/*************************************************************************
 *                                                                       *
 * File: PopWeb.java                                                     *
 * Date: April 4 2000                                                    *
 * Author: Donn Morrison donn_morrison@hotmail.com                       *
 * Purpose: Seng462 Final Project                                        *
 *                                                                       *
 * Description: PopWeb is a Java Servlet which allows a user to          *
 *              send/recieve email from a standard POP3 account.         *
 *                                                                       *
 * License: PopWeb can be copied, modified, pirated, traded, deleted,    *
 *          truncated, burnt to cd and driven over, etc. Just as long    *
 *          as this header is left in the source code and I am given     *
 *          credit for writing the original version as you pass it on.   *
 *                                                                       *
 *************************************************************************/

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.net.*;

/**
 * class PopWeb
 *
 * - provides methods and objects that enable use as a Java Servlet
 *
 */
public class PopWeb extends HttpServlet {
	PrintWriter clientout = null;		// writes data to clients' browser

	private Socket socket;			// used to connect to POP3/SMTP servers
	private PrintWriter popout;		// writes data to POP3/SMTP servers
	private BufferedReader popin;		// reads data from POP3/SMTP servers
	private Thread cm;			// Thread that monitors our connection
	private Object lock = new Object();	// a lock for our critical section

	private boolean sortbydatedec = true;	// sort email index by date descending
	private boolean showallheaders = false;	// show all email headers when viewing

	// ------------------------------------------------------
	// These variables are http GET/POST request parameters
	// ------------------------------------------------------
	private String command;			// http param: main command
	private String popserver;		// http param: pop3 server
	private String username;		// http param: username
	private String passwordstr;		// http param: password (shifted)
	private String password;		// http param: plain text password
	private String msgnumstr;		// http param: message number
	private String from;			// http param: 'from' address
	private String replyto;			// http param: 'reply-to' address
	private String to;			// http param: 'to' address
	private String cc;			// http param: 'cc' address
	private String message;			// http param: email message
	private String subject;			// http param: email subject
	private String showallheadersstr;	// http param: show all headers
	private String file;			// http param: attachment filename on server
	private String attachfilename;		// http param: attachment real filename
	private String attachcontenttype;	// http param: attachment content-type

	// ------------------------------------------------------
	// Constants
	// ------------------------------------------------------
	public static final int WRITE_NORMAL = 0;
	public static final int WRITE_REPLY = 1;
	public static final int WRITE_FORWARD = 2;
	public static final String SMTP_SERVER = "mail";
	public static final String HOST_NAME = "popweb.dyndns.org";
	public static final String XMAILER_INFO = "X-Mailer: PopWeb v.05 [en] (Java Servlet; Apache; Linux)\n";
	public static final String HTML_DIR = "/usr/local/apache/servlets/";

	public void service(HttpServletRequest req, HttpServletResponse res) throws IOException {
		res.setContentType("text/html");

		try {
			// ------------------------------------------------------
			// We attempt to retrieve the http parameters
			// ------------------------------------------------------
			command = req.getParameter("command");
			popserver = req.getParameter("popserver");
			username = req.getParameter("username");
			passwordstr = req.getParameter("password");
/*			if(passwordstr != null && username != null) {
				passwordstr = URLDecoder.decode(passwordstr);
				if(passwordstr.startsWith("==~%%$")) {
					password = Shift.unShift(passwordstr.substring(6),username);
					passwordstr = URLEncoder.encode(passwordstr);
				} else {
					password = passwordstr;
					passwordstr = Shift.Shift(passwordstr,username);
					passwordstr = URLEncoder.encode("==~%%$" + passwordstr);
				}
			}
*/			msgnumstr = req.getParameter("msgnum");
			message = req.getParameter("message");
			from = req.getParameter("from");
			replyto = req.getParameter("replyto");
			to = req.getParameter("to");
			cc = req.getParameter("cc");
			subject = req.getParameter("subject");
			showallheadersstr = req.getParameter("hdrs");
			attachfilename = req.getParameter("attachfilename");
			attachcontenttype = req.getParameter("attachcontenttype");
			file = req.getParameter("file");
			if(showallheadersstr != null) {
				if(showallheadersstr.equals("less")) showallheaders=false;
				else showallheaders=true;
			} else {
				showallheadersstr = "less";
				showallheaders=false;
			}

			  // log the current session for security reasons
			logSession(req);

			// ------------------------------------------------------
			// We determine which "command" was issued and take
			// appropriate action
			// ------------------------------------------------------
			if(command == null) {
				  // display login screen
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				showLogin();
			} else if(command.equals("index")) {
				  // show message index
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showIndex();
			} else if(command.equals("viewmsg")) {
				  // show an email message
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showMessage();
			} else if(command.equals("logout")) {
				  // display logout screen
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				showLogout();
			} else if(command.equals("write")) {
				  // show write message screen (normal write)
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showWrite(WRITE_NORMAL);
			} else if(command.equals("reply")) {
				  // show write message screen (reply)
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showWrite(WRITE_REPLY);
			} else if(command.equals("forward")) {
				  // show write message screen (forward)
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showWrite(WRITE_FORWARD);
			} else if(command.equals("send")) {
				  // send the written message and display confirmation
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showSend();
			} else if(command.equals("delete")) {
				  // delete the current message
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showDelete();
			} else if(command.equals("deleteall")) {
				  // confirm delete all
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showDeleteAllConfirm();
			} else if(command.equals("deleteall2")) {
				  // confirm delete all
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				checkParams();
				showDeleteAll();
			} else if(command.equals("disclaimer")) {
				  // show the disclaimer
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				showDisclaimer();
			} else if(command.equals("viewsource")) {
				  // view the PopWeb source
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				showSource();
			} else if(command.equals("getattach")) {
				  // send the requested attachment
				showGetAttach(res);
			} else if(command.equals("nojs")) {
				  // client browser does not have javascript enabled
				clientout = res.getWriter();
				printError("error","You do not have a JavaScript enabled browser.");
			} else if(command.equals("yesjs")) {
				  // client browser does have javascript enabled
				clientout = res.getWriter();
				printError("success","You have a JavaScript enabled browser.");
			} else {
				  // show an error message
				clientout = res.getWriter();
				cm = new ConnectionMonitor(clientout);
				printError("error","Invalid command");
			}

		} catch (Exception e) {
			//e.printStackTrace(clientout);
			clientout = res.getWriter();
			String msg = e.getMessage();
			if(msg == null) msg = "An error has occured. Unfortunately, the error itself is classified.";
			printError("error",msg);
			try {
				disconnect();
			} catch (Exception ex) {}
		} /* try catch */
	} /* service */

