package org.apache.maven.index.examples;
   
   /*
    * 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 org.apache.lucene.document.Document;
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.index.MultiBits;
  import org.apache.lucene.search.BooleanClause.Occur;
  import org.apache.lucene.search.BooleanQuery;
  import org.apache.lucene.search.IndexSearcher;
  import org.apache.lucene.search.Query;
  import org.apache.lucene.util.Bits;
  import org.apache.maven.index.ArtifactInfo;
  import org.apache.maven.index.ArtifactInfoFilter;
  import org.apache.maven.index.ArtifactInfoGroup;
  import org.apache.maven.index.Field;
  import org.apache.maven.index.FlatSearchRequest;
  import org.apache.maven.index.FlatSearchResponse;
  import org.apache.maven.index.GroupedSearchRequest;
  import org.apache.maven.index.GroupedSearchResponse;
  import org.apache.maven.index.Grouping;
  import org.apache.maven.index.Indexer;
  import org.apache.maven.index.IteratorSearchRequest;
  import org.apache.maven.index.IteratorSearchResponse;
  import org.apache.maven.index.MAVEN;
  import org.apache.maven.index.context.IndexCreator;
  import org.apache.maven.index.context.IndexUtils;
  import org.apache.maven.index.context.IndexingContext;
  import org.apache.maven.index.expr.SourcedSearchExpression;
  import org.apache.maven.index.expr.UserInputSearchExpression;
  import org.apache.maven.index.search.grouping.GAGrouping;
  import org.apache.maven.index.updater.IndexUpdateRequest;
  import org.apache.maven.index.updater.IndexUpdateResult;
  import org.apache.maven.index.updater.IndexUpdater;
  import org.apache.maven.index.updater.ResourceFetcher;
  import org.apache.maven.index.updater.WagonHelper;
  import org.apache.maven.wagon.Wagon;
  import org.apache.maven.wagon.events.TransferEvent;
  import org.apache.maven.wagon.events.TransferListener;
  import org.apache.maven.wagon.observers.AbstractTransferListener;
  import org.codehaus.plexus.DefaultContainerConfiguration;
  import org.codehaus.plexus.DefaultPlexusContainer;
  import org.codehaus.plexus.PlexusConstants;
  import org.codehaus.plexus.PlexusContainer;
  import org.codehaus.plexus.PlexusContainerException;
  import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
  import org.codehaus.plexus.util.StringUtils;
  import org.eclipse.aether.util.version.GenericVersionScheme;
  import org.eclipse.aether.version.InvalidVersionSpecificationException;
  import org.eclipse.aether.version.Version;
  
  import java.io.File;
  import java.io.IOException;
  import java.time.Duration;
  import java.time.Instant;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Date;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Collection of some use cases.
   */
  public class BasicUsageExample
  {
      public static void main( String[] args )
          throws Exception
      {
          new BasicUsageExample().perform();
      }
  
      // ==
  
      private final PlexusContainer plexusContainer;
  
      private final Indexer indexer;
  
      private final IndexUpdater indexUpdater;
  
      private final Wagon httpWagon;
  
     private IndexingContext centralContext;
 
     public BasicUsageExample()
         throws PlexusContainerException, ComponentLookupException
     {
         // here we create Plexus container, the Maven default IoC container
         // Plexus falls outside of MI scope, just accept the fact that
         // MI is a Plexus component ;)
         // If needed more info, ask on Maven Users list or Plexus Users list
         // google is your friend!
         final DefaultContainerConfiguration config = new DefaultContainerConfiguration();
         config.setClassPathScanning( PlexusConstants.SCANNING_INDEX );
         this.plexusContainer = new DefaultPlexusContainer( config );
 
         // lookup the indexer components from plexus
         this.indexer = plexusContainer.lookup( Indexer.class );
         this.indexUpdater = plexusContainer.lookup( IndexUpdater.class );
         // lookup wagon used to remotely fetch index
         this.httpWagon = plexusContainer.lookup( Wagon.class, "http" );
 
