import gleam/bit_array

pub fn decode(input: String) -> Result(BitArray, Nil) {
  case is_valid(input) {
    True -> bit_array.base64_url_decode(input)
    False -> Error(Nil)
  }
}

@external(erlang, "ywt_core_ffi", "is_base64url_unpadded")
@external(javascript, "../../ywt_core_ffi.mjs", "is_base64url_unpadded")
pub fn is_valid(input: String) -> Bool