package example9_3_RemoteProxy.client;

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import example9_3_RemoteProxy.dateService.DateService;
import example9_3_RemoteProxy.dateService.Message;

// This class implements a remote proxy to a "real" DateService-implemented object
public class DateProxy implements DateService {

	private Socket socket; // this client's socket
	private InetAddress netAddr;
	private ObjectInputStream fromServerStream; // for reading from server
	private DataOutputStream toServerStream; // for writing to server

	/**
	 * Constructor
	 */
	public DateProxy() throws Exception {
		//	Create and connect a client-side socket to a pre-existing server socket 
		// localhost is 127.0.0.1
		byte[] addr = {(byte)127,(byte)0,(byte)0, (byte)1}; // 127.0.0.1 is the local loopback IP address

		// Create the socket connection
		try{
			netAddr = InetAddress.getByAddress(addr);
			System.out.println("Connecting to server...");
			socket = new Socket(netAddr, 80); // connect to server at this IP address on the specified port
			System.out.println("Connected to server; starting to send and receive...");
			toServerStream = new DataOutputStream(socket.getOutputStream());
			fromServerStream = new ObjectInputStream(socket.getInputStream());
		} catch( UnknownHostException e ) {
			throw new Exception("Unknown host");
		} catch( IOException e ) {
			throw new Exception("Can't connect to server-side socket.");
		}
	}

	/**
	 * Form a request to return the current date from the server
	 * @return the current date as a String
	 */
	@Override
	public String getDate() {
		String retVal;
		try {
			toServerStream.writeInt(Message.DATEREQUEST);
			Message response = (Message)fromServerStream.readObject();
			retVal = response.getValue();
		} catch( ClassNotFoundException e ) {
			retVal = "proxy class cast error; possible JDK incompatibility";
		} catch( IOException e ) {
			retVal = "proxy read error.";
		}
		return retVal;

	}

	/**
	 * Serialize a request to return the current time from the server
	 * @return the current time in ms (after 1/1/1970) as a String
	 */
	@Override
	public String getTime() {
		String retVal;
		try {
			toServerStream.writeInt(Message.TIMEREQUEST);
			Message response = (Message)fromServerStream.readObject();
			retVal = response.getValue();
		} catch( ClassNotFoundException e ) {
			retVal = "proxy class cast error; possible JDK incompatibility";
		} catch( IOException e ) {
			retVal = "proxy read error.";
		}
		return retVal;
	}
}