// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import 'dart:async';

import 'package:js/js.dart';
import 'package:js/js_util.dart' as js_util;

/// A [Promise] executor callback.
typedef Executor<T> = void Function(
  void Function(T) resolve,
  void Function(Object) reject,
);

/// {@template aws_common.js.promise}
/// Represents the eventual completion (or failure) of an asynchronous operation
/// and its resulting value.
/// {@endtemplate}
@JS()
@staticInterop
abstract class Promise<T> {
  /// Creates a JS Promise.
  factory Promise(Executor<T> executor) => Promise._(allowInterop(executor));

  external factory Promise._(Executor<T> executor);

  /// Creates a Promise from a Dart [future].
  ///
  /// If [captureError] is `true`, all errors will be caught by the promise
  /// and not reported as unhandled errors in the current [Zone]. This can
  /// decrease the visibility of errors in Dart code depending on the level of
  /// integration with JS APIs and their error-handling specifics.
  factory Promise.fromFuture(
    Future<T> future, {
    bool captureError = false,
  }) =>
      Promise((resolve, reject) async {
        try {
          resolve(await future);
        } on Object catch (e) {
          reject(e);
          if (!captureError) {
            rethrow;
          }
        }
      });
}

/// {@macro aws_common.js.promise}
extension PropsPromise<T> on Promise<T> {
  /// Resolves `this` as a Dart [Future].
  Future<T> get future => js_util.promiseToFuture(this);
}