package org.apache.maven.index;
   
   /*
    * 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.IOException;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.lucene.document.Document;
  import org.apache.lucene.index.CorruptIndexException;
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.index.MultiBits;
  import org.apache.lucene.index.Term;
  import org.apache.lucene.search.IndexSearcher;
  import org.apache.lucene.search.TermQuery;
  import org.apache.lucene.search.TopScoreDocCollector;
  import org.apache.lucene.util.Bits;
  import org.apache.maven.index.context.IndexingContext;
  
  /**
   * A default scanning listener
   * 
   * @author Eugene Kuleshov
   */
  public class DefaultScannerListener
      implements ArtifactScanningListener
  {
      private final IndexingContext context;
  
      private final IndexerEngine indexerEngine;
  
      private final boolean update;
  
      private final ArtifactScanningListener listener;
  
      private final Set<String> uinfos = new HashSet<>();
  
      private final Set<String> processedUinfos = new HashSet<>();
  
      private final Set<String> allGroups = new HashSet<>();
  
      private final Set<String> groups = new HashSet<>();
  
      private final List<Exception> exceptions = new ArrayList<>();
  
      private int count = 0;
  
      public DefaultScannerListener( IndexingContext context, //
                              IndexerEngine indexerEngine, boolean update, //
                              ArtifactScanningListener listener )
      {
          this.context = context;
          this.indexerEngine = indexerEngine;
          this.update = update;
          this.listener = listener;
      }
  
      public void scanningStarted( IndexingContext ctx )
      {
          try
          {
              if ( update )
              {
                  initialize( ctx );
              }
          }
          catch ( IOException ex )
          {
              exceptions.add( ex );
          }
  
          if ( listener != null )
          {
              listener.scanningStarted( ctx );
          }
      }
  
      public void artifactDiscovered( ArtifactContext ac )
      {
          String uinfo = ac.getArtifactInfo().getUinfo();
 
         // TODO: scattered across commented out changes while I was fixing NEXUS-2712, cstamas
         // These changes should be applied by borks too much the fragile indexer
 
         // if ( VersionUtils.isSnapshot( ac.getArtifactInfo().version ) && processedUinfos.contains( uinfo ) )
         if ( processedUinfos.contains( uinfo ) )
         {
             return; // skip individual snapshots
         }
 
         boolean adding = processedUinfos.add( uinfo );
 
         if ( uinfos.contains( uinfo ) )
         {
             // already indexed
             uinfos.remove( uinfo );
             return;
         }
 
         try
         {
             if ( listener != null )
             {
                 listener.artifactDiscovered( ac );
             }
 
             if ( adding )
             {
                 indexerEngine.index( context, ac );
             }
             else
             {
                 indexerEngine.update( context, ac );
             }
 
             for ( Exception e : ac.getErrors() )
             {
                 artifactError( ac, e );
             }
 
             groups.add( ac.getArtifactInfo().getRootGroup() );
             allGroups.add( ac.getArtifactInfo().getGroupId() );
 
             count++;
         }
         catch ( IOException ex )
         {
             artifactError( ac, ex );
         }
     }
 
     public void scanningFinished( IndexingContext ctx, ScanningResult result )
     {
         result.setTotalFiles( count );
 
         for ( Exception ex : exceptions )
         {
             result.addException( ex );
         }
 
         try
         {
             context.optimize();
 
             context.setRootGroups( groups );
 
             context.setAllGroups( allGroups );
 
             if ( update && !context.isReceivingUpdates() )
             {
                 removeDeletedArtifacts( context, result, result.getRequest().getStartingPath() );
             }
         }
         catch ( IOException ex )
         {
             result.addException( ex );
         }
 
         if ( listener != null )
         {
             listener.scanningFinished( ctx, result );
         }
 
         if ( result.getDeletedFiles() > 0 || result.getTotalFiles() > 0 )
         {
             try
             {
                 context.updateTimestamp( true );
 
