-module(pf_route_util).
-export([module/0, parse_ip_address_with_netmask/1]).
-export([read_bitmask/2]).

read_bitmask(List, Integer) ->
    read_bitmask(List, Integer, []).

read_bitmask([{V, Name} | Rest], I, Acc) ->
    if
        (I band V) =:= V ->
            read_bitmask(Rest, I, [Name | Acc]);
        true ->
            read_bitmask(Rest, I, Acc)
    end;
read_bitmask([], _, Acc) ->
    lists:reverse(Acc).

module() ->
    case os:type() of
        {unix, linux} ->
            {ok, pf_route_linux};
        {unix, darwin} ->
            {ok, pf_route_macos};
        {unix, freebsd} ->
            {ok, pf_route_freebsd};
        unsupported ->
            {error, {unsupported_platform, unsupported}}
    end.

-spec parse_ip_address_with_netmask(string()) -> {inet:ip_address(), non_neg_integer()}.
parse_ip_address_with_netmask(S) ->
    logger:warning("IPNets ~p", [S]),
    case re:split(S, "/", [{return, list}, {parts, 2}]) of
        [Prefix, LenStr] ->
            {Prefix1, Scope} = ipv6_scope(Prefix),
            {ok, Addr} = inet:parse_address(Prefix1),
            {PrefixLen, _} = string:to_integer(LenStr),
            {Addr, Scope, PrefixLen};
        [Prefix] ->
            {Prefix1, Scope} = ipv6_scope(Prefix),
            {ok, Addr} = inet:parse_address(Prefix1),
            PrefixLen = case inet_cidr:is_ipv6(Addr) of
                            true -> 128;
                            false -> 32
                        end,
            {Addr, Scope, PrefixLen}
    end.

ipv6_scope(Addr) ->
    case re:split(Addr, "%", [{return, list}, {parts, 2}]) of
        [IP, Scope] ->
            {IP, Scope};
        [IP] ->
            {IP, undefined}
    end.