<?php

declare(strict_types=1);

namespace GuzzleHttp\Promise;

use Generator;
use Throwable;

/**
 * Creates a promise that is resolved using a generator that yields values or
 * promises (somewhat similar to C#'s async keyword).
 *
 * When called, the Coroutine::of method will start an instance of the generator
 * and returns a promise that is fulfilled with its final yielded value.
 *
 * Control is returned back to the generator when the yielded promise settles.
 * This can lead to less verbose code when doing lots of sequential async calls
 * with minimal processing in between.
 *
 *     use GuzzleHttp\Promise;
 *
 *     function createPromise($value) {
 *         return new Promise\FulfilledPromise($value);
 *     }
 *
 *     $promise = Promise\Coroutine::of(function () {
 *         $value = (yield createPromise('a'));
 *         try {
 *             $value = (yield createPromise($value . 'b'));
 *         } catch (\Throwable $e) {
 *             // The promise was rejected.
 *         }
 *         yield $value . 'c';
 *     });
 *
 *     // Outputs "abc"
 *     $promise->then(function ($v) { echo $v; });
 *
 * @param callable $generatorFn Generator function to wrap into a promise.
 *
 * @return Promise
 *
 * @see https://github.com/petkaantonov/bluebird/blob/master/API.md#generators inspiration
 */
final class Coroutine implements PromiseInterface
{
    /**
     * @var PromiseInterface|null
     */
    private $currentPromise;

    /**
     * @var Generator
     */
    private $generator;

    /**
     * @var Promise
     */
    private $result;

    public function __construct(callable $generatorFn)
    {
        $this->generator = $generatorFn();
        $this->result = new Promise(function (): void {
            while (isset($this->currentPromise)) {
                $this->currentPromise->wait();
            }
        });
        try {
            $this->nextCoroutine($this->generator->current());
        } catch (Throwable $throwable) {
            $this->result->reject($throwable);
        }
    }

    /**
     * Create a new coroutine.
     */
    public static function of(callable $generatorFn): self
    {
        return new self($generatorFn);
    }

    public function then(
        callable $onFulfilled = null,
        callable $onRejected = null
    ): PromiseInterface {
        return $this->result->then($onFulfilled, $onRejected);
    }

    public function otherwise(callable $onRejected): PromiseInterface
    {
        return $this->result->otherwise($onRejected);
    }

    public function wait(bool $unwrap = true)
    {
        return $this->result->wait($unwrap);
    }

    public function getState(): string
    {
        return $this->result->getState();
    }

    public function resolve($value): void
    {
        $this->result->resolve($value);
    }

    public function reject($reason): void
    {
        $this->result->reject($reason);
    }

    public function cancel(): void
    {
        $this->currentPromise->cancel();
        $this->result->cancel();
    }

    private function nextCoroutine($yielded): void
    {
        $this->currentPromise = Create::promiseFor($yielded)
            ->then([$this, '_handleSuccess'], [$this, '_handleFailure']);
    }

    /**
     * @internal
     */
    public function _handleSuccess($value): void
    {
        unset($this->currentPromise);
        try {
            $next = $this->generator->send($value);
            if ($this->generator->valid()) {
                $this->nextCoroutine($next);
            } else {
                $this->result->resolve($value);
            }
        } catch (Throwable $throwable) {
            $this->result->reject($throwable);
        }
    }

    /**
     * @internal
     */
    public function _handleFailure($reason): void
    {
        unset($this->currentPromise);
        try {
            $nextYield = $this->generator->throw(Create::exceptionFor($reason));
            // The throw was caught, so keep iterating on the coroutine
            $this->nextCoroutine($nextYield);
        } catch (Throwable $throwable) {
            $this->result->reject($throwable);
        }
    }
}

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• [F] CancellationException.php
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• [F] Coroutine.php
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• [F] Create.php
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• [F] Each.php
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• [F] EachPromise.php
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• [F] FulfilledPromise.php
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• [F] Is.php
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• [F] Promise.php
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• [F] PromiseInterface.php
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• [F] PromisorInterface.php
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• [F] RejectedPromise.php
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• [F] RejectionException.php
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• [F] TaskQueue.php
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• [F] TaskQueueInterface.php
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• [F] Utils.php
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About Section

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.

FAQ Section

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.

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