/*
 * 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 2010 Sun Microsystems, Inc.
 */
package org.opends.sdk.controls;



import static com.sun.opends.sdk.messages.Messages.ERR_SORTRES_CONTROL_BAD_OID;
import static com.sun.opends.sdk.messages.Messages.INFO_SORTRES_CONTROL_CANNOT_DECODE_VALUE;
import static com.sun.opends.sdk.messages.Messages.INFO_SORTRES_CONTROL_NO_VALUE;
import static com.sun.opends.sdk.util.StaticUtils.getExceptionMessage;

import java.io.IOException;

import org.opends.sdk.*;
import org.opends.sdk.asn1.ASN1;
import org.opends.sdk.asn1.ASN1Reader;
import org.opends.sdk.asn1.ASN1Writer;
import org.opends.sdk.schema.Schema;

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



/**
 * The server-side sort response control as defined in RFC 2891. This control is
 * included with a search result in response to a server-side sort request
 * included with a search request. The client application is assured that the
 * search results are sorted in the specified key order if and only if the
 * result code in this control is success. If the server omits this control from
 * the search result, the client SHOULD assume that the sort control was ignored
 * by the server.
 *
 * @see ServerSideSortRequestControl
 * @see <a href="http://tools.ietf.org/html/rfc2891">RFC 2891 - LDAP Control
 *      Extension for Server Side Sorting of Search Results </a>
 */
public final class ServerSideSortResponseControl implements Control
{
  /**
   * The OID for the server-side sort response control.
   */
  public static final String OID = "1.2.840.113556.1.4.474";

  /**
   * A decoder which can be used for decoding the server side sort response
   * control.
   */
  public static final ControlDecoder<ServerSideSortResponseControl> DECODER =
    new ControlDecoder<ServerSideSortResponseControl>()
  {

    public ServerSideSortResponseControl decodeControl(final Control control,
        final DecodeOptions options) throws DecodeException
    {
      Validator.ensureNotNull(control, options);

      if (control instanceof ServerSideSortResponseControl)
      {
        return (ServerSideSortResponseControl) control;
      }

      if (!control.getOID().equals(OID))
      {
        final LocalizableMessage message = ERR_SORTRES_CONTROL_BAD_OID.get(
            control.getOID(), OID);
        throw DecodeException.error(message);
      }

      if (!control.hasValue())
      {
        // The request control must always have a value.
        final LocalizableMessage message = INFO_SORTRES_CONTROL_NO_VALUE.get();
        throw DecodeException.error(message);
      }

      final ASN1Reader reader = ASN1.getReader(control.getValue());
      try
      {
        reader.readStartSequence();

        // FIXME: should really check that result code is one of the expected
        // values listed in the RFC.
        final ResultCode result = ResultCode.valueOf(reader.readEnumerated());

        AttributeDescription attributeDescription = null;
        if (reader.hasNextElement())
        {
          // FIXME: which schema should we use?
          final Schema schema = options.getSchemaResolver().resolveSchema("");
          final String ads = reader.readOctetStringAsString();
          attributeDescription = AttributeDescription.valueOf(ads, schema);
        }

        return new ServerSideSortResponseControl(control.isCritical(), result,
            attributeDescription);
      }
      catch (final IOException e)
      {
        final LocalizableMessage message = INFO_SORTRES_CONTROL_CANNOT_DECODE_VALUE
            .get(getExceptionMessage(e));
        throw DecodeException.error(message, e);
      }
      catch (final LocalizedIllegalArgumentException e)
      {
        final LocalizableMessage message = INFO_SORTRES_CONTROL_CANNOT_DECODE_VALUE
            .get(getExceptionMessage(e));
        throw DecodeException.error(message, e);
      }
    }



    public String getOID()
    {
      return OID;
    }
  };

  /**
   * The BER type to use when encoding the attribute type element.
   */
  private static final byte TYPE_ATTRIBUTE_TYPE = (byte) 0x80;



  /**
   * Creates a new server-side response control with the provided sort result
   * and no attribute description.
   *
   * @param result
   *          The result code indicating the outcome of the server-side sort
   *          request. {@link ResultCode#SUCCESS} if the search results were
   *          sorted in accordance with the keys specified in the server-side
   *          sort request control, or an error code indicating why the results
   *          could not be sorted (such as {@link ResultCode#NO_SUCH_ATTRIBUTE}
   *          or {@link ResultCode#INAPPROPRIATE_MATCHING}).
   * @return The new control.
   * @throws NullPointerException
   *           If {@code result} was {@code null}.
   */
  public static ServerSideSortResponseControl newControl(final ResultCode result)
      throws NullPointerException
  {
    Validator.ensureNotNull(result);

