/*
    *   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
    *
   *     https://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.ldap.client.api;
  
  
  import java.io.IOException;
  
  import org.apache.directory.api.i18n.I18n;
  import org.apache.directory.api.ldap.model.constants.Loggers;
  import org.apache.directory.api.ldap.model.cursor.AbstractCursor;
  import org.apache.directory.api.ldap.model.cursor.CursorException;
  import org.apache.directory.api.ldap.model.cursor.CursorLdapReferralException;
  import org.apache.directory.api.ldap.model.cursor.EntryCursor;
  import org.apache.directory.api.ldap.model.cursor.InvalidCursorPositionException;
  import org.apache.directory.api.ldap.model.cursor.SearchCursor;
  import org.apache.directory.api.ldap.model.entry.Entry;
  import org.apache.directory.api.ldap.model.exception.LdapException;
  import org.apache.directory.api.ldap.model.exception.LdapReferralException;
  import org.apache.directory.api.ldap.model.message.Response;
  import org.apache.directory.api.ldap.model.message.SearchResultDone;
  import org.apache.directory.api.ldap.model.message.SearchResultEntry;
  import org.apache.directory.api.ldap.model.message.SearchResultReference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * An implementation of Cursor based on the underlying SearchFuture instance.
   * 
   * Note: This is a forward only cursor hence the only valid operations are next(), get() and close() 
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class EntryCursorImpl extends AbstractCursor<Entry> implements EntryCursor
  {
      /** A dedicated log for cursors */
      private static final Logger LOG_CURSOR = LoggerFactory.getLogger( Loggers.CURSOR_LOG.getName() );
  
      /** a reference to hold the retrieved SearchResponse object from SearchFuture */
      private Response response;
  
      /** The encapsulated search cursor */
      private SearchCursor searchCursor;
  
      /** The underlying messageId */
      private int messageId;
  
  
      /**
       * Instantiates a new search cursor, embedding a SearchCursor.
       *
       * @param searchCursor the embedded SearchResponse cursor
       */
      public EntryCursorImpl( SearchCursor searchCursor )
      {
          if ( LOG_CURSOR.isDebugEnabled() )
          {
              LOG_CURSOR.debug( I18n.msg( I18n.MSG_04161_CREATING_ENTRY_CURSOR, this ) );
          }
  
          this.searchCursor = searchCursor;
          messageId = -1;
      }
  
  
      /**
       * {@inheritDoc}
       */
      @Override
      public boolean next() throws LdapException, CursorException
      {
          if ( !searchCursor.next() )
          {
              return false;
          }
  
          try
          {
              do
              {
                  response = searchCursor.get();
 
                 if ( response == null )
                 {
                     throw new LdapException( LdapNetworkConnection.TIME_OUT_ERROR );
                 }
 
                 messageId = response.getMessageId();
 
                 if ( response instanceof SearchResultEntry )
                 {
                     return true;
                 }
 
                 if ( response instanceof SearchResultReference )
                 {
                     return true;
                 }
             }
             while ( !( response instanceof SearchResultDone ) );
 
             return false;
         }
         catch ( Exception e )
         {
             LdapException ldapException = new LdapException( LdapNetworkConnection.NO_RESPONSE_ERROR );
             ldapException.initCause( e );
 
             // close the cursor
             try
             {
                 close( ldapException );
             }
             catch ( IOException ioe )
             {
                 throw new LdapException( ioe.getMessage(), ioe );
             }
 
             throw ldapException;
         }
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Entry get() throws CursorException
     {
         if ( !searchCursor.available() )
         {
             throw new InvalidCursorPositionException();
         }
 
         try
         {
             do
             {
                 if ( response instanceof SearchResultEntry )
                 {
                     return ( ( SearchResultEntry ) response ).getEntry();
                 }
 
                 if ( response instanceof SearchResultReference )
                 {
                     throw new LdapReferralException( ( ( SearchResultReference ) response ).getReferral().getLdapUrls() );
                 }
             }
             while ( next() && !( response instanceof SearchResultDone ) );
         }
         catch ( LdapReferralException lre )
         {
             throw new CursorLdapReferralException( lre );
         }
         catch ( Exception e )
         {
             throw new CursorException( e );
         }
 
         return null;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public SearchResultDone getSearchResultDone()
     {
         return searchCursor.getSearchResultDone();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean available()
     {
         return searchCursor.available();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void close() throws IOException
     {
         if ( LOG_CURSOR.isDebugEnabled() )
         {
             LOG_CURSOR.debug( I18n.msg( I18n.MSG_04162_CLOSING_ENTRY_CURSOR, this ) );
         }
 
         searchCursor.close();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void close( Exception cause ) throws IOException
     {
         if ( LOG_CURSOR.isDebugEnabled() )
         {
             LOG_CURSOR.debug( I18n.msg( I18n.MSG_04162_CLOSING_ENTRY_CURSOR, this ) );
         }
 
         searchCursor.close( cause );
     }
 
 
     // rest of all operations will throw UnsupportedOperationException
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public void after( Entry element ) throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "after( Response element )" ) ) );
     }
 
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public void afterLast() throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "afterLast()" ) ) );
     }
 
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public void before( Entry element ) throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "before( Response element )" ) ) );
     }
 
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public void beforeFirst() throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "beforeFirst()" ) ) );
     }
 
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public boolean first() throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "first()" ) ) );
     }
 
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public boolean last() throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "last()" ) ) );
     }
 
 
     /**
      * This operation is not supported in SearchCursor.
      * {@inheritDoc}
      */
     @Override
     public boolean previous() throws LdapException, CursorException
     {
         throw new UnsupportedOperationException( I18n.err( I18n.ERR_13102_UNSUPPORTED_OPERATION, getClass().getName()
             .concat( "." ).concat( "previous()" ) ) );
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getMessageId()
     {
         return messageId;
     }
 }