package org.red5.server.stream;

/*
 * RED5 Open Source Flash Server - http://www.osflash.org/red5
 * 
 * Copyright (c) 2006-2009 by respective authors (see below). All rights reserved.
 * 
 * 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 2.1 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; if not, write to the Free Software Foundation, Inc., 
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
 */

import java.util.LinkedList;
import java.util.Queue;

import org.red5.server.net.rtmp.event.IRTMPEvent;
import org.red5.server.stream.message.RTMPMessage;

/**
 * A Play buffer for sending VOD.
 * The implementation is not synchronized.
 * 
 * @author The Red5 Project (red5@osflash.org)
 * @author Steven Gong (steven.gong@gmail.com)
 */
public class PlayBuffer {
    /**
     * Buffer capacity
     */
	private long capacity;
    /**
     * Message size
     */
	private long messageSize;
    /**
     * Queue of RTMP messages
     */
	private Queue<RTMPMessage> messageQueue = new LinkedList<RTMPMessage>();

    /**
     * Create play buffer with given capacity
     * @param capacity          Capacity of buffer
     */
    public PlayBuffer(long capacity) {
		this.capacity = capacity;
	}

	/**
	 * Buffer capacity in bytes.
	 * 
	 * @return          Buffer capacity in bytes
	 */
	public long getCapacity() {
		return capacity;
	}

	/**
     * Setter for capacity
     *
     * @param capacity  New capacity
     */
    public void setCapacity(long capacity) {
		this.capacity = capacity;
	}

	/**
	 * Number of messages in buffer.
	 * 
	 * @return          Number of messages in buffer
	 */
	public int getMessageCount() {
		return messageQueue.size();
	}

	/**
	 * Total message size in bytes.
	 * 
	 * @return          Total message size in bytes
	 */
	public long getMessageSize() {
		return messageSize;
	}

	/**
	 * Put a message into this buffer.
	 * 
	 * @param message          RTMP message
	 * @return <tt>true</tt> indicates success and <tt>false</tt>
	 * indicates buffer is full.
	 */
	public boolean putMessage(RTMPMessage message) {
		IRTMPEvent body = message.getBody();
		if (!(body instanceof IStreamData)) {
			throw new RuntimeException("expected IStreamData but got " + body);
		}

		int size = ((IStreamData) body).getData().limit();
		if (messageSize + size > capacity) {
			return false;
		}
		messageSize += size;
		messageQueue.offer(message);
		return true;
	}

	/**
	 * Take a message from this buffer. The message count decreases.
	 * 
	 * @return <tt>null</tt> if buffer is empty.
	 */
	public RTMPMessage takeMessage() {
		RTMPMessage message = messageQueue.poll();
		if (message != null) {
			IRTMPEvent body = message.getBody();
			if (!(body instanceof IStreamData)) {
				throw new RuntimeException("expected IStreamData but got "
						+ body);
			}

			messageSize -= ((IStreamData) body).getData().limit();
		}
		return message;
	}

	/**
	 * Peek a message but not take it from the buffer. The message count
	 * doesn't change.
	 * @return <tt>null</tt> if buffer is empty.
	 */
	public RTMPMessage peekMessage() {
		return messageQueue.peek();
	}

	/**
	 * Empty this buffer.
	 */
	public void clear() {
		messageQueue.clear();
		messageSize = 0;
	}
}