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	diff --git a/lib/flake_id.ex b/lib/flake_id.ex
	index 1107a0e..34fbc45 100644
	--- a/lib/flake_id.ex
	+++ b/lib/flake_id.ex
	@@ -1,154 +1,154 @@
	# FlakeId: Decentralized, k-ordered ID generation service
	# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
	# SPDX-License-Identifier: LGPL-3.0-only

	defmodule FlakeId do
	@moduledoc """
	Decentralized, k-ordered ID generation service.
	"""

	import Kernel, except: [to_string: 1]
	alias FlakeId.Builder
	alias FlakeId.Worker
	alias FlakeId.Local

	@type error ::
	{:error, :clock_running_backwards} \| {:error, :clock_stuck} \| {:error, :invalid_state}

	@doc """
	Converts a binary Flake to a String

	## Examples

	iex> FlakeId.to_string(<<0, 0, 1, 109, 67, 124, 251, 125, 95, 28, 30, 59, 36, 42, 0, 0>>)
	"9n2ciuz1wdesFnrGJU"

	"""

	def to_string(<<_::integer-size(64), _::integer-size(48), _::integer-size(16)>> = binary_flake) do
	<<integer::integer-size(128)>> = binary_flake
	Base62.encode(integer)
	end

	def to_string(string), do: string

	@doc """
	Converts a String to a binary Flake

	## Examples

	iex> FlakeId.from_string("9n2ciuz1wdesFnrGJU")
	<<0, 0, 1, 109, 67, 124, 251, 125, 95, 28, 30, 59, 36, 42, 0, 0>>

	"""
	@spec from_string(String.t()) :: nil \| <<_::128>>
	def from_string(string)
	def from_string(<<_::integer-size(128)>> = flake), do: flake
	def from_string(string) when is_binary(string) and byte_size(string) < 18, do: nil
	def from_string(string), do: string \|> Base62.decode!() \|> from_integer

	@doc """
	Converts a binary Flake to an integer

	## Examples

	iex> FlakeId.to_integer(<<0, 0, 1, 109, 67, 124, 251, 125, 95, 28, 30, 59, 36, 42, 0, 0>>)
	28939165907792829150732718047232

	"""
	@spec to_integer(<<_::128>>) :: non_neg_integer
	def to_integer(binary_flake)
	def to_integer(<<integer::integer-size(128)>>), do: integer

	@doc """
	Converts an integer to a binary Flake

	## Examples

	iex> FlakeId.from_integer(28939165907792829150732718047232)
	<<0, 0, 1, 109, 67, 124, 251, 125, 95, 28, 30, 59, 36, 42, 0, 0>>

	"""
	@spec from_integer(integer) :: <<_::128>>
	def from_integer(integer) do
	<<_time::integer-size(64), _node::integer-size(48), _seq::integer-size(16)>> =
	<<integer::integer-size(128)>>
	end

	@doc """
	Generates a string with Flake
	"""
	- @spec get :: {:ok, String.t()} \| error()
	- def get do
	- case Worker.get() do
	+ @spec get(atom()) :: {:ok, String.t()} \| error()
	+ def get(name \\ Worker) do
	+ case Worker.get(name) do
	{:ok, flake} -> {:ok, to_string(flake)}
	error -> error
	end
	end

	@doc """
	Generates a local Flake (in-process state). Worker ID will be derived from global worker-id and the process pid.

	First call will be slower but subsequent calls will be faster than worker based `get/0` and is quite useful for long running processes.
	"""
	@spec get_local :: {:ok, String.t()} \| error()
	def get_local do
	case Local.get() do
	{:ok, flake} -> {:ok, to_string(flake)}
	error -> error
	end
	end

	@doc """
	Generates a predictable and back-dated FlakeId.

	This can be useful when you want to insert historical data without messing with sorting: be very careful at choosing a `unique` value that is _really unique_ for the given `datetime`, otherwise, collisons will happen.
	"""
	@spec backdate(any(), DateTime.t()) :: {:ok, String.t()} \| error()
	def backdate(datetime, unique) do
	hash = :erlang.phash2(unique)
	time = DateTime.to_unix(datetime, :millisecond)

	case Builder.get(time, %Builder{node: hash}) do
	{:ok, flake, _} -> {:ok, to_string(flake)}
	error -> error
	end
	end

	@doc """
	Generates a notional FlakeId (with an empty worker id) given a timestamp.

