(* HCoop Domtool (http://hcoop.sourceforge.net/)
 * Copyright (c) 2006-2009, Adam Chlipala
 * Copyright (c) 2014 Clinton Ebadi <clinton@unknownlamer.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *)

(* Administration of Courier IMAP virtual mailboxes *)

structure Vmail :> VMAIL = struct

open MsgTypes

fun rebuild () =
    let
	fun doNode (site, ok) =
	    (print ("New vmail data for node " ^ site ^ "\n");
	     Connect.commandWorker (Domain.get_context (), site, MsgVmailChanged))
    in
	foldl doNode true Config.mailNodes_all
    end

fun doChanged () =
    Slave.shell [Config.Courier.postReload]

datatype listing =
	 Error of string
       | Listing of {user : string, mailbox : string} list

fun list domain =
    let
	val file = OS.Path.joinDirFile {dir = Config.Vmail.userDatabase,
					file = domain}
    in
	if Posix.FileSys.access (file, []) then
	    let
		val inf = TextIO.openIn file

		fun loop users =
		    case TextIO.inputLine inf of
			NONE => Listing (rev users)
		      | SOME line =>
			case String.tokens Char.isSpace line of
			    [addr, fields] =>
			    (case String.fields (fn ch => ch = #"@") addr of
				 [user, _] =>
				 let
				     fun parseFields fields =
					 case fields of
					     "mail" :: mailbox :: _ => loop ({user = user, mailbox = mailbox} :: users)
					   | _ :: _ :: rest => parseFields rest
					   | _ => Error "Invalid fields in database"
				 in
				     parseFields (String.fields (fn ch => ch = #"|" orelse ch = #"=") fields)
				 end
			       | _ => Error "Invalid e-mail address format in database")
			  | _ => Error "Invalid entry in database"
	    in
		loop []
		before TextIO.closeIn inf
	    end
	else
	    Listing []
    end
    handle IO.Io {name, function, ...} =>
	   Error ("IO failure: " ^ name ^ ": " ^ function)

fun mailboxExists {domain, user} =
    let
	val inf = TextIO.openIn (OS.Path.joinDirFile {dir = Config.Vmail.userDatabase,
						      file = domain})

	fun loop () =
	    case TextIO.inputLine inf of
		NONE => false
	      | SOME line =>
		case String.tokens Char.isSpace line of
		    [addr, _] =>
		    (case String.fields (fn ch => ch = #"@") addr of
			 [user', _] =>
			 user' = user orelse loop ()
		       | _ => false)
		  | _ => false
    in
	loop ()
	before TextIO.closeIn inf
    end
	handle IO.Io _ => false

fun setpassword {domain, user, passwd} =
    let
	val proc = Unix.execute ("/bin/sh", ["-c",
					     String.concat [Config.Vmail.userdbpw, " | ", Config.Vmail.userdb,
							    " -f ", Config.Vmail.userDatabase, "/", domain,
							    " \"", user, "@", domain, "\" set systempw"]])
	val outf = Unix.textOutstreamOf proc
    in
	TextIO.output (outf, String.concat [passwd, "\n", passwd, "\n"]);
	TextIO.closeOut outf;
	OS.Process.isSuccess (Unix.reap proc)
    end

fun deluser {domain, user} =
    Slave.run (Config.Vmail.userdb, ["-f", Config.Vmail.userDatabase ^ "/" ^ domain,
				     user ^ "@" ^ domain, "del"])

fun add {domain, requester, user, passwd, mailbox} =
    let
	val udb = Posix.SysDB.getpwnam requester
	val uid = SysWord.toInt (Posix.ProcEnv.uidToWord (Posix.SysDB.Passwd.uid udb))
	val gid = SysWord.toInt (Posix.ProcEnv.gidToWord (Posix.SysDB.Passwd.gid udb))
	val home = Posix.SysDB.Passwd.home udb
    in
	if mailboxExists {domain = domain, user = user} then
	    SOME "Mailbox mapping already exists"
	else if not (Slave.run (Config.Vmail.userdb, ["-f", Config.Vmail.userDatabase ^ "/" ^ domain,
						      user ^ "@" ^ domain,
						      "set", "home=" ^ home, "mail=" ^ mailbox, "uid=" ^ Int.toString uid, "gid=" ^ Int.toString gid])) then
	    SOME "Error running userdb"
	else if not (setpassword {domain = domain, user = user, passwd = passwd}) then
	    (ignore (deluser {domain = domain, user = user});
	     SOME "Error setting password")
	else if not (rebuild ()) then
	    (ignore (deluser {domain = domain, user = user});
	     SOME "Error reloading userdb")
	else
	    NONE
    end

fun passwd {domain, user, passwd} =
    if not (mailboxExists {domain = domain, user = user}) then
	SOME "Mailbox doesn't exist"
    else  if not (setpassword {domain = domain, user = user, passwd = passwd}) then
	SOME "Error setting password"
    else if not (rebuild ()) then
	SOME "Error reloading userdb"
    else
	NONE

fun rm {domain, user} =
    if not (mailboxExists {domain = domain, user = user}) then
	SOME "Mailbox doesn't exist"
    else if not (deluser {domain = domain, user = user}) then
	SOME "Error deleting password entry"
    else if not (rebuild ()) then
	SOME "Error reloading userdb"
    else
	NONE

end