	/**
	 * class ConnectionMonitor
	 *
	 * - Allows us to determine whether the client has disconnected
	 * - If a disconnection occurs, we try to disconnect from the
	 *   Pop3/SMTP server
	 *
	 */
	private class ConnectionMonitor extends Thread {
		PrintWriter pw;
		ConnectionMonitor(PrintWriter pw) {
			this.pw = pw;
			this.start();
		}

		public void run() {
			while(true) {
				  // test if we can still write
				  // to the client
				if(pw.checkError()) {
					try {
						disconnect();
					} catch (Exception e) {}
					break;
				}

				try {
					Thread.sleep(100);
				} catch (Exception e) {}
			}
		}
	}

	/**
	 * checkParams()
	 *
	 * - Makes sure client has sent all information
	 *   required to complete a mail transaction
	 *
	 */
	private void checkParams() throws Exception {
		if((popserver == null || username == null || passwordstr == null) ||
		  (popserver.equals("") || username.equals("") || passwordstr.equals(""))) {
			throw new Exception("POP3 Server, Username, and Password are required.");
		}
	}

	/**
	 * showLogin()
	 *
	 * - Displays the login screen
	 *
	 */
	private void showLogin() {
		showFile("PopWebLogin.html",false);
	}

	/**
	 * showDisclaimer()
	 *
	 * - Displays the disclaimer screen
	 *
	 */
	private void showDisclaimer() {
		showFile("PopWebDisclaimer.html",false);
	}

	/**
	 * showLogout()
	 *
	 * - Displays the logout screen
	 *
	 */
	private void showLogout() {
		showFile("PopWebLogout.html",false);
	}

	/**
	 * showGetAttach()
	 *
	 * - Sends the attachment to the clients' web browser
	 * - Decodes the attachment using a base64 decoder
	 *
	 * - problem: does not support content encoding other than base64
	 *
	 */
	private void showGetAttach(HttpServletResponse res) throws Exception {
		  // make sure we stay in the attachment directory
		if(file.indexOf("..") >= 0) throw new Exception("Path error: Nice try, but I've thought of that");

		  // set the content-type
		if(!attachcontenttype.equals("")) {
			res.setContentType(attachcontenttype);
		} else {
			res.setContentType("text/plain");
		}

		File f = new File(HTML_DIR + "attach/" + file);
		  // ensure that the file exists
		if(f.exists()) {
			if(attachcontenttype.equalsIgnoreCase("text/html")) {
				  // attachment is embedded html
				clientout = res.getWriter();
				showFile("attach/" + file,false);
			} else {
				  // decode the attachment and send it to
				  // the clients' web browser
				InputStream fin = new FileInputStream(f);
				sun.misc.BASE64Decoder b64dec = new sun.misc.BASE64Decoder();
				b64dec.decodeBuffer(fin,res.getOutputStream());
			}
			  // delete the attachment
			//f.delete(); // (should be left up to a seperate process on the server: eg cron)
		} else throw new Exception("Path error: Your attachment has been deleted; reload the message again to retrieve it");
	}

	/**
	 * showSource()
	 *
	 * - Displays the PopWeb source code to the client
	 *
	 */
	private void showSource() {
		  // html source 1
		showFile("pwbody1.thtml",false);
		clientout.println("PopWeb view source");
		  // html source 2
		showFile("pwbody2.thtml",false);
		clientout.println("<pre><font face=\"courier new,courier\" size=2>");

		  // show PopWeb source
		showFile("PopWeb.java",true);

		clientout.println("</pre></font>");
		  // html source 3
		showFile("pwbody3.thtml",false);
	}

	/**
	 * showIndex()
	 *
	 * - Displays the message index to the client
	 *
	 * - problem: If the client has a large volume
	 *            of email messages, it will take
	 *            a while to display the headers and
	 *            the client may give up (press stop
	 *            or cancel)
	 *
	 */
	private void showIndex() throws Exception {
		  // attempt to connect to the server
		connect();

		  // attempt to login to the server
		login();

		  // get STAT (message count)
		int total = doSTAT();

		  // retreive the current message number
		int msgnum = 1;
		if(msgnumstr != null) {
			try {
				msgnum = Integer.parseInt(msgnumstr);
			} catch (Exception e) {}
		}

		clientout.println(showtoolbar(1,1,false));

		String waittime = total > 20?"<br><b>&nbsp;Please be patient as downloading headers may take some time.</b>":"";

		String output = "<html><head><title>PopWeb [" + username + "@" + popserver + "]</title></head>\n" +
				"<body bgcolor=white><font face=lucida,tahoma,arial size=2>\n" +
				"&nbsp;Welcome, " + username + ", you have " + total +
				(total == 1 ? " message ":" messages ") + "on " + popserver + "."+waittime+"<br><br>\n";
		clientout.println(output);

		  // display the message index
		output = "<table cellpadding=0 cellspacing=0 bgcolor=black fbgcolor=#8b7355 width=100%>\n" +
			 "<tr><td>\n" +
			 "	<table width=100% border=0 cellpadding=3>\n" +
			 "	<tr><td width=5% bgcolor=#cdb38b>\n" +
			 "		&nbsp;\n" +
			 "	</td><td width=22% bgcolor=#cdb38b>\n" +
			 "		<font face=lucida,tahoma,arial size=2>\n" +
			 "		<b>&nbsp;From</b>\n" +
			 "	</td><td bgcolor=#cdb38b>\n" +
			 "		<font face=lucida,tahoma,arial size=2>\n" +
			 "		<b>&nbsp;Date</b>\n" +
			 "	</td><td width=50% bgcolor=#cdb38b>\n" +
			 "		<font face=lucida,tahoma,arial size=2>\n" +
			 "		<b>&nbsp;Subject</b>\n" +
			 "	</td></tr>\n";

		clientout.println(output);
		clientout.flush();

		  // get the message headers (from, subject, date)
		String [] headers = getFromDateSubject(1,total);
		for(int i=0;i<headers.length;i+=3) {
			int thismsg = sortbydatedec ? headers.length/3-(i/3) : (i/3+1);
			String bgcolor = i%6 == 0 ? "#ffebcd" : "#fdf5e6";
			output = "	<form method=post action=/servlets/PopWeb name=form"+thismsg+
				  "><tr><td align=center width=5% bgcolor=" + bgcolor + ">\n" +
				  "		<font face=lucida,tahoma,arial size=2>\n" +
				  "		" + showviewbutton(thismsg) + "\n" +
				  "</td><td width=22% bgcolor=" + bgcolor + ">\n" +
				  "	<font face=lucida,tahoma,arial size=2>\n" +
				  "		&nbsp;" + headers[i] + "\n" +
				  "</td><td bgcolor=" + bgcolor + ">\n" +
				  "	<font face=lucida,tahoma,arial size=2>\n" +
				  "		&nbsp;" + headers[i+1] + "\n" +
				  "</td><td width=50% bgcolor=" + bgcolor + ">\n" +
				  "	<font face=lucida,tahoma,arial size=2>\n" +
				  "		&nbsp;<input type=hidden name=hdrs value="+showallheadersstr+
				  "><a href='/servlets/PopWeb?command=nojs&view_message(\""+headers[i+2]+
				  "\")' onClick=\"document.form" +thismsg +
				  ".submit(); return false;\"><font face=lucida,tahoma,arial color=navy size=2>"+
				  headers[i+2] + "</font></a>\n" +
				  "             \n" +
				  "</td></tr></form>\n";
			clientout.println(output);
			clientout.flush();
		}

		output =  "	</table>\n" +
			  "</td></tr>\n" +
			  "</table>\n" +
			  "<br>" + shownextindexpagebutton();
		clientout.println(output);
		clientout.flush();

