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

-export([new_application/4, on_alt_screen/1, run/1]).
-export_type([application/2]).

-opaque application(GDE, GDF) :: {application,
        GDE,
        fun((GDE) -> binary()),
        fun((GDE, GDF) -> {GDE, boolean()}),
        list(fun(() -> {gleam@erlang@process:subject(GDF), fun(() -> nil)})),
        boolean()}.

-spec new_application(
    GDL,
    fun((GDL) -> binary()),
    fun((GDL, GDN) -> {GDL, boolean()}),
    list(fun(() -> {gleam@erlang@process:subject(GDN), fun(() -> nil)}))
) -> application(GDL, GDN).
new_application(State, Render, Update, Events) ->
    {application, State, Render, Update, Events, false}.

-spec on_alt_screen(application(GDU, GDV)) -> application(GDU, GDV).
on_alt_screen(Appl) ->
    erlang:setelement(6, Appl, true).

-spec clear_lines(integer()) -> nil.
clear_lines(Num) ->
    gleam@io:print(
        gleam@string:repeat(
            <<<<<<"\x{001b}["/utf8, "2K"/utf8>>/binary, "\x{001b}["/utf8>>/binary,
                "1A"/utf8>>,
            Num
        )
    ),
    gleam@io:print(<<"\r"/utf8>>).

-spec show(application(GEC, any()), GEC, integer()) -> integer().
show(Application, State, Previous_lines) ->
    clear_lines(Previous_lines),
    Content = (erlang:element(3, Application))(State),
    gleam@io:print(Content),
    erlang:length(gleam@string:split(Content, <<"\n"/utf8>>)).

-spec do_run(
    application(GEK, GEL),
    GEK,
    gleam@erlang@process:selector(GEL),
    list(fun(() -> nil)),
    integer()
) -> nil.
do_run(Application, State, Selector, Cleanup, Previous_lines) ->
    Lines = show(Application, State, Previous_lines - 1),
    Msg = gleam_erlang_ffi:select(Selector),
    {New_state, Running} = (erlang:element(4, Application))(State, Msg),
    case Running of
        true ->
            do_run(Application, New_state, Selector, Cleanup, Lines);

        false ->
            show(Application, New_state, Previous_lines - 1),
            case erlang:element(6, Application) of
                true ->
                    gleam@io:print(<<"\x{001b}["/utf8, "?1049l"/utf8>>);

                false ->
                    nil
            end,
            _pipe = Cleanup,
            gleam@list:map(_pipe, fun(X) -> X() end),
            nil
    end.

-spec run(application(any(), any())) -> nil.
run(Application) ->
    Subjects = begin
        _pipe = erlang:element(5, Application),
        gleam@list:map(_pipe, fun(T) -> T() end)
    end,
    case erlang:element(6, Application) of
        true ->
            gleam@io:print(<<"\x{001b}["/utf8, "?1049h"/utf8>>);

        false ->
            nil
    end,
    Selector = gleam_erlang_ffi:new_selector(),
    Added_selector = begin
        _pipe@1 = Subjects,
        gleam@list:fold(
            _pipe@1,
            Selector,
            fun(Sel, Sub) ->
                gleam@erlang@process:selecting(
                    Sel,
                    erlang:element(1, Sub),
                    fun gleam@function:identity/1
                )
            end
        )
    end,
    Cleanup = begin
        _pipe@2 = Subjects,
        gleam@list:map(_pipe@2, fun(T@1) -> erlang:element(2, T@1) end)
    end,
    do_run(
        Application,
        erlang:element(2, Application),
        Added_selector,
        Cleanup,
        1
    ).