/*
 * Created on 27-Apr-2004
 * Created by Paul Gardner
 * 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.
 * 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.pluginsimpl.local.ui.components;

/**
 * @author parg
 *
 */

import java.io.File;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.LinkedList;

import org.gudy.azureus2.core3.util.*;
import org.gudy.azureus2.plugins.ui.components.UIPropertyChangeListener;
import org.gudy.azureus2.plugins.ui.components.UITextArea;


public class 
UITextAreaImpl	
	extends		UIComponentImpl
	implements 	UITextArea
{
	private final boolean enable_history = System.getProperty( "az.logging.keep.ui.history", "true" ).equals( "true" );
	
	private int	max_size		= DEFAULT_MAX_SIZE;
	private int max_file_size = 20 * max_size;
	
	PoopWriter pw;
	int current_file_size;
	File poop_file;
	boolean useFile = true;
	
	AEMonitor file_mon = new AEMonitor("filemon");
	
	LinkedList<String>	delay_text	= new LinkedList<String>();
	int					delay_size	= 0;
	
	FrequencyLimitedDispatcher	dispatcher = 
		new FrequencyLimitedDispatcher(
			new AERunnable()
			{
				public void
				runSupport()
				{
					delayAppend();
				}
			},
			500 );
	
	public
	UITextAreaImpl()
	{
		setText("");
	}
	
	public void
	setText(
		String		text )
	{
		if ( !enable_history ){
			
			return;
		}
		
		if ( useFile ){
			
			try{
				file_mon.enter();
				
				if ( pw == null ){
					
					pw = new PoopWriter();

					pw.print(text);
					
					current_file_size = text.length();

					return;
				}
			}finally{
				
				file_mon.exit();
			}
		}
		
		// has property change listener, or error while doing file (fallthrough)
		
		if ( text.length() > max_size ){
				
			int	size_to_show = max_size - 10000;
			
			if ( size_to_show < 0 ){
				
				size_to_show	= max_size;
			}
			
			text = text.substring( text.length() - size_to_show );
		}
		
		setProperty( PT_VALUE, text );
	}
		
	public void
	appendText(
		String		text )
	{
		if ( !enable_history ){
			
			return;
		}
		
		if ( useFile && pw != null ){
			
			try{
				file_mon.enter();
				
					// shrink the file occasionally
				
				if ( current_file_size > max_file_size ){
					
					current_file_size = getFileText().length();
				}
				
				pw.print(text);
				
				current_file_size += text.length();
				
				return;
				
			}finally{
				
				file_mon.exit();
			}
		}

		synchronized( this ){
			
			delay_text.addLast( text );
			
			delay_size += text.length();
			
			while( delay_size > max_size ){
		
				if ( delay_text.size() == 0 ){
					
					break;
				}
				
				String	s = (String)delay_text.removeFirst();
				
				delay_size -= s.length();
			}
		}
		
		dispatcher.dispatch();
	}
	
	protected void
	delayAppend()
	{
		String	str = getText();

		String	text;
		
		synchronized( this ){

			if ( delay_text.size() == 1 ){
				
				text = (String)delay_text.get(0);
				
			}else{
				
				StringBuffer sb = new StringBuffer( delay_size );
				
				Iterator<String>	it = delay_text.iterator();
				
				while( it.hasNext()){
				
					sb.append( it.next());
				}
				
				text = sb.toString();
			}
			
			delay_text.clear();
			delay_size = 0;
		}
		
		if ( str == null ){
			
			setText( text );
			
		}else{
			
			setText( str + text );
		}
	}
	
	public String
	getText()
	{
		if ( !enable_history ){
			
			return( "" );
		}
		
		if ( useFile && pw != null ){
			
			return( getFileText());
		}

		return((String)getProperty( PT_VALUE ));
	}
	
	public void
	setMaximumSize(
		int	_max_size )
	{
		max_size	= _max_size;
	}
	
	private String 
	getFileText() 
	{
		try{
			file_mon.enter();

			String text = null;

			if ( pw != null ){
				
				pw.close();
			
				text = pw.getText();
			}
			
			if ( text == null ){
				
				text = "";
			}

			pw = null;
			
			if ( useFile ){
			
				pw = new PoopWriter();
				
				pw.print(text);
				
				current_file_size = text.length();
			}
			
			return text;
			
		}finally{
			
			file_mon.exit();
		}
	}
	
	public void 
	addPropertyChangeListener(
		UIPropertyChangeListener l ) 
	{
		if ( useFile ){

			useFile = false;
			
			setText( getFileText());
		}

		super.addPropertyChangeListener(l);
	}
	
	protected class
	PoopWriter
	{	
		private StringBuffer	buffer = new StringBuffer(256);
		
		private PrintWriter		pw;
		
		private void
		print(
			String	text )
		{
			if ( pw == null ){
				
				buffer.append( text );
				
				if ( buffer.length() > 8*1024 ){
					
					if ( poop_file == null ){
						
						try{
							poop_file = AETemporaryFileHandler.createTempFile();
							
						}catch( Throwable e ){
						}
					}
					
					if ( poop_file != null ){
						
						try{
							pw = new PrintWriter( poop_file );
						
							pw.print( buffer.toString());
							
						}catch( Throwable e ){
						}
					}
					
					buffer.setLength( 0 );
				}
			}else{
				
				pw.print( text );
			}
		}
		
		private String
		getText()
		{
			if ( poop_file == null ){
				
				return( buffer.toString());
				
			}else{
				
				try{
					return( FileUtil.readFileEndAsString( poop_file, max_size ));
					
				}catch( Throwable e ){
					
					return( "" );
				}
			}
		}
		
		private void
		close()
		{
			if ( pw != null ){
				
				pw.close();
				
				pw = null;
			}
		}
	}
}