-module(chip@registry).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([register/3, find/2, start/0]).
-export_type([message/2, index/0, state/2]).

-opaque message(HJZ, HKA) :: {tag,
        gleam@erlang@process:subject({ok, gleam@erlang@process:subject(HKA)} |
            {error, nil}),
        HJZ} |
    {registrant, gleam@erlang@process:subject(HKA), HJZ} |
    {demonitor, index()}.

-type index() :: {index,
        gleam@erlang@process:pid_(),
        gleam@erlang@process:process_monitor()}.

-type state(HKB, HKC) :: {state,
        gleam@erlang@process:subject(message(HKB, HKC)),
        gleam@dict:dict(HKB, gleam@erlang@process:subject(HKC)),
        gleam@dict:dict(gleam@erlang@process:pid_(), gleam@set:set(HKB)),
        gleam@erlang@process:selector(message(HKB, HKC))}.

-spec register(
    gleam@erlang@process:subject(message(HKO, HKP)),
    gleam@erlang@process:subject(HKP),
    HKO
) -> nil.
register(Registry, Subject, Name) ->
    gleam@erlang@process:send(Registry, {registrant, Subject, Name}).

-spec find(gleam@erlang@process:subject(message(HKV, HKW)), HKV) -> {ok,
        gleam@erlang@process:subject(HKW)} |
    {error, nil}.
find(Registry, Name) ->
    gleam@erlang@process:call(
        Registry,
        fun(_capture) -> {tag, _capture, Name} end,
        10
    ).

-spec handle_init() -> gleam@otp@actor:init_result(state(HOT, HOS), message(HOT, HOS)).
handle_init() ->
    Self = gleam@erlang@process:new_subject(),
    State = {state,
        Self,
        gleam@dict:new(),
        gleam@dict:new(),
        begin
            _pipe = gleam_erlang_ffi:new_selector(),
            gleam@erlang@process:selecting(
                _pipe,
                Self,
                fun gleam@function:identity/1
            )
        end},
    {ready, State, erlang:element(5, State)}.

-spec into_names(state(HLI, HLJ), HLI, gleam@erlang@process:subject(HLJ)) -> state(HLI, HLJ).
into_names(State, Name, Subject) ->
    erlang:setelement(
        3,
        State,
        gleam@dict:insert(erlang:element(3, State), Name, Subject)
    ).

-spec into_tracker(state(HLP, HLQ), gleam@erlang@process:pid_(), HLP) -> state(HLP, HLQ).
into_tracker(State, Pid, Location) ->
    Add_location = fun(Option) -> case Option of
            {some, Locations} ->
                gleam@set:insert(Locations, Location);

            none ->
                gleam@set:insert(gleam@set:new(), Location)
        end end,
    erlang:setelement(
        4,
        State,
        gleam@dict:update(erlang:element(4, State), Pid, Add_location)
    ).

-spec into_selector(
    state(HLV, HLW),
    gleam@option:option(gleam@erlang@process:selector(message(HLV, HLW)))
) -> state(HLV, HLW).
into_selector(State, Selection) ->
    case Selection of
        {some, Selector} ->
            erlang:setelement(5, State, Selector);

        none ->
            State
    end.

-spec remove_from_group(state(HMF, HMG), gleam@erlang@process:pid_()) -> state(HMF, HMG).
remove_from_group(State, Pid) ->
    Names = case gleam@dict:get(erlang:element(4, State), Pid) of
        {ok, Locations} ->
            gleam@set:to_list(Locations);

        {error, nil} ->
            erlang:error(#{gleam_error => panic,
                    message => <<"Impossible state, couldn't find a pid when removing from group."/utf8>>,
                    module => <<"chip/registry"/utf8>>,
                    function => <<"remove_from_group"/utf8>>,
                    line => 181})
    end,
    gleam@list:fold(
        Names,
        State,
        fun(State@1, Name) ->
            Names@1 = gleam@dict:delete(erlang:element(3, State@1), Name),
            erlang:setelement(3, State@1, Names@1)
        end
    ).

-spec remove_from_tracker(state(HML, HMM), gleam@erlang@process:pid_()) -> state(HML, HMM).
remove_from_tracker(State, Pid) ->
    erlang:setelement(
        4,
        State,
        gleam@dict:delete(erlang:element(4, State), Pid)
    ).

-spec select_process_down(
    gleam@erlang@process:selector(message(HMZ, HNA)),
    gleam@erlang@process:pid_(),
    gleam@erlang@process:process_monitor()
) -> gleam@erlang@process:selector(message(HMZ, HNA)).
select_process_down(Selector, Pid, Monitor) ->
    Index = {index, Pid, Monitor},
    Handle = fun(_) -> {demonitor, Index} end,
    gleam@erlang@process:selecting_process_down(Selector, Monitor, Handle).

-spec monitor(state(HMR, HMS), gleam@erlang@process:pid_()) -> gleam@option:option(gleam@erlang@process:selector(message(HMR, HMS))).
monitor(State, Pid) ->
    case gleam@dict:get(erlang:element(4, State), Pid) of
        {ok, _} ->
            none;

        {error, nil} ->
            Monitor = gleam@erlang@process:monitor_process(Pid),
            Selector = select_process_down(
                erlang:element(5, State),
                Pid,
                Monitor
            ),
            {some, Selector}
    end.

-spec handle_message(message(HLB, HLC), state(HLB, HLC)) -> gleam@otp@actor:next(message(HLB, HLC), state(HLB, HLC)).
handle_message(Message, State) ->
    case Message of
        {tag, Client, Name} ->
            Result = gleam@dict:get(erlang:element(3, State), Name),
            gleam@erlang@process:send(Client, Result),
            gleam@otp@actor:continue(State);

        {registrant, Subject, Name@1} ->
            Pid = gleam@erlang@process:subject_owner(Subject),
            Selection = monitor(State, Pid),
            _pipe = State,
            _pipe@1 = into_names(_pipe, Name@1, Subject),
            _pipe@2 = into_tracker(_pipe@1, Pid, Name@1),
            _pipe@3 = into_selector(_pipe@2, Selection),
            {continue, _pipe@3, Selection};

        {demonitor, {index, Pid@1, Monitor}} ->
            gleam_erlang_ffi:demonitor(Monitor),
            _pipe@4 = State,
            _pipe@5 = remove_from_group(_pipe@4, Pid@1),
            _pipe@6 = remove_from_tracker(_pipe@5, Pid@1),
            gleam@otp@actor:continue(_pipe@6)
    end.

-spec start() -> {ok, gleam@erlang@process:subject(message(any(), any()))} |
    {error, gleam@otp@actor:start_error()}.
start() ->
    gleam@otp@actor:start_spec(
        {spec, fun handle_init/0, 10, fun handle_message/2}
    ).