-module(clad@internal@args).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([split_equals/1, do_add_bools/2, add_bools/1]).

-spec is_alpha(binary()) -> boolean().
is_alpha(Character) ->
    _assert_subject = gleam@regex:from_string(<<"^[A-Za-z]"/utf8>>),
    {ok, Re} = case _assert_subject of
        {ok, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"clad/internal/args"/utf8>>,
                        function => <<"is_alpha"/utf8>>,
                        line => 50})
    end,
    gleam@regex:check(Re, Character).

-spec is_name(binary()) -> boolean().
is_name(Input) ->
    case gleam@string:to_graphemes(Input) of
        [<<"-"/utf8>>, <<"-"/utf8>>, Next | _] ->
            is_alpha(Next);

        [<<"-"/utf8>>, Next@1 | _] ->
            is_alpha(Next@1);

        _ ->
            false
    end.

-spec split_equals(list(binary())) -> list(binary()).
split_equals(Arguments) ->
    gleam@list:flat_map(
        Arguments,
        fun(Arg) ->
            gleam@bool:guard(
                not is_name(Arg),
                [Arg],
                fun() -> case gleam@string:split_once(Arg, <<"="/utf8>>) of
                        {ok, {Arg@1, Value}} ->
                            [Arg@1, Value];

                        {error, _} ->
                            [Arg]
                    end end
            )
        end
    ).

-spec one_arg(binary()) -> list(binary()).
one_arg(Arg) ->
    case is_name(Arg) of
        true ->
            [Arg, <<"true"/utf8>>];

        false ->
            [Arg]
    end.

-spec do_add_bools(list(binary()), list(binary())) -> list(binary()).
do_add_bools(Arguments, Acc) ->
    case Arguments of
        [] ->
            Acc;

        [Arg] ->
            lists:append(Acc, one_arg(Arg));

        [First, Second | Rest] ->
            case {is_name(First), is_name(Second)} of
                {true, true} ->
                    do_add_bools(
                        [Second | Rest],
                        lists:append(Acc, [First, <<"true"/utf8>>])
                    );

                {true, false} ->
                    do_add_bools(Rest, lists:append(Acc, [First, Second]));

                {_, _} ->
                    do_add_bools([Second | Rest], Acc)
            end
    end.

-spec add_bools(list(binary())) -> list(binary()).
add_bools(Arguments) ->
    do_add_bools(Arguments, []).