-module(lustre).
-compile(no_auto_import).

-export([element/1, simple/3, application/3, start/2]).
-export_type([app/2, error/0]).

-opaque app(GEV, GEW) :: {app,
        {GEV, lustre@cmd:cmd(GEW)},
        fun((GEV, GEW) -> {GEV, lustre@cmd:cmd(GEW)}),
        fun((GEV) -> lustre@element:element(GEW))}.

-type error() :: element_not_found.

-spec element(lustre@element:element(GFN)) -> app(nil, GFN).
element(Element) ->
    Init = {nil, lustre@cmd:none()},
    Update = fun(_, _) -> {nil, lustre@cmd:none()} end,
    Render = fun(_) -> Element end,
    {app, Init, Update, Render}.

-spec simple(
    GFR,
    fun((GFR, GFS) -> GFR),
    fun((GFR) -> lustre@element:element(GFS))
) -> app(GFR, GFS).
simple(Init, Update, Render) ->
    Init@1 = {Init, lustre@cmd:none()},
    Update@1 = fun(Model, Msg) -> {Update(Model, Msg), lustre@cmd:none()} end,
    {app, Init@1, Update@1, Render}.

-spec application(
    {GFW, lustre@cmd:cmd(GFX)},
    fun((GFW, GFX) -> {GFW, lustre@cmd:cmd(GFX)}),
    fun((GFW) -> lustre@element:element(GFX))
) -> app(GFW, GFX).
application(Init, Update, Render) ->
    {app, Init, Update, Render}.

-spec start(app(any(), GGG), binary()) -> {ok, fun((GGG) -> nil)} |
    {error, error()}.
start(App, Selector) ->
    _pipe = '.@ffi.mjs':mount(App, Selector),
    gleam@result:replace_error(_pipe, element_not_found).