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 javax.inject.Named;
  import javax.inject.Singleton;
  import java.io.IOException;
  import java.io.StringReader;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.index.Term;
  import org.apache.lucene.queryparser.classic.ParseException;
  import org.apache.lucene.queryparser.classic.QueryParser;
  import org.apache.lucene.queryparser.classic.QueryParser.Operator;
  import org.apache.lucene.search.BooleanClause.Occur;
  import org.apache.lucene.search.BooleanQuery;
  import org.apache.lucene.search.BoostQuery;
  import org.apache.lucene.search.PrefixQuery;
  import org.apache.lucene.search.Query;
  import org.apache.lucene.search.TermQuery;
  import org.apache.lucene.search.WildcardQuery;
  import org.apache.maven.index.context.NexusAnalyzer;
  import org.apache.maven.index.creator.JarFileContentsIndexCreator;
  import org.apache.maven.index.creator.MinimalArtifactInfoIndexCreator;
  import org.apache.maven.index.expr.SearchExpression;
  import org.apache.maven.index.expr.SearchTyped;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A default {@link QueryCreator} constructs Lucene query for provided query text.
   * <p>
   * By default wildcards are created such as query text matches beginning of the field value or beginning of the
   * class/package name segment for {@link ArtifactInfo#NAMES NAMES} field. But it can be controlled by using special
   * markers:
   * <ul>
   * <li>* - any character</li>
   * <li>'^' - beginning of the text</li>
   * <li>'$' or '&lt;' or ' ' end of the text</li>
   * </ul>
   * For example:
   * <ul>
   * <li>junit - matches junit and junit-foo, but not foo-junit</li>
   * <li>*junit - matches junit, junit-foo and foo-junit</li>
   * <li>^junit$ - matches junit, but not junit-foo, nor foo-junit</li>
   * </ul>
   * 
   * @author Eugene Kuleshov
   */
  @Singleton
  @Named
  public class DefaultQueryCreator
      implements QueryCreator
  {
  
      private final Logger logger = LoggerFactory.getLogger( getClass() );
  
      protected Logger getLogger()
      {
          return logger;
      }
  
      // ==
  
      public IndexerField selectIndexerField( final Field field, final SearchType type )
      {
          IndexerField lastField = null;
  
          for ( IndexerField indexerField : field.getIndexerFields() )
          {
              lastField = indexerField;
  
              if ( type.matchesIndexerField( indexerField ) )
              {
                  return indexerField;
              }
          }
  
          return lastField;
      }
  
      public Query constructQuery( final Field field, final SearchExpression expression )
          throws ParseException
     {
         SearchType searchType = SearchType.SCORED;
 
         if ( expression instanceof SearchTyped )
         {
             searchType = ( (SearchTyped) expression ).getSearchType();
         }
 
         return constructQuery( field, expression.getStringValue(), searchType );
     }
 
     public Query constructQuery( final Field field, final String query, final SearchType type )
         throws ParseException
     {
         if ( type == null )
         {
             throw new NullPointerException( "Cannot construct query with type of \"null\"!" );
         }
 
         if ( field == null )
         {
             throw new NullPointerException( "Cannot construct query for field \"null\"!" );
         }
         else
         {
             return constructQuery( field, selectIndexerField( field, type ), query, type );
         }
     }
 
     @Deprecated
     public Query constructQuery( String field, String query )
     {
         Query result;
 
         if ( MinimalArtifactInfoIndexCreator.FLD_GROUP_ID_KW.getKey().equals( field )
             || MinimalArtifactInfoIndexCreator.FLD_ARTIFACT_ID_KW.getKey().equals( field )
             || MinimalArtifactInfoIndexCreator.FLD_VERSION_KW.getKey().equals( field )
             || JarFileContentsIndexCreator.FLD_CLASSNAMES_KW.getKey().equals( field ) )
         {
             // these are special untokenized fields, kept for use cases like TreeView is (exact matching).
             result = legacyConstructQuery( field, query );
         }
         else
         {
             QueryParser qp = new QueryParser( field, new NexusAnalyzer() );
 
