package org.apache.maven.index.incremental;
   
   /*
    * 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
   *
   *   http://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.
   */
  
  import java.io.File;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.ArrayList;
  import java.util.Date;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Properties;
  import java.util.Set;
  import java.util.TimeZone;
  import java.util.TreeMap;
  
  import org.apache.lucene.document.Document;
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.search.IndexSearcher;
  import org.apache.maven.index.ArtifactInfo;
  import org.apache.maven.index.context.IndexingContext;
  import org.apache.maven.index.packer.IndexPackingRequest;
  import org.apache.maven.index.updater.IndexUpdateRequest;
  import org.codehaus.plexus.component.annotations.Component;
  import org.codehaus.plexus.logging.AbstractLogEnabled;
  import org.codehaus.plexus.util.StringUtils;
  
  @Component( role = IncrementalHandler.class )
  public class DefaultIncrementalHandler
      extends AbstractLogEnabled
      implements IncrementalHandler
  {
      public List<Integer> getIncrementalUpdates( IndexPackingRequest request, Properties properties )
          throws IOException
      {
          getLogger().debug( "Handling Incremental Updates" );
  
          if ( !validateProperties( properties ) )
          {
              getLogger().debug( "Invalid properties found, resetting them and doing no incremental packing." );
              return null;
          }
  
          // Get the list of document ids that have been added since the last time
          // the index ran
          List<Integer> chunk =
              getIndexChunk( request, parse( properties.getProperty( IndexingContext.INDEX_TIMESTAMP ) ) );
  
          getLogger().debug( "Found " + chunk.size() + " differences to put in incremental index." );
  
          // if no documents, then we don't need to do anything, no changes
          if ( chunk.size() > 0 )
          {
              updateProperties( properties, request );
          }
  
          cleanUpIncrementalChunks( request, properties );
  
          return chunk;
      }
  
      public List<String> loadRemoteIncrementalUpdates( IndexUpdateRequest request, Properties localProperties,
                                                        Properties remoteProperties )
          throws IOException
      {
          List<String> filenames = null;
          // If we have local properties, will parse and see what we need to download
          if ( canRetrieveAllChunks( localProperties, remoteProperties ) )
          {
              filenames = new ArrayList<String>();
  
              int maxCounter = Integer.parseInt( remoteProperties.getProperty( IndexingContext.INDEX_CHUNK_COUNTER ) );
              int currentCounter = Integer.parseInt( localProperties.getProperty( IndexingContext.INDEX_CHUNK_COUNTER ) );
  
              // Start with the next one
              currentCounter++;
  
              while ( currentCounter <= maxCounter )
             {
                 filenames.add( IndexingContext.INDEX_FILE_PREFIX + "." + currentCounter++ + ".gz" );
             }
         }
 
         return filenames;
     }
 
     private boolean validateProperties( Properties properties )
     {
         if ( properties == null || properties.isEmpty() )
         {
             return false;
         }
 
         if ( properties.getProperty( IndexingContext.INDEX_TIMESTAMP ) == null )
         {
             return false;
         }
 
         if ( parse( properties.getProperty( IndexingContext.INDEX_TIMESTAMP ) ) == null )
         {
             return false;
         }
 
         initializeProperties( properties );
 
         return true;
     }
 
     public void initializeProperties( Properties properties )
     {
         if ( properties.getProperty( IndexingContext.INDEX_CHAIN_ID ) == null )
         {
             properties.setProperty( IndexingContext.INDEX_CHAIN_ID, Long.toString( new Date().getTime() ) );
             properties.remove( IndexingContext.INDEX_CHUNK_COUNTER );
         }
 
         if ( properties.getProperty( IndexingContext.INDEX_CHUNK_COUNTER ) == null )
         {
             properties.setProperty( IndexingContext.INDEX_CHUNK_COUNTER, "0" );
         }
     }
 
     // Note Toni:
     private List<Integer> getIndexChunk( IndexPackingRequest request, Date timestamp )
         throws IOException
     {
         final List<Integer> chunk = new ArrayList<Integer>();
         final IndexSearcher indexSearcher = request.getContext().acquireIndexSearcher();
         try
         {
             final IndexReader r = indexSearcher.getIndexReader();
             for ( int i = 0; i < r.maxDoc(); i++ )
             {
                 if ( !r.isDeleted( i ) )
                 {
                     Document d = r.document( i );
 
                     String lastModified = d.get( ArtifactInfo.LAST_MODIFIED );
 
                     if ( lastModified != null )
                     {
                         Date t = new Date( Long.parseLong( lastModified ) );
 
