-module(butler_functions).
-export([
  butler_nav_pid/1,
  rack_loc_pid/1,
  get_rack_location/1,
  get_butler_location/1,
  get_butler_status/1,
  set_butler_lift_down/1,
  set_butler_lift_up/1,
  teleport_butler/2,
  lift_already_up/1,
  lift_already_down/1,
  rack_already_at_location/2,
  rack_already_at_pps/2,
  butler_already_at_location/2,
  gen_random_barcode/0
]).

butler_nav_pid(BId) ->
  gproc:lookup_local_name({dummy_navigator, BId}).

rack_loc_pid(RId) ->
  gproc:lookup_local_name({dummy_rack_location_service, RId}).

%% helpers for getting/modifying butler/rack state
get_rack_location(RId) ->
  dummy_rack_location_service:get_rack_location(rack_loc_pid(RId)).

get_butler_location(BId) ->
  dummy_navigator:get_location(butler_nav_pid(BId)).

get_butler_status(BId) ->
  Pid = butler_nav_pid(BId),
  {dummy_navigator:get_location(Pid), dummy_navigator:get_lift_state(Pid)}.

set_butler_lift_down(BId) ->
  dummy_navigator:lift(butler_nav_pid(BId), down).

set_butler_lift_up(BId) ->
  dummy_navigator:lift(butler_nav_pid(BId), up).

teleport_butler(BId, Location) ->
  dummy_navigator:teleport_butler(butler_nav_pid(BId), Location).

lift_state(BId) ->
  dummy_navigator:get_lift_state(butler_nav_pid(BId)).
lift_already_up(BId) ->
  lift_state(BId) =:= up.
lift_already_down(BId) ->
  lift_state(BId) =:= down.

rack_already_at_location(RId, RackDestination) ->
  get_rack_location(RId) =:= RackDestination.

rack_already_at_pps(RId, _PPSId) ->
  %% just assume pps is at 003.002...
  rack_already_at_location(RId, "003.002").

butler_already_at_location(BId, Location) ->
  get_butler_location(BId) =:= Location.

%% private
%% eg 050, 021 etc. min is 050
gen_random_3_digit_string() ->
  "0" ++ erlang:float_to_list(rand:uniform()*50+20, [{decimals, 0}]).

%% public
gen_random_barcode() ->
  gen_random_3_digit_string() ++ "." ++ gen_random_3_digit_string().