package com.ericsson.tic.vi;

import java.util.TimerTask;
import java.util.Timer;

import java.io.IOException;
import java.net.SocketTimeoutException;
import java.net.DatagramSocket;
import java.net.DatagramPacket;
import java.net.SocketException;

/**
 * The BufferReader thread continuously reads both the socket buffer and the
 * user input buffer.
 *
 * @author	Sami Matilainen
 * @version 1.0 (2008-12-04)
 */
public class BufferReader extends TimerTask {
	
	/** The port this listener listens on. */
	private int portListen;
	
	/** A UDP socket. */
	private DatagramSocket socket;
	
	/** A UDP packet. */
	private DatagramPacket packet;
	
	/** A temporary buffer. */
	private byte[] tempBuffer;
	
	/** A temporary buffer. */
	private char[] tempCharBuffer;
	
	/**
	 * Create a BufferReader and start listening to messages.
	 * Not to be confused with BufferedReader in the Java API.
	 */
	public BufferReader(int portListen) throws SocketException  {
		
		this.portListen = portListen;
		
		tempBuffer = new byte[VI.MESSAGE_MAX_WIDTH];
		tempCharBuffer = new char[VI.MESSAGE_MAX_WIDTH];
		
		socket = new DatagramSocket(portListen);
		socket.setSoTimeout(1);
		
		// default on mac is 65507
		if (socket.getReceiveBufferSize() < VI.socketBufferSize) {
			socket.setReceiveBufferSize(VI.socketBufferSize);
		}
		
		packet = new DatagramPacket(tempBuffer, tempBuffer.length);
		
		Timer t = new Timer(true);
		t.schedule(this, 500, 500);
		
	}
	
	/**
	 * Continuously reads the buffers.
	 */
	public void run() {
		
		checkUserInputBuffer(VI.consoleInputBuffer);
			
		if (!VI.pauseGUI) {
			checkSocketInputBuffer();
		}
		
	}
	
	/**
	 * Checks and parses the content of the specified user input buffer.
	 * 
	 * @param buffer the buffer which holds messages.
	 */
	private void checkUserInputBuffer(RawBuffer buffer) {
		
		buffer.swap();
		
		// buffer.fetch will throw an exception if the buffer is empty
		
		while (true) {
			try {
				tempCharBuffer = buffer.fetch();
				Parser.parseUserInput(new String(tempCharBuffer));
			} catch (Exception e) {
				break;
			}
		}
		
	}
	
	/**
	 * Checks and parses the content of the socket input buffer.
	 */
	private void checkSocketInputBuffer() {
		
		while (true) {
			try {
				
				tempBuffer = new byte[VI.MESSAGE_MAX_WIDTH];
				packet = new DatagramPacket(tempBuffer, tempBuffer.length);
				socket.receive(packet);
				
				Parser.parseMessageInput(new String(tempBuffer));
				
			} catch (SocketTimeoutException e) {
				break;
			} catch (IOException e) {
				e.printStackTrace();
			}
			
		}
		
	}
	
}