		  // disconnect from server
		disconnect();
	}

	/**
	 * showMessage()
	 *
	 * - Displays an email message to the client
	 * - Saves any attachments to the attachment directory
	 *   on the server
	 *
	 * - problem: If message size is large, client will
	 *            be waiting for a long time, and may
	 *            give up (press stop or cancel)
	 *
	 */
	private void showMessage() throws Exception {
		  // attempt to connect to the server
		connect();

		  // attempt to login to the server
		login();

		  // get STAT (message count)
		int total = doSTAT();

		  // get the current message number
		int msgnum = 0;
		if(msgnumstr != null) {
			try {
				msgnum = Integer.parseInt(msgnumstr);
			} catch (Exception e) {}
		}
		  // message number is invalid, show the index instead
		if(msgnum < 1 || msgnum > total) {
			disconnect();
			showIndex();
			return;
		}

		String output = "<html><head><title>PopWeb [" + username + "@" + popserver + "]</title></head>\n" +
				"<body bgcolor=white>";
		clientout.println(output);

		output = showtoolbar(msgnum,total,true);
		clientout.println(output);

		output = "<table border=0 cellpadding=1 cellspacing=0 bgcolor=black width=100%>\n" +
			 "<tr><td>\n" +
			 "	<table width=100% border=0 cellspacing=1 cellpadding=3>\n" +
			 "	<form method=post action=/servlets/PopWeb name=formhdrs>" +
			 "	<input type=hidden name=popserver value=" + popserver + ">\n" +
			 "	<input type=hidden name=username value=\"" + username + "\">\n" +
			 "	<input type=hidden name=password value=\"" + passwordstr + "\">\n" +
			 "	<input type=hidden name=msgnum value=" + msgnumstr + ">\n" +
			 "	<input type=hidden name=command value=viewmsg>\n" +
			 "	<input type=hidden name=hdrs value=" + (showallheadersstr.equals("less") ? "all":"less") + ">\n" +
			 "	<tr><td falign=center bgcolor=#cdb38b>\n" +
			 "		<b><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "		&nbsp;Message " + msgnum + " of " + total + "</b>\n" +
			 "	</td><td align=right bgcolor=#cdb38b width=1%>\n" +
			 "		&nbsp;<a href=/servlets/PopWeb?command=nojs onclick=\"document.formhdrs.submit();return false;\">"+
			 "<font face=lucida,tahoma,arial color=black size=2>show&nbsp;" +
			 (showallheadersstr.equals("less") ? "all":"less") + "&nbsp;headers</a></font>&nbsp;\n" +
			 "		</font></b>\n" +
			 "	</td></tr>\n" +
			 "	</form>\n" +
			 "	</table>\n" +
			 "</td></tr>\n" +
			 "</table>\n";
		clientout.println(output);

		  // display the specified message
		output = "<table width=100% bgcolor=#fdf5e6 cellspacing=0 cellpadding=5>" +
			 "<tr><td>" +
			 "<font face=\"courier new,courier\" size=3><pre>\n" +
			 doRETR(msgnum,showallheaders,false,false) +
			 "</pre></font>" +
			 "</td></tr></table>";
		clientout.println(output);

		output = "<table border=0 cellpadding=1 cellspacing=0 bgcolor=black width=100%>\n" +
			 "<tr><td>\n" +
			 "	<table width=100% border=0 cellspacing=1 cellpadding=3>\n" +
			 "	<tr><td falign=center bgcolor=#cdb38b>\n" +
			 "		<b><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "		&nbsp;" + "\n" +
			 "		</font></b>\n" +
			 "	</td></tr>\n" +
			 "	</table>\n" +
			 "</td></tr>\n" +
			 "</table>\n";
		clientout.println(output);
		clientout.flush();

		  // disconnect from server
		disconnect();
	}

	/**
	 * showWrite()
	 *
	 * - Displays the write message screen to the client
	 * - If client pressed "reply" or "forward", we want to
	 *   copy the message body into the textarea of the new
	 *   message.
	 *
	 * - problem: If the message being replied to is large, the
	 *            client will have to wait for a long time
	 *            and may give up (press stop or cancel)
	 *
	 */
	private void showWrite(int type) {
		  // get the current message number
		int msgnum = 0;
		if(msgnumstr != null) {
			try {
				msgnum = Integer.parseInt(msgnumstr);
			} catch (Exception e) {}
		}

		  // initialize message variables
		message = "";
		subject = "";
		if(to == null) to = "";
		cc = "";

		// ------------------------------------------------------
		// Determine if we are writing, replying or forwarding
		// (to) a message
		// ------------------------------------------------------
		switch(type) {
		case WRITE_NORMAL:
			if(to.startsWith("mailto:")) {
				to = to.substring(to.indexOf(":")+1);
			}
			break;
		case WRITE_REPLY:
			try {
				  // we need to download the message
				  // and place it in the textarea so
				  // the client can include the original
				  // message in his reply
				connect();
				login();
				  // get the message
				message = doRETR(msgnum,false,false,true);
				  // get the subject
				subject = getHeaderValue("Subject: ",message,"\n");
				if(subject == null) subject = "";
				subject = stripQuotes(subject);
				if(subject.toLowerCase().startsWith("re:"))
					subject = "\"" + subject + "\"";
				else
					subject = "\"re: " + subject + "\"";
				  // get the 'to' address
				to = getHeaderValue("Reply-To: ",message,"\n");
				if(to == null)
					to = getHeaderValue("From: ",message,"\n");
				if(to == null) to = "";
				to = stripQuotes(to);
				to = "\"" + to + "\"";

				disconnect();
			} catch (Exception e) {try {disconnect();} catch (Exception ex) {}}
			message = "\n\n\n---original message---\n" + message;
			break;
		case WRITE_FORWARD:
			String newmsg = "";
			try {
				  // we need to download the message
				  // and place it in the textarea so
				  // the client can include the original
				  // message in his forward
				connect();
				login();
				  // get the message
				message = doRETR(msgnum,false,false,true);
				  // get the subject
				subject = getHeaderValue("Subject: ",message,"\n");
				if(subject == null) subject = "";
				subject = stripQuotes(subject);
				subject = "\"" + subject + " (fwd)\"";
				  // 'to' address left blank
				to = "";

				disconnect();

