//
//  ========================================================================
//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.server;

import java.io.IOException;

import org.eclipse.jetty.http.HttpException;
import org.eclipse.jetty.http.HttpStatus;
import org.eclipse.jetty.io.AsyncEndPoint;
import org.eclipse.jetty.io.EndPoint;
import org.eclipse.jetty.io.nio.AsyncConnection;
import org.eclipse.jetty.io.nio.SelectChannelEndPoint;
import org.eclipse.jetty.server.nio.SelectChannelConnector;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/* ------------------------------------------------------------ */
/** Asychronous Server HTTP connection
 *
 */
public final class AsyncHttpConnection extends AbstractHttpConnection implements AsyncConnection
{
	private final static int NO_PROGRESS_INFO = Integer.getInteger("org.mortbay.jetty.NO_PROGRESS_INFO",100);
	private final static int NO_PROGRESS_CLOSE = Integer.getInteger("org.mortbay.jetty.NO_PROGRESS_CLOSE",200);

	private static final Logger LOG = LoggerFactory.getLogger(AsyncHttpConnection.class);
	private int _total_no_progress;
	private final AsyncEndPoint _asyncEndp;
	private boolean _readInterested = true;

	public AsyncHttpConnection(SelectChannelConnector connector, AsyncEndPoint endpoint)
	{
		super(connector,endpoint);
		_asyncEndp = endpoint;
	}

	@Override
	public void handle() throws IOException
	{
		boolean some_progress = false;
		boolean progress = true;

		try
		{
			// While progress and the connection has not changed
			while (progress)
			{
				progress=false;
				try
				{
					// Parse more input
					if (!_parser.isComplete() && _parser.parseAvailable())
						progress = true;

					// Generate more output
					if (_generator.isCommitted() && !_generator.isComplete() && !_endp.isOutputShutdown())
						if (_generator.flushBuffer()>0)
							progress = true;

					// Flush output
					_endp.flush();

					// Has any IO been done by the endpoint itself since last loop
					if (_asyncEndp.hasProgressed())
						progress = true;
				}
				catch (HttpException e)
				{
					if (LOG.isDebugEnabled())
					{
						LOG.debug("uri="+_uri);
						LOG.debug("fields="+_requestFields);
						LOG.debug("",e);
					}
					progress = true;
					_generator.sendError(e.getStatus(), e.getReason(), null, true);
				}
				finally
				{
					some_progress |= progress;
					//  Is this request/response round complete and are fully flushed?
					boolean parserComplete = _parser.isComplete();
					boolean generatorComplete = _generator.isComplete();
					boolean complete = parserComplete && generatorComplete;
					if (parserComplete)
					{
						if (generatorComplete)
						{
							// Reset the parser/generator
							progress=true;

							reset();

							// TODO Is this still required?
							if (!_generator.isPersistent() && !_endp.isOutputShutdown())
							{
								LOG.warn("Safety net oshut!!!  IF YOU SEE THIS, PLEASE RAISE BUGZILLA");
								_endp.shutdownOutput();
							}
						}
						else
						{
							// We have finished parsing, but not generating so
							// we must not be interested in reading until we
							// have finished generating and we reset the generator
							_readInterested = false;
							LOG.debug("Disabled read interest while writing response {}", _endp);
						}
					}
				}
			}
		}
		finally
		{
			// return buffers
			_parser.returnBuffers();
			_generator.returnBuffers();

			// Safety net to catch spinning
			if (some_progress)
				_total_no_progress = 0;
			else
			{
				_total_no_progress++;
				if (NO_PROGRESS_INFO>0 && _total_no_progress%NO_PROGRESS_INFO==0 && (NO_PROGRESS_CLOSE<=0 || _total_no_progress< NO_PROGRESS_CLOSE))
					LOG.info("EndPoint making no progress: "+_total_no_progress+" "+_endp+" "+this);
				if (NO_PROGRESS_CLOSE>0 && _total_no_progress==NO_PROGRESS_CLOSE)
				{
					LOG.warn("Closing EndPoint making no progress: "+_total_no_progress+" "+_endp+" "+this);
					if (_endp instanceof SelectChannelEndPoint)
						_endp.getChannel().close();
				}
			}
		}
	}

	@Override
	public void onInputShutdown() throws IOException
	{
		// If we don't have a committed response and we are not suspended
		if (_generator.isIdle())
		{
			// then no more can happen, so close.
			_endp.close();
		}

		// Make idle parser seek EOF
		if (_parser.isIdle())
			_parser.setPersistent(false);
	}

	@Override
	protected void reset()
	{
		_readInterested = true;
		LOG.debug("Enabled read interest {}", _endp);
		super.reset();
	}

	@Override
	public boolean isSuspended()
	{
		return !_readInterested;
	}
}