-module(parse).
-compile(no_auto_import).

-export([int/1, valid_int/3, day/1, days/1]).

-spec int(binary()) -> {ok, integer()} | {error, snag:snag()}.
int(S) ->
    _pipe = S,
    _pipe@1 = gleam@int:parse(_pipe),
    gleam@result:replace_error(
        _pipe@1,
        begin
            _pipe@2 = [<<"failed to parse \""/utf8>>, S, <<"\" as int"/utf8>>],
            _pipe@3 = gleam@string:concat(_pipe@2),
            snag:new(_pipe@3)
        end
    ).

-spec valid_int(binary(), fun((integer()) -> boolean()), binary()) -> {ok,
                                                                       integer()} |
    {error, snag:snag()}.
valid_int(S, Is_valid, Invalid_msg) ->
    case int(S) of
        {error, _try} -> {error, _try};
        {ok, I} ->
            case Is_valid(I) of
                false ->
                    {error, snag:new(Invalid_msg)};

                true ->
                    {ok, I}
            end
    end.

-spec greater_than_0(integer()) -> boolean().
greater_than_0(I) ->
    I > 0.

-spec less_than_26(integer()) -> boolean().
less_than_26(I) ->
    I < 26.

-spec valid_day(integer()) -> boolean().
valid_day(I) ->
    greater_than_0(I) andalso less_than_26(I).

-spec day(binary()) -> {ok, integer()} | {error, snag:snag()}.
day(S) ->
    _pipe = valid_int(
        S,
        fun valid_day/1,
        <<"day must be an integer from 1 to 25"/utf8>>
    ),
    snag:context(
        _pipe,
        gleam@string:concat(
            [<<"invalid day value "/utf8>>, <<"'"/utf8>>, S, <<"'"/utf8>>]
        )
    ).

-spec days(list(binary())) -> {ok, list(integer())} | {error, snag:snag()}.
days(L) ->
    case L of
        [] ->
            {error, snag:new(<<"no days selected"/utf8>>)};

        _@1 ->
            _pipe = L,
            _pipe@1 = gleam@list:try_map(_pipe, fun day/1),
            snag:context(
                _pipe@1,
                <<"could not map day values to integers"/utf8>>
            )
    end.