				  // add '> ' to the beginning of each line
				  // so we know its a forwarded message
				String fwchar = "> ";
				BufferedReader strin = new BufferedReader(new StringReader(message));
				String line;
				while((line = strin.readLine()) != null) {
					newmsg = newmsg + fwchar + line + "\n";
				}
			} catch (Exception e) { try {disconnect();} catch (Exception ex) {}}
			message = "\n\n\n---forwarded message---\n" + newmsg;
			break;
		default:
		}

		  // display the page title
		String output = "<html><head><title>PopWeb [send message]</title></head>\n" +
				"<body bgcolor=white>";
		clientout.println(output);

		  // display the toolbar
		clientout.println(showtoolbar(1,1,false));

		  // display the page heading
		output = "<table border=0 cellpadding=1 cellspacing=0 bgcolor=black width=100%>\n" +
			 "<tr><td>\n" +
			 "	<table width=100% border=0 cellspacing=1 cellpadding=3>\n" +
			 "	<tr><td falign=center bgcolor=#cdb38b>\n" +
			 "		<b><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "		&nbsp;PopWeb [message from " + username + "@" + popserver + "]\n" +
			 "		</font></b>\n" +
			 "	</td></tr>\n" +
			 "	</table>\n" +
			 "</td></tr>\n" +
			 "</table>\n";
		clientout.println(output);

		  // display the message composition area
		output = "<table width=100% bgcolor=#fdf5e6 cellspacing=0 cellpadding=5>" +
			 "<tr><td><center>" +
			 "	<font face=lucida,tahoma,arial color=black size=2>" +
			 "	<form method=POST action=/servlets/PopWeb>" +
			 "	<table><tr><td><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "	From:<br><input type=text name=from size=40 value=" + username + "@" + popserver + "><br>\n" +
			 "	To:<br><input type=text name=to size=40 value=" + to + "><br>\n" +
			 "	</td><td><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "	Cc:<br><input type=text name=cc size=40><br>\n" +
			 "	</td></tr><tr><td colspan=2><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "	Subject:<br><input type=text name=subject size=40 value=" + subject + ">\n" +
			 "	</td></tr><tr><td colspan=2><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "	Message:<br><textarea rows=20 cols=80 name=message wrap=hard>"+ message +"</textarea><br>\n" +
			 "	<input type=hidden name=command value=send>\n" +
			 "	<input type=hidden name=popserver value=" + popserver + ">\n" +
			 "	<input type=hidden name=username value=\"" + username + "\">\n" +
			 "	<input type=hidden name=password value=\"" + passwordstr + "\">\n" +
			 "	<input type=submit value=\"     Send     \">\n" +
			 "	</table></form>\n" +
			 "	</font>\n" +
			 "</td></tr></table>";
		clientout.println(output);

		output = "<table border=0 cellpadding=1 cellspacing=0 bgcolor=black width=100%>\n" +
			 "<tr><td>\n" +
			 "	<table width=100% border=0 cellspacing=1 cellpadding=3>\n" +
			 "	<tr><td falign=center bgcolor=#cdb38b>\n" +
			 "		<b><font face=lucida,tahoma,arial color=black size=2>\n" +
			 "		&nbsp;" + "\n" +
			 "		</font></b>\n" +
			 "	</td></tr>\n" +
			 "	</table>\n" +
			 "</td></tr>\n" +
			 "</table>\n";
		clientout.println(output);
		clientout.flush();
	}

	/**
	 * showDelete()
	 *
	 * - Deletes a message from the POP3 server
	 * - Displays the message index
	 *
	 * - problem: Client has to actually view the
	 *            message in order to delete it
	 *
	 */
	private void showDelete() throws Exception {
		  // get the current message number
		int msgnum = 0;
		if(msgnumstr != null) {
			try {
				msgnum = Integer.parseInt(msgnumstr);
			} catch (Exception e) {}
		}

		connect();
		login();
		  // delete the message
		doDELE(msgnum);
		disconnect();
		msgnum--;
		msgnumstr = msgnum + "";
		showMessage();
	}

	/**
	 * showDeleteAllConfirm()
	 *
	 * - Asks user for confirmation before deleting all messages
	 *
	 */
	private void showDeleteAllConfirm() throws Exception {
		String message = "Are you sure you want to delete all messages?<br><br>" +
				 "<table width=40% border=0 cellpadding=20><tr><td align=right>\n" +
				 "<form method=POST action=/servlets/PopWeb name=formdallyes>\n" +
				 "<input type=hidden name=popserver value="+popserver+">\n" +
				 "<input type=hidden name=username value=\""+username+"\">\n" +
				 "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
				 "<input type=hidden name=command value=deleteall2>\n" +
				 "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formdallyes.submit(); return false;\">" +
				 "<font face=lucida,tahoma,arial color=black size=2><b>yes</b></font></a></form>\n</td>" +
				 "<td align=left><form method=POST action=/servlets/PopWeb name=formdallno>\n" +
				 "<input type=hidden name=popserver value="+popserver+">\n" +
				 "<input type=hidden name=username value=\""+username+"\">\n" +
				 "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
				 "<input type=hidden name=command value=index>\n" +
				 "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formdallno.submit(); return false;\">" +
				 "<font face=lucida,tahoma,arial color=black size=2><b>no</b></font></a></form>\n" +
				 "</td></tr></table>\n";

		printError("Confirm delete", message);
	}

	private void showDeleteAll() throws Exception {
		connect();
		login();

		  // get total message count
		int total = doSTAT();

		for(int i=1; i <= total; i++) {
			doDELE(i);
		}
		disconnect();
		showIndex();
	}


	/**
	 * showSend()
	 *
	 * - Sends the written, replied, or forwared message
	 * - Displays a confirmation box if send was successful,
	 *   or an error if unsuccessful
	 *
	 * - problem: If client sends a large message, it may
	 *            take a while to deliver to the SMTP server
	 *            and the client may grow impatient and
	 *            give up (press stop or cancel)
	 * - problem: Client cannot attach files to the message (yet)
	 *
	 */
	private void showSend() throws Exception {
		clientout.println("<html><head><title>PopWeb [send result]</title></head><body bgcolor=white>");

		  // display the toolbar
		clientout.println(showtoolbar(1,1,false));

		  // check the destination email addresses
		parseAddresses(to);
		parseAddresses(cc);
		  // connect to the SMTP server
		connectSMTP();
		  // send the message
		dosend();

