import util from 'util';
const promiseDebugging = util.debuglog('promises').enabled;
const danglingPromise = new FinalizationRegistry((stack) => {
  danglingStacks.delete(stack);
  console.log(stack);
});
const danglingStacks = new Set();
const stackCache = new WeakMap();
/**
 * @template T
 * @param {TemplateStringsArray} uniqLocation 
 * @param {Promise<T>} promise 
 * @returns {Promise<T>}
 */
function mustAwait(uniqLocation, promise) {
  if (!promiseDebugging) return promise;
  let stack = stackCache.get(uniqLocation);
  if (!stack) {
    stack = new Error('dangling promise').stack;
    stackCache.set(uniqLocation, stack);
  }
  try {
    danglingPromise.register(promise, stack);
    danglingStacks.add(stack);
  } catch {
    return promise;
  }
  const proxy = new Proxy(promise, {
    get(target, prop, receiver) {
      if (prop === 'then' || prop === 'catch' || prop === 'finally') {
        const real = Reflect.get(target, prop, receiver);
        return function () {
          let recv = this;
          if (this === proxy) {
            danglingPromise.unregister(promise);
            danglingStacks.delete(stack);
            recv = promise;
          }
          return Reflect.apply(real, recv, arguments);
        };
      } else {
        console.log(new Error('attempted to do something prior to awaiting Promise').stack);
      }
      return Reflect.get(target, prop, receiver);
    }
  });
  return proxy;
}
process.on('exit', () => {
  for (const stack of danglingStacks) {
    console.log(stack);
  }
})
let one = Promise.resolve(1);
let tracker = mustAwait`${one}`;
let { x } = tracker;