(* HCoop Domtool (http://hcoop.sourceforge.net/)
 * Copyright (c) 2006, Adam Chlipala
 *
 * 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.
 *)

(* Configuring e-mail aliases *)

structure Alias :> ALIAS = struct

open Ast

structure SM = DataStructures.StringMap

val aliases : TextIO.outstream SM.map ref = ref SM.empty
fun aliasesF node = valOf (SM.find (!aliases, node))

val aliasesD : TextIO.outstream SM.map ref = ref SM.empty
fun aliasesDF node = valOf (SM.find (!aliasesD, node))

fun write nodes =
    let
	val files = map (fn node => aliasesF node) nodes
    in
	fn s => app (fn file => TextIO.output (file, s)) files
    end

fun writeD nodes =
    let
	val files = map (fn node => aliasesDF node) nodes
    in
	fn s => app (fn file => TextIO.output (file, s)) files
    end

fun openInAll base = foldl (fn (node, r) =>
			       SM.insert (r,
					  node,
					  Domain.domainFile {node = node, name = base}))
			   SM.empty Domain.nodes

val _ = Domain.registerBefore
	    (fn _ => (aliases := openInAll "aliases";
		      aliasesD := openInAll "aliases.default"))
	
val _ = Domain.registerAfter
	(fn _ => (SM.app TextIO.closeOut (!aliases);
		  SM.app TextIO.closeOut (!aliasesD)))

fun validEmailUser s =
    size s > 0 andalso size s < 50
    andalso CharVector.all (fn ch => Char.isAlphaNum ch
				     orelse ch = #"."
				     orelse ch = #"_"
				     orelse ch = #"-"
				     orelse ch = #"+") s

val _ = Env.type_one "emailUser"
	Env.string
	validEmailUser

fun validEmail s =
    case String.fields (fn ch => ch = #"@") s of
	[user] => validEmailUser user
      | [user, host] => validEmailUser user andalso Domain.validDomain host
      | _ => false

val _ = Env.type_one "email"
	Env.string
	validEmail

datatype aliasSource =
	 User of string
       | Default
       | CatchAll

val source = fn (EApp ((EVar "userSource", _), e), _) =>
		Option.map User (Env.string e)
	      | (EVar "defaultSource", _) => SOME Default
	      | (EVar "catchAllSource", _) => SOME CatchAll
	      | _ => NONE

datatype aliasTarget =
	 Address of string
       | Addresses of string list
       | Drop

val target = fn (EApp ((EVar "addressTarget", _), e), _) =>
		Option.map Address (Env.string e)
	      | (EApp ((EVar "addressesTarget", _), e), _) =>
		Option.map Addresses (Env.list Env.string e)
	      | (EVar "dropTarget", _) => SOME Drop
	      | _ => NONE

fun localhostify s =
    let
	val (prefix, suffix) = Substring.splitl (fn ch => ch <> #"@") (Substring.full s)
    in
	if Substring.size suffix = 0 then
	    s ^ "@localhost"
	else
	    s
    end

fun writeSource (env, s, t) =
    let
	val nodes = Env.env (Env.list Env.string) (env, "MailNodes")

	val write = write nodes
	val writeD = writeD nodes

	fun writeTarget (writer, t) =
	    case t of
		Address s => writer (localhostify s)
	      | Addresses [] => writer "!"
	      | Addresses ss => writer (String.concatWith "," (map localhostify ss))
	      | Drop => writer "!"
    in
	case s of
	    User s => (write s;
		       write "@";
		       write (Domain.currentDomain ());
		       write ": ";
		       writeTarget (write, t);
		       write "\n")
	  | Default => (write "*@";
			write (Domain.currentDomain ());
			write ": ";
			writeTarget (write, t);
			write "\n")
	  | CatchAll => (writeD "*@";
			 writeD (Domain.currentDomain ());
			 writeD ": ";
			 writeTarget (writeD, t);
			 writeD "\n")
    end
			
val _ = Env.actionV_two "aliasPrim"
			("from", source, "to", target)
			writeSource

end