/*
 * 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.messages.Messages.*;

import java.util.LinkedList;
import java.util.List;

import org.opends.sdk.*;

import com.sun.opends.sdk.util.SubstringReader;



/**
 * This class implements a default substring matching rule that matches
 * normalized substring assertion values in byte order.
 */
abstract class AbstractSubstringMatchingRuleImpl extends
    AbstractMatchingRuleImpl
{
  static class DefaultSubstringAssertion implements Assertion
  {
    private final ByteString normInitial;
    private final ByteString[] normAnys;
    private final ByteString normFinal;



    protected DefaultSubstringAssertion(final ByteString normInitial,
        final ByteString[] normAnys, final ByteString normFinal)
    {
      this.normInitial = normInitial;
      this.normAnys = normAnys;
      this.normFinal = normFinal;
    }



    public ConditionResult matches(final ByteSequence attributeValue)
    {
      final int valueLength = attributeValue.length();

      int pos = 0;
      if (normInitial != null)
      {
        final int initialLength = normInitial.length();
        if (initialLength > valueLength)
        {
          return ConditionResult.FALSE;
        }

        for (; pos < initialLength; pos++)
        {
          if (normInitial.byteAt(pos) != attributeValue.byteAt(pos))
          {
            return ConditionResult.FALSE;
          }
        }
      }

      if (normAnys != null && normAnys.length != 0)
      {
        for (final ByteSequence element : normAnys)
        {
          final int anyLength = element.length();
          if (anyLength == 0)
          {
            continue;
          }
          final int end = valueLength - anyLength;
          boolean match = false;
          for (; pos <= end; pos++)
          {
            if (element.byteAt(0) == attributeValue.byteAt(pos))
            {
              boolean subMatch = true;
              for (int i = 1; i < anyLength; i++)
              {
                if (element.byteAt(i) != attributeValue.byteAt(pos + i))
                {
                  subMatch = false;
                  break;
                }
              }

              if (subMatch)
              {
                match = subMatch;
                break;
              }
            }
          }

          if (match)
          {
            pos += anyLength;
          }
          else
          {
            return ConditionResult.FALSE;
          }
        }
      }

      if (normFinal != null)
      {
        final int finalLength = normFinal.length();

        if (valueLength - finalLength < pos)
        {
          return ConditionResult.FALSE;
        }

        pos = valueLength - finalLength;
        for (int i = 0; i < finalLength; i++, pos++)
        {
          if (normFinal.byteAt(i) != attributeValue.byteAt(pos))
          {
            return ConditionResult.FALSE;
          }
        }
      }

      return ConditionResult.TRUE;
    }
  }



  AbstractSubstringMatchingRuleImpl()
  {
    // Nothing to do.
  }



  @Override
  public Assertion getAssertion(final Schema schema, final ByteSequence value)
      throws DecodeException
  {
    if (value.length() == 0)
    {
      throw DecodeException.error(WARN_ATTR_SYNTAX_SUBSTRING_EMPTY.get());
    }

    ByteSequence initialString = null;
    ByteSequence finalString = null;
    List<ByteSequence> anyStrings = null;

    final String valueString = value.toString();

    if (valueString.length() == 1 && valueString.charAt(0) == '*')
    {
      return getAssertion(schema, initialString, anyStrings, finalString);
    }

    final char[] escapeChars = new char[] { '*' };
    final SubstringReader reader = new SubstringReader(valueString);

    ByteString bytes = evaluateEscapes(reader, escapeChars, false);
    if (bytes.length() > 0)
    {
      initialString = normalizeSubString(schema, bytes);
    }
    if (reader.remaining() == 0)
    {
      throw DecodeException.error(WARN_ATTR_SYNTAX_SUBSTRING_NO_WILDCARDS
          .get(value.toString()));
    }
    while (true)
    {
      reader.read();
      bytes = evaluateEscapes(reader, escapeChars, false);
      if (reader.remaining() > 0)
      {
        if (bytes.length() == 0)
        {
          throw DecodeException
              .error(WARN_ATTR_SYNTAX_SUBSTRING_CONSECUTIVE_WILDCARDS.get(value
                  .toString(), reader.pos()));
        }
        if (anyStrings == null)
        {
          anyStrings = new LinkedList<ByteSequence>();
        }
        anyStrings.add(normalizeSubString(schema, bytes));
      }
      else
      {
        if (bytes.length() > 0)
        {
          finalString = normalizeSubString(schema, bytes);
        }
        break;
      }
    }

    return getAssertion(schema, initialString, anyStrings, finalString);
  }



  @Override
  public Assertion getAssertion(final Schema schema,
      final ByteSequence subInitial,
      final List<? extends ByteSequence> subAnyElements,
      final ByteSequence subFinal) throws DecodeException
  {
    final ByteString normInitial = subInitial == null ? null
        : normalizeSubString(schema, subInitial);