		  // display success message
		showFile("pwbody1.thtml",false);
		clientout.println("PopWeb message delivered");
		showFile("pwbody2.thtml",false);
		clientout.println("Your message was successfully sent.");
		showFile("pwbody3.thtml",false);

		disconnect();
	}

	/**
	 * logSession()
	 *
	 * - Logs the current PopWeb transaction to a logfile
	 * - Records username, pop3 server, and the command
	 *
	 * - note: Does not record sensitive information
	 *         such as the client's password or
	 *         email messages
	 * - problem: May cause deadlocks when two
	 *            clients simultaneously connect
	 *            and file is written to by both
	 *
	 */
	private void logSession(ServletRequest req) {
		  // get the clients' ip address
		String ipaddr = req.getRemoteAddr();
		try {
			  // write the information to the logfile
			synchronized(lock) {
				FileWriter fw = new FileWriter("/usr/local/apache/servlets/PopWebLog.txt",true);
				fw.write(ipaddr + ":" + username + "@" + popserver + ":" + command + "\n");
				fw.close();
			}
		} catch (Exception e) {}
	}

	/**
	 * showFile()
	 *
	 * - Displays the contents of a plain text file to the client
	 * - Used to display static html pages and other server files
	 *
	 */
	private void showFile(String file, boolean stripHTML) {
		try {
			  // read the file and print it to the client
			BufferedReader filein = new BufferedReader(new FileReader(HTML_DIR + file));
			String line;
			while((line = filein.readLine()) != null) {
				if(stripHTML) {
					line = stripHTML(line);
				}
				clientout.println(line);
			}
		} catch (Exception e) {}
	}

	/**
	 * connect()
	 *
	 * - Attempts to connect to the clients' POP3 server
	 *
	 */
	private void connect() throws IOException {
		try {
			socket = new Socket(popserver,110);
			popout = new PrintWriter(socket.getOutputStream());
			popin = new BufferedReader(new InputStreamReader(
							socket.getInputStream()));
		} catch (UnknownHostException e) {
			throw new IOException("Unknown host: " + e.getMessage());
		} catch (IOException e) {
			throw new IOException("Connection error: " + e.getMessage());
		}

		String resp;

		try {
			resp = popin.readLine();
		} catch (Exception e) {
			throw new IOException("Connection error: connection closed by remote host");
		}
		if(resp == null || !resp.startsWith("+OK")) throw new IOException("Connection error: " + resp);
	}

	/**
	 * connectSMTP()
	 *
	 * - Attempts to connect to the SMTP server
	 *
	 */
	private void connectSMTP() throws IOException {
		try {
			socket = new Socket(SMTP_SERVER,25);
			popout = new PrintWriter(socket.getOutputStream());
			popin = new BufferedReader(new InputStreamReader(
							socket.getInputStream()));
		} catch (UnknownHostException e) {
			throw new IOException("Unknown Host: " + e.getMessage());
		} catch (IOException e) {
			throw new IOException("Connection error: " + e.getMessage());
		}

		String resp;

		try {
			resp = popin.readLine();
		} catch (Exception e) {
			throw new IOException("Connection error: connection closed by remote host");
		}
		if(resp == null || !resp.startsWith("2")) throw new IOException("Connection error: " + resp);
	}

	/**
	 * disconnect()
	 *
	 * - Disconnects from the clients' POP3/SMTP server
	 *
	 */
	private void disconnect() throws IOException {
		if(socket == null) return;
		  // disconnect gracefully
		popout.println("QUIT\r");
		popout.flush();
		String resp = popin.readLine();
		  // close i/o objects
		popout.close();
		popin.close();
		socket.close();
		socket = null;
	}

	/**
	 * login()
	 *
	 * - Attempts to login with clients' username and password
	 *
	 */
	private void login() throws Exception {
		  // send username
		popout.println("USER " + username + "\r");
		popout.flush();
		String resp = popin.readLine();
		if(!resp.startsWith("+OK")) throw new Exception("Login error (username): " + resp);

		  // send password
		popout.println("PASS " + password + "\r");
		popout.flush();
		resp = popin.readLine();
		if(!resp.startsWith("+OK")) throw new Exception("Login error (password): " + resp);
	}

	/**
	 * dosend()
	 *
	 * - Attempts to send clients' written, replied, or forwarded
	 *   message to the SMTP server
	 *
	 */
	private void dosend() throws Exception {
		if(to == null || to.equals("")) {
			throw new IOException("\"To:\" address field cannot be left blank");
		}

		// store outgoing message - to be used for OUTBOX in future
		// not fully implemented yet
		FileWriter fw = new FileWriter("/usr/local/apache/servlets/outmail/" + username + "@" + popserver,true);

		  // parse 'to' and 'cc' addresses
		String tolist [] = parseAddresses(to);
		String cclist [] = parseAddresses(cc);

		String ccstr = "";
		if(cclist.length != 0) ccstr = "CC: " + cc + "\n";

		String resp;
		if(from == null || from.equals("")) from = username + "@" + popserver;

		  // form the message header
		String header = "From: " + from + "\n" +
				XMAILER_INFO +
				"To: " + to + "\n" +
				ccstr +
				"Subject: " + subject + "\n" +
				"\n";

		  // greet SMTP server
		popout.println("HELO " + HOST_NAME);
		popout.flush();
		resp = popin.readLine();
		if(!resp.startsWith("2")) throw new Exception("Error sending message: " + resp);

		  // mail from
		popout.println("MAIL From: " + from  + "");
		popout.flush();
		resp = popin.readLine();
		if(!resp.startsWith("2")) throw new Exception("Error sending message: " + resp);

		  // mail to
		for(int i=0;i<tolist.length;i++) {
			popout.println("RCPT To: " + tolist[i] + "");
			popout.flush();
			resp = popin.readLine();
			if(!resp.startsWith("2")) throw new Exception("Error sending message: " + resp);
		}

		  // mail to cc
		for(int i=0;i<cclist.length;i++) {
			popout.println("RCPT To: " + cclist[i] + "");
			popout.flush();
			resp = popin.readLine();
			if(!resp.startsWith("2")) throw new Exception("Error sending message: " + resp);
		}

		  // check message for CRLF.CRLF and replace with CRLF..CRLF
		int idx;
		while((idx = message.indexOf("\n.\n")) > 0) {
			message = message.substring(0,idx) + "\n..\n" + message.substring(idx+3,message.length());
		}

		  // data
		popout.println("DATA");
		popout.flush();
		resp = popin.readLine();
		if(!resp.startsWith("354")) throw new Exception("Error sending message: " + resp);

		  // send message header
		popout.println(header);
		  // send message
		message = message + "\n\n___________________________________\n";
		message = message + "This message was sent using PopWeb.\nhttp://popweb.dyndns.org";
		popout.println(message);

		fw.write(header);
		fw.write("\n\n");
		fw.write(message + "\n\n");
		fw.close();

		popout.flush();
		  // end message with CRLF.CRLF
		popout.println("\n.");
		popout.flush();
		resp = popin.readLine();
		if(!resp.startsWith("2")) throw new Exception("Error sending message: " + resp);
	}

