-module(oaspec_ffi).
-export([find_executable/1, run_executable/2, is_stdout_tty/0, no_color_set/0]).

%% Find an executable on PATH. Returns {ok, Path} or {error, nil}.
-spec find_executable(binary()) -> {ok, binary()} | {error, nil}.
find_executable(Name) ->
    case os:find_executable(binary_to_list(Name)) of
        false -> {error, nil};
        Path -> {ok, list_to_binary(Path)}
    end.

%% Run an executable with arguments. Returns the exit code as an integer.
%% Uses spawn_executable to avoid shell injection.
-spec run_executable(binary(), list(binary())) -> integer().
run_executable(Executable, Args) ->
    Port = open_port(
        {spawn_executable, binary_to_list(Executable)},
        [exit_status, stderr_to_stdout, binary, {args, [binary_to_list(A) || A <- Args]}]
    ),
    collect_exit(Port).

collect_exit(Port) ->
    receive
        {Port, {data, _}} ->
            collect_exit(Port);
        {Port, {exit_status, Code}} ->
            Code
    after 60000 ->
        catch port_close(Port),
        1
    end.

%% Detect whether standard_io is connected to a terminal. io:getopts/1
%% reports a `terminal' flag for interactive sessions; non-TTY (pipe,
%% redirection, escript captured stdout) returns false or omits the key.
-spec is_stdout_tty() -> boolean().
is_stdout_tty() ->
    case io:getopts(standard_io) of
        {ok, Opts} ->
            case lists:keyfind(terminal, 1, Opts) of
                {terminal, true} -> true;
                _ -> false
            end;
        _ -> false
    end.

%% Honor the NO_COLOR convention (https://no-color.org/): an unset or
%% empty value means "do not opt out"; any non-empty value means "no
%% color".
-spec no_color_set() -> boolean().
no_color_set() ->
    case os:getenv("NO_COLOR") of
        false -> false;
        "" -> false;
        _ -> true
    end.