/**
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details ( see the LICENSE file ).
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package org.gudy.azureus2.core3.internat;

import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.*;

import org.gudy.azureus2.core3.config.COConfigurationManager;
import org.gudy.azureus2.core3.util.*;

public class
LocaleUtil 
{
  
  private static final String systemEncoding = System.getProperty("file.encoding");
  
  private static final String[] manual_charset = {
	systemEncoding,	// must be first entry due to code below that gets the system decoder
	"Big5","EUC-JP","EUC-KR","GB18030","GB2312","GBK","ISO-2022-JP","ISO-2022-KR",
	"Shift_JIS","KOI8-R",
	"TIS-620",	// added for bug #1008848 
	Constants.DEFAULT_ENCODING,"windows-1251",Constants.BYTE_ENCODING 
  };
  
	// the general ones *must* also be members of the above manual ones
  	
  protected static final String[] generalCharsets = {
	Constants.BYTE_ENCODING, Constants.DEFAULT_ENCODING, systemEncoding
  };
  
   private static LocaleUtil singleton = new LocaleUtil();
  
   public static LocaleUtil
   getSingleton()
   {
   	return( singleton );
   }
   
   private LocaleUtilDecoder[] 	all_decoders;
   private LocaleUtilDecoder[]	general_decoders;
   private LocaleUtilDecoder	system_decoder;
   private LocaleUtilDecoder	fallback_decoder;
     
  
  
  private 
  LocaleUtil() 
  {
	List	decoders 		= new ArrayList();
  	List	decoder_names	= new ArrayList();
  	
	for (int i = 0; i < manual_charset.length; i++) {
	   try {
		 String	name = manual_charset[i];
		 
		 CharsetDecoder decoder = Charset.forName(name).newDecoder();
		 
		 if ( decoder != null ){
		 	
			 LocaleUtilDecoder	lu_decoder =  new LocaleUtilDecoderReal(decoders.size(),decoder);
			 
			 decoder_names.add( lu_decoder.getName());
			
			 if ( i == 0 ){
			 	
			 	system_decoder = lu_decoder;
			 }
			 
			 decoders.add( lu_decoder );
			 
		 }else if ( i == 0 ){
		 	
		 	Debug.out( "System decoder failed to be found!!!!" );
		 }
		 
	   }catch (Exception ignore) {
	   }
	 }

	general_decoders = new LocaleUtilDecoder[generalCharsets.length];
	
	for (int i=0;i<general_decoders.length;i++){
		
		int	gi = decoder_names.indexOf( generalCharsets[i]);
		
		if ( gi != -1 ){
		
			general_decoders[i] = (LocaleUtilDecoder)decoders.get(gi);
		}
	}

	boolean show_all = COConfigurationManager.getBooleanParameter("File.Decoder.ShowAll" );

	if ( show_all ){
		
		Map m = Charset.availableCharsets();
	  	
		Iterator it = m.keySet().iterator();
	
		while(it.hasNext()){
	  		
			String	charset_name = (String)it.next();
	  		
			if ( !decoder_names.contains( charset_name)){
	  		
				try {
				  CharsetDecoder decoder = Charset.forName(charset_name).newDecoder();
				 
				  if ( decoder != null ){
				  	
				  	LocaleUtilDecoder	lu_decoder = new LocaleUtilDecoderReal(decoders.size(),decoder);
				  
				  	decoders.add( lu_decoder);
				  
				  	decoder_names.add( lu_decoder.getName());
				  }
				 
				} catch (Exception ignore) {
				}
			}
		}
	}
    
	fallback_decoder = new LocaleUtilDecoderFallback(decoders.size());
	
	decoders.add( fallback_decoder );

	all_decoders	= new LocaleUtilDecoder[ decoders.size()];
	
	decoders.toArray( all_decoders); 
  }
  
  public String
  getSystemEncoding()
  {
  	return( systemEncoding );
  }
  
  public LocaleUtilDecoder[]
  getDecoders()
  {
  	return( all_decoders );
  }
 
    public LocaleUtilDecoder[]
	getGeneralDecoders()
	{
	   	return( general_decoders );
	}
    
  public LocaleUtilDecoder getFallBackDecoder() {
  	return fallback_decoder;
  }
  
  public LocaleUtilDecoder
  getSystemDecoder()
  {
  	return( system_decoder );
  }
  
  /**
   * Determine which locales are candidates for handling the supplied type of 
   * string
   * 
   * @param array String in an byte array 
   * @return list of candidates.  Valid candidates have getDecoder() non-null
   */
  protected LocaleUtilDecoderCandidate[] 
  getCandidates(
	byte[] array ) 
  {
	LocaleUtilDecoderCandidate[] candidates = new LocaleUtilDecoderCandidate[all_decoders.length];
    
	boolean show_less_likely_conversions = COConfigurationManager.getBooleanParameter("File.Decoder.ShowLax" );

	for (int i = 0; i < all_decoders.length; i++){
    	
	  candidates[i] = new LocaleUtilDecoderCandidate(i);
      
	  try{
			LocaleUtilDecoder decoder = all_decoders[i];
      	      	
			String str = decoder.tryDecode( array, show_less_likely_conversions );

			if ( str != null ){
				
				candidates[i].setDetails( decoder, str );
			}
	  } catch (Exception ignore) {
      	
	  }
	}
    
	/*
	System.out.println( "getCandidates: = " + candidates.length );
	
	for (int i=0;i<candidates.length;i++){
		
		LocaleUtilDecoderCandidate	cand = candidates[i];
		
		if ( cand != null ){
		
			String	value = cand.getValue();
			
			if ( value != null ){
			
				System.out.println( cand.getDecoder().getName() + "/" + (value==null?-1:value.length()) + "/" + value );
			}
		}  
	}
	*/
	
	return candidates;
  }
    
  /**
   * Determine which decoders are candidates for handling the supplied type of
   * string
   * 
   * @param array String in a byte array
   * @return list of possibly valid decoders.  LocaleUtilDecoder
   */
  protected List
  getCandidateDecoders(
  	byte[]		array )
  {
  	LocaleUtilDecoderCandidate[] 	candidates = getCandidates( array );
  	
  	List	decoders = new ArrayList();
  	
  	for (int i=0;i<candidates.length;i++){
  	
  		LocaleUtilDecoder	d = candidates[i].getDecoder();
  		
  		if (d != null)
  			decoders.add(d);
  	}
  	
  	return decoders;
  }
  
  /**
   * 
   * @param array
   * @return List of LocaleUtilDecoderCandidate
   */
  protected List getCandidatesAsList(byte[] array) {
		LocaleUtilDecoderCandidate[] candidates = getCandidates(array);

		List candidatesList = new ArrayList();

		for (int i = 0; i < candidates.length; i++) {
			if (candidates[i].getDecoder() != null)
				candidatesList.add(candidates[i]);
		}

		return candidatesList;
	}
  
}