glimit

-module(glimit).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([new/0, per_second/2, per_minute/2, per_hour/2, handler/2, identifier/2, build/1, apply/2]).
-export_type([rate_limiter/3, rate_limiter_builder/3]).

-type rate_limiter(HSK, HSL, HSM) :: {rate_limiter,
        gleam@erlang@process:subject(glimit@actor:message(HSM)),
        fun((HSK) -> HSL),
        fun((HSK) -> HSM)}.

-type rate_limiter_builder(HSN, HSO, HSP) :: {rate_limiter_builder,
        gleam@option:option(integer()),
        gleam@option:option(integer()),
        gleam@option:option(integer()),
        gleam@option:option(fun((HSN) -> HSP)),
        gleam@option:option(fun((HSN) -> HSO))}.

-spec new() -> rate_limiter_builder(any(), any(), any()).
new() ->
    {rate_limiter_builder, none, none, none, none, none}.

-spec per_second(rate_limiter_builder(HSW, HSX, HSY), integer()) -> rate_limiter_builder(HSW, HSX, HSY).
per_second(Limiter, Limit) ->
    erlang:setelement(2, Limiter, {some, Limit}).

-spec per_minute(rate_limiter_builder(HTF, HTG, HTH), integer()) -> rate_limiter_builder(HTF, HTG, HTH).
per_minute(Limiter, Limit) ->
    erlang:setelement(3, Limiter, {some, Limit}).

-spec per_hour(rate_limiter_builder(HTO, HTP, HTQ), integer()) -> rate_limiter_builder(HTO, HTP, HTQ).
per_hour(Limiter, Limit) ->
    erlang:setelement(4, Limiter, {some, Limit}).

-spec handler(rate_limiter_builder(HTX, HTY, HTZ), fun((HTX) -> HTY)) -> rate_limiter_builder(HTX, HTY, HTZ).
handler(Limiter, Handler) ->
    erlang:setelement(6, Limiter, {some, Handler}).

-spec identifier(rate_limiter_builder(HUG, HUH, HUI), fun((HUG) -> HUI)) -> rate_limiter_builder(HUG, HUH, HUI).
identifier(Limiter, Identifier) ->
    erlang:setelement(5, Limiter, {some, Identifier}).

-spec build(rate_limiter_builder(HUP, HUQ, HUR)) -> rate_limiter(HUP, HUQ, HUR).
build(Config) ->
    {rate_limiter,
        case glimit@actor:new(
            erlang:element(2, Config),
            erlang:element(3, Config),
            erlang:element(4, Config)
        ) of
            {ok, Subject} ->
                Subject;

            {error, _} ->
                erlang:error(#{gleam_error => panic,
                        message => <<"Failed to start rate limiter actor"/utf8>>,
                        module => <<"glimit"/utf8>>,
                        function => <<"build"/utf8>>,
                        line => 132})
        end,
        case erlang:element(6, Config) of
            {some, Handler} ->
                Handler;

            none ->
                erlang:error(#{gleam_error => panic,
                        message => <<"Handler function is required"/utf8>>,
                        module => <<"glimit"/utf8>>,
                        function => <<"build"/utf8>>,
                        line => 140})
        end,
        case erlang:element(5, Config) of
            {some, Identifier} ->
                Identifier;

            none ->
                erlang:error(#{gleam_error => panic,
                        message => <<"Identifier function is required"/utf8>>,
                        module => <<"glimit"/utf8>>,
                        function => <<"build"/utf8>>,
                        line => 136})
        end}.

-spec apply(fun((HUY) -> HUZ), rate_limiter(HUY, HUZ, any())) -> fun((HUY) -> HUZ).
apply(Func, Limiter) ->
    fun(Input) ->
        Identifier = (erlang:element(4, Limiter))(Input),
        case glimit@actor:hit(erlang:element(2, Limiter), Identifier) of
            {ok, nil} ->
                Func(Input);

            {error, nil} ->
                (erlang:element(3, Limiter))(Input)
        end
    end.