// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the Apache Public Source License 2.0 ("the License").
// You may not use this file except in compliance with the License.

// 500 unrec. command
// 501 syntax error
// 503 optional subfeature not supported 
// Xref header
// LIST EXTENSIONS is probably incomplete
// pull mode (ie suck)
// FEATURE: control message processing?
//          cancel <Message-ID>      (do not forward if I am unable to cancel locally)
//          ihave/sendme:            do not support
//          newgroup <groupname> [moderated] -- body of message is a description of the group
//          rmgroup  <groupname>

package org.ibex.mail;
import org.ibex.util.*;
import org.ibex.io.*;
import org.ibex.net.*;
import org.ibex.mail.target.*;
import org.ibex.jinetd.*;
import java.io.*;
import java.net.*;
import java.util.*;
import java.text.*;

/** NNTP send/recieve */
public class NNTP {

    public static final DateFormat serverDateFormat = new SimpleDateFormat("yyyyMMDDhhmmss");
    public static final DateFormat shortNewNewsDateFormat = new SimpleDateFormat("yyMMDD HHMMSS");
    public static final DateFormat longNewNewsDateFormat = new SimpleDateFormat("yyyyMMDD HHMMSS");
    static {
        serverDateFormat.setTimeZone(new SimpleTimeZone(SimpleTimeZone.UTC_TIME, "GMT"));
        shortNewNewsDateFormat.setTimeZone(new SimpleTimeZone(SimpleTimeZone.UTC_TIME, "GMT"));
        longNewNewsDateFormat.setTimeZone(new SimpleTimeZone(SimpleTimeZone.UTC_TIME, "GMT"));
    }

    public static class No  extends RuntimeException { int code = 400; }                                       // 4xx response codes
    public static class Bad extends RuntimeException { int code = 500; public Bad(String s) { super(s); } }    // 5xx response codes

    public static class Group {
        public Group(String n, boolean p, int f, int l, int c) {
            this.name=n;
            this.post=p;
            this.first=f;
            this.last=l;
            this.count=c;
        }
        public final String  name;    // case insensitive
        public final boolean post;
        public final int     first;
        public final int     last;
        public final int     count;   // an approximation; must be >= actual number
    }

    public static class Article {
        public Article(int num, Message message) { this.message = message; this.num = num; }
        public final int     num;
        public final Message message;
    }


    /**
     *  The API exposed by an NNTP server; remote NNTP servers appear
     *  as instances of this class, and implementations of this class
     *  may be exported as NNTP servers.
     */
    public static interface Server {
        public Group    group(String s);
        public boolean  ihave(String messageid);
        public boolean  want(String messageid);
        public Article  next();
        public Article  last();
        public boolean  postok();
        public void     post(Message m);
        public Article  article(String messageid,  boolean head, boolean body);
        public Article  article(int    messagenum, boolean head, boolean body);
        public Group[]  list();
        public Group[]  newgroups(Date d);
        public String[] newnews(String[] groups, Date d);
    }

    public static class MailboxServer implements Server {
        private final MailTree root;
        private Mailbox current = null;
        private int currentMessageNumber = 0;
        public MailboxServer(MailTree root) { this.root = root; }
        public boolean  postok() { return true; }
        public void     post(Message m) { current.post(m); }
        public Group    group(String s) {
            currentMessageNumber = 0;
            MailTree ncurrent = resolve(s);
            if (ncurrent == null) return null;
            current = ncurrent.getMailbox();
            return new Group(s, true, 1, current.count(Query.all()), current.count(Query.all()));
        }
        public boolean  ihave(String messageid)                   { /* FEATURE */ return false; }
        public boolean  want(String messageid)                    { /* FEATURE */ return true; }
        public Group[]  newgroups(Date d)                         { /* FEATURE */ return new Group[] { }; }
        public Article  next()                                    { return article(currentMessageNumber++, false, false); }
        public Article  last()                                    { return article(currentMessageNumber--, false, false); }
        public String[] newnews(String[] groups, Date d) {
            Vec ret = new Vec();
            for(String g : groups) {
                Mailbox group = resolve(g).getMailbox();
                for(Mailbox.Iterator mit = group.iterator(Query.arrival(d, null));
                    mit.next();) {
                    ret.add(mit.head().get("message-id"));
                }
            }
            return (String[])ret.copyInto(new String[ret.size()]);
        }
        public Article  article(String i, boolean h, boolean b) { return article(Query.header("message-id",i),h,b); }
        public Article  article(int    n, boolean h, boolean b) { currentMessageNumber = n; return article(Query.nntpNumber(n,n),h,b); }
        private Article article(Query q,  boolean head, boolean body) {
            Mailbox.Iterator it = current.iterator(q);
            if (!it.next()) return null;
            return new Article(it.nntpNumber(), body ? it.cur() : Message.newMessage(it.head()));
        }
        public Group[]  list() { return list(root, ""); }
        private Group[] list(MailTree who, String prefix) {
            Vec v = new Vec();
            if (who == null) who = root;
            String[] s = who.children();
            for(int i=0; i<s.length; i++) {
                MailTree mtree = who.slash(s[i], false);

