class Each

final class Each {
    
    /**
     * Given an iterator that yields promises or values, returns a promise that
     * is fulfilled with a null value when the iterator has been consumed or
     * the aggregate promise has been fulfilled or rejected.
     *
     * $onFulfilled is a function that accepts the fulfilled value, iterator
     * index, and the aggregate promise. The callback can invoke any necessary
     * side effects and choose to resolve or reject the aggregate if needed.
     *
     * $onRejected is a function that accepts the rejection reason, iterator
     * index, and the aggregate promise. The callback can invoke any necessary
     * side effects and choose to resolve or reject the aggregate if needed.
     *
     * @param mixed $iterable Iterator or array to iterate over.
     */
    public static function of($iterable, ?callable $onFulfilled = null, ?callable $onRejected = null) : PromiseInterface {
        return (new EachPromise($iterable, [
            'fulfilled' => $onFulfilled,
            'rejected' => $onRejected,
        ]))->promise();
    }
    
    /**
     * Like of, but only allows a certain number of outstanding promises at any
     * given time.
     *
     * $concurrency may be an integer or a function that accepts the number of
     * pending promises and returns a numeric concurrency limit value to allow
     * for dynamic a concurrency size.
     *
     * @param mixed        $iterable
     * @param int|callable $concurrency
     */
    public static function ofLimit($iterable, $concurrency, ?callable $onFulfilled = null, ?callable $onRejected = null) : PromiseInterface {
        return (new EachPromise($iterable, [
            'fulfilled' => $onFulfilled,
            'rejected' => $onRejected,
            'concurrency' => $concurrency,
        ]))->promise();
    }
    
    /**
     * Like limit, but ensures that no promise in the given $iterable argument
     * is rejected. If any promise is rejected, then the aggregate promise is
     * rejected with the encountered rejection.
     *
     * @param mixed        $iterable
     * @param int|callable $concurrency
     */
    public static function ofLimitAll($iterable, $concurrency, ?callable $onFulfilled = null) : PromiseInterface {
        return self::ofLimit($iterable, $concurrency, $onFulfilled, function ($reason, $idx, PromiseInterface $aggregate) : void {
            $aggregate->reject($reason);
        });
    }

}