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

-export([new/0, add_dir/2, add_dirs/2, set_actor_handler/2, set_initial_state/2, set_handler/2, set_initializer/2, selector/0, spec/1, start/1]).
-export_type([no_directories/0, has_directories/0, no_handler/0, has_handler/0, no_initial_state/0, has_initial_state/0, event/0, change/1, builder/5]).

-type no_directories() :: any().

-type has_directories() :: any().

-type no_handler() :: any().

-type has_handler() :: any().

-type no_initial_state() :: any().

-type has_initial_state() :: any().

-type event() :: created |
    modified |
    closed |
    deleted |
    renamed |
    attribute |
    {unknown, gleam@erlang@atom:atom_()}.

-type change(HEN) :: {change, binary(), list(event())} | {custom, HEN}.

-opaque builder(HEO, HEP, HEQ, HER, HES) :: {builder,
        list(binary()),
        gleam@option:option(fun((change(HES), HEO) -> gleam@otp@actor:next(change(HES), HEO))),
        gleam@option:option(fun(() -> HEO))} |
    {gleam_phantom, HEP, HEQ, HER}.

-spec new() -> builder(any(), no_directories(), no_handler(), no_initial_state(), nil).
new() ->
    {builder, [], none, none}.

-spec add_dir(builder(HFH, any(), HFJ, HFK, HFL), binary()) -> builder(HFH, has_directories(), HFJ, HFK, HFL).
add_dir(Builder, Directory) ->
    {builder,
        [Directory | erlang:element(2, Builder)],
        erlang:element(3, Builder),
        erlang:element(4, Builder)}.

-spec add_dirs(builder(HFW, any(), HFY, HFZ, HGA), list(binary())) -> builder(HFW, has_directories(), HFY, HFZ, HGA).
add_dirs(Builder, Directories) ->
    {builder,
        lists:append(Directories, erlang:element(2, Builder)),
        erlang:element(3, Builder),
        erlang:element(4, Builder)}.

-spec set_actor_handler(
    builder(HGY, HGZ, no_handler(), HHA, HHB),
    fun((change(HHB), HGY) -> gleam@otp@actor:next(change(HHB), HGY))
) -> builder(HGY, HGZ, has_handler(), HHA, HHB).
set_actor_handler(Builder, Handler) ->
    {builder,
        erlang:element(2, Builder),
        {some, Handler},
        erlang:element(4, Builder)}.

-spec set_initial_state(builder(HHO, HHP, HHQ, no_initial_state(), HHR), HHO) -> builder(HHO, HHP, HHQ, has_initial_state(), HHR).
set_initial_state(Builder, State) ->
    {builder,
        erlang:element(2, Builder),
        erlang:element(3, Builder),
        {some, fun() -> State end}}.

-spec set_handler(
    builder(nil, HGM, no_handler(), no_initial_state(), HGN),
    fun((binary(), event()) -> nil)
) -> builder(nil, HGM, has_handler(), has_initial_state(), HGN).
set_handler(Builder, Handler) ->
    Wrapped_handler = fun(Event, _) ->
        case Event of
            {change, Path, Events} ->
                gleam@list:each(Events, fun(Ev) -> Handler(Path, Ev) end);

            _ ->
                nil
        end,
        gleam@otp@actor:continue(nil)
    end,
    _pipe = Builder,
    _pipe@1 = set_actor_handler(_pipe, Wrapped_handler),
    set_initial_state(_pipe@1, nil).

-spec set_initializer(
    builder(HIC, HID, HIE, no_initial_state(), HIF),
    fun(() -> HIC)
) -> builder(HIC, HID, HIE, has_initial_state(), HIF).
set_initializer(Builder, Initializer) ->
    {builder,
        erlang:element(2, Builder),
        erlang:element(3, Builder),
        {some, Initializer}}.

