/*
 * 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 2009-2010 Sun Microsystems, Inc.
 */

package com.sun.opends.sdk.tools;



import org.opends.sdk.*;
import org.opends.sdk.requests.BindRequest;
import org.opends.sdk.responses.BindResult;

import com.sun.opends.sdk.util.AsynchronousConnectionDecorator;
import com.sun.opends.sdk.util.FutureResultTransformer;
import com.sun.opends.sdk.util.RecursiveFutureResult;
import com.sun.opends.sdk.util.Validator;



/**
 * An authenticated connection factory can be used to create pre-authenticated
 * connections to a Directory Server.
 * <p>
 * The connections returned by an authenticated connection factory support all
 * operations with the exception of Bind requests. Attempts to perform a Bind
 * will result in an {@code UnsupportedOperationException}.
 * <p>
 * In addition, the returned connections support retrieval of the
 * {@code BindResult} returned from the initial Bind request, or last rebind.
 * <p>
 * Support for connection re-authentication is provided through the
 * {@link #setRebindAllowed} method which, if set to {@code true}, causes
 * subsequent connections created using the factory to support the
 * {@code rebind} method.
 * <p>
 * If the Bind request fails for some reason (e.g. invalid credentials), then
 * the connection attempt will fail and an {@code ErrorResultException} will be
 * thrown.
 */
final class AuthenticatedConnectionFactory extends AbstractConnectionFactory
    implements ConnectionFactory
{

  /**
   * An authenticated asynchronous connection supports all operations except
   * Bind operations.
   */
  public static final class AuthenticatedAsynchronousConnection extends
      AsynchronousConnectionDecorator
  {

    private final BindRequest request;

    private volatile BindResult result;



    private AuthenticatedAsynchronousConnection(
        final AsynchronousConnection connection, final BindRequest request,
        final BindResult result)
    {
      super(connection);
      this.request = request;
      this.result = result;
    }



    /**
     * Bind operations are not supported by pre-authenticated connections. This
     * method will always throw {@code UnsupportedOperationException}.
     */
    public FutureResult<BindResult> bind(final BindRequest request,
        final ResultHandler<? super BindResult> handler)
        throws UnsupportedOperationException, IllegalStateException,
        NullPointerException
    {
      throw new UnsupportedOperationException();
    }



    /**
     * Bind operations are not supported by pre-authenticated connections. This
     * method will always throw {@code UnsupportedOperationException}.
     */
    public FutureResult<BindResult> bind(final BindRequest request,
        final ResultHandler<? super BindResult> resultHandler,
        final IntermediateResponseHandler intermediateResponseHandler)
        throws UnsupportedOperationException, IllegalStateException,
        NullPointerException
    {
      throw new UnsupportedOperationException();
    }



    /**
     * Returns an unmodifiable view of the Bind result which was returned from
     * the server after authentication.
     *
     * @return The Bind result which was returned from the server after
     *         authentication.
     */
    public BindResult getAuthenticatedBindResult()
    {
      return result;
    }



    /**
     * Re-authenticates to the Directory Server using the bind request
     * associated with this connection. If re-authentication fails for some
     * reason then this connection will be automatically closed.
     *
     * @param handler
     *          A result handler which can be used to asynchronously process the
     *          operation result when it is received, may be {@code null}.
     * @return A future representing the result of the operation.
     * @throws UnsupportedOperationException
     *           If this connection does not support rebind operations.
     * @throws IllegalStateException
     *           If this connection has already been closed, i.e. if
     *           {@code isClosed() == true}.
     */
    public FutureResult<BindResult> rebind(
        final ResultHandler<? super BindResult> handler)
        throws UnsupportedOperationException, IllegalStateException
    {
      if (request == null)
      {
        throw new UnsupportedOperationException();
      }

      // Wrap the client handler so that we can update the connection
      // state.
      final ResultHandler<? super BindResult> clientHandler = handler;

      final ResultHandler<BindResult> handlerWrapper = new ResultHandler<BindResult>()
      {

        public void handleErrorResult(final ErrorResultException error)
        {
          // This connection is now unauthenticated so prevent
          // further use.
          connection.close();

          if (clientHandler != null)
          {
            clientHandler.handleErrorResult(error);
          }
        }



        public void handleResult(final BindResult result)
        {
          // Save the result.
          AuthenticatedAsynchronousConnection.this.result = result;

          if (clientHandler != null)
          {
            clientHandler.handleResult(result);
          }
        }

      };

      return connection.bind(request, handlerWrapper);
    }



    /**
     * {@inheritDoc}
     */
    public String toString()
    {
      StringBuilder builder = new StringBuilder();
      builder.append("AuthenticatedConnection(");
      builder.append(connection);
      builder.append(')');
      return builder.toString();
    }

  }



  /**
   * An authenticated synchronous connection supports all operations except Bind
   * operations.
   */
  public static final class AuthenticatedConnection extends
      SynchronousConnection
  {
    private final AuthenticatedAsynchronousConnection connection;



    private AuthenticatedConnection(
        final AuthenticatedAsynchronousConnection connection)
    {
      super(connection);
      this.connection = connection;
    }



    /**
     * Bind operations are not supported by pre-authenticated connections. This
     * method will always throw {@code UnsupportedOperationException}.
     */
    @Override
    public BindResult bind(final BindRequest request)
        throws UnsupportedOperationException
    {
      throw new UnsupportedOperationException();
    }