                         // Only add documents that were added after the last time we indexed
                         if ( t.after( timestamp ) )
                         {
                             chunk.add( i );
                         }
                     }
                 }
             }
 
             return chunk;
         }
         finally
         {
             request.getContext().releaseIndexSearcher( indexSearcher );
         }
     }
 
     private void updateProperties( Properties properties, IndexPackingRequest request )
         throws IOException
     {
         Set<Object> keys = new HashSet<Object>( properties.keySet() );
         Map<Integer, String> dataMap = new TreeMap<Integer, String>();
 
         // First go through and retrieve all keys and their values
         for ( Object key : keys )
         {
             String sKey = (String) key;
 
             if ( sKey.startsWith( IndexingContext.INDEX_CHUNK_PREFIX ) )
             {
                 Integer count = Integer.valueOf( sKey.substring( IndexingContext.INDEX_CHUNK_PREFIX.length() ) );
                 String value = properties.getProperty( sKey );
 
                 dataMap.put( count, value );
                 properties.remove( key );
             }
         }
 
         String val = (String) properties.getProperty( IndexingContext.INDEX_CHUNK_COUNTER );
 
         int i = 0;
         // Next put the items back in w/ proper keys
         for ( Entry<Integer, String> entry : dataMap.entrySet() )
         {
             // make sure to end if we reach limit, 0 based
             if ( i >= ( request.getMaxIndexChunks() - 1 ) )
             {
                 break;
             }
 
             properties.put( IndexingContext.INDEX_CHUNK_PREFIX + ( entry.getKey() + 1 ), entry.getValue() );
 
             i++;
         }
 
         int nextValue = Integer.parseInt( val ) + 1;
 
         // Now put the new one in, and update the counter
         properties.put( IndexingContext.INDEX_CHUNK_PREFIX + "0", Integer.toString( nextValue ) );
         properties.put( IndexingContext.INDEX_CHUNK_COUNTER, Integer.toString( nextValue ) );
     }
 
     private void cleanUpIncrementalChunks( IndexPackingRequest request, Properties properties )
         throws IOException
     {
         File[] files = request.getTargetDir().listFiles( new FilenameFilter()
         {
             public boolean accept( File dir, String name )
             {
                 String[] parts = name.split( "\\." );
 
                 if ( parts.length == 3 && parts[0].equals( IndexingContext.INDEX_FILE_PREFIX )
                     && parts[2].equals( "gz" ) )
                 {
                     return true;
                 }
 
                 return false;
             }
         } );
 
         for ( int i = 0; i < files.length; i++ )
         {
             String[] parts = files[i].getName().split( "\\." );
 
             boolean found = false;
             for ( Entry<Object, Object> entry : properties.entrySet() )
             {
                 if ( entry.getKey().toString().startsWith( IndexingContext.INDEX_CHUNK_PREFIX )
                     && entry.getValue().equals( parts[1] ) )
                 {
                     found = true;
                     break;
                 }
             }
 
             if ( !found )
             {
                 files[i].delete();
             }
         }
     }
 
     private Date parse( String s )
     {
         try
         {
             SimpleDateFormat df = new SimpleDateFormat( IndexingContext.INDEX_TIME_FORMAT );
             df.setTimeZone( TimeZone.getTimeZone( "GMT" ) );
             return df.parse( s );
         }
         catch ( ParseException e )
         {
             return null;
         }
     }
 
     private boolean canRetrieveAllChunks( Properties localProps, Properties remoteProps )
     {
         // no localprops, can't retrieve chunks
         if ( localProps == null )
         {
             return false;
         }
 
         String localChainId = localProps.getProperty( IndexingContext.INDEX_CHAIN_ID );
         String remoteChainId = remoteProps.getProperty( IndexingContext.INDEX_CHAIN_ID );
 
         // If no chain id, or not the same, do whole download
         if ( StringUtils.isEmpty( localChainId ) || !localChainId.equals( remoteChainId ) )
         {
             return false;
         }
 
         String counterProp = localProps.getProperty( IndexingContext.INDEX_CHUNK_COUNTER );
 
         // no counter, cant retrieve chunks
         // not a number, cant retrieve chunks
         if ( StringUtils.isEmpty( counterProp ) || !StringUtils.isNumeric( counterProp ) )
         {
             return false;
         }
 
         int currentLocalCounter = Integer.parseInt( counterProp );
 
         // check remote props for existence of next chunk after local
         // if we find it, then we are ok to retrieve the rest of the chunks
         for ( Object key : remoteProps.keySet() )
         {
             String sKey = (String) key;
 
             if ( sKey.startsWith( IndexingContext.INDEX_CHUNK_PREFIX ) )
             {
                 String value = remoteProps.getProperty( sKey );
 
                 // If we have the current counter, or the next counter, we are good to go
                 if ( Integer.toString( currentLocalCounter ).equals( value )
                     || Integer.toString( currentLocalCounter + 1 ).equals( value ) )
                 {
                     return true;
                 }
             }
         }
 
         return false;
     }
 }