import type { QuickJSDeferredPromise, QuickJSHandle, QuickJSContext } from "quickjs-emscripten";

export default function marshalPromise(
  ctx: QuickJSContext,
  target: unknown,
  marshal: (target: unknown) => QuickJSHandle,
  preMarshal: (target: unknown, handle: QuickJSDeferredPromise) => QuickJSHandle | undefined,
) {
  if (!(target instanceof Promise)) return;

  const promise = ctx.newPromise();

  promise.settled.then(ctx.runtime.executePendingJobs);

  target.then(
    d => promise.resolve(marshal(d)),
    d => promise.reject(marshal(d)),
  );

  return preMarshal(target, promise) ?? promise.handle;
}