/*
 * Copyright (c) 2001 Matthew Feldt. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided the copyright notice above is
 * retained.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND WITHOUT ANY EXPRESSED OR
 * IMPLIED WARRANTIES.
 */

/**
 * PasswordManagerService.java
 *
 * Java Examples In A Nutshell Copyright (c) 2000 David Flanagan
 * Exercise 6-2:
 * Write a network service and client that allows a user to change his current
 * pasword that is registered with your PasswordManager class. If you've read
 * Chapter 16, Remote Method Invocation, modify PasswordManager so that it
 * runs as a RMI remote object and write a client program that uses the remote
 * object to change a pasword. If you have not read that chapter yet, write the
 * password-changing service to run under the Server class developed in Chapter
 * 5 and use the GenericClient class from that same chapter to interact with
 * the service. In either case, create a security policy file that defines the set
 * of permissions required by your network service, and use this policy file to
 * enable your service to run with the -Djava.security.manager option to the
 * Java interpreter.
 *
 * @author Matthew Feldt <developer@feldt.com>
 * @version 1.0, 03/20/2001 18:09
 */

package com.feldt.examples.security;
import com.davidflanagan.examples.net.Server;
import java.io.*;
import java.util.*;
import java.security.*;

public class PasswordManagerService implements Server.Service {
	static final String OK = "+OK ";
	static final String ERR = "-ERR ";
	static final String COMMANDS =
		"Invalid command; valid commands: ADD, DEL, MDFY, QUIT";

	public void serve(InputStream i, OutputStream o) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(i));
		PrintWriter out = new PrintWriter(o);
		PasswordManager pwm = new PasswordManager("password");
		String line, username, password, newPassword;

		// print welcome banner
		out.print(OK + "Password Manager Service 1.0 server ready. \r\n");
		out.flush();

		while (true) {
			line = in.readLine();
			StringTokenizer tokenizer = new StringTokenizer(line);
			if (! tokenizer.hasMoreTokens()) continue;  // input was empty
			// Get first word of the input and convert to lower case
			String command = tokenizer.nextToken().toLowerCase();
			if (command.equals("add")) {
				if (tokenizer.countTokens() != 2) {
					out.print(ERR + "ADD <username> <password> \r\n");
				} else {
					username = tokenizer.nextToken();
					password = tokenizer.nextToken();
					try {
						if (pwm.create(username, password) == false)
							throw new Exception("create failed.");
						pwm.store();
						out.print(OK + command + " " + username + "\r\n");
					} catch (Exception e) {
						out.println(ERR + "PasswordManager: " + e.getMessage());
					}
				}
			} else if (command.equals("del")) {
				if (tokenizer.countTokens() != 2) {
					out.print(ERR + "DEL <username> <password> \r\n");
				} else {
					username = tokenizer.nextToken();
					password = tokenizer.nextToken();
					try {
						if (pwm.delete(username, password) == false)
							throw new Exception("DEL failed, " +
								"invalid password or no such user.");
						pwm.store();
						out.print(OK + command + " " + username + "\r\n");
					} catch (Exception e) {
						out.println(ERR + "PasswordManager: " + e.getMessage());
					}
				}
			} else if (command.equals("mdfy")) {
				if (tokenizer.countTokens() != 3) {
					out.print(ERR + "MDFY <username> <password> <newPassword>\r\n");
				} else {
					username = tokenizer.nextToken();
					password = tokenizer.nextToken();
					newPassword = tokenizer.nextToken();
					try {
						if (pwm.modify(username, password, newPassword) == false)
							throw new Exception("MDFY failed, " +
								"invalid password or no such user.");
						pwm.store();
						out.print(OK + command + " " + username + "\r\n");
					} catch (Exception e) {
						out.println(ERR + "PasswordManager: " + e.getMessage());
					}
				}
			} else if (command.equals("quit")) {
				break;
			} else {
				out.print(ERR + COMMANDS + "\r\n");
			}
			out.flush();
		}

		// print farewell banner and close connections
		out.print(OK + "Password Manager Service 1.0 server signing off. \r\n");
		out.close();
		in.close();
	}
}