     }
 
     public void perform()
         throws IOException, ComponentLookupException, InvalidVersionSpecificationException
     {
         // Files where local cache is (if any) and Lucene Index should be located
         File centralLocalCache = new File( "target/central-cache" );
         File centralIndexDir = new File( "target/central-index" );
 
         // Creators we want to use (search for fields it defines)
         List<IndexCreator> indexers = new ArrayList<>();
         indexers.add( plexusContainer.lookup( IndexCreator.class, "min" ) );
         indexers.add( plexusContainer.lookup( IndexCreator.class, "jarContent" ) );
         indexers.add( plexusContainer.lookup( IndexCreator.class, "maven-plugin" ) );
 
         // Create context for central repository index
         centralContext =
             indexer.createIndexingContext( "central-context", "central", centralLocalCache, centralIndexDir,
                                            "https://repo1.maven.org/maven2", null, true, true, indexers );
 
         // Update the index (incremental update will happen if this is not 1st run and files are not deleted)
         // This whole block below should not be executed on every app start, but rather controlled by some configuration
         // since this block will always emit at least one HTTP GET. Central indexes are updated once a week, but
         // other index sources might have different index publishing frequency.
         // Preferred frequency is once a week.
         if ( true )
         {
             Instant updateStart = Instant.now();
             System.out.println( "Updating Index..." );
             System.out.println( "This might take a while on first run, so please be patient!" );
             // Create ResourceFetcher implementation to be used with IndexUpdateRequest
             // Here, we use Wagon based one as shorthand, but all we need is a ResourceFetcher implementation
             TransferListener listener = new AbstractTransferListener()
             {
                 Instant start;
                 public void transferStarted( TransferEvent transferEvent )
                 {
                     start = Instant.now();
                     System.out.print( "  Downloading " + transferEvent.getResource().getName() );
                 }
 
                 public void transferProgress( TransferEvent transferEvent, byte[] buffer, int length )
                 {
                 }
 
                 public void transferCompleted( TransferEvent transferEvent )
                 {
                     System.out.println( " - Done in "
                             + Duration.between( start, Instant.now() ).getSeconds() + " sec" );
                 }
             };
             ResourceFetcher resourceFetcher = new WagonHelper.WagonFetcher( httpWagon, listener, null, null );
 
             Date centralContextCurrentTimestamp = centralContext.getTimestamp();
             IndexUpdateRequest updateRequest = new IndexUpdateRequest( centralContext, resourceFetcher );
             IndexUpdateResult updateResult = indexUpdater.fetchAndUpdateIndex( updateRequest );
             if ( updateResult.isFullUpdate() )
             {
                 System.out.println( "Full update happened!" );
             }
             else if ( updateResult.getTimestamp().equals( centralContextCurrentTimestamp ) )
             {
                 System.out.println( "No update needed, index is up to date!" );
             }
             else
             {
                 System.out.println(
                     "Incremental update happened, change covered " + centralContextCurrentTimestamp + " - "
                         + updateResult.getTimestamp() + " period." );
             }
 
             System.out.println( "Finished in " + Duration.between( updateStart, Instant.now() ).getSeconds() + " sec" );
             System.out.println();
         }
 
         System.out.println();
         System.out.println( "Using index" );
         System.out.println( "===========" );
         System.out.println();
 
         // ====
         // Case:
         // dump all the GAVs
         // NOTE: will not actually execute do this below, is too long to do (Central is HUGE), but is here as code
         // example
         if ( false )
         {
             final IndexSearcher searcher = centralContext.acquireIndexSearcher();
             try
             {
                 final IndexReader ir = searcher.getIndexReader();
                 Bits liveDocs = MultiBits.getLiveDocs( ir );
                 for ( int i = 0; i < ir.maxDoc(); i++ )
                 {
                     if ( liveDocs == null || liveDocs.get( i ) )
                     {
                         final Document doc = ir.document( i );
                         final ArtifactInfo ai = IndexUtils.constructArtifactInfo( doc, centralContext );
                         System.out.println( ai.getGroupId() + ":" + ai.getArtifactId() + ":" + ai.getVersion() + ":"
                                                 + ai.getClassifier() + " (sha1=" + ai.getSha1() + ")" );
                     }
                 }
             }
             finally
             {
                 centralContext.releaseIndexSearcher( searcher );
             }
         }
 