	/**
	 * doSTAT()
	 *
	 * - Retrieves the number of messages on the clients' POP3 server
	 *   and returns an integer parsed from the response
	 *
	 */
	private int doSTAT() throws Exception {
		  // stat
		popout.println("STAT\r");
		popout.flush();
		  // get response
		String statinfo = popin.readLine().substring(4);
		int intend = statinfo.indexOf(" ");
		statinfo = statinfo.substring(0,intend);
		  // return parsed integer
		return Integer.parseInt(statinfo);
	}

	/**
	 * doUIDL()
	 *
	 * - Retrieves the unique identifiers for all messages
	 *   on the clients' POP3 server
	 *
	 * - note: This method is not currently used
	 *
	 */
	private String [] doUIDL() throws Exception {
		Vector v = new Vector();
		popout.println("UIDL\r");
		popout.flush();

		String resp = popin.readLine();
		if(!resp.startsWith("+OK")) throw new Exception("Error getting UIDL information: " + resp);

		String line = null;

		while(!(line = popin.readLine()).equals(".")) {
			v.addElement(line);
		}

		String uidlinfo [] = new String[v.size()];
		for(int i=0;i<v.size();i++) {
			uidlinfo[i] = (String)v.elementAt(i);
		}

		return uidlinfo;
	}

	/**
	 * doDELE()
	 *
	 * - Deletes a message from the clients' POP3 server
	 *
	 */
	private void doDELE(int msgnum) throws Exception {
		popout.println("DELE " + msgnum + "\r");
		popout.flush();

		String resp = popin.readLine();
		if(!resp.startsWith("+OK")) throw new Exception("Error deleting message " + msgnum + ": " + resp);
	}

	/**
	 * doRETR()
	 *
	 * - Retrieves a message from the clients' POP3 server
	 * - Optionally adds "<br>" to end of line for html formatting
	 * - Optionally returns all headers
	 * - Optionally cleans message for use in reply or forward
	 *
	 */
	private String doRETR(int msgnum, boolean allHeaders, boolean addBR, boolean isReply) throws Exception {
		  // retr (get the message)
		popout.println("RETR " + msgnum + "\r");
		popout.flush();

		String resp = popin.readLine();
		if(!resp.startsWith("+OK")) throw new Exception("Error retrieving message " + msgnum + ": " + resp);

		  // constants define sections of the email we can be in
		final int MAIN_HDR = 0;		// message header
		final int MIME_HDR = 1;		// mime info header
		final int MIME_BDY = 2;		// message/mime body

		int inSection = MAIN_HDR;	// what section of msg we are in
		boolean attachExists = false;	// does an attachment exist? (also embedded html)
		boolean writeAttach = false;	// tells us whether to write body to file

		String message = "";		// message to be returned
		String line = null;		// current line
		String boundaryCode = null;	// attachment delim
		String attachFName = null;	// attach file name
		String attachCT = null;		// attach content-type
		String attachList = "";		// html-ized attachment listing
		String tmp;			// used for string operations

		String brstr = addBR ? "<br>\n":"\n";	// string to add to end of line
		FileWriter fw = null;		// used to write attachment to disk

		// ------------------------------------------------------
		// Loop until we reach a CRLF.CRLF
		// ------------------------------------------------------
		while(!(line = popin.readLine()).equals(".")) {
			// ------------------------------------------------------
			// Determine which part of the message we are reading
			//
			// An email message is in the following BNF format:
			//
			// message := HEADER + body
			// body    := TEXT | mimes
			// mimes   := mime | mime + mimes
			// mime    := MIMEHDR + MIMEBDY | NOTHING
			//
			// Each mime is seperated by a boundary code.
			//
			// ------------------------------------------------------
			switch(inSection) {
			case MAIN_HDR:
				  // remove any html tag delims
				line = stripHTML(line);

				  // get boundary code from headers (if it exists)
				tmp = getHeaderValue("boundary=",line,"\n");
				if(tmp != null) {
					boundaryCode = stripQuotes(tmp);
					  // remove the prepending -'s
					boundaryCode = boundaryCode.substring(boundaryCode.lastIndexOf("-")+1);
					attachExists = true;
				}

				  // get the message headers
				if(allHeaders) {
					message = message + line + brstr;
				} else {
					if(line.startsWith("To:")      || line.startsWith("From:") ||
					   line.startsWith("Subject:") || line.startsWith("Date:") ||
					   line.toLowerCase().startsWith("cc:")) {
						message = message + line + brstr;
					}
				}

				  // if we come to an empty line,
				  // change section state
				if(line.equals("")) {
					if(attachExists) inSection = MIME_HDR;
					else inSection = MIME_BDY;
					if(!allHeaders) message = message + brstr;
				}
				break;
			case MIME_HDR:
				  // attempt to get the content-type for this
				  // section
				tmp = getHeaderValue("Content-Type: ",line,";");
				if(tmp != null) {
					attachCT = tmp;
				}
				  // attempt to get the name of the
				  // attachment
				tmp = getHeaderValue("name=",line,"\n");
				if(tmp != null) {
					attachFName = stripQuotes(tmp);
				}

				  // if we come to an empty line,
				  // change section state
				if(line.equals("")) {
					inSection = MIME_BDY;
					if(attachCT != null && !attachCT.equalsIgnoreCase("text/plain")) {
						if(attachFName == null) attachFName = "embedded html";
						  // add this attachment to the attachment list
						attachList = attachList +
							     "PopWeb Attachment: <a href=\"/servlets/PopWeb?command=getattach" +
							     "&file=" + URLEncoder.encode(boundaryCode) + URLEncoder.encode(attachFName) +
							     "&attachcontenttype=" + URLEncoder.encode(attachCT) +
							     "&attachfilename=" + URLEncoder.encode(attachFName) +
							     "\">" + attachFName + "</a>" + brstr;
						writeAttach = true;
					}
				}
				break;
			case MIME_BDY:
				  // look for boundary code
				if(attachExists && line.indexOf(boundaryCode) != -1) {
					inSection = MIME_HDR;
					if(fw != null) {
						  // close the filewriter and re-init attach vars
						  // in case we have another attachment
						fw.close();
						fw = null;
						writeAttach = false;
						attachCT = null;
						attachFName = null;
					}
					break;
				}
				  // either write the attachment to a file (if it is
				  // an attachment) or add it to the message variable
				  // for display to client
				if(writeAttach && !isReply) {
					  // we write the attachment in raw format to file
					if(fw == null) {
						  // init filewriter
						fw = new FileWriter(HTML_DIR + "attach/" + boundaryCode + attachFName);
					}
					fw.write(line + "\n");
				} else if(!writeAttach) {
					  // add the line to message for viewing
					line = stripHTML(line);
					if(!isReply) line = highlightURLS(line);
					message = message + line + brstr;
				}
				break;
			default:
			}
		}
		  // if we are replying, don't include the attachment list
		if(isReply) return message;
		else return message + brstr + attachList;
	}