    ByteString[] normAnys = null;
    if (subAnyElements != null && !subAnyElements.isEmpty())
    {
      normAnys = new ByteString[subAnyElements.size()];
      for (int i = 0; i < subAnyElements.size(); i++)
      {
        normAnys[i] = normalizeSubString(schema, subAnyElements.get(i));
      }
    }
    final ByteString normFinal = subFinal == null ? null : normalizeSubString(
        schema, subFinal);

    return new DefaultSubstringAssertion(normInitial, normAnys, normFinal);
  }



  ByteString normalizeSubString(final Schema schema, final ByteSequence value)
      throws DecodeException
  {
    return normalizeAttributeValue(schema, value);
  }



  private char evaluateEscapedChar(final SubstringReader reader,
      final char[] escapeChars) throws DecodeException
  {
    final char c1 = reader.read();
    byte b;
    switch (c1)
    {
    case '0':
      b = 0x00;
      break;
    case '1':
      b = 0x10;
      break;
    case '2':
      b = 0x20;
      break;
    case '3':
      b = 0x30;
      break;
    case '4':
      b = 0x40;
      break;
    case '5':
      b = 0x50;
      break;
    case '6':
      b = 0x60;
      break;
    case '7':
      b = 0x70;
      break;
    case '8':
      b = (byte) 0x80;
      break;
    case '9':
      b = (byte) 0x90;
      break;
    case 'A':
    case 'a':
      b = (byte) 0xA0;
      break;
    case 'B':
    case 'b':
      b = (byte) 0xB0;
      break;
    case 'C':
    case 'c':
      b = (byte) 0xC0;
      break;
    case 'D':
    case 'd':
      b = (byte) 0xD0;
      break;
    case 'E':
    case 'e':
      b = (byte) 0xE0;
      break;
    case 'F':
    case 'f':
      b = (byte) 0xF0;
      break;
    default:
      if (c1 == 0x5C)
      {
        return c1;
      }
      if (escapeChars != null)
      {
        for (final char escapeChar : escapeChars)
        {
          if (c1 == escapeChar)
          {
            return c1;
          }
        }
      }
      final LocalizableMessage message = ERR_INVALID_ESCAPE_CHAR.get(reader
          .getString(), c1);
      throw DecodeException.error(message);
    }

    // The two positions must be the hex characters that
    // comprise the escaped value.
    if (reader.remaining() == 0)
    {
      final LocalizableMessage message = ERR_HEX_DECODE_INVALID_LENGTH
          .get(reader.getString());

      throw DecodeException.error(message);
    }

    final char c2 = reader.read();
    switch (c2)
    {
    case '0':
      // No action required.
      break;
    case '1':
      b |= 0x01;
      break;
    case '2':
      b |= 0x02;
      break;
    case '3':
      b |= 0x03;
      break;
    case '4':
      b |= 0x04;
      break;
    case '5':
      b |= 0x05;
      break;
    case '6':
      b |= 0x06;
      break;
    case '7':
      b |= 0x07;
      break;
    case '8':
      b |= 0x08;
      break;
    case '9':
      b |= 0x09;
      break;
    case 'A':
    case 'a':
      b |= 0x0A;
      break;
    case 'B':
    case 'b':
      b |= 0x0B;
      break;
    case 'C':
    case 'c':
      b |= 0x0C;
      break;
    case 'D':
    case 'd':
      b |= 0x0D;
      break;
    case 'E':
    case 'e':
      b |= 0x0E;
      break;
    case 'F':
    case 'f':
      b |= 0x0F;
      break;
    default:
      final LocalizableMessage message = ERR_HEX_DECODE_INVALID_CHARACTER.get(
          new String(new char[] { c1, c2 }), c1);
      throw DecodeException.error(message);
    }
    return (char) b;
  }



  private ByteString evaluateEscapes(final SubstringReader reader,
      final char[] escapeChars, final boolean trim) throws DecodeException
  {
    return evaluateEscapes(reader, escapeChars, escapeChars, trim);
  }



  private ByteString evaluateEscapes(final SubstringReader reader,
      final char[] escapeChars, final char[] delimiterChars, final boolean trim)
      throws DecodeException
  {
    int length = 0;
    int lengthWithoutSpace = 0;
    char c;
    ByteStringBuilder valueBuffer = null;

    if (trim)
    {
      reader.skipWhitespaces();
    }

    reader.mark();
    while (reader.remaining() > 0)
    {
      c = reader.read();
      if (c == 0x5C) // The backslash character
      {
        if (valueBuffer == null)
        {
          valueBuffer = new ByteStringBuilder();
        }
        valueBuffer.append(reader.read(length));
        valueBuffer.append(evaluateEscapedChar(reader, escapeChars));
        reader.mark();
        length = lengthWithoutSpace = 0;
      }
      if (delimiterChars != null)
      {
        for (final char delimiterChar : delimiterChars)
        {
          if (c == delimiterChar)
          {
            reader.reset();
            if (valueBuffer != null)
            {
              if (trim)
              {
                valueBuffer.append(reader.read(lengthWithoutSpace));
              }
              else
              {
                valueBuffer.append(reader.read(length));
              }
              return valueBuffer.toByteString();
            }
            else
            {
              if (trim)
              {
                if (lengthWithoutSpace > 0)
                {
                  return ByteString.valueOf(reader.read(lengthWithoutSpace));
                }
                return ByteString.empty();
              }
              if (length > 0)
              {
                return ByteString.valueOf(reader.read(length));
              }
              return ByteString.empty();
            }
          }
        }
      }
      length++;
      if (c != ' ')
      {
        lengthWithoutSpace = length;
      }
      else
      {
        lengthWithoutSpace++;
      }
    }

    reader.reset();
    if (valueBuffer != null)
    {
      if (trim)
      {
        valueBuffer.append(reader.read(lengthWithoutSpace));
      }
      else
      {
        valueBuffer.append(reader.read(length));
      }
      return valueBuffer.toByteString();
    }
    else
    {
      if (trim)
      {
        if (lengthWithoutSpace > 0)
        {
          return ByteString.valueOf(reader.read(lengthWithoutSpace));
        }
        return ByteString.empty();
      }
      if (length > 0)
      {
        return ByteString.valueOf(reader.read(length));
      }
      return ByteString.empty();
    }
  }
}