//@ts-check

import withResolvers from '@webreflection/utils/with-resolvers';

/**
 * @template V
 * @callback Resolve
 * @param {V?} [value]
 * @returns {void}
 */

/**
 * @callback Reject
 * @param {any?} [error]
 * @returns {void}
 */

/**
 * @template V
 * @typedef {object} Resolvers
 * @prop {Promise<V>} promise
 * @prop {Resolve<V>} resolve
 * @prop {Reject} reject
 */

/**
 * @template K,V
 * @typedef {() => [K, Promise<V>]} Next
 */

/**
 * @template K,V
 * @callback Resolver
 * @param {K} uid
 * @param {V?} [value]
 * @param {any?} [error]
 */

/**
 * @template K,V
 * @typedef {[Next<K,V>, Resolver<K,V>]} NextResolver
 */

/**
 * @template K,V
 * @param {(id: number) => K} [as]
 * @returns
 */
export default (as = (id => /** @type {K} */(id))) => {
  /** @type {Map<K,Resolvers<V>>} */
  const map = new Map;
  let id = 0;
  return /** @type {NextResolver<K,V>} */([
    /** @type {Next<K,V>} */
    () => {
      let uid;
      do { uid = as(id++) }
      while (map.has(uid));
      const wr = /** @type {Resolvers<V>} */(/** @type {unknown} */(withResolvers()));
      map.set(uid, wr);
      return [uid, wr.promise];
    },
    /** @type {Resolver<K,V>} */
    (uid, value, error) => {
      const wr = map.get(uid);
      map.delete(uid);
      if (error) wr?.reject(error);
      else wr?.resolve(value);
    },
  ]);
};