(* 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.
 *)

(* Network messages *)

structure Msg :> MSG = struct

open OpenSSL MsgTypes Slave

val a2i = fn Add => 0
	   | Delete => 1
	   | Modify => 2

val i2a = fn 0 => Add
	   | 1 => Delete
	   | 2 => Modify
	   | _ => raise OpenSSL.OpenSSL "Bad action number to deserialize"

fun sendAcl (bio, {user, class, value}) =
    (OpenSSL.writeString (bio, user);
     OpenSSL.writeString (bio, class);
     OpenSSL.writeString (bio, value))

fun recvAcl bio =
    case (OpenSSL.readString bio, OpenSSL.readString bio, OpenSSL.readString bio) of
	(SOME user, SOME class, SOME value) => SOME {user = user, class = class, value = value}
      | _ => NONE

fun send (bio, m) =
    case m of
	MsgOk => OpenSSL.writeInt (bio, 1)
      | MsgError s => (OpenSSL.writeInt (bio, 2);
		       OpenSSL.writeString (bio, s))
      | MsgConfig s => (OpenSSL.writeInt (bio, 3);
		       OpenSSL.writeString (bio, s))
      | MsgFile {action, domain, dir, file} =>
	(OpenSSL.writeInt (bio, 4);
	 OpenSSL.writeInt (bio, a2i action);
	 OpenSSL.writeString (bio, domain);
	 OpenSSL.writeString (bio, dir);
	 OpenSSL.writeString (bio, file))
      | MsgDoFiles => OpenSSL.writeInt (bio, 5)
      | MsgGrant acl => (OpenSSL.writeInt (bio, 6);
			 sendAcl (bio, acl))
      | MsgRevoke acl => (OpenSSL.writeInt (bio, 7);
			  sendAcl (bio, acl))
      | MsgListPerms user => (OpenSSL.writeInt (bio, 8);
			      OpenSSL.writeString (bio, user))
      | MsgPerms classes => (OpenSSL.writeInt (bio, 9);
			     app (fn (class, values) =>
				     (OpenSSL.writeInt (bio, 1);
				      OpenSSL.writeString (bio, class);
				      app (fn value =>
					      (OpenSSL.writeInt (bio, 1);
					       OpenSSL.writeString (bio, value))) values;
				      OpenSSL.writeInt (bio, 0))) classes;
			     OpenSSL.writeInt (bio, 0))

fun checkIt v =
    case v of
	NONE => raise OpenSSL.OpenSSL "Bad Msg format"
      | _ => v

fun recv bio =
    case OpenSSL.readInt bio of
	NONE => NONE
      | SOME n =>
	checkIt (case n of
		     1 => SOME MsgOk
		   | 2 => Option.map MsgError (OpenSSL.readString bio)
		   | 3 => Option.map MsgConfig (OpenSSL.readString bio)
		   | 4 => (case (OpenSSL.readInt bio,
				 OpenSSL.readString bio,
				 OpenSSL.readString bio,
				 OpenSSL.readString bio) of
			       (SOME action, SOME domain, SOME dir, SOME file) =>
			       SOME (MsgFile {action = i2a action,
					      domain = domain,
					      dir = dir,
					      file = file})
			     | _ => NONE)
		   | 5 => SOME MsgDoFiles
		   | 6 => (case recvAcl bio of
			       SOME acl => SOME (MsgGrant acl)
			     | _ => NONE)
		   | 7 => (case recvAcl bio of
			       SOME acl => SOME (MsgRevoke acl)
			     | _ => NONE)
		   | 8 => (case OpenSSL.readString bio of
			       SOME user => SOME (MsgListPerms user)
			     | _ => NONE)
		   | 9 => let
			 fun loop classes =
			     case OpenSSL.readInt bio of
				 SOME 0 => SOME (MsgPerms (rev classes))
			       | SOME 1 =>
				 (case OpenSSL.readString bio of
				      SOME class =>
				      let
					  fun loop' values =
					      case OpenSSL.readInt bio of
						  SOME 0 => loop ((class, rev values) :: classes)
						| SOME 1 =>
						  (case OpenSSL.readString bio of
						       SOME value => loop' (value :: values)
						     | NONE => NONE)
						| _ => NONE
				      in
					  loop' []
				      end
				    | NONE => NONE)
			       | _ => NONE
		     in
			 loop []
		     end
		   | _ => NONE)
	 
end