import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

/**
 * @author Isaac
 * This class creates a client which sends messages and recieve the server response
 * the client connect to the server through port 9876
 */

class Client { 
	
	public Client(){
	}
	
	/**
	 * 
	 * @return message to be sent
	 * 
	 * This procedure gets a message from the standard input
	 */
	public String getCommandMessage(){
		
		BufferedReader inFromUser = 
			new BufferedReader(new InputStreamReader(System.in)); 
		String sentence="";
		try {
			sentence = inFromUser.readLine();
		} catch (IOException e) {
	
		}
		return sentence;
	}
	/**
	 * This procedure send a message to server
	 * 
	 * @param msg
	 * @throws IOException
	 */
	public void sendMessage(String msg) throws IOException{
		DatagramSocket clientSocket = new DatagramSocket(); 
		
		InetAddress IPAddress = InetAddress.getByName("127.0.0.1"); 
		
		byte[] sendData = new byte[1024]; 
		byte[] receiveData = new byte[1024]; 
		sendData = msg.getBytes();  
		DatagramPacket sendPacket = 
			new DatagramPacket(sendData, sendData.length, IPAddress, 9876); 
		
		clientSocket.send(sendPacket); 
		
		DatagramPacket receivePacket = 
			new DatagramPacket(receiveData, receiveData.length); 
		
		clientSocket.receive(receivePacket); 
		
		String modifiedSentence = 
			new String(receivePacket.getData()); 
		
		System.out.println("FROM SERVER:" + modifiedSentence); 
		clientSocket.close();
	}
	
	/**
	 * This main is to use if the client is used as a stand alone application
	 * @param args
	 * @throws Exception
	 */
	public static void main(String args[]) throws Exception 
	{ 
		
		Client c = new Client();
		
		String sentence = "";
		sentence = c.getCommandMessage();
		while (sentence.compareTo("exit") != 0){
			c.sendMessage(sentence);
			sentence = c.getCommandMessage();
		}
	} 
}