	This is useful for generating a lexical range of values that could have been generated in a span of time.
	"""
	def notional(datetime) do
	time = DateTime.to_unix(datetime, :millisecond)

	case Builder.get(time, %Builder{node: 0}) do
	{:ok, flake, _} -> {:ok, to_string(flake)}
	error -> error
	end
	end

	@doc """
	Checks that ID is a valid FlakeId

	## Examples

	iex> FlakeId.flake_id?("9n2ciuz1wdesFnrGJU")
	true

	iex> FlakeId.flake_id?("#cofe")
	false

	iex> FlakeId.flake_id?("pleroma.social")
	false
	"""
	@spec flake_id?(String.t()) :: boolean
	def flake_id?(id), do: flake_id?(String.to_charlist(id), true)

	defp flake_id?([c \| cs], true) when c >= ?0 and c <= ?9, do: flake_id?(cs, true)
	defp flake_id?([c \| cs], true) when c >= ?A and c <= ?Z, do: flake_id?(cs, true)
	defp flake_id?([c \| cs], true) when c >= ?a and c <= ?z, do: flake_id?(cs, true)
	defp flake_id?([], true), do: true
	defp flake_id?(_, _), do: false
	end
	diff --git a/lib/flake_id/application.ex b/lib/flake_id/application.ex
	index 61fbc50..72e42b4 100644
	--- a/lib/flake_id/application.ex
	+++ b/lib/flake_id/application.ex
	@@ -1,27 +1,36 @@
	# FlakeId: Decentralized, k-ordered ID generation service
	# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
	# SPDX-License-Identifier: LGPL-3.0-only

	defmodule FlakeId.Application do
	@moduledoc false

	use Application
	require Logger

	def start(_type, _args) do
	- unless :erlang.system_info(:time_warp_mode) == :multi_time_warp do
	+ if elem(default_clock(), 1) == :os do
	Logger.error("""
	FlakeId: Time consistency is not optimal, using system time.
	More information at: https://hexdocs.pm/flake_id/readme.html#time-warp
	""")
	end

	children = [
	FlakeId.TimeHint,
	FlakeId.Worker
	]

	opts = [strategy: :one_for_one, name: FlakeId.Supervisor]
	Supervisor.start_link(children, opts)
	end
	+
	+ def default_clock() do
	+ if :erlang.system_info(:time_warp_mode) == :multi_time_warp do
	+ {:erlang, :system_time}
	+ else
	+ {:os, :system_time}
	+ end
	+ end
	+
	end
	diff --git a/lib/flake_id/builder.ex b/lib/flake_id/builder.ex
	index e363044..9164dcc 100644
	--- a/lib/flake_id/builder.ex
	+++ b/lib/flake_id/builder.ex
	@@ -1,130 +1,122 @@
	# FlakeId: Decentralized, k-ordered ID generation service
	# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
	# SPDX-License-Identifier: LGPL-3.0-only

	defmodule FlakeId.Builder do
	@moduledoc false

	defstruct node: nil, time: 0, sq: 0, clock: nil

	@type t :: %__MODULE__{
	node: non_neg_integer,
	time: non_neg_integer,
	sq: non_neg_integer
	}

	- @type options :: [worker_id_option() \| time_hint_option() \| clock_option()]
	- @type worker_id_option :: {:worker_id, any()}
	- @type time_hint_option :: {:time_hint, false \| true \| atom()}
	- @type clock_option :: {module(), atom()}
	-
	- @spec new(options()) :: t()
	+ @spec new(options) :: t() when options: [worker_id \| time_hint \| clock],
	+ worker_id: {:worker_id, :random \| :node \| {:iface, String.t()} \| Integer.t \| String.t()},
	+ time_hint: {:time_hint, false \| true \| atom()},
	+ clock: {module(), atom()}
	def new(options \\ []) do
	worker_id = worker_id(Keyword.get(options, :worker_id))

	time =
	case Keyword.get(options, :time_hint) do
	false -> 0
	name when is_atom(name) -> FlakeId.TimeHint.get(name)
	_ -> FlakeId.TimeHint.get()
	end

	- clock = Keyword.get(options, :clock, default_clock())
	+ clock = Keyword.get(options, :clock, FlakeId.Application.default_clock())
	%__MODULE__{node: worker_id, time: time, clock: clock}
	end

	+ @spec backwards?(t()) :: boolean()
	def backwards?(%__MODULE__{time: time, clock: clock}) do
	time > time(clock)
	end

	def time() do
	- time(default_clock())
	+ time(FlakeId.Application.default_clock())
	end

	+ @spec time(t() \| {module(), atom()}) :: non_neg_integer()
	def time(%__MODULE__{clock: clock}) do
	time(clock)
	end

	def time({mod, fun}) do
	apply(mod, fun, [:millisecond])
	end

	@spec get(t) :: {:ok, <<_::128>>, t} \| FlakeId.error()
	def get(state = %__MODULE__{clock: clock}) do
	get(time(clock), state)
	end

