import java.io.*;
import java.net.*;
import java.util.regex.*;
import java.util.*;

public class SmtpSink
{
    boolean finished = false;

    public static void main( String[] args )
    {
        new SmtpSink( 2000 );
    }

    SmtpSink( int port )
    {
        int count = 0;
        try
        {
            ServerSocket listener = new ServerSocket( port );
            while ( ! finished )
            {
                Socket client = listener.accept();
                new Connection( client, ++count );
            }
        }
        catch (Exception e)
        {
        }
    }
}

class Connection
{
    Socket client;
    int id;
    BufferedReader in;
    PrintWriter out;
    Pattern p_DATA;
    Pattern p_QUIT;

    Connection( Socket client, int id ) throws IOException
    {
        try
        {
            p_DATA = Pattern.compile( "data", Pattern.CASE_INSENSITIVE );
            p_QUIT = Pattern.compile( "quit", Pattern.CASE_INSENSITIVE );
        }
        catch (Exception e)
        {
            System.out.println( "Error compiling pattern: " + e );
        }
        this.client = client;
        this.id = id;
        InputStream in_stream = client.getInputStream();
        InputStreamReader in_stream_reader = new InputStreamReader( in_stream );
        in = new BufferedReader( in_stream_reader );

        OutputStream out_stream = client.getOutputStream();
        OutputStreamWriter out_stream_writer = new OutputStreamWriter( out_stream );
        out = new PrintWriter( out_stream_writer, true );

        new Thread(
            new Runnable()
            {
                public void run()
                {
                    handle_message();
                }
            }
        ).start();
    }

    void handle_message()
    {
        int state = 0;  // 0 == processing commands
                        // 1 == processing DATA

        String remote = client.getInetAddress().getHostAddress();
        Calendar now = new GregorianCalendar();
        File msgfile = new File( "msgs", "msg." + now.get(Calendar.YEAR) + "."
                                                + now.get(Calendar.MONTH) + "."
                                                + now.get(Calendar.DAY_OF_MONTH) + "-"
                                                + now.get(Calendar.HOUR_OF_DAY) + "."
                                                + now.get(Calendar.MINUTE) + "."
                                                + now.get(Calendar.SECOND) + "-"
                                                + id + "-" + remote );

        try
        {
            FileOutputStream fileout = new FileOutputStream( msgfile );
            PrintWriter file = new PrintWriter( fileout );

            String line;
            out.println( "220 hello " + remote );
            while ( (line = in.readLine()) != null )
            {
                file.println( line );

                if ( state == 0 )
                {
                    Matcher m = p_QUIT.matcher( line );
                    if ( m.lookingAt() )
                    {
                        out.println( "221 bye" );
                        client.close();
                        client = null;
                        break;
                    }
                    m = p_DATA.matcher( line );
                    if ( m.lookingAt() )
                    {
                        state = 1;
                        out.println( "354 send the message" );
                    }
                    else
                        out.println( "250 OK" );
                }
                else
                {
                    if ( line.equals( "." ) )
                    {
                        out.println( "250 OK" );
                        state = 0;
                    }
                }
            }
            if ( client != null )
                client.close();

            file.close();
        }
        catch (Exception e)
        {
            System.out.println( "handle_message exception: " + e );
        }
    }
}