// SmtpSender.java - a sample to send email to an SMTP server
// by Rowland http://home.comcast.net/~rowland3

import java.io.*;
import java.net.*;
import java.text.DateFormat;
import java.util.*;

class MailMessage  {
    String  subject;
    String  date;
    Vector  vbodylines;   // message text is a vector of strings
    public final String sender, recipient;
    TreeMap header= new TreeMap();
    
    public MailMessage(String _sender, String _recipient)   {
	sender= _sender;  recipient= _recipient;
	vbodylines = new Vector();
    }
    public void addHeaderLine(String line)  {
	try {
	    int ix= line.indexOf(": ");
	    if (ix< 0)  return;
	    String key= line.substring(0, ix);
	    String val= line.substring(ix+2);
	    if (val.endsWith("\n"))  val= val.substring(val.length()-1);  // get rid of trailing LF
	    if (val.endsWith("\r"))  val= val.substring(val.length()-1);  // get rid of trailing CRLF
	    header.put(key, val);
	} catch (Exception E) {
	    System.err.println("MailMessage.addheaderLine: "+ line);
	}
    }
    public void addHeaderVal(String key, String val) {
	header.put(key, val);
    }
    public void addMailMessageLine(String _line)    { vbodylines.add(_line); }
    
    public Enumeration getMailMessageLines()    { return vbodylines.elements(); }
    public Iterator getHeaderFields()    { return header.keySet().iterator(); }
    public String getHeaderVal(String key) {
	Object O= header.get(key);
	if (O== null)  return null;
	return (String)O;
    }
    public String senderUname() {
	int ix= sender.indexOf("@");
	if (ix< 0)  return sender;
	return sender.substring(0, ix);
    }
    public String toString() {
	String s= "Sender: "+ sender+ "\tRecipient: "+ recipient+ "\n";
	Iterator hi= header.keySet().iterator();
	while (hi.hasNext()) {
	    String key= (String)hi.next();
	    String hline= key+ ": "+ header.get(key)+ "\n";
	    s+= hline;
	}
	s+= "\n";
	Enumeration e= vbodylines.elements();
	while(e.hasMoreElements()) {
	    s+= (String)e.nextElement()+ "\n";
	}
	return s;
    }
}

//------------------------------------------------------------------------------

class SmtpSender {
    Socket sserver;
    BufferedReader in;
    OutputStreamWriter out;
    static final int SMTP_PORT= 25;

    SmtpSender(MailMessage message, String server) {
	try {
	    sserver= new Socket(server, SMTP_PORT);
	    send(message, sserver);
	    sserver.close();
	} catch (Exception E) {
	    System.err.println("SmtpSender.SmtpSender: "+ E.toString()+ " "+ E.getMessage());
	}
    }

    protected void send(MailMessage message, Socket sserver) {
	try {
	    // A bit convoluted, but doesn't depend on DNS in any way...
	    InetAddress localhost= sserver.getLocalAddress();
	    String localaddress= localhost.getHostAddress();

	    // Mandatory header fields, Date and From
	    if (message.getHeaderVal("Date")== null)
		message.addHeaderVal("Date", new java.util.Date().toString());
	    if (message.getHeaderVal("From")== null)
		message.addHeaderVal("From", message.senderUname()+ " <"+ message.sender+ ">");
	    
	    out= new OutputStreamWriter(sserver.getOutputStream());
	    in = new BufferedReader(new InputStreamReader(sserver.getInputStream()));
	    String sintro= readln();
	    if (!sintro.startsWith("220")) {  // 220
		System.err.println("SmtpSender: intro=="+ sintro);
		return;
	    }

	    writeln("EHLO "+ localaddress);
	    if (!expect250())
		return;

	    String sender= message.sender;
	    int ix= sender.indexOf("@");
	    if (ix< 0) { // fill in sender domain
		sender+= "@"+ localaddress;
	    }
	    writeln("MAIL FROM:<"+ sender+ ">");
	    if (!expect250())
		return;
	    writeln("RCPT TO:<"+ message.recipient+ ">");
	    if (!expect250())
		return;
	    writeln("DATA");
	    while (true) { // may be multiple 250 replies pending from server
		String line= readln();
		if (line.startsWith("3"))  break; // ready to send
		if (!line.startsWith("2")) {
		    System.err.println("SmtpSender.send reponse to DATA: "+ line);
		    return;
		}
	    }
	    Iterator hi= message.getHeaderFields();
	    while (hi.hasNext()) {
		String key= (String)hi.next();
		writeln(key+ ": "+ message.getHeaderVal(key));
	    }
	    writeln("");  // end of header;
	    Enumeration e= message.getMailMessageLines();
	    while(e.hasMoreElements()) {
		String bline= (String)e.nextElement();
		if (bline.startsWith("."))
		    bline= "."+ bline;
		writeln(bline);
	    }
	    writeln(".");
	    expect250();
	    writeln("QUIT");
	} catch (Exception E) {
	    System.err.println("SmtpSender.send: "+ E.toString());
	}
    }

    final boolean expect250()  throws IOException {
	String line= readln();
	if (!line.startsWith("2")) {
	    System.err.println("SmtpSender.expect250: "+ line);
	    return false;
	}
	return true;
    }

    final void writeln(String s) throws IOException  {
	System.err.println("From client: "+ s);
	out.write(s+ "\r\n");  out.flush();
    }

    final String readln()  throws IOException {
	String line= in.readLine();
	System.err.println("From server: "+ line);
	return line;
    }

    protected static Socket serverConnect(String server) {
	Socket ss= null;
	try { ss= new Socket(server, SMTP_PORT); }
	catch (Exception E) { ss= null; }
	return ss;
    }
    protected static String serverConnectTest(String server) {
	Socket ss= serverConnect(server);
	if (ss== null)
	    return null;
	try { ss.close(); } catch (Exception E) { }
	return server;
    }

    public static void main(String args[]) {
	// usage: java SmtpSender mailaddress smtpserver
	String mailaddress= args[0];
	MailMessage message= new MailMessage("SmtpSender", mailaddress);
	message.addHeaderVal("Subject", "SmtpSender test");
	message.addMailMessageLine("SmtpSender test body");
	new SmtpSender(message, args[1]);
    }
}