         // ====
         // Case:
         // Search for all GAVs with known G and A and having version greater than V
 
         final GenericVersionScheme versionScheme = new GenericVersionScheme();
         final String versionString = "3.1.0";
         final Version version = versionScheme.parseVersion( versionString );
 
         // construct the query for known GA
         final Query groupIdQ =
             indexer.constructQuery( MAVEN.GROUP_ID, new SourcedSearchExpression( "org.apache.maven" ) );
         final Query artifactIdQ =
             indexer.constructQuery( MAVEN.ARTIFACT_ID, new SourcedSearchExpression( "maven-plugin-api" ) );
 
         final BooleanQuery query = new BooleanQuery.Builder()
             .add( groupIdQ, Occur.MUST )
             .add( artifactIdQ, Occur.MUST )
             // we want "jar" artifacts only
             .add( indexer.constructQuery( MAVEN.PACKAGING, new SourcedSearchExpression( "jar" ) ), Occur.MUST )
             // we want main artifacts only (no classifier)
             // Note: this below is unfinished API, needs fixing
             .add( indexer.constructQuery( MAVEN.CLASSIFIER,
                     new SourcedSearchExpression( Field.NOT_PRESENT ) ), Occur.MUST_NOT )
             .build();
 
         // construct the filter to express "V greater than"
         final ArtifactInfoFilter versionFilter = ( ctx, ai ) ->
         {
             try
             {
                 final Version aiV = versionScheme.parseVersion( ai.getVersion() );
                 // Use ">=" if you are INCLUSIVE
                 return aiV.compareTo( version ) > 0;
             }
             catch ( InvalidVersionSpecificationException e )
             {
                 // do something here? be safe and include?
                 return true;
             }
         };
 
         System.out.println(
             "Searching for all GAVs with org.apache.maven:maven-plugin-api having V greater than 3.1.0" );
         final IteratorSearchRequest request =
             new IteratorSearchRequest( query, Collections.singletonList( centralContext ), versionFilter );
         final IteratorSearchResponse response = indexer.searchIterator( request );
         for ( ArtifactInfo ai : response )
         {
             System.out.println( ai.toString() );
         }
 
         // Case:
         // Use index
         // Searching for some artifact
         Query gidQ =
             indexer.constructQuery( MAVEN.GROUP_ID, new SourcedSearchExpression( "org.apache.maven.indexer" ) );
         Query aidQ = indexer.constructQuery( MAVEN.ARTIFACT_ID, new SourcedSearchExpression( "indexer-core" ) );
 
         BooleanQuery bq = new BooleanQuery.Builder()
                 .add( gidQ, Occur.MUST )
                 .add( aidQ, Occur.MUST )
                 .build();
 
         searchAndDump( indexer, "all artifacts under GA org.apache.maven.indexer:indexer-core", bq );
 
         // Searching for some main artifact
         bq = new BooleanQuery.Builder()
                 .add( gidQ, Occur.MUST )
                 .add( aidQ, Occur.MUST )
                 .add( indexer.constructQuery( MAVEN.CLASSIFIER, new SourcedSearchExpression( "*" ) ), Occur.MUST_NOT )
                 .build();
 
         searchAndDump( indexer, "main artifacts under GA org.apache.maven.indexer:indexer-core", bq );
 