	/**
	 * getFromDateSubject()
	 *
	 * - Iterates through messages on clients' POP3 server and
	 *   retrieves From, Date, and Subject headers for display
	 *   in the message index
	 *
	 */
	private String [] getFromDateSubject(int start, int end) throws Exception {
		Vector datev = new Vector();
		Vector fromv = new Vector();
		Vector subjv = new Vector();

		for(int i=start; i<=end; i++) {
			  // show the TOP of the message
			popout.println("TOP " + i + " 0\r");
			popout.flush();

			String resp = popin.readLine();
			if(!resp.startsWith("+OK")) continue;

			String line;
			int found = 0;

			  // loop through and pick out headers
			while(!(line = popin.readLine()).equals(".")) {
				line = stripHTML(line);
				if(line.startsWith("From:") && found < 3) {
					line = stripQuotes(line);
					int ltidx = line.indexOf("&lt;");
					ltidx = ltidx < 0 ? line.length():ltidx;
					line = line.substring(6,ltidx);
					fromv.addElement(line);
					found++;
					continue;
				} else if(line.startsWith("Subject:") && found < 3) {
					if(line.length() == 9) subjv.addElement("no subject");
					else subjv.addElement(line.substring(9));
					found++;
					continue;
				} else if(line.startsWith("Date:") && found < 3) {
					int dashidx = line.indexOf("-");
					dashidx = dashidx < 0 ? line.length():dashidx;
					int plusidx = line.indexOf("+");
					plusidx = plusidx < 0 ? line.length():plusidx;
					String datestr = line.substring(6, plusidx > dashidx ? dashidx: plusidx);
					datev.addElement(datestr);
					found++;
					continue;
				}
			}
			  // subject line has no value, default "no subject" so
			  // client has something to click on to get the message
			if(found == 2) subjv.addElement("no subject");
		}

		  // make an array of strings to return
		String fromdatesubject [] = new String[fromv.size()*3];

		  // convert the Vector to array of strings
		for(int i=0; i<fromv.size(); i++) {
			int msgnum  = sortbydatedec ? fromv.size()-i-1:i;
			fromdatesubject[i*3] = (String)fromv.elementAt(msgnum);
			fromdatesubject[i*3+1] = (String)datev.elementAt(msgnum);
			fromdatesubject[i*3+2] = (String)subjv.elementAt(msgnum);
		}

		return fromdatesubject;
	}

	// ------------------------------------------------------
	// The following methods are all similar. They return
	// HTML code that creates links for the client to click
	// on to navigate around the PopWeb interface.
	// ------------------------------------------------------
	private String shownextbutton(int current, int total) {
		if(current == total) return "<form><font face=lucida,tahoma,arial color=black size=2>next msg | </font></form>\n";
		else return "<form method=POST action=/servlets/PopWeb name=formnext>\n" +
			    "<input type=hidden name=popserver value="+popserver+">\n" +
			    "<input type=hidden name=username value="+username+">\n" +
			    "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
			    "<input type=hidden name=command value=viewmsg>\n" +
			    "<input type=hidden name=hdrs value=" + showallheadersstr + ">\n" +
			    "<input type=hidden name=msgnum value=" + (current+1) + ">\n" +
			    "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formnext.submit(); return false;\"><font color=black face=lucida,tahoma,arial size=2><b>next msg</b></font></a> | </form>\n";
	}
	private String showprevbutton(int current, int total) {
		if(current == 1) return "<form><font face=lucida,tahoma,arial color=black size=2>prev msg | </font></form>\n";
		else return "<form method=POST action=/servlets/PopWeb name=formprev>\n" +
			    "<input type=hidden name=popserver value="+popserver+">\n" +
			    "<input type=hidden name=username value=\""+username+"\">\n" +
			    "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
			    "<input type=hidden name=command value=viewmsg>\n" +
			    "<input type=hidden name=hdrs value=" + showallheadersstr + ">\n" +
			    "<input type=hidden name=msgnum value=" + (current-1) + ">\n" +
			    "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formprev.submit(); return false;\"><font color=black face=lucida,tahoma,arial size=2><b>prev msg</b></font></a> | </form>\n";
	}
	private String showindexbutton() {
		return "<form method=POST action=/servlets/PopWeb name=formindex>\n" +
		       "<input type=hidden name=popserver value="+popserver+">\n" +
		       "<input type=hidden name=username value=\""+username+"\">\n" +
		       "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
		       "<input type=hidden name=hdrs value=" + showallheadersstr + ">\n" +
		       "<input type=hidden name=command value=index>\n" +
		       "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formindex.submit(); return false;\"><font color=black face=lucida,tahoma,arial size=2><b>index</b></font></a> | </form>\n";
	}
	private String showwritebutton() {
		return "<form method=POST action=/servlets/PopWeb name=formwrite>\n" +
		       "<input type=hidden name=popserver value="+popserver+">\n" +
		       "<input type=hidden name=username value=\""+username+"\">\n" +
		       "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
		       "<input type=hidden name=command value=write>\n" +
		       "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formwrite.submit(); return false;\"><font face=lucida,tahoma,arial color=black size=2><b>write msg</b></font></a> | </form>\n";
	}
	private String showreplybutton(int current, boolean inmsg) {
		if(!inmsg) return "<form><font face=lucida,tahoma,arial color=black size=2>reply | </font></form>\n";
		else return "<form method=POST action=/servlets/PopWeb name=formreply>\n" +
			    "<input type=hidden name=popserver value="+popserver+">\n" +
			    "<input type=hidden name=username value=\""+username+"\">\n" +
			    "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
			    "<input type=hidden name=command value=reply>\n" +
			    "<input type=hidden name=msgnum value=" + (current) + ">\n" +
			    "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formreply.submit(); return false;\"><font face=lucida,tahoma,arial color=black size=2><b>reply</b></font></a> | </form>\n";
	}
	private String showforwardbutton(int current, boolean inmsg) {
		if(!inmsg) return "<form><font face=lucida,tahoma,arial color=black size=2>forward | </font></form>\n";
		else return "<form method=POST action=/servlets/PopWeb name=formfwd>\n" +
			    "<input type=hidden name=popserver value="+popserver+">\n" +
			    "<input type=hidden name=username value=\""+username+"\">\n" +
			    "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
			    "<input type=hidden name=command value=forward>\n" +
			    "<input type=hidden name=msgnum value=" + (current) + ">\n" +
			    "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formfwd.submit(); return false;\"><font face=lucida,tahoma,arial color=black size=2><b>forward</b></font></a> | </form>\n";
	}
	private String showdeletebutton(int current, boolean inmsg) {
		if(!inmsg) return "<form><font face=lucida,tahoma,arial color=black size=2>delete | </font></form>\n";
		else return "<form method=POST action=/servlets/PopWeb name=formdel>\n" +
			    "<input type=hidden name=popserver value="+popserver+">\n" +
			    "<input type=hidden name=username value=\""+username+"\">\n" +
			    "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
			    "<input type=hidden name=command value=delete>\n" +
			    "<input type=hidden name=msgnum value=" + (current) + ">\n" +
			    "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formdel.submit(); return false;\"><font face=lucida,tahoma,arial color=black size=2><b>delete</b></font></a> | </form>\n";
	}
	private String showdeleteallbutton() {
		return "<form method=POST action=/servlets/PopWeb name=formdelall>\n" +
		       "<input type=hidden name=popserver value="+popserver+">\n" +
		       "<input type=hidden name=username value=\""+username+"\">\n" +
		       "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
		       "<input type=hidden name=command value=deleteall>\n" +
		       "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formdelall.submit(); return false;\"><font face=lucida,tahoma,arial color=black size=2><b>delete all</b></font></a> | </form>\n";
	}
	private String showlogoutbutton() {
		return "<form method=POST action=/servlets/PopWeb name=formlogout>\n" +
		       "<input type=hidden name=popserver value="+popserver+">\n" +
		       "<input type=hidden name=username value=\""+username+"\">\n" +
		       "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
		       "<input type=hidden name=command value=logout>\n" +
		       "<a href=/servlets/PopWeb?command=nojs onclick=\"document.formlogout.submit(); return false;\"><font face=lucida,tahoma,arial color=black size=2><b>logout</b></font></a> </form>\n";
	}
	private String showviewbutton(int current) {
		return "<input type=hidden name=popserver value="+popserver+">\n" +
		       "<input type=hidden name=username value=\""+username+"\">\n" +
		       "<input type=hidden name=password value=\""+passwordstr+"\">\n" +
		       "<input type=hidden name=hdrs value=" + showallheadersstr + ">\n" +
		       "<input type=hidden name=command value=viewmsg>\n" +
		       "<input type=hidden name=msgnum value=" + (current) + ">\n" +
		       "<input type=image src=/images/square.gif border=0>\n";
	}
	private String shownextindexpagebutton() {
		  // not implemented (yet)
		return "";
	}

