-module(bigben@fake_clock).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).
-define(FILEPATH, "src/bigben/fake_clock.gleam").
-export([now/1, set_now/2, advance/2, new_at/1, new/0]).
-export_type([fake_clock/0, message/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(" A fake clock for manipulating the flow of time.\n").

-opaque fake_clock() :: {fake_clock, gleam@erlang@process:subject(message())}.

-type message() :: {get,
        gleam@erlang@process:subject(gleam@time@timestamp:timestamp())} |
    {set, gleam@time@timestamp:timestamp()} |
    {advance, gleam@time@duration:duration()}.

-file("src/bigben/fake_clock.gleam", 28).
?DOC(" Returns the current time on the given `FakeClock`.\n").
-spec now(fake_clock()) -> gleam@time@timestamp:timestamp().
now(Clock) ->
    gleam@erlang@process:call(
        erlang:element(2, Clock),
        10,
        fun(Field@0) -> {get, Field@0} end
    ).

-file("src/bigben/fake_clock.gleam", 33).
?DOC(" Sets the current time on the given `FakeClock` to the specified value.\n").
-spec set_now(fake_clock(), gleam@time@timestamp:timestamp()) -> nil.
set_now(Clock, Now) ->
    gleam@erlang@process:send(erlang:element(2, Clock), {set, Now}).

-file("src/bigben/fake_clock.gleam", 38).
?DOC(" Advances the given `FakeClock` by the specified duration.\n").
-spec advance(fake_clock(), gleam@time@duration:duration()) -> nil.
advance(Clock, Duration) ->
    gleam@erlang@process:send(erlang:element(2, Clock), {advance, Duration}).

-file("src/bigben/fake_clock.gleam", 48).
-spec handle_message(gleam@time@timestamp:timestamp(), message()) -> gleam@otp@actor:next(gleam@time@timestamp:timestamp(), any()).
handle_message(State, Message) ->
    case Message of
        {get, Client} ->
            gleam@erlang@process:send(Client, State),
            gleam@otp@actor:continue(State);

        {set, Now} ->
            gleam@otp@actor:continue(Now);

        {advance, Duration} ->
            gleam@otp@actor:continue(gleam@time@timestamp:add(State, Duration))
    end.

-file("src/bigben/fake_clock.gleam", 21).
?DOC(" Returns a new `FakeClock` at the given time.\n").
-spec new_at(gleam@time@timestamp:timestamp()) -> fake_clock().
new_at(Now) ->
    Actor@1 = case begin
        _pipe = gleam@otp@actor:new(Now),
        _pipe@1 = gleam@otp@actor:on_message(_pipe, fun handle_message/2),
        gleam@otp@actor:start(_pipe@1)
    end of
        {ok, Actor} -> Actor;
        _assert_fail ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
                        file => <<?FILEPATH/utf8>>,
                        module => <<"bigben/fake_clock"/utf8>>,
                        function => <<"new_at"/utf8>>,
                        line => 22,
                        value => _assert_fail,
                        start => 557,
                        'end' => 649,
                        pattern_start => 568,
                        pattern_end => 577})
    end,
    {fake_clock, erlang:element(3, Actor@1)}.

-file("src/bigben/fake_clock.gleam", 16).
?DOC(
    " Returns a new `FakeClock`.\n"
    "\n"
    " The current time will be the instant the clock was created.\n"
).
-spec new() -> fake_clock().
new() ->
    new_at(gleam@time@timestamp:system_time()).