-module(telega@message).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([decode/1]).
-export_type([message_kind/0, message/0]).

-type message_kind() :: common_message | command_message | text_message.

-type message() :: {message, message_kind(), telega@models@message:message()}.

-spec is_command_message(binary(), telega@models@message:message()) -> boolean().
is_command_message(Text, Raw_message) ->
    gleam@bool:guard(
        not gleam@string:starts_with(Text, <<"/"/utf8>>),
        false,
        fun() -> case erlang:element(18, Raw_message) of
                none ->
                    false;

                {some, Entities} ->
                    Is_command_entity = fun(Entity) ->
                        ((erlang:element(2, Entity) =:= <<"bot_command"/utf8>>)
                        andalso (erlang:element(3, Entity) =:= 0))
                        andalso (erlang:element(4, Entity) =:= gleam@string:length(
                            Text
                        ))
                    end,
                    gleam@list:any(Entities, Is_command_entity)
            end end
    ).

-spec raw_message_to_message(telega@models@message:message()) -> message().
raw_message_to_message(Raw_message) ->
    case erlang:element(17, Raw_message) of
        none ->
            {message, common_message, Raw_message};

        {some, Text} ->
            case is_command_message(Text, Raw_message) of
                true ->
                    {message, command_message, Raw_message};

                false ->
                    {message, text_message, Raw_message}
            end
    end.

-spec decode(gleam@dynamic:dynamic_()) -> {ok, message()} |
    {error, list(gleam@dynamic:decode_error())}.
decode(Json) ->
    gleam@result:'try'(
        telega@models@update:decode(Json),
        fun(Update) ->
            {ok, raw_message_to_message(erlang:element(2, Update))}
        end
    ).