             // small cheap trick
             // if a query is not "expert" (does not contain field:val kind of expression)
             // but it contains star and/or punctuation chars, example: "common-log*"
             if ( !query.contains( ":" ) )
             {
                 if ( query.contains( "*" ) && query.matches( ".*(\\.|-|_).*" ) )
                 {
                     query = query.toLowerCase().replaceAll( "\\*", "X" ).replaceAll( "\\.|-|_", " " ).replaceAll( "X",
                                                                                                                   "*" );
                 }
             }
 
             try
             {
                 result = qp.parse( query );
             }
             catch ( ParseException e )
             {
                 getLogger().debug(
                     "Query parsing with \"legacy\" method, we got ParseException from QueryParser: " + e.getMessage() );
 
                 result = legacyConstructQuery( field, query );
             }
         }
 
         if ( getLogger().isDebugEnabled() )
         {
             getLogger().debug( "Query parsed as: " + result.toString() );
         }
 
         return result;
     }
 
     // ==
 
     public Query constructQuery( final Field field, final IndexerField indexerField, final String query,
                                  final SearchType type )
         throws ParseException
     {
         if ( indexerField == null )
         {
             getLogger().warn( "Querying for field \"" + field.toString() + "\" without any indexer field was tried. "
                 + "Please review your code, and consider adding this field to index!" );
 
             return null;
         }
         if ( !indexerField.isIndexed() )
         {
             getLogger().warn(
                 "Querying for non-indexed field " + field.toString()
                     + " was tried. Please review your code or consider adding this field to index!" );
 
             return null;
         }
 
         if ( Field.NOT_PRESENT.equals( query ) )
         {
             return new WildcardQuery( new Term( indexerField.getKey(), "*" ) );
         }
 
         if ( SearchType.EXACT.equals( type ) )
         {
             if ( indexerField.isKeyword() )
             {
                 // no tokenization should happen against the field!
                 if ( query.contains( "*" ) || query.contains( "?" ) )
                 {
                     return new WildcardQuery( new Term( indexerField.getKey(), query ) );
                 }
                 else
                 {
                     // exactly what callee wants
                     return new TermQuery( new Term( indexerField.getKey(), query ) );
                 }
             }
             else if ( !indexerField.isKeyword() && indexerField.isStored() )
             {
                 // TODO: resolve this better! Decouple QueryCreator and IndexCreators!
                 // This is a hack/workaround here
                 if ( JarFileContentsIndexCreator.FLD_CLASSNAMES_KW.equals( indexerField ) )
                 {
                     if ( query.startsWith( "/" ) )
                     {
                         return new TermQuery( new Term( indexerField.getKey(), query.toLowerCase().replaceAll( "\\.",
                             "/" ) ) );
                     }
                     else
                     {
                         return new TermQuery( new Term( indexerField.getKey(), "/"
                             + query.toLowerCase().replaceAll( "\\.", "/" ) ) );
                     }
                 }
                 else
                 {
                     getLogger().warn(
                         type.toString()
                             + " type of querying for non-keyword (but stored) field "
                             + indexerField.getOntology().toString()
                             + " was tried. Please review your code, or indexCreator involved, "
                             + "since this type of querying of this field is currently unsupported." );
 
                     // will never succeed (unless we supply him "filter" too, but that would kill performance)
                     // and is possible with stored fields only
                     return null;
                 }
             }
             else
             {
                 getLogger().warn(
                     type.toString()
                         + " type of querying for non-keyword (and not stored) field "
                         + indexerField.getOntology().toString()
                         + " was tried. Please review your code, or indexCreator involved, "
                         + "since this type of querying of this field is impossible." );
 
                 // not a keyword indexerField, nor stored. No hope at all. Impossible even with "filtering"
                 return null;
             }
         }
         else if ( SearchType.SCORED.equals( type ) )
         {
             if ( JarFileContentsIndexCreator.FLD_CLASSNAMES.equals( indexerField ) )
             {
                 String qpQuery = query.toLowerCase().replaceAll( "\\.", " " ).replaceAll( "/", " " );
                 // tokenization should happen against the field!
                 QueryParser qp = new QueryParser( indexerField.getKey(), new NexusAnalyzer() );
                 qp.setDefaultOperator( Operator.AND );
                 return qp.parse( qpQuery );
             }
             else if ( indexerField.isKeyword() )
             {
                 // no tokenization should happen against the field!
                 if ( query.contains( "*" ) || query.contains( "?" ) )
                 {
                     return new WildcardQuery( new Term( indexerField.getKey(), query ) );
                 }
                 else
                 {
                     Term t = new Term( indexerField.getKey(), query );
                     return new BooleanQuery.Builder()
                         .add( new TermQuery( t ), Occur.SHOULD )
                         .add( new BoostQuery( new PrefixQuery( t ), 0.8f ), Occur.SHOULD )
                         .build();
             }
             }
             else
             {
                 // to save "original" query
                 String qpQuery = query;
 
                 // tokenization should happen against the field!
                 QueryParser qp = new QueryParser( indexerField.getKey(), new NexusAnalyzer() );
                 qp.setDefaultOperator( Operator.AND );
 
