// Project 1 for CMSC 838P
// Charles B. Cranston xxx-xx-xxxx <zben@ni.umd.edu>
// April 8, 1997

// Democratic chat system

import java.rmi.*;
import java.util.Vector;
import java.io.*;

public class Phone extends java.rmi.server.UnicastRemoteObject
	implements PhoneAPI {

	String userid;
	Vector peers;
	Vector names;

	public Phone(String uid) throws RemoteException {
		userid = uid;
		peers = new Vector(0,20);
		names = new Vector(0,20);
	}

	public void addpeer(PhoneAPI[] newbies) {
		for (int i=0; i<newbies.length; i++)
			addpeer(newbies[i]);
	}

	public void addpeer(PhoneAPI newby) {
		if ( !peers.contains(newby) ) {
			try {
				String name = newby.identify();
				names.addElement(name);
				peers.addElement(newby);
			} catch (Exception e) {
				diagnose("addpeer",e);
			}
		}
	}

	// Someone else calls us, can refuse here someday
	public PhoneAPI[] apply(PhoneAPI[] newbies) throws RemoteException {
		int n = peers.size();
		PhoneAPI[] result = new PhoneAPI[n+1];
		for (int i=0; i<n; i++) {
			PhoneAPI p = (PhoneAPI) peers.elementAt(i);
			result[i] = p;
			try {
				p.sponsor(newbies);
			} catch (Exception e) {
				diagnose("sponsor",e);
			}
		}
		result[n] = this;
		addpeer(newbies);
		dowho();
		return(result);
	}

	public void sponsor(PhoneAPI[] newbies) throws RemoteException {
		addpeer(newbies);
		dowho();
	}

	public void resign(PhoneAPI caller) throws RemoteException {
		int i = peers.indexOf(caller);
		if (0 <= i) {
			System.err.println(
				"Exit '"+(String)names.elementAt(i)+"'");
			peers.removeElementAt(i);
			names.removeElementAt(i);
		}
	}

	public void transfer(PhoneAPI from, Object thing)
		throws RemoteException {
		String f = (String) names.elementAt(peers.indexOf(from));
		if ( thing instanceof String ) {
			String s = (String) thing;
			System.err.println(f + ": " + s);
		} else {
			System.err.println("Unknown thing from '" + f + "'");
		}
	}

	public String identify() throws RemoteException {
		return(userid);
	}

	// Try to register but field errors.
	public boolean register() {
		System.setSecurityManager(new RMISecurityManager());
		String url = "//:1070/phone/" + userid;
		try {
			Naming.rebind(url,this);
		} catch (ConnectException e) {
			System.err.println("Could not register: " + url);
			return(false);
		} catch (Exception e) {
			System.err.println("Could not register: " + url);
			diagnose("register",e);
		}
		return(true);
	}

	// Try to connect but field errors.
	public boolean connect(String userid) {
		String host = "";
		int a = userid.indexOf('@');
		if (0 < a) {
			host = userid.substring(a+1);
			userid = userid.substring(0,a);
		}
		String url = "//" + host + ":1070/phone/" + userid;
		try {
			PhoneAPI p;
			p = (PhoneAPI) Naming.lookup(url);
			int n = peers.size();
			PhoneAPI[] us = new PhoneAPI[n+1];
			for (int i=0; i<n; i++)
				us[i] = (PhoneAPI) peers.elementAt(i);
			us[n] = this;
			PhoneAPI[] newbies = p.apply(us);
			addpeer(newbies);
			for (int i=0; i<n; i++) {
				p = (PhoneAPI) peers.elementAt(i);
				p.sponsor(newbies);
			}
		} catch (ConnectException e) {
			System.err.println("Could not connect to: " + url);
			return(false);
		} catch (Exception e) {
			System.err.println("Could not connect to: " + url);
			diagnose("connect",e);
		}
		return(true);
	}

	public void dosay(String s) {
		int n = peers.size();
		if (0 == n) {
			System.err.println("(not connected)");
		} else {
			for (int i=0; i<n; i++) {
				PhoneAPI p = (PhoneAPI) peers.elementAt(i);
				try {
					p.transfer(this,s);
				} catch (Exception e) {
					diagnose("send",e);
				}
			}
		}
	}

	public void dobye() {
		int errors = 0;
		for (int i=0; i<peers.size(); i++) {
			try {
				( (PhoneAPI) peers.elementAt(i) ).resign(this);
			} catch (Exception e) {
				errors++;
			}
		}
		if (0 < errors)
			System.err.println(errors + " errors in disconnect");
		peers.setSize(0);
		names.setSize(0);
	}

	public void dowho() {
		int n = peers.size();
		if (0 == n) {
			System.err.println("(nobody)");
		} else {
			StringBuffer b = new StringBuffer(80);
			b.append( "{" + (String) names.elementAt(0) );
			for (int i=1; i<n; i++)
				b.append( ',' + (String) names.elementAt(i) );
			b.append('}');
			System.err.println(b);
		}
	}

	public void doline(String s) {
		if ( s.startsWith("@") ) {
			if ( s.equalsIgnoreCase("@bye") ) {
				dobye();
			} else if ( s.equalsIgnoreCase("@quit") ) {
				dobye();
				System.exit(0);
			} else if ( s.equalsIgnoreCase("@who") ) {
				dowho();
			} else if ( s.startsWith("@call ") ) {
				if ( connect(s.substring(6)) )
					dowho();
				else
					System.err.println("Connection failed");
			} else {
				System.err.println("RTFM!");
			}
		} else {
			dosay(s);
		}
	}

	public void readloop(InputStream is) {
		BufferedReader in = new BufferedReader(
			new InputStreamReader(is));
		while (true) {
			try {
				while ( 0 == is.available() )
					Thread.sleep(300);
				doline( in.readLine() );
			} catch (Exception e) {
				diagnose("read",e);
			}
		}
	}

	public static void diagnose(String where, Exception e) {
		System.err.println("Exception during " + where);
		System.err.println(e.getMessage());
		System.exit(1);
	}

	public static void main(String args[]) {
		int argv = 0;
		int argc = args.length;
		String handle = System.getProperty("user.name");
		if ( 0 < argc ) {
			if ( args[argv].startsWith("-") ) {
				handle = args[argv++].substring(1);
				argc--;
			}
		}
		Phone p = null;
		try {
			p = new Phone(handle);
		} catch (Exception e) {
			diagnose("new phone",e);
		}
		boolean registered = p.register();
		boolean connected  = false;
		if (0 < argc) 
			connected = p.connect(args[argv]);
		if (connected)
			p.dowho();
		else if (registered)
			System.err.println("Listening as '" + handle + "'");
		else
			System.err.println("Not listening");
		p.readloop(System.in);
	}

}