-module(sprocket@context).
-compile([no_auto_import, nowarn_unused_vars]).

-export([new/1, reset_for_render/1, fetch_or_init_hook/2, update_hook/3, push_event_handler/2, get_event_handler/2]).
-export_type([event_handler/0, updater/1, component_wip/0, context/0]).

-type event_handler() :: {event_handler,
        sprocket@internal@utils@unique:unique(),
        sprocket@internal@identifiable_callback:callback_fn()}.

-type updater(JXZ) :: {updater, fun((JXZ) -> {ok, nil} | {error, nil})}.

-type component_wip() :: {component_wip,
        sprocket@internal@utils@ordered_map:ordered_map(integer(), sprocket@hooks:hook()),
        integer(),
        boolean()}.

-type context() :: {context,
        component_wip(),
        list(event_handler()),
        gleam@option:option(gleam@erlang@process:subject(glisten@handler:handler_message())),
        fun(() -> nil),
        fun((sprocket@internal@utils@unique:unique(), fun((sprocket@hooks:hook()) -> sprocket@hooks:hook())) -> nil)}.

-spec new(
    gleam@option:option(gleam@erlang@process:subject(glisten@handler:handler_message()))
) -> context().
new(Ws) ->
    {context,
        {component_wip, sprocket@internal@utils@ordered_map:new(), 0, true},
        [],
        Ws,
        fun() -> nil end,
        fun(_, _) -> nil end}.

-spec reset_for_render(context()) -> context().
reset_for_render(Ctx) ->
    erlang:setelement(3, Ctx, []).

-spec fetch_or_init_hook(context(), fun(() -> sprocket@hooks:hook())) -> {context(),
    sprocket@hooks:hook(),
    integer()}.
fetch_or_init_hook(Ctx, Init) ->
    Index = erlang:element(3, erlang:element(2, Ctx)),
    Hooks = erlang:element(2, erlang:element(2, Ctx)),
    case sprocket@internal@utils@ordered_map:get(Hooks, Index) of
        {ok, Hook} ->
            {erlang:setelement(
                    2,
                    Ctx,
                    erlang:setelement(3, erlang:element(2, Ctx), Index + 1)
                ),
                Hook,
                Index};

        {error, nil} ->
            case erlang:element(4, erlang:element(2, Ctx)) of
                true ->
                    nil;

                false ->
                    sprocket@internal@logger:error(
                        <<<<"
            Hook not found for index: "/utf8,
                                (gleam@int:to_string(Index))/binary>>/binary,
                            ". This indicates a hook was dynamically
            created since first render which is not allowed.
          "/utf8>>
                    ),
                    erlang:error(#{gleam_error => panic,
                            message => <<"panic expression evaluated"/utf8>>,
                            module => <<"sprocket/context"/utf8>>,
                            function => <<"fetch_or_init_hook"/utf8>>,
                            line => 84})
            end,
            Hook@1 = Init(),
            {erlang:setelement(
                    2,
                    Ctx,
                    {component_wip,
                        sprocket@internal@utils@ordered_map:insert(
                            erlang:element(2, erlang:element(2, Ctx)),
                            Index,
                            Hook@1
                        ),
                        Index + 1,
                        erlang:element(4, erlang:element(2, Ctx))}
                ),
                Hook@1,
                Index}
    end.

-spec update_hook(context(), sprocket@hooks:hook(), integer()) -> context().
update_hook(Ctx, Hook, Index) ->
    erlang:setelement(
        2,
        Ctx,
        erlang:setelement(
            2,
            erlang:element(2, Ctx),
            sprocket@internal@utils@ordered_map:update(
                erlang:element(2, erlang:element(2, Ctx)),
                Index,
                Hook
            )
        )
    ).

-spec push_event_handler(
    context(),
    sprocket@internal@identifiable_callback:identifiable_callback()
) -> {context(), sprocket@internal@utils@unique:unique()}.
push_event_handler(Ctx, Identifiable_cb) ->
    {identifiable_callback, Id, Cb} = Identifiable_cb,
    {erlang:setelement(
            3,
            Ctx,
            [{event_handler, Id, Cb} | erlang:element(3, Ctx)]
        ),
        Id}.

-spec get_event_handler(context(), sprocket@internal@utils@unique:unique()) -> {context(),
    {ok, event_handler()} | {error, nil}}.
get_event_handler(Ctx, Id) ->
    Handler = gleam@list:find(
        erlang:element(3, Ctx),
        fun(H) ->
            {event_handler, I, _} = H,
            I =:= Id
        end
    ),
    {Ctx, Handler}.