         // doing sha1 search
         searchAndDump( indexer, "SHA1 7ab67e6b20e5332a7fb4fdf2f019aec4275846c2",
                        indexer.constructQuery( MAVEN.SHA1,
                                                new SourcedSearchExpression( "7ab67e6b20e5332a7fb4fdf2f019aec4275846c2" )
                        )
         );
 
         searchAndDump( indexer, "SHA1 7ab67e6b20 (partial hash)",
                        indexer.constructQuery( MAVEN.SHA1, new UserInputSearchExpression( "7ab67e6b20" ) ) );
 
         // doing classname search (incomplete classname)
         searchAndDump( indexer, "classname DefaultNexusIndexer (note: Central does not publish classes in the index)",
                        indexer.constructQuery( MAVEN.CLASSNAMES,
                                                new UserInputSearchExpression( "DefaultNexusIndexer" ) ) );
 
         // doing search for all "canonical" maven plugins latest versions
         bq = new BooleanQuery.Builder()
             .add( indexer.constructQuery( MAVEN.PACKAGING, new SourcedSearchExpression( "maven-plugin" ) ), Occur.MUST )
             .add( indexer.constructQuery( MAVEN.GROUP_ID,
                     new SourcedSearchExpression( "org.apache.maven.plugins" ) ), Occur.MUST )
             .build();
 
         searchGroupedAndDumpFlat( indexer, "all \"canonical\" maven plugins", bq, new GAGrouping() );
 
         // doing search for all archetypes latest versions
         searchGroupedAndDump( indexer, "all maven archetypes (latest versions)",
                               indexer.constructQuery( MAVEN.PACKAGING,
                                                       new SourcedSearchExpression( "maven-archetype" ) ),
                               new GAGrouping() );
 
         // close cleanly
         indexer.closeIndexingContext( centralContext, false );
     }
 
     public void searchAndDump( Indexer nexusIndexer, String descr, Query q )
         throws IOException
     {
         System.out.println( "Searching for " + descr );
 
         FlatSearchResponse response = nexusIndexer.searchFlat( new FlatSearchRequest( q, centralContext ) );
 
         for ( ArtifactInfo ai : response.getResults() )
         {
             System.out.println( ai.toString() );
         }
 
         System.out.println( "------" );
         System.out.println( "Total: " + response.getTotalHitsCount() );
         System.out.println();
     }
 
     private static final int MAX_WIDTH = 60;
 
     public void searchGroupedAndDumpFlat( Indexer nexusIndexer, String descr, Query q, Grouping g )
             throws IOException
     {
         System.out.println( "Searching for " + descr );
 
         GroupedSearchResponse response = nexusIndexer.searchGrouped( new GroupedSearchRequest( q, g, centralContext ) );
 
         for ( Map.Entry<String, ArtifactInfoGroup> entry : response.getResults().entrySet() )
         {
             ArtifactInfo ai = entry.getValue().getArtifactInfos().iterator().next();
             System.out.println( "* " + ai.getGroupId() + ":" + ai.getArtifactId() + ":" + ai.getVersion() );
         }
 
         System.out.println( "------" );
         System.out.println( "Total record hits: " + response.getTotalHitsCount() );
         System.out.println();
     }
 
     public void searchGroupedAndDump( Indexer nexusIndexer, String descr, Query q, Grouping g )
         throws IOException
     {
         System.out.println( "Searching for " + descr );
 
         GroupedSearchResponse response = nexusIndexer.searchGrouped( new GroupedSearchRequest( q, g, centralContext ) );
 
         for ( Map.Entry<String, ArtifactInfoGroup> entry : response.getResults().entrySet() )
         {
             ArtifactInfo ai = entry.getValue().getArtifactInfos().iterator().next();
             System.out.println( "* Entry " + ai );
             System.out.println( "  Latest version:  " + ai.getVersion() );
             System.out.println( StringUtils.isBlank( ai.getDescription() )
                                     ? "No description in plugin's POM."
                                     : StringUtils.abbreviate( ai.getDescription(), MAX_WIDTH ) );
             System.out.println();
         }
 
         System.out.println( "------" );
         System.out.println( "Total record hits: " + response.getTotalHitsCount() );
         System.out.println();
     }
 }