-module(lustre@effect).
-compile([no_auto_import, nowarn_unused_vars]).

-export([from/1, none/0, batch/1, map/2]).
-export_type([effect/1]).

-opaque effect(EXE) :: {effect, list(fun((fun((EXE) -> nil)) -> nil))}.

-spec from(fun((fun((EXF) -> nil)) -> nil)) -> effect(EXF).
from(Effect) ->
    {effect, [Effect]}.

-spec none() -> effect(any()).
none() ->
    {effect, []}.

-spec batch(list(effect(EXJ))) -> effect(EXJ).
batch(Effects) ->
    {effect,
        (gleam@list:fold(
            Effects,
            [],
            fun(B, _use1) ->
                {effect, A} = _use1,
                gleam@list:append(B, A)
            end
        ))}.

-spec map(effect(EXN), fun((EXN) -> EXP)) -> effect(EXP).
map(Effect, F) ->
    {effect, L} = Effect,
    {effect,
        gleam@list:map(
            L,
            fun(Effect@1) ->
                fun(Dispatch) -> Effect@1(fun(A) -> Dispatch(F(A)) end) end
            end
        )}.