import ffi from "@inigolabs/ffi-napi";

const knl32 = ffi.Library("kernel32.dll", {
  GetLastError: ["uint32", []],
  FormatMessageW: [
    "uint",
    ["uint", "pointer", "uint", "uint", "pointer", "uint", "pointer"],
  ],
});

export default function getLastErrMsg() {
  const errcode = knl32.GetLastError();
  let errMsg = "";

  if (errcode) {
    const len = 255;
    const buf = Buffer.alloc(len);
    // eslint-disable-next-line no-bitwise
    const p = 0x00001000 | 0x00000200; // FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS
    const langid = 0x0409; // 0x0409: US, 0x0000: Neutral locale language
    const msglen = knl32.FormatMessageW(
      p,
      null,
      errcode,
      langid,
      buf,
      len,
      null
    );
    errMsg = msglen
      ? `${errcode}: ${buf.toString("ucs2")}`
      : `${errcode}: unknown error message`;
  }

  return errMsg;
}