@@ -23,13 +23,29 @@
  *******************************************************************************/
 package com.github.mob41.blapi;
 
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.SocketTimeoutException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.github.mob41.blapi.mac.Mac;
+import com.github.mob41.blapi.pkt.DiscoveryPacket;
+
 /**
  * This is the base class of all Broadlink devices (e.g. SP1, RMPro)
  * @author Anthony
  *
  */
 public abstract class BLDevice {
 
+	private static final Logger log = LoggerFactory.getLogger(BLDevice.class);
+	
 	public static final byte[] INITIAL_KEY = {
 			0x09, 0x76, 0x28, 0x34,
 			0x3f, (byte) 0xe9, (byte) 0x9e, 0x23,
@@ -89,9 +105,139 @@ public abstract class BLDevice {
 	public static final short DEV_A1 = 0x2714;
 
 	public static final short DEV_MP1 = 0x4EB5;
+	
+	public static final int DISCOVERY_DEST_PORT = 80;
+	
+	public static final int DISCOVERY_RECEIVE_BUFFER_SIZE = 0x40; //64-bytes
 
-	public BLDevice(short deviceType, String host, String mac) {
+	protected BLDevice(short deviceType, String host, Mac mac) {
 
 	}
-
+	
+	public static BLDevice createInstance(short deviceType, String host, Mac mac){
+		switch (deviceType){
+		case DEV_RM_2:
+		}
+		return null;
+	}
+	
+	public static BLDevice[] discoverDevices(InetAddress sourceIpAddr, int sourcePort, int timeout) throws IOException{
+		  List<BLDevice> devices = new ArrayList<BLDevice>(50);
+		  
+		  DiscoveryPacket dpkt = new DiscoveryPacket(sourceIpAddr, sourcePort);
+		  
+		  DatagramSocket sock = new DatagramSocket(sourcePort, sourceIpAddr);
+		  sock.setBroadcast(true);
+		  sock.setReuseAddress(true);
+		  
+		  byte[] sendBytes = dpkt.getData();
+		  DatagramPacket sendpack = new DatagramPacket(sendBytes, sendBytes.length,
+				  InetAddress.getByName("255.255.255.255"), DISCOVERY_DEST_PORT);
+		  sock.send(sendpack);
+		  
+		  byte[] receBytes = new byte[DISCOVERY_RECEIVE_BUFFER_SIZE];
+		  
+		  DatagramPacket recePacket = new DatagramPacket(receBytes, 0, receBytes.length);
+		  if (timeout == 0){
+			 sock.receive(recePacket);
+			 sock.close();
+			 
+			 String host = recePacket.getAddress().getHostAddress();
+			 Mac mac = new Mac(subbytes(receBytes, 0x3a, 0x40));
+			 short deviceType = (short) (receBytes[0x34] | receBytes[0x35] << 8);
+			 
+			 BLDevice inst = createInstance(deviceType, host, mac);
+			 
+			 if (inst != null){
+				 devices.add(inst);
+			 }
+		  } else {
+			  long startTime = System.currentTimeMillis();
+			  long elapsed;
+			  while ((elapsed = System.currentTimeMillis() - startTime) < timeout){
+				  sock.setSoTimeout((int) (timeout - elapsed));
+				  
+				  try {
+					  sock.receive(recePacket);
+				  } catch (SocketTimeoutException e){
+					  break;
+				  }
+				  
+				  String host = recePacket.getAddress().getHostAddress();
+				  Mac mac = new Mac(subbytes(receBytes, 0x3a, 0x40));
+				  short deviceType = (short) (receBytes[0x34] | receBytes[0x35] << 8);
+				  
+				  BLDevice inst = createInstance(deviceType, host, mac);
+				  
+				  if (inst != null){
+					  devices.add(inst);
+				  }
+			  }
+		  }
+		  
+		  BLDevice[] out = new BLDevice[devices.size()];
+		  for (int i = 0; i < out.length; i++){
+			  out[i] = devices.get(i);
+		  }
+		  
+		  return out;
+	}
+	
+	/**
+	 * Picks bytes from start-set to the end-set in a bytes array
+	 * @param data The bytes array to be used
+	 * @param start The starting position to be picked
+	 * @param end The ending position to be picked
+	 * @return The bytes array picked with length (<code>end - start</code>)
+	 */
+	public static byte[] subbytes(byte[] data, int start, int end){
+		byte[] out = new byte[end - start];
+		
+		int outi = 0;
+		for (int i = start; i < end; i += 0x01, outi++){
+			out[outi] = data[i];
+		}
+		
+		return out;
+	}
+	
+	/* Not this! This will only send once and close the connection
+	/**
+	 * Sends a compiled packet to a destination host and port, and
+	 * receives a datagram from the source port specified.
+	 * @param pkt The compiled packet to be sent
+	 * @param sourceIpAddr Source IP address to be binded for receiving datagrams
+	 * @param sourcePort Source Port to be bineded for receiving datagrams
+	 * @param destIpAddr Destination IP address
+	 * @param destPort Destination Port
+	 * @param timeout Socket timeout. 0 will disable the timeout
+	 * @param bufSize Receiving datagram's buffer size
+	 * @return The received datagram
+	 * @throws IOException Thrown if socket timed out, cannot bind source IP and source port, no permission, etc.
+	 *\/
+	public static DatagramPacket sendPkt(Packet pkt, 
+			InetAddress sourceIpAddr, int sourcePort,
+			InetAddress destIpAddr, int destPort,
+			int timeout, int bufSize) throws IOException{
+		DatagramSocket sock = new DatagramSocket(sourcePort, sourceIpAddr);
+		sock.setBroadcast(true);
+		sock.setReuseAddress(true);
+		
+		//sock.bind(new InetSocketAddress(ipAddr, sourcePort));
+		
+		byte[] data = pkt.getData();
+		DatagramPacket sendpack = new DatagramPacket(data, data.length, destIpAddr, destPort);
+		sock.send(sendpack);
+		
+		byte[] rece = new byte[bufSize];
+		
+		DatagramPacket recepack = new DatagramPacket(rece, 0, rece.length);
+		sock.setSoTimeout(timeout);
+		sock.receive(recepack);
+		
+		sock.close();
+		
+		return recepack;
+	}
+	*/
 }
@@ -69,7 +69,7 @@ public DiscoveryPacket(InetAddress localIpAddr, int sourcePort, Calendar cal, Ti
 		int year = cal.get(Calendar.YEAR);
 		int dayOfWk = dayOfWeekConv(cal.get(Calendar.DAY_OF_WEEK)); //Day of week (May return -1 if Calendar return a wrong field value)
 		int dayOfMn = cal.get(Calendar.DAY_OF_MONTH); //Day of month
-		int month = cal.get(Calendar.MONTH); //Month
+		int month = cal.get(Calendar.MONTH + 1); //Month
 
 		if (debug){
 			log.debug("min=" + min + " hr=" + hr);