    /**
     * Bind operations are not supported by pre-authenticated connections. This
     * method will always throw {@code UnsupportedOperationException}.
     */
    @Override
    public BindResult bind(final String name, final char[] password)
        throws UnsupportedOperationException
    {
      throw new UnsupportedOperationException();
    }



    /**
     * Returns an unmodifiable view of the Bind result which was returned from
     * the server after authentication.
     *
     * @return The Bind result which was returned from the server after
     *         authentication.
     */
    public BindResult getAuthenticatedBindResult()
    {
      return connection.getAuthenticatedBindResult();
    }



    /**
     * Re-authenticates to the Directory Server using the bind request
     * associated with this connection. If re-authentication fails for some
     * reason then this connection will be automatically closed.
     *
     * @return The result of the operation.
     * @throws ErrorResultException
     *           If the result code indicates that the request failed for some
     *           reason.
     * @throws InterruptedException
     *           If the current thread was interrupted while waiting.
     * @throws UnsupportedOperationException
     *           If this connection does not support rebind operations.
     * @throws IllegalStateException
     *           If this connection has already been closed, i.e. if
     *           {@code isClosed() == true}.
     */
    public BindResult rebind() throws ErrorResultException,
        InterruptedException, UnsupportedOperationException,
        IllegalStateException
    {

      if (connection.request == null)
      {
        throw new UnsupportedOperationException();
      }
      return super.bind(connection.request);
    }
  }



  private static final class FutureResultImpl
  {
    private final FutureResultTransformer<BindResult, AsynchronousConnection> futureBindResult;

    private final RecursiveFutureResult<AsynchronousConnection, BindResult> futureConnectionResult;

    private final BindRequest bindRequest;

    private AsynchronousConnection connection;



    private FutureResultImpl(final BindRequest request,
        final ResultHandler<? super AsynchronousConnection> handler)
    {
      this.bindRequest = request;
      this.futureBindResult = new FutureResultTransformer<BindResult, AsynchronousConnection>(
          handler)
      {

        @Override
        protected ErrorResultException transformErrorResult(
            final ErrorResultException errorResult)
        {
          // Ensure that the connection is closed.
          try
          {
            connection.close();
            connection = null;
          }
          catch (final Exception e)
          {
            // Ignore.
          }
          return errorResult;
        }



        @Override
        protected AuthenticatedAsynchronousConnection transformResult(
            final BindResult result) throws ErrorResultException
        {
          // FIXME: should make the result unmodifiable.
          return new AuthenticatedAsynchronousConnection(connection,
              bindRequest, result);
        }

      };
      this.futureConnectionResult = new RecursiveFutureResult<AsynchronousConnection, BindResult>(
          futureBindResult)
      {

        @Override
        protected FutureResult<? extends BindResult> chainResult(
            final AsynchronousConnection innerResult,
            final ResultHandler<? super BindResult> handler)
            throws ErrorResultException
        {
          connection = innerResult;
          return connection.bind(bindRequest, handler);
        }
      };
      futureBindResult.setFutureResult(futureConnectionResult);
    }

  }



  private final BindRequest request;

  private final ConnectionFactory parentFactory;

  private boolean allowRebinds = false;



  /**
   * Creates a new authenticated connection factory which will obtain
   * connections using the provided connection factory and immediately perform
   * the provided Bind request.
   *
   * @param factory
   *          The connection factory to use for connecting to the Directory
   *          Server.
   * @param request
   *          The Bind request to use for authentication.
   * @throws NullPointerException
   *           If {@code factory} or {@code request} was {@code null}.
   */
  public AuthenticatedConnectionFactory(final ConnectionFactory factory,
      final BindRequest request) throws NullPointerException
  {
    Validator.ensureNotNull(factory, request);
    this.parentFactory = factory;

    // FIXME: should do a defensive copy.
    this.request = request;
  }



  @Override
  public FutureResult<AsynchronousConnection> getAsynchronousConnection(
      final ResultHandler<? super AsynchronousConnection> handler)
  {
    final FutureResultImpl future = new FutureResultImpl(request, handler);
    future.futureConnectionResult.setFutureResult(parentFactory
        .getAsynchronousConnection(future.futureConnectionResult));
    return future.futureBindResult;
  }



  /**
   * Indicates whether or not rebind requests are to be supported by connections
   * created by this authenticated connection factory.
   * <p>
   * Rebind requests are invoked using the connection's {@code rebind} method
   * which will throw an {@code UnsupportedOperationException} if rebinds are
   * not supported (the default).
   *
   * @return allowRebinds {@code true} if the {@code rebind} operation is to be
   *         supported, otherwise {@code false}.
   */
  public boolean isRebindAllowed()
  {
    return allowRebinds;
  }



  /**
   * Specifies whether or not rebind requests are to be supported by connections
   * created by this authenticated connection factory.
   * <p>
   * Rebind requests are invoked using the connection's {@code rebind} method
   * which will throw an {@code UnsupportedOperationException} if rebinds are
   * not supported (the default).
   *
   * @param allowRebinds
   *          {@code true} if the {@code rebind} operation is to be supported,
   *          otherwise {@code false}.
   * @return A reference to this connection factory.
   */
  public AuthenticatedConnectionFactory setRebindAllowed(
      final boolean allowRebinds)
  {
    this.allowRebinds = allowRebinds;
    return this;
  }



  /**
   * {@inheritDoc}
   */
  public String toString()
  {
    final StringBuilder builder = new StringBuilder();
    builder.append("AuthenticatedConnectionFactory(");
    builder.append(String.valueOf(parentFactory));
    builder.append(')');
    return builder.toString();
  }

}