                 // small cheap trick
                 // if a query is not "expert" (does not contain field:val kind of expression)
                 // but it contains star and/or punctuation chars, example: "common-log*"
                 // since Lucene does not support multi-terms WITH wildcards.
                 // So, here, we "mimic" NexusAnalyzer (this should be fixed!)
                 // but do this with PRESERVING original query!
                 if ( qpQuery.matches( ".*(\\.|-|_|/).*" ) )
                 {
                     qpQuery =
                         qpQuery.toLowerCase().replaceAll( "\\*", "X" ).replaceAll( "\\.|-|_|/", " " ).replaceAll( "X",
                             "*" ).replaceAll( " \\* ", "" ).replaceAll( "^\\* ", "" ).replaceAll( " \\*$", "" );
                 }
 
                 // "fix" it with trailing "*" if not there, but only if it not ends with a space
                 if ( !qpQuery.endsWith( "*" ) && !qpQuery.endsWith( " " ) )
                 {
                     qpQuery += "*";
                 }
 
                 try
                 {
                     // qpQuery = "\"" + qpQuery + "\"";
 
                     BooleanQuery.Builder q1b = new BooleanQuery.Builder()
                             .add( qp.parse( qpQuery ), Occur.SHOULD );
 
                     if ( qpQuery.contains( " " ) )
                     {
                         q1b.add( qp.parse( "\"" + qpQuery + "\"" ), Occur.SHOULD );
                     }
 
                     Query q2 = null;
 
                     int termCount = countTerms( indexerField, query );
 
                     // try with KW only if the processed query in qpQuery does not have spaces!
                     if ( !query.contains( " " ) && termCount > 1 )
                     {
                         // get the KW field
                         IndexerField keywordField = selectIndexerField( indexerField.getOntology(), SearchType.EXACT );
 
                         if ( keywordField.isKeyword() )
                         {
                             q2 = constructQuery( indexerField.getOntology(), keywordField, query, type );
                         }
                     }
 
                     if ( q2 == null )
                     {
                         return q1b.build();
                     }
                     else
                     {
                         return new BooleanQuery.Builder()
                             // trick with order
                             .add( q2, Occur.SHOULD )
                             .add( q1b.build(), Occur.SHOULD )
                             .build();
                     }
                 }
                 catch ( ParseException e )
                 {
                     // TODO: we are not falling back anymore to legacy!
                     throw e;
 
                     // getLogger().debug(
                     // "Query parsing with \"legacy\" method, we got ParseException from QueryParser: "
                     // + e.getMessage() );
                     //
                     // return legacyConstructQuery( indexerField.getKey(), query );
                 }
             }
         }
         else
         {
             // what search type is this?
             return null;
         }
     }
 
     public Query legacyConstructQuery( String field, String query )
     {
         if ( query == null || query.length() == 0 )
         {
             getLogger().info( "Empty or null query for field:" + field );
 
             return null;
         }
 
         String q = query.toLowerCase();
 
         char h = query.charAt( 0 );
 
         if ( JarFileContentsIndexCreator.FLD_CLASSNAMES_KW.getKey().equals( field )
             || JarFileContentsIndexCreator.FLD_CLASSNAMES.getKey().equals( field ) )
         {
             q = q.replaceAll( "\\.", "/" );
 
             if ( h == '^' )
             {
                 q = q.substring( 1 );
 
                 if ( q.charAt( 0 ) != '/' )
                 {
                     q = '/' + q;
                 }
             }
             else if ( h != '*' )
             {
                 q = "*/" + q;
             }
         }
         else
         {
             if ( h == '^' )
             {
                 q = q.substring( 1 );
             }
             else if ( h != '*' )
             {
                 q = "*" + q;
             }
         }
 
         int l = q.length() - 1;
         char c = q.charAt( l );
         if ( c == ' ' || c == '<' || c == '$' )
         {
             q = q.substring( 0, q.length() - 1 );
         }
         else if ( c != '*' )
         {
             q += "*";
         }
 
         int n = q.indexOf( '*' );
         if ( n == -1 )
         {
             return new TermQuery( new Term( field, q ) );
         }
         else if ( n > 0 && n == q.length() - 1 )
         {
             return new PrefixQuery( new Term( field, q.substring( 0, q.length() - 1 ) ) );
         }
 
         return new WildcardQuery( new Term( field, q ) );
     }
 
     // ==
 
     private NexusAnalyzer nexusAnalyzer = new NexusAnalyzer();
 
     protected int countTerms( final IndexerField indexerField, final String query )
     {
         try
         {
             TokenStream ts = nexusAnalyzer.tokenStream( indexerField.getKey(), new StringReader( query ) );
             ts.reset();
 
             int result = 0;
 
             while ( ts.incrementToken() )
             {
                 result++;
             }
             
             ts.end();
             ts.close();
 
             return result;
         }
         catch ( IOException e )
         {
             // will not happen
             return 1;
         }
     }
 }