                // this is inefficient
                int low = Integer.MAX_VALUE;
                int high = 0;
                int count = 0;
                for(Mailbox.Iterator mit = mtree.getMailbox().iterator(); mit.next();) {
                    count++;
                    low = Math.min(low, mit.nntpNumber());
                    high = Math.max(low, mit.nntpNumber());
                }
                if (count==0) { low = 1; high = 0; }

                v.addElement(new Group(prefix + s[i], true, low, high, count));
                Group[] g2 = list(mtree, prefix + s[i] + ".");
                for(int j=0; j<g2.length; j++) v.addElement(g2[j]);
            }
            Group[] ret = new Group[v.size()];
            v.copyInto(ret);
            return ret;
        }
        private MailTree resolve(String s) {
            MailTree box = root;
            for(StringTokenizer st = new StringTokenizer(s, ".");
                box!=null && st.hasMoreTokens();
                box = box.slash(st.nextToken(), false));
            return box;
        }
    }

    public static class Listener {
        private Server api = null;
        private Login login;
        private Connection conn;
        public Listener(Login l) { this.login = l; }

        private void println(String s) { conn.println(s); }
        private void println()         { conn.println(""); }
        private void print(String s)   { conn.print(s); }

        private void article(String numOrMessageId, boolean head, boolean body) {
            String s = numOrMessageId.trim();
            Article a;
            if (s.startsWith("<")) a = api.article(s.substring(0, s.length() - 1), head, body);
            else                   a = api.article(Integer.parseInt(s), head, body);
            if (a == null) {
                println("423 No such article.");
                return;
            }
            int code = (head && body) ? 220 : head ? 221 : body ? 222 : 223;
            println(code + " " + a.num + " <" + a.message.messageid + "> get ready for some stuff...");
            if (head) { a.message.headers.getStream().transcribe(conn); println(); }
            if (head && body) println();
            if (body) {
                Stream stream = a.message.getBody().getStream();
                while(true) {
                    s = stream.readln();
                    if (s == null) break;
                    if (s.startsWith(".")) print(".");
                    println(s);
                }
            }
            println(".");
        }
        public void handleRequest(Connection conn) {
            this.conn = conn;
            conn.setTimeout(30 * 60 * 1000);
            conn.setNewline("\r\n");
            println("200 " + conn.vhost + " [" + NNTP.class.getName() + "]");
            String user = null;
            String pass = null;
            Account account = login.anonymous();
            this.api = account == null ? null : new MailboxServer(account.getMailbox(NNTP.class));
            for(String line = conn.readln(); line != null; line = conn.readln()) try {
                Log.warn("[nntp-read]", line);
                StringTokenizer st = new StringTokenizer(line, " ");
                String command = st.nextToken().toUpperCase();
                if (command.equals("AUTHINFO")) {
                    String uop = st.nextToken().toUpperCase();
                    if (uop.equals("USER")) {
                        user = st.nextToken();
                        println("381 More authentication required");
                        continue;
                    } else if (uop.equals("PASS")) {
                        pass = st.nextToken();
                        account = login.login(user, pass);
                        if (account == null) { println("502 Invalid"); continue; }
                        this.api = new MailboxServer(account.getMailbox(NNTP.class));
                        println("281 Good to go");
                        continue;
                    }
                    throw new Bad("wtf are you talking about?");
                }
                if (this.api == null) {
                    if (user == null) { println("480 Authentication required"); continue; }
                    if (pass == null) { println("381 Password required"); continue; }
                }
                if        (command.equals("ARTICLE"))   { article(st.hasMoreTokens() ? st.nextToken() : null, true,  true); 