	/**
	 * showtoolbar()
	 *
	 * - Creates a toolbar out of the above methods return values
	 * - User can navigate PopWeb easily using this toolbar
	 *   that always looks the same
	 *
	 */
	private String showtoolbar(int current, int total, boolean inmsg) {
		return "<table border=0>\n" +
		       "<tr><td>" + showindexbutton() +
		       "\n</td><td>" + showprevbutton(current,total) +
		       "\n</td><td>" + shownextbutton(current,total) +
		       "\n</td><td>" + showwritebutton() +
		       "\n</td><td>" + showreplybutton(current, inmsg) +
		       "\n</td><td>" + showforwardbutton(current, inmsg) +
		       "\n</td><td>" + showdeletebutton(current, inmsg) +
		       "\n</td><td>" + showdeleteallbutton() +
		       "\n</td><td>" + showlogoutbutton() +
		       "\n</td></tr></table>\n";
	}

	/**
	 * stripQuotes()
	 *
	 * - Removes quotation marks from a String
	 *
	 */
	private String stripQuotes(String str) {
		String result = "";
		StringTokenizer st = new StringTokenizer(str, "\"");
		while(st.hasMoreElements()) {
			result = result + (String)st.nextElement();
		}
		return result;
	}

	/**
	 * stripHTML()
	 *
	 * - Converts ">" to "&gt;" and "<" to "&lt;" in a String
	 *
	 */
	private String stripHTML(String str) {
		String result = "";
		char buff [] = new char[str.length()];
		str.getChars(0,str.length(),buff,0);

		for(int i=0; i<buff.length; i++) {
			switch(buff[i]) {
			case '>': result = result + "&gt;"; break;
			case '<': result = result + "&lt;"; break;
			case '&': result = result + "&amp;"; break;
			default: result = result + new String(new char[] {buff[i]});
			}
		}
		return result;
	}

	/**
	 * highlightURLS()
	 *
	 * - Searches a String for the http:// prefix and
	 *   creates a hyperlink out of it
	 *
	 * - problem: Space (" ") is the only delimiter
	 *
	 */
	private String highlightURLS(String str) {
		int urlidx = str.indexOf("http://");
		if(urlidx < 0) urlidx = str.indexOf("ftp://");
		if(urlidx < 0) return str;
		String url = str.substring(urlidx);
		int endurlidx = url.indexOf(" ");
		if(endurlidx == -1) endurlidx = url.length();
		url = url.substring(0, endurlidx);
		return str.substring(0,urlidx) + "<a href=\"" + url + "\">" + url + "</a>" +
		       highlightURLS(str.substring(url.length() + urlidx));
	}

	/**
	 * parseAddresses()
	 *
	 * - Parses single email addresses from a String
	 *   of email addresses seperated by commas (",")
	 *
	 */
	private String [] parseAddresses(String str) throws Exception {
		Vector v = new Vector();
		StringTokenizer st = new StringTokenizer(str, ",");
		while(st.hasMoreElements()) {
			String anaddr = (String)st.nextElement();
			if(anaddr.length() < 3 ||
			   anaddr.indexOf("@") < 1 ||
			   anaddr.indexOf("@") == anaddr.length()-1)
				throw new Exception("Invalid email address: " + anaddr);
			v.addElement(anaddr);
		}
		String [] result = new String[v.size()];
		for(int i=0;i<v.size();i++) {
			result[i] = (String)v.elementAt(i);
		}
		return result;
//		return (String[])v.toArray(result);
	}

	/**
	 * getHeaderValue()
	 *
	 * - Searches _text_ for _header_ and returns the value between
	 *   _header_ and _delim_
	 * - Used to get values from email headers ("From:") etc.
	 *
	 */
	private String getHeaderValue(String header, String text, String delim) {
		int hdridx = text.indexOf(header);
		if(hdridx < 0) return null;
		text = text.substring(hdridx);
		int newlnidx = text.indexOf(delim);
		if(newlnidx < 0) newlnidx = text.length();
		return text.substring(header.length(),newlnidx);
	}

	/**
	 * WrapLines()
	 *
	 * - Wraps long lines in a string
	 *
	 *
	private String WrapLines(String string, int linelength) {
		String result = null;
		BufferedReader br = new BufferedReader(new
						StringReader(string));
		String line = null;
		while( (line=br.readLine()) != null ) {
			if(line.length() > linelength) {

			} else {
				result += line + "\n";
			}
		}
		return result;
	}
	*/
	/**
	 * printError()
	 *
	 * - Displays an error message to the client
	 *
	 */
	private void printError(String title, String str) {
		clientout.println("<html><head><title>PopWeb [" + title + "]</title></head>");
		showFile("pwbody1.thtml",false);
		clientout.println("PopWeb " + title);
		showFile("pwbody2.thtml",false);
		clientout.println(str);
		showFile("pwbody3.thtml",false);
	}
}