<?php

declare(strict_types=1);

namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Reads from multiple streams, one after the other.
 *
 * This is a read-only stream decorator.
 */
final class AppendStream implements StreamInterface
{
    /** @var StreamInterface[] Streams being decorated */
    private $streams = [];

    /** @var bool */
    private $seekable = true;

    /** @var int */
    private $current = 0;

    /** @var int */
    private $pos = 0;

    /**
     * @param StreamInterface[] $streams Streams to decorate. Each stream must
     *                                   be readable.
     */
    public function __construct(array $streams = [])
    {
        foreach ($streams as $stream) {
            $this->addStream($stream);
        }
    }

    public function __toString(): string
    {
        try {
            $this->rewind();

            return $this->getContents();
        } catch (\Throwable $e) {
            if (\PHP_VERSION_ID >= 70400) {
                throw $e;
            }
            trigger_error(sprintf('%s::__toString exception: %s', self::class, (string) $e), E_USER_ERROR);

            return '';
        }
    }

    /**
     * Add a stream to the AppendStream
     *
     * @param StreamInterface $stream Stream to append. Must be readable.
     *
     * @throws \InvalidArgumentException if the stream is not readable
     */
    public function addStream(StreamInterface $stream): void
    {
        if (!$stream->isReadable()) {
            throw new \InvalidArgumentException('Each stream must be readable');
        }

        // The stream is only seekable if all streams are seekable
        if (!$stream->isSeekable()) {
            $this->seekable = false;
        }

        $this->streams[] = $stream;
    }

    public function getContents(): string
    {
        return Utils::copyToString($this);
    }

    /**
     * Closes each attached stream.
     */
    public function close(): void
    {
        $this->pos = $this->current = 0;
        $this->seekable = true;

        foreach ($this->streams as $stream) {
            $stream->close();
        }

        $this->streams = [];
    }

    /**
     * Detaches each attached stream.
     *
     * Returns null as it's not clear which underlying stream resource to return.
     */
    public function detach()
    {
        $this->pos = $this->current = 0;
        $this->seekable = true;

        foreach ($this->streams as $stream) {
            $stream->detach();
        }

        $this->streams = [];

        return null;
    }

    public function tell(): int
    {
        return $this->pos;
    }

    /**
     * Tries to calculate the size by adding the size of each stream.
     *
     * If any of the streams do not return a valid number, then the size of the
     * append stream cannot be determined and null is returned.
     */
    public function getSize(): ?int
    {
        $size = 0;

        foreach ($this->streams as $stream) {
            $s = $stream->getSize();
            if ($s === null) {
                return null;
            }
            $size += $s;
        }

        return $size;
    }

    public function eof(): bool
    {
        return !$this->streams
            || ($this->current >= count($this->streams) - 1
             && $this->streams[$this->current]->eof());
    }

    public function rewind(): void
    {
        $this->seek(0);
    }

    /**
     * Attempts to seek to the given position. Only supports SEEK_SET.
     */
    public function seek($offset, $whence = SEEK_SET): void
    {
        if (!$this->seekable) {
            throw new \RuntimeException('This AppendStream is not seekable');
        } elseif ($whence !== SEEK_SET) {
            throw new \RuntimeException('The AppendStream can only seek with SEEK_SET');
        }

        $this->pos = $this->current = 0;

        // Rewind each stream
        foreach ($this->streams as $i => $stream) {
            try {
                $stream->rewind();
            } catch (\Exception $e) {
                throw new \RuntimeException('Unable to seek stream '
                    .$i.' of the AppendStream', 0, $e);
            }
        }

        // Seek to the actual position by reading from each stream
        while ($this->pos < $offset && !$this->eof()) {
            $result = $this->read(min(8096, $offset - $this->pos));
            if ($result === '') {
                break;
            }
        }
    }

    /**
     * Reads from all of the appended streams until the length is met or EOF.
     */
    public function read($length): string
    {
        $buffer = '';
        $total = count($this->streams) - 1;
        $remaining = $length;
        $progressToNext = false;

        while ($remaining > 0) {
            // Progress to the next stream if needed.
            if ($progressToNext || $this->streams[$this->current]->eof()) {
                $progressToNext = false;
                if ($this->current === $total) {
                    break;
                }
                ++$this->current;
            }

            $result = $this->streams[$this->current]->read($remaining);

            if ($result === '') {
                $progressToNext = true;
                continue;
            }

            $buffer .= $result;
            $remaining = $length - strlen($buffer);
        }

        $this->pos += strlen($buffer);

        return $buffer;
    }

    public function isReadable(): bool
    {
        return true;
    }

    public function isWritable(): bool
    {
        return false;
    }

    public function isSeekable(): bool
    {
        return $this->seekable;
    }

    public function write($string): int
    {
        throw new \RuntimeException('Cannot write to an AppendStream');
    }

    /**
     * @return mixed
     */
    public function getMetadata($key = null)
    {
        return $key ? null : [];
    }
}

• [D] Exception
• [F] AppendStream.php
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• [F] BufferStream.php
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• [F] CachingStream.php
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• [F] DroppingStream.php
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• [F] FnStream.php
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• [F] Header.php
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• [F] HttpFactory.php
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• [F] InflateStream.php
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• [F] LazyOpenStream.php
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• [F] LimitStream.php
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• [F] Message.php
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• [F] MessageTrait.php
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• [F] MimeType.php
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• [F] MultipartStream.php
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• [F] NoSeekStream.php
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• [F] PumpStream.php
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• [F] Query.php
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• [F] Request.php
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• [F] Response.php
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• [F] Rfc7230.php
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• [F] ServerRequest.php
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• [F] Stream.php
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• [F] StreamDecoratorTrait.php
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• [F] StreamWrapper.php
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• [F] UploadedFile.php
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• [F] Uri.php
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• [F] UriComparator.php
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• [F] UriNormalizer.php
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• [F] UriResolver.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