/**************************************************************************
/* This class implements a configurable Lucene-index 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.analysis.*;
import org.apache.lucene.analysis.de.*;
import org.apache.lucene.analysis.ru.*;
import org.apache.lucene.analysis.standard.*;
import org.apache.lucene.index.*;
import org.pdfbox.searchengine.lucene.*;

import de.bablokb.luala.lib.*;

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

   @version $Revision: 1.6 $
   @author  $Author: bablokb $
*/

public class IndexEngine {

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

  /**
     The index-directory.
  */

  private String iIndexDir;

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

  /**
     The analyzer for the index.
  */

  private Analyzer iAnalyzer;

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

  /**
     The {@link IndexWriter} used by this engine.
  */

  private IndexWriter iWriter;

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

  /**
     The {@link DocumentFactoryManager} used by this engine.
  */

  private DocumentFactoryManager iDocFacManager;

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

  /**
     The creation-flag used by this engine. If set to true (default), a new
     index will be created, otherwise, an existing index will be updated.
  */

  private boolean iCreateFlag;

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

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

  public IndexEngine() {
    String currentCountry = Locale.getDefault().getCountry();
    if (currentCountry.equals("DE"))
	iAnalyzer = new GermanAnalyzer();
//     else if (currentCountry.equals("RU"))
// 	iAnalyzer = new RussianAnalyzer(???);
    else
      iAnalyzer = new StandardAnalyzer();
    iDocFacManager = new DocumentFactoryManager();
    iCreateFlag = true;
  }

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

  /**
     Construct a IndexEngine with given directory.

     @param dir The directory with the index.

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

  public IndexEngine(String dir) throws IllegalArgumentException {
    this();
    setIndexDirectory(dir);
  }

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

  /**
     Sets the index directory.

     @param dir The directory with the index.

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

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

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

  /**
     Sets the analyzer.

     @param a The analyzer to use.
  */

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

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

  /**
     Sets the create-flag. If set to true (default), a new
     index will be created, otherwise, an existing index will be updated.

     @param flag true, if a new index should be created (replacing an old
                 index if necessary)
  */

  public void setCreateFlag(boolean flag) {
    iCreateFlag = flag;
  }

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

  /**
     Open the index. This initializes the {@link IndexWriter}.

     @throws IOException
  */

  public void open()  throws IOException {
    iWriter = new IndexWriter(iIndexDir,iAnalyzer,iCreateFlag);
  }

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

  /**
     Index a file given a {@link File}..

     @param file The file

     @throws IOException
  */

  public void indexFile(File file) throws IOException {
    if (file.isDirectory())
      indexDir(file);
    String name = file.getPath();
    try {
      DocumentFactory fac = iDocFacManager.getFactory(name);
      if (fac == null) {
	System.out.println("failed to index " + 
          name + ": no DocumentFactory available");
	return;
      }
      iWriter.addDocument(fac.createDocument(name));
    } catch (Exception e) {
      System.err.println("failed to index " + name + ": " + e.getMessage());
    }
  }

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

  /**
     Index a file with given name.

     @param name The name of the file

     @throws IOException
  */

  public void indexFile(String name) throws IOException {
    indexFile(new File(name));
  }

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

  /**
     Index a directory tree.

     @throws IOException
  */

  public void indexDir(File file) throws IOException {
    if (file.isDirectory()) {
      String[] files = file.list();
      for (int i = 0; i < files.length; i++)
	indexDir(new File(file,files[i]));
    } else {
      indexFile(file);
    }
  }

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

  /**
     Close the index.

     @throws IOException
  */

  public void close() throws IOException {
    iWriter.optimize();
    iWriter.close();
  }
}