converting rfc3339 to timestamp and back, like a boss.

convert_date_like_hell.erl

-module(main).
-export([start/0]).

to_rfc3339(DateTime) ->
  {{Y, M, D}, {H, I, S}} = DateTime,
  io_lib:format(
    "~4.10.0B-~2.10.0B-~2.10.0BT~2.10.0B:~2.10.0B:~2.10.0BZ",
    [Y, M, D, H, I, S]
  ).

to_rfc3339_serialize(DateTime) ->
  lists:flatten(to_rfc3339(DateTime)).

start() ->
  Tz = to_rfc3339_serialize(
    calendar:local_time()
  ),
  SysTime = calendar:rfc3339_to_system_time(
    Tz,
    [{unit, nanosecond}]
  ),
  io:fwrite(
    "RFC 3339 to system time: ~p~n",
    [SysTime]
  ).