module promise

pub interface JS.Promise {
	then(onFullfilled JS.Any, onRejected JS.Any)
	catch(onCatch JS.Any) JS.Promise
	finally(callback JS.Any) JS.Promise
}

[use_new]
pub fn JS.Promise.prototype.constructor(JS.Any) JS.Promise
pub fn JS.Promise.reject(JS.Any) JS.Promise
pub fn JS.Promise.resolve(JS.Any) JS.Promise
pub fn JS.Promise.race(JS.Array) JS.Promise

// The Promise object represents the eventual completion (or failure)
// of an asynchronous operation and its resulting value.
pub struct Promise<T, E> {
mut:
	promise JS.Promise [noinit]
}

pub fn new<T, E>(executor fn (resolve fn (T), reject fn (E))) Promise<T, E> {
	promise := JS.Promise.prototype.constructor(executor)
	return Promise<T, E>{promise}
}

pub fn (p Promise<T, E>) then(on_fullfilled fn (T), on_rejected fn (E)) {
	p.promise.then(on_fullfilled, on_rejected)
}

// catch method returns a Promise and deals with rejected cases only.
pub fn (p Promise<T, E>) catch(callback fn (error JS.Any)) Promise<T, E> {
	promise := p.promise.catch(callback)
	return Promise<T, E>{promise}
}

pub fn (p Promise<T, E>) finally(callback fn ()) Promise<int, int> {
	promise := p.promise.finally(callback)
	return Promise<int, int>{promise}
}

// reject<E> returns promise which was rejected because of specified error
pub fn reject<E>(error E) Promise<int, E> {
	promise := JS.Promise.reject(error)
	return Promise<int, E>{promise}
}

// resolve<E> returns promise which was resolved with specified value
pub fn resolve<T>(result T) Promise<T, int> {
	promise := JS.Promise.resolve(error)
	return Promise<T, int>{promise}
}

// race returns returns a promise that fulfills or rejects as soon as one of
//  the promises in an iterable fulfills or rejects, with the value or reason from that promise.
pub fn race<T, E>(promises []Promise<T, E>) Promise<T, E> {
	promises_ := JS.Array.prototype.constructor()

	for elem in promises {
		promises_.push(elem.promise)
	}

	promise := JS.Promise.race(promises_)
	return Promise<T, E>{promise}
}

pub fn JS.Promise.all(JS.Array) JS.Promise
pub fn JS.Promise.allSettled(JS.Array) JS.Promise

/*
// all takes an iterable of promises as an input, and returns a single Promise that resolves to an array of
// the results of the input promises
pub fn all(array []JS.Promise) Promise<JS.Array, JS.Any> {
	mut promise := JS.Promise(JS.Any(voidptr(0)))
	#promise = Promise.all(array.arr.arr);

	return Promise<Array,Any>{promise}
}
*/