/* 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 3 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, see <http://www.gnu.org/licenses/>.
 */

package com.l2jserver.util;

import java.lang.management.LockInfo;
import java.lang.management.ManagementFactory;
import java.lang.management.MonitorInfo;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.l2jserver.Config;
import com.l2jserver.gameserver.Announcements;
import com.l2jserver.gameserver.Shutdown;


/**
 * Thread to check for deadlocked threads.
 * 
 * @author -Nemesiss- L2M
 */
public class DeadLockDetector extends Thread
{
	private static Logger _log = Logger.getLogger(DeadLockDetector.class.getName());

	/** Interval to check for deadlocked threads */
	private static final int _sleepTime = Config.DEADLOCK_CHECK_INTERVAL*1000;
	
	private final ThreadMXBean tmx;
	
	public DeadLockDetector()
	{
		super("DeadLockDetector");
		tmx = ManagementFactory.getThreadMXBean();
	}
	
	@Override
	public final void run()
	{
		boolean deadlock = false;
		while(!deadlock)
		{
			try
			{
				long[] ids = tmx.findDeadlockedThreads();
				
				if(ids != null)
				{
					deadlock = true;
					ThreadInfo[] tis = tmx.getThreadInfo(ids,true,true);
					StringBuilder info = new StringBuilder();
					info.append("DeadLock Found!\n");
					for(ThreadInfo ti : tis)
					{
						info.append(ti.toString());
					}
					
					for(ThreadInfo ti : tis)
					{
						LockInfo[] locks = ti.getLockedSynchronizers();
						MonitorInfo[] monitors = ti.getLockedMonitors();
						if(locks.length == 0 && monitors.length == 0)
						{
							continue;
						}
						
						ThreadInfo dl = ti;
						info.append("Java-level deadlock:\n");
						info.append("\t");
						info.append(dl.getThreadName());
						info.append(" is waiting to lock ");
						info.append(dl.getLockInfo().toString());
						info.append(" which is held by ");
						info.append(dl.getLockOwnerName());
						info.append("\n");
						while((dl = tmx.getThreadInfo(new long[]{dl.getLockOwnerId()},true,true)[0]).getThreadId() != ti.getThreadId())
						{
							info.append("\t");
							info.append(dl.getThreadName());
							info.append(" is waiting to lock ");
							info.append(dl.getLockInfo().toString());
							info.append(" which is held by ");
							info.append(dl.getLockOwnerName());
							info.append("\n");
						}
					}
					_log.warning(info.toString());
					
					if(Config.RESTART_ON_DEADLOCK)
					{
						Announcements an = Announcements.getInstance();
						an.announceToAll("Server has stability issues - restarting now.");
						Shutdown.getInstance().startTelnetShutdown("DeadLockDetector - Auto Restart",60,true);
					}
					
				}
				Thread.sleep(_sleepTime);
			}
			catch(Exception e)
			{
				_log.log(Level.WARNING,"DeadLockDetector: ",e);
			}
		}
	}
}