/home/kueuepay/public_html/vendor/guzzlehttp/promises/src/EachPromise.php
<?php

declare(strict_types=1);

namespace GuzzleHttp\Promise;

/**
 * Represents a promise that iterates over many promises and invokes
 * side-effect functions in the process.
 *
 * @final
 */
class EachPromise implements PromisorInterface
{
    private $pending = [];

    private $nextPendingIndex = 0;

    /** @var \Iterator|null */
    private $iterable;

    /** @var callable|int|null */
    private $concurrency;

    /** @var callable|null */
    private $onFulfilled;

    /** @var callable|null */
    private $onRejected;

    /** @var Promise|null */
    private $aggregate;

    /** @var bool|null */
    private $mutex;

    /**
     * Configuration hash can include the following key value pairs:
     *
     * - fulfilled: (callable) Invoked when a promise fulfills. The function
     *   is invoked with three arguments: the fulfillment value, the index
     *   position from the iterable list of the promise, and the aggregate
     *   promise that manages all of the promises. The aggregate promise may
     *   be resolved from within the callback to short-circuit the promise.
     * - rejected: (callable) Invoked when a promise is rejected. The
     *   function is invoked with three arguments: the rejection reason, the
     *   index position from the iterable list of the promise, and the
     *   aggregate promise that manages all of the promises. The aggregate
     *   promise may be resolved from within the callback to short-circuit
     *   the promise.
     * - concurrency: (integer) Pass this configuration option to limit the
     *   allowed number of outstanding concurrently executing promises,
     *   creating a capped pool of promises. There is no limit by default.
     *
     * @param mixed $iterable Promises or values to iterate.
     * @param array $config   Configuration options
     */
    public function __construct($iterable, array $config = [])
    {
        $this->iterable = Create::iterFor($iterable);

        if (isset($config['concurrency'])) {
            $this->concurrency = $config['concurrency'];
        }

        if (isset($config['fulfilled'])) {
            $this->onFulfilled = $config['fulfilled'];
        }

        if (isset($config['rejected'])) {
            $this->onRejected = $config['rejected'];
        }
    }

    /** @psalm-suppress InvalidNullableReturnType */
    public function promise(): PromiseInterface
    {
        if ($this->aggregate) {
            return $this->aggregate;
        }

        try {
            $this->createPromise();
            /** @psalm-assert Promise $this->aggregate */
            $this->iterable->rewind();
            $this->refillPending();
        } catch (\Throwable $e) {
            $this->aggregate->reject($e);
        }

        /**
         * @psalm-suppress NullableReturnStatement
         */
        return $this->aggregate;
    }

    private function createPromise(): void
    {
        $this->mutex = false;
        $this->aggregate = new Promise(function (): void {
            if ($this->checkIfFinished()) {
                return;
            }
            reset($this->pending);
            // Consume a potentially fluctuating list of promises while
            // ensuring that indexes are maintained (precluding array_shift).
            while ($promise = current($this->pending)) {
                next($this->pending);
                $promise->wait();
                if (Is::settled($this->aggregate)) {
                    return;
                }
            }
        });

        // Clear the references when the promise is resolved.
        $clearFn = function (): void {
            $this->iterable = $this->concurrency = $this->pending = null;
            $this->onFulfilled = $this->onRejected = null;
            $this->nextPendingIndex = 0;
        };

        $this->aggregate->then($clearFn, $clearFn);
    }

    private function refillPending(): void
    {
        if (!$this->concurrency) {
            // Add all pending promises.
            while ($this->addPending() && $this->advanceIterator()) {
            }

            return;
        }

        // Add only up to N pending promises.
        $concurrency = is_callable($this->concurrency)
            ? ($this->concurrency)(count($this->pending))
            : $this->concurrency;
        $concurrency = max($concurrency - count($this->pending), 0);
        // Concurrency may be set to 0 to disallow new promises.
        if (!$concurrency) {
            return;
        }
        // Add the first pending promise.
        $this->addPending();
        // Note this is special handling for concurrency=1 so that we do
        // not advance the iterator after adding the first promise. This
        // helps work around issues with generators that might not have the
        // next value to yield until promise callbacks are called.
        while (--$concurrency
            && $this->advanceIterator()
            && $this->addPending()) {
        }
    }

    private function addPending(): bool
    {
        if (!$this->iterable || !$this->iterable->valid()) {
            return false;
        }

        $promise = Create::promiseFor($this->iterable->current());
        $key = $this->iterable->key();

        // Iterable keys may not be unique, so we use a counter to
        // guarantee uniqueness
        $idx = $this->nextPendingIndex++;

        $this->pending[$idx] = $promise->then(
            function ($value) use ($idx, $key): void {
                if ($this->onFulfilled) {
                    ($this->onFulfilled)(
                        $value,
                        $key,
                        $this->aggregate
                    );
                }
                $this->step($idx);
            },
            function ($reason) use ($idx, $key): void {
                if ($this->onRejected) {
                    ($this->onRejected)(
                        $reason,
                        $key,
                        $this->aggregate
                    );
                }
                $this->step($idx);
            }
        );

        return true;
    }

    private function advanceIterator(): bool
    {
        // Place a lock on the iterator so that we ensure to not recurse,
        // preventing fatal generator errors.
        if ($this->mutex) {
            return false;
        }

        $this->mutex = true;

        try {
            $this->iterable->next();
            $this->mutex = false;

            return true;
        } catch (\Throwable $e) {
            $this->aggregate->reject($e);
            $this->mutex = false;

            return false;
        }
    }

    private function step(int $idx): void
    {
        // If the promise was already resolved, then ignore this step.
        if (Is::settled($this->aggregate)) {
            return;
        }

        unset($this->pending[$idx]);

        // Only refill pending promises if we are not locked, preventing the
        // EachPromise to recursively invoke the provided iterator, which
        // cause a fatal error: "Cannot resume an already running generator"
        if ($this->advanceIterator() && !$this->checkIfFinished()) {
            // Add more pending promises if possible.
            $this->refillPending();
        }
    }

    private function checkIfFinished(): bool
    {
        if (!$this->pending && !$this->iterable->valid()) {
            // Resolve the promise if there's nothing left to do.
            $this->aggregate->resolve(null);

            return true;
        }

        return false;
    }
}
About
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About NFC Pay: Our Story and Mission

NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.

  • Simplifying Payments, One Tap at a Time.
  • Reinventing Your Wallet for Modern Convenience.
  • Smart Payments for a Effortless Lifestyle.
  • Experience the Ease of Tap and Pay.
  • Innovative Solutions for Your Daily Transactions.

Frequently Asked Questions About NFC Pay

Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.

faq-img

How do I register for NFC Pay?

Download the app and sign up using your email or phone number, then complete the verification process.

Is my payment information secure?

Yes, we use advanced encryption and security protocols to protect your payment details.

Can I add multiple cards to my NFC Pay wallet?

Absolutely, you can link multiple debit or credit cards to your wallet.

How do I transfer money to another user?

Go to the transfer section, select the recipient, enter the amount, and authorize the transfer.

What should I do if I forget my PIN?

Use the “Forgot PIN” feature in the app to reset it following the provided instructions.

How can I activate my merchant account?

Sign up for a merchant account through the app and follow the setup instructions to start accepting payments.

Can I track my payment status?

Yes, you can view and track your payment status in the account dashboard