/**************************************************************************
/* This class implements a configurable Lucene-search engine.
/*
/* Copyright (c) 2003-2004 by Bernhard Bablok (mail@bablokb.de)
/*
/* This library is free software; you can redistribute it and/or modify
/* it under the terms of the GNU Lesser General Public License as published
/* by  the Free Software Foundation; either version 2 of the License or
/* (at your option) any later version.
/*
/* This library is distributed in the hope that it will be useful, but
/* WITHOUT ANY WARRANTY; without even the implied warranty of
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
/* GNU Lesser General Public License for more details.
/*
/* You should have received a copy of the GNU Lesser General Public License
/* along with this library; see the file COPYING.LESSER.  If not, write to
/* the Free Software Foundation Inc., 59 Temple Place - Suite 330,
/* Boston, MA  02111-1307 USA
/**************************************************************************/

package de.bablokb.luala.lib;

import java.io.*;
import java.util.*;
import org.apache.lucene.document.*;
import org.apache.lucene.store.*;
import org.apache.lucene.search.*;
import org.apache.lucene.queryParser.*;
import org.apache.lucene.analysis.*;
import org.apache.lucene.analysis.de.*;
import org.apache.lucene.analysis.ru.*;
import org.apache.lucene.analysis.standard.*;

import de.bablokb.luala.lib.*;

/**
   This class implements a configurable Lucene-search engine.

   @version $Revision: 1.10 $
   @author  $Author: bablokb $
*/

public class SearchEngine {

  ////////////////////////////////////////////////////////////////////////////

  /**
     The index-directory. If this directory is not-writable, we will
     disable locks.
  */

  private String iIndexDir;

  ////////////////////////////////////////////////////////////////////////////

  /**
     The default field for the query. This defaults to
     {@link StandardDocumentFactory#CONTENT}.
  */

  private String iDefaultField;

  ////////////////////////////////////////////////////////////////////////////

  /**
     The analyzer for the search. This should be the same analyzer as for
     indexing.
  */

  private Analyzer iAnalyzer;

  ////////////////////////////////////////////////////////////////////////////

  /**
     Default-Constructor. Creates a default analyzer based on the current
     default locale.
  */

  public SearchEngine() {
    String currentCountry = Locale.getDefault().getCountry();
    if (currentCountry.equals("DE"))
	iAnalyzer = new GermanAnalyzer();
//     else if (currentCountry.equals("RU"))
// 	iAnalyzer = new RussianAnalyzer(???);
    else
      iAnalyzer = new StandardAnalyzer();
    iDefaultField = StandardDocumentFactory.CONTENT;
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Construct a SearchEngine with given directory.

     @param dir The directory with the index.

     @throws FileNotFoundException if the directory does not exist
     @throws IllegalArgumentException if the argument is not a directory
  */

  public SearchEngine(String dir)
                      throws FileNotFoundException, IllegalArgumentException {
    this();
    setIndexDirectory(dir);
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Sets the index directory.

     @param dir The directory with the index.

     @throws FileNotFoundException if the directory does not exist
     @throws IllegalArgumentException if the argument is not a directory
  */

  public void setIndexDirectory(String dir)
                     throws FileNotFoundException, IllegalArgumentException {
    File d = new File(dir);
    if (!d.exists())
      throw new FileNotFoundException("could not find directory: " + dir);
    if (!d.isDirectory())
      throw new IllegalArgumentException("not a directory: " + dir);
    iIndexDir = dir;
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Sets the analyzer.

     @param a The analyzer to use.
  */

  public void setAnalyzer(Analyzer a) {
    iAnalyzer = a;
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Sets the default fields for queries.

     @param name The name of the default field.
  */

  public void setField(String name) {
    iDefaultField = name;
  }

  ////////////////////////////////////////////////////////////////////////////

  /**
     Search the index and return the results.

     @param queryString The query to perform

     @return An array with all documents matching the query

     @throws IOException
     @throws ParseException
  */

  public Document[] search(String queryString) throws IOException,
                               org.apache.lucene.queryParser.ParseException {
    // Directory dir = RODirectory.getDirectory(iIndexDir);
    String dir = iIndexDir;
    Searcher searcher = new IndexSearcher(dir);
    Query query = QueryParser.parse(queryString,iDefaultField,iAnalyzer);
    Hits hits = searcher.search(query);

    Document[] results = new Document[hits.length()];
    for (int i = 0; i<results.length; ++i)
      results[i] = hits.doc(i);
    searcher.close();
    return results;
  }
}