Api.php

<?php

namespace Payum\Paypal\Masspay\Nvp;

use Http\Message\MessageFactory;
use Payum\Core\Bridge\Spl\ArrayObject;
use Payum\Core\Exception\Http\HttpException;
use Payum\Core\Exception\InvalidArgumentException;
use Payum\Core\HttpClientInterface;

class Api
{
    public const VERSION = '2.3';

    public const ACK_SUCCESS = 'Success';

    public const ACK_SUCCESS_WITH_WARNING = 'SuccessWithWarning';

    public const ACK_FAILURE = 'Failure';

    public const ACK_FAILURE_WITH_WARNING = 'FailureWithWarning';

    /**
     * @var HttpClientInterface
     */
    protected $client;

    /**
     * @var MessageFactory
     */
    protected $messageFactory;

    /**
     * @var array
     */
    protected $options = [
        'username' => null,
        'password' => null,
        'signature' => null,
    ];

    /**
     * @param HttpClientInterface|null $client
     * @param MessageFactory|null      $messageFactory
     */
    public function __construct(array $options, HttpClientInterface $client, MessageFactory $messageFactory)
    {
        $options = ArrayObject::ensureArrayObject($options);
        $options->defaults($this->options);
        $options->validateNotEmpty([
            'username',
            'password',
            'signature',
        ]);

        if (! is_bool($options['sandbox'])) {
            throw new InvalidArgumentException('The boolean sandbox option must be set.');
        }

        $this->options = $options;
        $this->client = $client;
        $this->messageFactory = $messageFactory;
    }

    /**
     * @return array
     */
    public function massPay(array $fields)
    {
        $fields['METHOD'] = 'MassPay';

        $this->addVersionField($fields);
        $this->addAuthorizeFields($fields);

        return $this->doRequest($fields);
    }

    /**
     * @throws HttpException
     *
     * @return array
     */
    protected function doRequest(array $fields)
    {
        $headers = [
            'Content-Type' => 'application/x-www-form-urlencoded',
        ];

        $request = $this->messageFactory->createRequest('POST', $this->getApiEndpoint(), $headers, http_build_query($fields));

        $response = $this->client->send($request);

        if (! ($response->getStatusCode() >= 200 && $response->getStatusCode() < 300)) {
            throw HttpException::factory($request, $response);
        }

        $result = [];
        parse_str($response->getBody()->getContents(), $result);
        foreach ($result as &$value) {
            $value = urldecode($value);
        }

        return $result;
    }

    /**
     * @return string
     */
    protected function getApiEndpoint()
    {
        return $this->options['sandbox'] ?
            'https://api-3t.sandbox.paypal.com/nvp' :
            'https://api-3t.paypal.com/nvp'
        ;
    }

    protected function addAuthorizeFields(array &$fields): void
    {
        $fields['PWD'] = $this->options['password'];
        $fields['USER'] = $this->options['username'];
        $fields['SIGNATURE'] = $this->options['signature'];
    }

    protected function addVersionField(array &$fields): void
    {
        $fields['VERSION'] = self::VERSION;
    }
}