                } else if (command.equals("HEAD"))      { article(st.hasMoreTokens() ? st.nextToken() : null, true,  false); 
                } else if (command.equals("DATE"))      { println("111 " + serverDateFormat.format(new Date()));
                } else if (command.equals("MODE"))      {
                    if (st.hasMoreTokens()) {
                        String arg = st.nextToken();
                        if (arg.equalsIgnoreCase("STREAM"));
                        println("203 Streaming permitted");
                    } else {
                        println("201 Hello, you can post.");
                    }
                } else if (command.equals("BODY"))      { article(st.hasMoreTokens() ? st.nextToken() : null, false, true); 
                } else if (command.equals("STAT"))      { article(st.hasMoreTokens() ? st.nextToken() : null, false, false); 
                } else if (command.equals("HELP"))      { println("100 you are beyond help."); println(".");
                } else if (command.equals("SLAVE"))     { println("220 SLAVE was removed in RFC3977, you should not use it");
                } else if (command.equals("XOVER") || command.equals("OVER"))     {
                    println("224 Overview information follows");
                    MailboxServer api = (MailboxServer)this.api;
                    String range = st.hasMoreTokens() ? st.nextToken() : (api.currentMessageNumber+"-"+api.currentMessageNumber);
                    int start = Integer.parseInt(range.substring(0, range.indexOf('-')));
                    int end   = Integer.parseInt(range.substring(range.indexOf('-') + 1));
                    Mailbox.Iterator it = api.current.iterator(Query.nntpNumber(start, end));
                    while(it.next()) {
                        try {
                            Message m = it.cur();
                            println(it.nntpNumber()+"\t"+m.subject+"\t"+m.from+"\t"+m.date+"\t"+m.messageid+"\t"+
                                    m.headers.get("references") + "\t" + m.getLength() + "\t" + m.getNumLines());
                        } catch (Exception e) { Log.error(this, e); }
                    }
                    println(".");
                } else if (command.equals("LAST"))      {
                    Article a = api.last(); println("223 "+a.num+" "+a.message.messageid+" ok");
                } else if (command.equals("NEXT"))      {
                    Article a = api.next(); println("223 "+a.num+" "+a.message.messageid+" ok");
                } else if (command.equals("QUIT"))      { println("205 Bye."); conn.close(); return; 
                } else if (command.equals("GROUP"))     {
                    Group g = api.group(st.nextToken().toLowerCase());
                    if (g==null) println("411 no such group");
                    else         println("211 " + g.count + " " + g.first + " " + g.last + " " + g.name);
                } else if (command.equals("NEWGROUPS") || command.equals("NEWNEWS")) { 
                    // FIXME: * and ! unsupported
                    String groups = command.equals("NEWNEWS") ? st.nextToken() : null;
                    String datetime = st.nextToken() + " " + st.nextToken();
                    String gmt = st.nextToken();

                    Date d = new Date();
                    try { d = (datetime.length() == 13 ? shortNewNewsDateFormat : longNewNewsDateFormat)
                              .parse(datetime);
                    } catch (ParseException pe) { Log.warn(this, pe); }

                    if (command.equals("NEWGROUPS")) {
                        Group[] g = api.newgroups(d);
                        println("231 list of groups follows");
                        for(int i=0; i<g.length; i++)
                            println(g[i].name + " " + g[i].last + " " + g[i].first + " " + (g[i].post ? "y" : "n"));
                        println(".");
                    } else {
                        st = new StringTokenizer(groups, ",");
                        String[] g = new String[st.countTokens()];
                        for(int i=0; st.hasMoreTokens(); i++) g[i] = st.nextToken();
                        String[] a = api.newnews(g, d);
                        println("230 list of article messageids follows");
                        for(int i=0; i<a.length; i++) println(a[i]);
                        println(".");
                    }

