-module(string_width_ffi).
-export([ansi_re/0, scan_poslen/2, fold_codepoints/3, utf_codepoint_to_string/1]).
-on_load(load/0).

load() ->
    {ok, AnsiRe} = re:compile("[\x1B\x9B][[\\]()#;?]*(?:(?:(?:(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]+)*|[a-zA-Z\\d]+(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*)?(?:\x07|\x1B\x5C|\x9C))|(?:(?:\\d{1,4}(?:;\\d{0,4})*)?[\\dA-PR-TZcf-nq-uy=><~]))", [multiline]),
    ok = persistent_term:put({?MODULE, ansi_re}, AnsiRe),
    ok.

ansi_re() ->
    persistent_term:get({?MODULE, ansi_re}).

scan_poslen(Re, Str) ->
    case re:run(Str, Re, [global]) of
        nomatch -> [];
        {match, Matches} -> [Match || [Match] <- Matches]
    end.

fold_codepoints(Binary, State, Fun) ->
    case Binary of
        <<Cp/utf8, Rest/binary>> -> fold_codepoints(Rest, Fun(State, Cp), Fun);
        _ -> State
    end.

utf_codepoint_to_string(Cp) ->
    <<Cp/utf8>>.