(* 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.
 *)

(* BIND DNS *)

structure Bind :> BIND = struct

open Ast

val namedChanged = ref false
val zoneChanged = ref false

val didDomain = ref ""

val () = Slave.registerPreHandler (fn () => (namedChanged := false;
					     zoneChanged := false;
					     didDomain := ""))

val dns : TextIO.outstream option ref = ref NONE

val _ = Domain.registerBefore
	    (fn _ => dns := Option.map (fn node => Domain.domainFile {node = node,
								      name = "dns"})
				       (Domain.dnsMaster ()))
	
val _ = Domain.registerAfter
	    (fn _ => (Option.app TextIO.closeOut (!dns);
		      dns := NONE))

val dl = ErrorMsg.dummyLoc

datatype dns_record =
	 A of string * string
       | CNAME of string * string
       | MX of int * string
       | NS of string

val record = fn (EApp ((EApp ((EVar "dnsA", _), e1), _), e2), _) =>
		(case (Env.string e1, Env.string e2) of
		     (SOME v1, SOME v2) => SOME (A (v1, v2))
		   | _ => NONE)
	      | (EApp ((EApp ((EVar "dnsCNAME", _), e1), _), e2), _) =>
		(case (Env.string e1, Env.string e2) of
		     (SOME v1, SOME v2) => SOME (CNAME (v1, v2))
		   | _ => NONE)
	      | (EApp ((EApp ((EVar "dnsMX", _), e1), _), e2), _) =>
		(case (Env.int e1, Env.string e2) of
		     (SOME v1, SOME v2) => SOME (MX (v1, v2))
		   | _ => NONE)
	      | (EApp ((EVar "dnsNS", _), e), _) =>
		Option.map NS (Env.string e)
	      | _ => NONE

fun writeRecord (evs, r) =
    case !dns of
	NONE => print "Warning: DNS directive ignored because no master DNS server is configured for this domain\n"
      | SOME file =>
	let
	    fun write s = TextIO.output (file, s)
	    val ttl = Env.env Env.int (evs, "TTL")
	in
	    case r of
		A (from, to) => (write from;
				 write ".";
				 write (Domain.currentDomain ());
				 write ".\t";
				 write (Int.toString ttl);
				 write "\tIN\tA\t";
				 write to;
				 write "\n")
	      | CNAME (from, to) => (write from;
				     write ".";
				     write (Domain.currentDomain ());
				     write ".\t";
				     write (Int.toString ttl);
				     write "\tIN\tCNAME\t";
				     write to;
				     write ".\n")
	      | MX (num, host) => (write "\t";
				   write (Int.toString ttl);
				   write "\tIN\tMX\t";
				   write (Int.toString num);
				   write "\t";
				   write host;
				   write ".\n")
	      | NS host => (write "\t";
			    write (Int.toString ttl);
			    write "\tIN\tNS\t";
			    write host;
			    write ".\n")
	end

val () = Env.actionV_one "dns"
			 ("record", record)
			 writeRecord

fun readLine inf =
    case TextIO.inputLine inf of
	NONE => raise Fail "Expected a line for BIND"
      | SOME s => String.substring (s, 0, size s - 1)

fun readILine inf = valOf (Int.fromString (readLine inf))

val () = Slave.registerFileHandler (fn fs =>
				       let
					   val {dir, file} = OS.Path.splitDirFile (#file fs)
							     
					   fun dnsChanged () =
					       if #domain fs = !didDomain then
						   ()
					       else if #action fs = Slave.Delete then
						   let
						       val fname = OS.Path.joinBaseExt {base = #domain fs,
											ext = SOME "zone"}
						       val fname = OS.Path.joinDirFile {dir = Config.Bind.zonePath,
											file = fname}
						   in
						       Slave.shellF ([Config.rm, " -f ", fname],
								  fn cl => "Error deleting file: " ^ cl)
						   end
					       else
						   let
						       val inf = TextIO.openIn (OS.Path.joinDirFile {dir = #dir fs,
												     file = "soa"})
						       val kind = readLine inf
						       val ttl = readILine inf
						       val ns = readLine inf
						       val serial = case readLine inf of
									"" => NONE
								      | s => Int.fromString s
						       val rf = readILine inf
						       val ret = readILine inf
						       val exp = readILine inf
						       val min = readILine inf
						       val () = TextIO.closeIn inf

						       val dns = OS.Path.joinDirFile {dir = #dir fs,
										      file = "dns"}

						       val fname = OS.Path.joinBaseExt {base = #domain fs,
											ext = SOME "zone"}
						       val fname = OS.Path.joinDirFile {dir = Config.Bind.zonePath,
											file = fname}

						       val outf = TextIO.openOut fname
						   in
						       zoneChanged := true;
						       TextIO.output (outf, "$TTL ");
						       TextIO.output (outf, Int.toString ttl);
						       TextIO.output (outf, "\n\n@\tIN\tSOA\t");
						       TextIO.output (outf, ns);
						       TextIO.output (outf, ".\thostmaster.");
						       TextIO.output (outf, #domain fs);
						       TextIO.output (outf, ".\n( ");
						       TextIO.output (outf, Int.toString 123456789);
						       TextIO.output (outf, " ");
						       TextIO.output (outf, Int.toString rf);
						       TextIO.output (outf, " ");
						       TextIO.output (outf, Int.toString ret);
						       TextIO.output (outf, " ");
						       TextIO.output (outf, Int.toString exp);
						       TextIO.output (outf, " ");
						       TextIO.output (outf, Int.toString min);
						       TextIO.output (outf, " )\n\n");
						       TextIO.closeOut outf;
						       if Posix.FileSys.access (dns, []) then
							   Slave.shellF ([Config.cat, " ", dns, " >>", fname],
								      fn cl => "Error concatenating file: " ^ cl)
						       else
							   ();
						       didDomain := #domain fs
						   end
				       in
					   case file of
					       "soa" => dnsChanged ()
					     | "dns" => dnsChanged ()
					     | "named.conf" => namedChanged := true
					     | _ => ()
				       end)

val () = Slave.registerPostHandler
	     (fn () =>
		 (if !namedChanged then
		      Slave.concatTo (fn s => s = "named.conf") Config.Bind.namedConf
		  else
		     ();
		  if !namedChanged orelse !zoneChanged then
		      Slave.shellF ([Config.Bind.reload],
				 fn cl => "Error reloading bind with " ^ cl)
		  else
		      ()))
end