                } else if (command.equals("POST"))      { 
                    boolean postok = api.postok();
                    if (!postok) {
                        println("440 no posting allowed");
                    } else {
		      println("340 send the article");
		      try {
                          Message m = Message.readDotEncodedMessage(conn);
                          if (m.headers.get("newsgroups")==null)
                              println("441 posted messages must have a Newsgroups header per RFC 977");
                          else if (m.headers.get("newsgroups").indexOf('*')!=-1)
                              println("441 Newsgroups header in posted messages may not contain wildcards (*) per RFC 977");
                          else if (m.headers.get("subject")==null)
                              println("441 posted messages must have a Subject header per RFC 977");
                          else if (m.headers.get("from")==null)
                              println("441 posted messages must have a From header per RFC 977");
                          else if (m.headers.get("date")==null)
                              println("441 posted messages must have a Date header per RFC 977");
                          else {
                              api.post(m);
                              println("240 article posted ok");
                          }
		      } catch (Exception e) {
                          e.printStackTrace();
                          println("441 posting failed: " + e);
		      }
		    }

                } else if (command.equals("XROVER"))      { 
                    // equivalent to "XHDR References"

                } else if (command.equals("XHDR") || (command.equals("HDR")))      { 
                    // argument: header name
                    // argument: 1 | 1- | 1-2 | <mid> | nothing (use current article)
                    println("221 yep");
                    // print art#+header for all matching messages
                    println(".");
                    // 412 if no group selected and numeric form used
                    // 430 if <mid> and not found
                    // 420 if no messages in range

                } else if (command.equals("XPAT"))      { 
                    // just like XHDR, but a pattern follows the last argument (may contain whitespace)
                    println("221 yep");
                    // print 
                    println(".");

                } else if (command.equals("LIST"))      { 
                    if (st.hasMoreTokens()) {
                        String argument = st.nextToken().toUpperCase();
                        if (argument.equalsIgnoreCase("EXTENSIONS")) {
                            println("202 Extensions supported:");
                            println("STREAMING");
                            println("");
                            println(".");
                        } else if (argument.equals("ACTIVE")) {
                            String wildmat = st.hasMoreTokens() ? st.nextToken() : null;
                            // FIXME: deal with wildmat
                            // just like list, but only show active groups
                            throw new Bad("not implemented yet");
                        } else if (argument.equals("SUBSCRIPTIONS")) {
                            // FIXME: show 215, default subscription list for new users, period
                        } else if (argument.equals("OVERVIEW.FMT")) {
                            println("215 Overview format:");
                            println("Subject:");
                            println("From:");
                            println("Date:");
                            println("Message-ID:");
                            println("References:");
                            println("Bytes:");
                            println("Lines:");
                            //println("Xref:full");
                            println(".");
                        } else if (argument.equals("NEWSGROUPS")) {
                            String wildmat = st.hasMoreTokens() ? st.nextToken() : null;
                            // respond 215, print each newsgroup, a space, and the description; end with lone period
                        } else {
                            // barf here
                        }
                    } else {
                        Group[] g = api.list();
                        println("215 list of groups follows");
                        for(int i=0; i<g.length; i++)
                            println(g[i].name + " " + g[i].last + " " + g[i].first + " " + (g[i].post ? "y" : "n"));
                        println(".");
                    }

                } else if (command.equals("LISTGROUP"))     {
                    String groupname = st.hasMoreTokens() ? st.nextToken() : null;
                    // 211, all article numbers in group, period.  Set article currentMessageNumber to first item in group

                } else if (command.equals("XGTITLE"))     {
                    String wildmat = st.hasMoreTokens() ? st.nextToken() : null;
                    // 282, then identical to LIST NEWSGROUP

                } else if (command.equals("CHECK"))     {
                    String mid = st.nextToken();
                    boolean want = api.want(mid);
                    if (!want) println("438 "+ mid+" No thanks");
                    else       println("238 "+mid+" Yes, I'd like that");

                } else if (command.equals("TAKETHIS"))     {
                    String mid = st.nextToken();
                    boolean want = api.want(mid);
                    Message m = Message.readDotEncodedMessage(conn);
                    if (want) {
                        api.post(m);
                        println("239 "+mid+" Rock on.");
                    } else {
                        println("439 "+ mid+" I really didn't want that; don't send it again.");
                    }

                } else if (command.equals("IHAVE"))     {
                    boolean want = api.ihave(st.nextToken());
                    if (!want) {
                        println("435 No thanks");
                    } else {
                        println("335 Proceed");
                        api.post(Message.readDotEncodedMessage(conn));
                        println("235 Got it");
                    }
                } else {
                    throw new Bad("wtf are you talking about?");
                }
            } catch (No n)  { println(n.code + " " + n.getMessage());
            } catch (Bad b) { println(b.code + " " + b.getMessage()); Log.warn(this, b); }
            conn.close();
        }
    }
}