                 context.optimize();
             }
             catch ( Exception ex )
             {
                 result.addException( ex );
             }
         }
     }
 
     public void artifactError( ArtifactContext ac, Exception e )
     {
         exceptions.add( e );
 
         if ( listener != null )
         {
             listener.artifactError( ac, e );
         }
     }
 
     private void initialize( IndexingContext ctx )
         throws IOException, CorruptIndexException
     {
         final IndexSearcher indexSearcher = ctx.acquireIndexSearcher();
         try
         {
             final IndexReader r = indexSearcher.getIndexReader();
             Bits liveDocs = MultiBits.getLiveDocs( r );
 
             for ( int i = 0; i < r.maxDoc(); i++ )
             {
                 if ( liveDocs == null || liveDocs.get( i ) )
                 {
                     Document d = r.document( i );
 
                     String uinfo = d.get( ArtifactInfo.UINFO );
 
                     if ( uinfo != null )
                     {
                         // if ctx is receiving updates (in other words, is a proxy),
                         // there is no need to build a huge Set of strings with all uinfo's
                         // as deletion detection in those cases have no effect. Also, the
                         // removeDeletedArtifacts() method, that uses info gathered in this set
                         // is invoked with same condition. As indexes of Central are getting huge,
                         // the set grows enormously too, but is actually not used
                         if ( !ctx.isReceivingUpdates() )
                         {
                             uinfos.add( uinfo );
                         }
 
                         // add all existing groupIds to the lists, as they will
                         // not be "discovered" and would be missing from the new list..
                         String groupId = uinfo.substring( 0, uinfo.indexOf( '|' ) );
                         int n = groupId.indexOf( '.' );
                         groups.add( n == -1 ? groupId : groupId.substring( 0, n ) );
                         allGroups.add( groupId );
                     }
                 }
             }
         }
         finally
         {
             ctx.releaseIndexSearcher( indexSearcher );
         }
     }
 
     private void removeDeletedArtifacts( IndexingContext context, ScanningResult result, String contextPath )
         throws IOException
     {
         int deleted = 0;
 
         final IndexSearcher indexSearcher = context.acquireIndexSearcher();
         try
         {
             for ( String uinfo : uinfos )
             {
                 TopScoreDocCollector collector = TopScoreDocCollector.create( 1, Integer.MAX_VALUE );
 
                 indexSearcher.search( new TermQuery( new Term( ArtifactInfo.UINFO, uinfo ) ), collector );
 
                 if ( collector.getTotalHits() > 0 )
                 {
                     String[] ra = ArtifactInfo.FS_PATTERN.split( uinfo );
 
                     ArtifactInfo ai = new ArtifactInfo();
 
                     ai.setRepository( context.getRepositoryId() );
 
                     ai.setGroupId( ra[0] );
 
                     ai.setArtifactId( ra[1] );
 
                     ai.setVersion( ra[2] );
 
                     if ( ra.length > 3 )
                     {
                         ai.setClassifier( ArtifactInfo.renvl( ra[3] ) );
                     }
 
                     if ( ra.length > 4 )
                     {
                         ai.setPackaging( ArtifactInfo.renvl( ra[4] ) );
                     }
 
                     // minimal ArtifactContext for removal
                     ArtifactContext ac = new ArtifactContext( null, null, null, ai, ai.calculateGav() );
 
                     for ( int i = 0; i < collector.getTotalHits(); i++ )
                     {
                         if ( contextPath == null
                             || context.getGavCalculator().gavToPath( ac.getGav() ).startsWith( contextPath ) )
                         {
                             indexerEngine.remove( context, ac );
                         }
 
                         deleted++;
                     }
                 }
             }
         }
         finally
         {
             context.releaseIndexSearcher( indexSearcher );
         }
 
         if ( deleted > 0 )
         {
             context.commit();
         }
 
         result.setDeletedFiles( deleted );
     }
 
 }