    return new ServerSideSortResponseControl(false, result, null);
  }



  /**
   * Creates a new server-side response control with the provided sort result
   * and attribute description.
   *
   * @param result
   *          The result code indicating the outcome of the server-side sort
   *          request. {@link ResultCode#SUCCESS} if the search results were
   *          sorted in accordance with the keys specified in the server-side
   *          sort request control, or an error code indicating why the results
   *          could not be sorted (such as {@link ResultCode#NO_SUCH_ATTRIBUTE}
   *          or {@link ResultCode#INAPPROPRIATE_MATCHING}).
   * @param attributeDescription
   *          The first attribute description specified in the list of sort keys
   *          that was in error, may be {@code null}.
   * @return The new control.
   * @throws NullPointerException
   *           If {@code result} was {@code null}.
   */
  public static ServerSideSortResponseControl newControl(
      final ResultCode result, final AttributeDescription attributeDescription)
      throws NullPointerException
  {
    Validator.ensureNotNull(result);

    return new ServerSideSortResponseControl(false, result,
        attributeDescription);
  }



  /**
   * Creates a new server-side response control with the provided sort result
   * and attribute description. The attribute description will be decoded using
   * the default schema.
   *
   * @param result
   *          The result code indicating the outcome of the server-side sort
   *          request. {@link ResultCode#SUCCESS} if the search results were
   *          sorted in accordance with the keys specified in the server-side
   *          sort request control, or an error code indicating why the results
   *          could not be sorted (such as {@link ResultCode#NO_SUCH_ATTRIBUTE}
   *          or {@link ResultCode#INAPPROPRIATE_MATCHING}).
   * @param attributeDescription
   *          The first attribute description specified in the list of sort keys
   *          that was in error, may be {@code null}.
   * @return The new control.
   * @throws LocalizedIllegalArgumentException
   *           If {@code attributeDescription} could not be parsed using the
   *           default schema.
   * @throws NullPointerException
   *           If {@code result} was {@code null}.
   */
  public static ServerSideSortResponseControl newControl(
      final ResultCode result, final String attributeDescription)
      throws LocalizedIllegalArgumentException, NullPointerException
  {
    Validator.ensureNotNull(result);

    if (attributeDescription != null)
    {
      return new ServerSideSortResponseControl(false, result,
          AttributeDescription.valueOf(attributeDescription));
    }
    else
    {
      return new ServerSideSortResponseControl(false, result, null);
    }
  }



  private final ResultCode result;

  private final AttributeDescription attributeDescription;

  private final boolean isCritical;



  private ServerSideSortResponseControl(final boolean isCritical,
      final ResultCode result, final AttributeDescription attributeDescription)
  {
    this.isCritical = isCritical;
    this.result = result;
    this.attributeDescription = attributeDescription;
  }



  /**
   * Returns the first attribute description specified in the list of sort keys
   * that was in error, or {@code null} if the attribute description was not
   * included with this control.
   *
   * @return The first attribute description specified in the list of sort keys
   *         that was in error.
   */
  public AttributeDescription getAttributeDescription()
  {
    return attributeDescription;
  }



  /**
   * {@inheritDoc}
   */
  public String getOID()
  {
    return OID;
  }



  /**
   * Returns a result code indicating the outcome of the server-side sort
   * request. This will be {@link ResultCode#SUCCESS} if the search results were
   * sorted in accordance with the keys specified in the server-side sort
   * request control, or an error code indicating why the results could not be
   * sorted (such as {@link ResultCode#NO_SUCH_ATTRIBUTE} or
   * {@link ResultCode#INAPPROPRIATE_MATCHING}).
   *
   * @return The result code indicating the outcome of the server-side sort
   *         request.
   */
  public ResultCode getResult()
  {
    return result;
  }



  /**
   * {@inheritDoc}
   */
  public ByteString getValue()
  {
    final ByteStringBuilder buffer = new ByteStringBuilder();
    final ASN1Writer writer = ASN1.getWriter(buffer);
    try
    {
      writer.writeStartSequence();
      writer.writeEnumerated(result.intValue());
      if (attributeDescription != null)
      {
        writer.writeOctetString(TYPE_ATTRIBUTE_TYPE, attributeDescription
            .toString());
      }
      writer.writeEndSequence();
      return buffer.toByteString();
    }
    catch (final IOException ioe)
    {
      // This should never happen unless there is a bug somewhere.
      throw new RuntimeException(ioe);
    }
  }



  /**
   * {@inheritDoc}
   */
  public boolean hasValue()
  {
    return true;
  }



  /**
   * {@inheritDoc}
   */
  public boolean isCritical()
  {
    return isCritical;
  }



  /**
   * {@inheritDoc}
   */
  @Override
  public String toString()
  {
    final StringBuilder builder = new StringBuilder();
    builder.append("ServerSideSortResponseControl(oid=");
    builder.append(getOID());
    builder.append(", criticality=");
    builder.append(isCritical());
    builder.append(", result=");
    builder.append(result);
    if (attributeDescription != null)
    {
      builder.append(", attributeDescription=");
      builder.append(attributeDescription);
    }
    builder.append(")");
    return builder.toString();
  }
}