	- @spec get(non_neg_integer, t) :: {:ok, <<_::128>>, t} \| FlakeId.error()
	+ @spec get(non_neg_integer(), t()) :: {:ok, <<_::128>>, t()} \| FlakeId.error()

	# Error when time didn't change and sequence is too big for 16bit int.
	def get(time, %__MODULE__{time: time, sq: sq}) when sq >= 65_535 do
	{:error, :clock_stuck}
	end

	# Matches when the calling time is the same as the state time. Incr. sq
	def get(time, %__MODULE__{node: node, time: time, sq: seq} = state)
	when is_integer(time) and is_integer(node) and is_integer(seq) do
	new_state = %__MODULE__{state \| sq: seq + 1}
	{:ok, gen_flake(new_state), new_state}
	end

	# Error when clock is running backwards
	def get(newtime, %__MODULE__{time: time}) when newtime < time do
	{:error, :clock_running_backwards}
	end

	# Matches when the times are different, reset sq
	def get(newtime, %__MODULE__{node: node, time: time, sq: seq} = state)
	when is_integer(time) and is_integer(node) and is_integer(seq) and newtime > time do
	new_state = %__MODULE__{state \| time: newtime, sq: 0}
	{:ok, gen_flake(new_state), new_state}
	end

	def get(_, _) do
	{:error, :invalid_state}
	end

	@spec gen_flake(t) :: <<_::128>>
	defp gen_flake(%__MODULE__{time: time, node: node, sq: seq}) do
	<<time::integer-size(64), node::integer-size(48), seq::integer-size(16)>>
	end

	- defp default_clock() do
	- if :erlang.system_info(:time_warp_mode) == :multi_time_warp do
	- {:erlang, :system_time}
	- else
	- {:os, :system_time}
	- end
	- end
	-
	def worker_id(setting \\ nil)

	def worker_id(nil) do
	worker_id(Application.get_env(:flake_id, :worker_id, :random))
	end

	def worker_id(:node) do
	:erlang.phash2(node())
	end

	def worker_id({:mac, iface}) do
	{:ok, addresses} = :inet.getifaddrs()
	proplist = :proplists.get_value(iface, addresses)
	hwaddr = Enum.take(:proplists.get_value(:hwaddr, proplist), 6)
	<<worker::integer-size(48)>> = :binary.list_to_bin(hwaddr)
	worker
	end

	def worker_id(:random) do
	<<worker::integer-size(48)>> = :crypto.strong_rand_bytes(6)
	worker
	end

	def worker_id(integer) when is_integer(integer) do
	integer
	end

	def worker_id(binary) when is_binary(binary) do
	:erlang.phash2(binary)
	end
	end
	diff --git a/lib/flake_id/time_hint.ex b/lib/flake_id/time_hint.ex
	index 08846f2..633e7e3 100644
	--- a/lib/flake_id/time_hint.ex
	+++ b/lib/flake_id/time_hint.ex
	@@ -1,121 +1,125 @@
	# FlakeId: Decentralized, k-ordered ID generation service
	# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
	# SPDX-License-Identifier: LGPL-3.0-only

	defmodule FlakeId.TimeHint do
	@moduledoc false
	use GenServer
	require Logger

	@tick :timer.minutes(1)
	@default_env false
	@default_file "flake_id_time"
	- @clock {FlakeId.Builder, :time}

	@spec get() :: 0 \| non_neg_integer
	@doc "Returns the latest time hint, or zero if disabled"
	def get(name \\ nil) do
	if name \|\| Application.get_env(:flake_id, :time_hint, @default_env) do
	GenServer.call(name \|\| __MODULE__, :get)
	else
	0
	end
	end

	+ @spec start_link([] \| options) :: GenServer.on_start when options: [name \| file \| tick \| clock],
	+ name: {:name, atom()},
	+ file: {:file, Path.t()},
	+ tick: {:tick, non_neg_integer()},
	+ clock: {module(), atom()}
	def start_link(options)

	def start_link([]) do
	if Application.get_env(:flake_id, :time_hint, false) do
	file =
	Application.get_env(
	:flake_id,
	:time_hint_file,
	Application.app_dir(:flake_id, ["priv", @default_file])
	)

	tick = Application.get_env(:flake_id, :time_hint_tick, @tick)
	- clock = Application.get_env(:flake_id, :time_hint_clock, @clock)
	+ clock = Application.get_env(:flake_id, :time_hint_clock, FlakeId.Application.default_clock())
	GenServer.start_link(__MODULE__, [file, tick, clock], name: __MODULE__)
	else
	:ignore
	end
	end

	def start_link(options) do
	name = Keyword.fetch!(options, :name)
	file = Keyword.fetch!(options, :file)
	tick = Keyword.get(options, :tick, @tick)
	- clock = Keyword.get(options, :clock, @clock)
	+ clock = Keyword.get(options, :clock, FlakeId.Application.default_clock())
	GenServer.start_link(__MODULE__, [file, tick, clock], name: name)
	end