-spec to_event(gleam@dynamic:dynamic_()) -> {ok, event()} |
    {error, list(gleam@dynamic:decode_error())}.
to_event(From) ->
    gleam@result:'try'(
        gleam_erlang_ffi:atom_from_dynamic(From),
        fun(Event) ->
            Created = erlang:binary_to_atom(<<"created"/utf8>>),
            Deleted = erlang:binary_to_atom(<<"deleted"/utf8>>),
            Modified = erlang:binary_to_atom(<<"modified"/utf8>>),
            Closed = erlang:binary_to_atom(<<"closed"/utf8>>),
            Renamed = erlang:binary_to_atom(<<"renamed"/utf8>>),
            Attrib = erlang:binary_to_atom(<<"attribute"/utf8>>),
            Removed = erlang:binary_to_atom(<<"removed"/utf8>>),
            case Event of
                Ev when Ev =:= Created ->
                    {ok, created};

                Ev@1 when Ev@1 =:= Deleted ->
                    {ok, deleted};

                Ev@2 when Ev@2 =:= Modified ->
                    {ok, modified};

                Ev@3 when Ev@3 =:= Closed ->
                    {ok, closed};

                Ev@4 when Ev@4 =:= Renamed ->
                    {ok, renamed};

                Ev@5 when Ev@5 =:= Removed ->
                    {ok, deleted};

                Ev@6 when Ev@6 =:= Attrib ->
                    {ok, attribute};

                Other ->
                    {ok, {unknown, Other}}
            end
        end
    ).

-spec selector() -> gleam@erlang@process:selector(change(any())).
selector() ->
    Change_selector = gleam@dynamic:tuple3(
        fun gleam@dynamic:dynamic/1,
        fun gleam@dynamic:dynamic/1,
        gleam@dynamic:tuple2(fun(L) -> _pipe = filespy_ffi:identity(L),
                _pipe@1 = unicode:characters_to_binary(_pipe),
                {ok, _pipe@1} end, gleam@dynamic:list(fun to_event/1))
    ),
    _pipe@2 = gleam_erlang_ffi:new_selector(),
    gleam@erlang@process:selecting_anything(
        _pipe@2,
        fun(Event) -> case Change_selector(Event) of
                {ok, {_, _, {Path, Events}}} ->
                    {change, Path, Events};

                _ ->
                    {change, <<""/utf8>>, []}
            end end
    ).

-spec spec(
    builder(HIW, has_directories(), has_handler(), has_initial_state(), HIX)
) -> gleam@otp@actor:spec(HIW, change(HIX)).
spec(Builder) ->
    _assert_subject = erlang:element(3, Builder),
    {some, Handler} = case _assert_subject of
        {some, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"filespy"/utf8>>,
                        function => <<"spec"/utf8>>,
                        line => 256})
    end,
    _assert_subject@1 = erlang:element(4, Builder),
    {some, Initializer} = case _assert_subject@1 of
        {some, _} -> _assert_subject@1;
        _assert_fail@1 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@1,
                        module => <<"filespy"/utf8>>,
                        function => <<"spec"/utf8>>,
                        line => 257})
    end,
    {spec,
        fun() ->
            {Oks, Errs} = begin
                _pipe = erlang:element(2, Builder),
                _pipe@2 = gleam@list:map(
                    _pipe,
                    fun(Dir) ->
                        Atom = erlang:binary_to_atom(
                            <<"fs_watcher"/utf8, Dir/binary>>
                        ),
                        _pipe@1 = fs:start_link(Atom, Dir),
                        gleam@result:map(_pipe@1, fun(Pid) -> {Pid, Atom} end)
                    end
                ),
                gleam@result:partition(_pipe@2)
            end,
            case Errs of
                [] ->
                    _pipe@3 = Oks,
                    gleam@list:each(
                        _pipe@3,
                        fun(Res) ->
                            {_, Atom@1} = Res,
                            fs:subscribe(Atom@1)
                        end
                    ),
                    {ready, Initializer(), selector()};

                Errs@1 ->
                    gleam@list:each(
                        Oks,
                        fun(Res@1) ->
                            {Pid@1, _} = Res@1,
                            gleam@erlang@process:kill(Pid@1)
                        end
                    ),
                    {failed,
                        <<"Failed to start watcher: "/utf8,
                            (gleam@string:inspect(Errs@1))/binary>>}
            end
        end,
        5000,
        Handler}.

-spec start(
    builder(any(), has_directories(), has_handler(), has_initial_state(), HJH)
) -> {ok, gleam@erlang@process:subject(change(HJH))} |
    {error, gleam@otp@actor:start_error()}.
start(Builder) ->
    _pipe = spec(Builder),
    gleam@otp@actor:start_spec(_pipe).