</LI>
 * <LI>A dash</LI>
 * <LI>An underscore</LI>
 * <LI>An octothorpe</LI>
 * <LI>An equal sign</LI>
 * </UL>
 */
final class KeywordEqualityMatchingRuleImpl extends
    AbstractMatchingRuleImpl
{
  @Override
  public Assertion getAssertion(Schema schema, ByteSequence value)
      throws DecodeException
  {
    final String normalStr = normalize(value);

    return new Assertion()
    {
      public ConditionResult matches(ByteSequence attributeValue)
      {
        // See if the assertion value is contained in the attribute
        // value. If not, then it isn't a match.
        final String valueStr1 = attributeValue.toString();

        final int pos = valueStr1.indexOf(normalStr);
        if (pos < 0)
        {
          return ConditionResult.FALSE;
        }

        if (pos > 0)
        {
          final char c = valueStr1.charAt(pos - 1);
          switch (c)
          {
          case ' ':
          case '.':
          case ',':
          case '/':
          case '$':
          case '+':
          case '-':
          case '_':
          case '#':
          case '=':
            // These are all acceptable.
            break;

          default:
            // Anything else is not.
            return ConditionResult.FALSE;
          }
        }

        if (valueStr1.length() > pos + normalStr.length())
        {
          final char c = valueStr1.charAt(pos + normalStr.length());
          switch (c)
          {
          case ' ':
          case '.':
          case ',':
          case '/':
          case '$':
          case '+':
          case '-':
          case '_':
          case '#':
          case '=':
            // These are all acceptable.
            break;

          default:
            // Anything else is not.
            return ConditionResult.FALSE;
          }
        }

        // If we've gotten here, then we can assume it is a match.
        return ConditionResult.TRUE;
      }
    };
  }



  public ByteString normalizeAttributeValue(Schema schema,
      ByteSequence value)
  {
    return ByteString.valueOf(normalize(value));
  }



  private String normalize(ByteSequence value)
  {
    final StringBuilder buffer = new StringBuilder();
    prepareUnicode(buffer, value, TRIM, CASE_FOLD);

    final int bufferLength = buffer.length();
    if (bufferLength == 0)
    {
      if (value.length() > 0)
      {
        // This should only happen if the value is composed entirely of
        // spaces. In that case, the normalized value is a single space.
        return " ".intern();
      }
      else
      {
        // The value is empty, so it is already normalized.
        return "".intern();
      }
    }

    // Replace any consecutive spaces with a single space.
    for (int pos = bufferLength - 1; pos > 0; pos--)
    {
      if (buffer.charAt(pos) == ' ')
      {
        if (buffer.charAt(pos - 1) == ' ')
        {
          buffer.delete(pos, pos + 1);
        }
      }
    }

    return buffer.toString();
  }
}