	@impl true
	def init([file, tick, clock]) do
	Process.send_after(self(), :tick, tick)
	{:ok, {file, tick, clock, read_and_update(file, clock)}}
	end

	@impl true
	def handle_call(:get, _, state = {_, _, _, time}) do
	{:reply, time, state}
	end

	@impl true
	def handle_info(:tick, {file, tick, clock, prev_time}) do
	Process.send_after(self(), :tick, tick)
	{:noreply, {file, tick, clock, update(file, clock, prev_time)}}
	end

	if Mix.env() == :test do
	@impl true
	def handle_info(:stop, state) do
	{:stop, :normal, state}
	end
	end

	@impl true
	def terminate(_, {file, _, clock, prev_time}) do
	update(file, clock, prev_time)
	end

	defp read_and_update(file, clock) do
	update(file, clock, read(file))
	end

	- defp update(file, {mod, fun}, prev_time) do
	- time = :erlang.apply(mod, fun, [])
	+ defp update(file, {mod,fun}, prev_time) do
	+ time = apply(mod, fun, [:millisecond])

	if time > prev_time do
	:ok = write(file, time)
	time
	else
	prev_time
	end
	end

	defp read(file) do
	case File.read(file) do
	{:ok, data} ->
	{__MODULE__, time} = :erlang.binary_to_term(data)
	time

	{:error, :enoent} ->
	0

	error ->
	Logger.error("#{__MODULE__}: could not read file #{file}: #{inspect(error)}")
	throw(error)
	end
	end

	defp write(file, time) do
	case File.write(file, :erlang.term_to_binary({__MODULE__, time})) do
	:ok ->
	:ok

	error ->
	Logger.error("#{__MODULE__}: could not write file #{file}: #{inspect(error)}")
	error
	end
	end
	end
	diff --git a/lib/flake_id/worker.ex b/lib/flake_id/worker.ex
	index e253594..7dc7be6 100644
	--- a/lib/flake_id/worker.ex
	+++ b/lib/flake_id/worker.ex
	@@ -1,45 +1,43 @@
	# FlakeId: Decentralized, k-ordered ID generation service
	# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
	# SPDX-License-Identifier: LGPL-3.0-only

	defmodule FlakeId.Worker do
	@moduledoc false

	use GenServer
	require Logger
	alias FlakeId.Builder

	- @type options :: [{:name, atom()} \| Builder.options()]
	-
	def start_link(options \\ []) do
	name = Keyword.get(options, :name, __MODULE__)
	GenServer.start_link(__MODULE__, [options], name: name)
	end

	- @spec get :: {:ok, String.t()} \| FlakeId.error()
	- def get(name \\ __MODULE__), do: GenServer.call(name, :get)
	+ @spec get(atom()) :: {:ok, String.t()} \| FlakeId.error()
	+ def get(name), do: GenServer.call(name, :get)

	@impl true
	@spec init([]) :: {:ok, Builder.t()} \| {:stop, :clock_is_backwards}
	def init([options]) do
	state = Builder.new(options)

	if Builder.backwards?(state) do
	Logger.error("#{__MODULE__} Current time is backwards, not starting")
	{:stop, :clock_is_backwards}
	else
	{:ok, Builder.new()}
	end
	end

	@impl true
	def handle_call(:get, _from, state) do
	case Builder.get(state) do
	{:ok, flake, new_state} ->
	{:reply, {:ok, flake}, new_state}

	error ->
	{:reply, error, state}
	end
	end
	end
	diff --git a/test/support/fake_clock.ex b/test/support/fake_clock.ex
	index 3c84038..3a85455 100644
	--- a/test/support/fake_clock.ex
	+++ b/test/support/fake_clock.ex
	@@ -1,4 +1,4 @@
	defmodule FakeClock do
	def set(time), do: :persistent_term.put(__MODULE__, time)
	- def time(), do: :persistent_term.get(__MODULE__)
	+ def time(_), do: :persistent_term.get(__MODULE__)
	end

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