structure PassGen :> PASSGEN = struct

open Config Sql
structure C = PgClient

val db = ref (NONE : C.conn option)
fun getDb () = valOf (!db)

fun begin () =
    let
	val c = C.conn passgenDbstring
    in
	db := SOME c;
	ignore (C.dml c "BEGIN")
    end

fun commit () =
    let
	val db = getDb ()
    in
	C.dml db "COMMIT";
	C.close db
    end

fun gen () =
    let
	val db = getDb ()

	val id = case C.oneRow db "SELECT nextval('PassSeq')" of
		     [id] => C.intFromSql id
		   | _ => raise Fail "Bad nextval() return"

	val proc = Unix.execute ("/usr/bin/apg", ["/usr/bin/apg", "-d", "-n", "1"])
	val inf = Unix.textInstreamOf proc

	val pass = case TextIO.inputLine inf of
		       NONE => raise Fail "No apg output"
		     | SOME line => String.substring (line, 0, size line - 1)
    in
	ignore (Unix.reap proc);
	ignore (C.dml db ($`INSERT INTO Pass (id, pass) VALUES (^(C.intToSql id), ^(C.stringToSql pass))`));
	(id, pass)
    end

end