(*
   Copyright 2003 Sean Proctor

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

   The license is at <http://www.gnu.org/licenses/gpl.txt>.
*)

exception BadInput;

fun mkshoes(date) =
  let
    val colors = #["red", "orange", "yellow", "green", "blue", "khaki",
      "black"];
    val random = Rand.mkRandom(Word.fromInt(date));
    fun rand() = Rand.range(0, 6)(random());
    val shoe1 = Vector.sub(colors, rand());
    val shoe2 = Vector.sub(colors, rand());
  in
    if shoe1 <> shoe2 then (shoe1, shoe2)
    else (Vector.sub(colors, rand()), Vector.sub(colors, rand()))
  end;

fun current_date() =
  valOf(Int.fromString(Date.fmt("%Y%m%d")(Date.fromTimeLocal(Time.now()))));

fun check_input(x) =
  let
    val date = Int.fromString(x);
  in
    if isSome(date) andalso size(x) = 8 then valOf(date)
    else raise BadInput
  end;

fun mkdate(nil) = current_date()
  | mkdate(x::nil) = check_input(x)
  | mkdate(_) = raise BadInput;

fun print_shoes(_, args) =
  let
    val date = mkdate(args);
    val shoes = mkshoes(date);
  in
  (
    print("On " ^ Int.toString(date) ^ "\nshoe 1: " ^ #1(shoes) ^ "\nshoe 2: "
      ^ #2(shoes) ^ "\n");
    OS.Process.success
  )
  end;