envie

-module(envie_ffi).
-export([get_env/1, set_env/2, unset_env/1, all_env/0, read_file/1, rescue/1]).

get_env(Name) when is_binary(Name) ->
    case os:getenv(binary_to_list(Name)) of
        false -> {error, nil};
        Value -> {ok, list_to_binary(Value)}
    end.

set_env(Name, Value) when is_binary(Name), is_binary(Value) ->
    os:putenv(binary_to_list(Name), binary_to_list(Value)),
    nil.

unset_env(Name) when is_binary(Name) ->
    os:unsetenv(binary_to_list(Name)),
    nil.

all_env() ->
    Env = os:getenv(),
    lists:foldl(
        fun(Entry, Acc) ->
            case string:split(Entry, "=", leading) of
                [Key, Value] ->
                    maps:put(list_to_binary(Key), list_to_binary(Value), Acc);
                [Key] ->
                    maps:put(list_to_binary(Key), <<>>, Acc);
                _ ->
                    Acc
            end
        end,
        #{},
        Env
    ).

read_file(Path) when is_binary(Path) ->
    case file:read_file(Path) of
        {ok, Content} -> {ok, Content};
        {error, _} -> {error, nil}
    end.

rescue(Fn) ->
    try
        {ok, Fn()}
    catch
        Class:Reason:Stacktrace ->
            Msg = io_lib:format("~p:~p at ~p", [Class, Reason, Stacktrace]),
            {error, list_to_binary(lists:flatten(Msg))}
    end.