magento2/app/code/Magento/Sales/Model/EmailSenderHandler.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Sales\Model;

use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Framework\App\Config\ValueFactory;
use Magento\Framework\App\Config\ValueInterface;
use Magento\Framework\App\ObjectManager;
use Magento\Sales\Model\Order\Email\Container\IdentityInterface;
use Magento\Sales\Model\Order\Email\Sender;
use Magento\Sales\Model\ResourceModel\Collection\AbstractCollection;
use Magento\Sales\Model\ResourceModel\EntityAbstract;
use Magento\Store\Model\StoreManagerInterface;

/**
 * Sales emails sending
 *
 * Performs handling of cron jobs related to sending emails to customers
 * after creation/modification of Order, Invoice, Shipment or Creditmemo.
 */
class EmailSenderHandler
{
    /**
     * Configuration path for defining asynchronous email sending attempts
     */
    public const XML_PATH_ASYNC_SENDING_ATTEMPTS = 'sales_email/general/async_sending_attempts';

    /**
     * Email sender model.
     *
     * @var Sender
     */
    protected $emailSender;

    /**
     * Entity resource model.
     *
     * @var EntityAbstract
     */
    protected $entityResource;

    /**
     * Entity collection model.
     *
     * @var AbstractCollection
     */
    protected $entityCollection;

    /**
     * Global configuration storage.
     *
     * @var ScopeConfigInterface
     */
    protected $globalConfig;

    /**
     * @var IdentityInterface
     */
    private $identityContainer;

    /**
     * @var StoreManagerInterface
     */
    private $storeManager;

    /**
     * Config data factory
     *
     * @var ValueFactory
     */
    private $configValueFactory;

    /**
     * @var string
     */
    private $modifyStartFromDate;

    /**
     * @param Sender $emailSender
     * @param EntityAbstract $entityResource
     * @param AbstractCollection $entityCollection
     * @param ScopeConfigInterface $globalConfig
     * @param IdentityInterface|null $identityContainer
     * @param StoreManagerInterface|null $storeManager
     * @param ValueFactory|null $configValueFactory
     * @param string|null $modifyStartFromDate
     */
    public function __construct(
        Sender $emailSender,
        EntityAbstract $entityResource,
        AbstractCollection $entityCollection,
        ScopeConfigInterface $globalConfig,
        IdentityInterface $identityContainer = null,
        StoreManagerInterface $storeManager = null,
        ?ValueFactory $configValueFactory = null,
        ?string $modifyStartFromDate = null,
    ) {
        $this->emailSender = $emailSender;
        $this->entityResource = $entityResource;
        $this->entityCollection = $entityCollection;
        $this->globalConfig = $globalConfig;

        $this->identityContainer = $identityContainer ?: ObjectManager::getInstance()
            ->get(\Magento\Sales\Model\Order\Email\Container\NullIdentity::class);
        $this->storeManager = $storeManager ?: ObjectManager::getInstance()
            ->get(StoreManagerInterface::class);

        $this->configValueFactory = $configValueFactory ?: ObjectManager::getInstance()->get(ValueFactory::class);
        $this->modifyStartFromDate = $modifyStartFromDate ?: $this->modifyStartFromDate;
    }

    /**
     * Handles asynchronous email sending
     *
     * @return void
     */
    public function sendEmails()
    {
        if ($this->globalConfig->getValue('sales_email/general/async_sending')) {
            $this->entityCollection->addFieldToFilter('send_email', ['eq' => 1]);
            $this->entityCollection->addFieldToFilter(
                'email_sent',
                [
                    ['null' => true],
                    ['lteq' => -1]
                ]
            );
            $this->filterCollectionByStartFromDate($this->entityCollection);
            $this->entityCollection->setPageSize(
                $this->globalConfig->getValue('sales_email/general/sending_limit')
            );

            /** @var \Magento\Store\Api\Data\StoreInterface[] $stores */
            $stores = $this->getStores(clone $this->entityCollection);

            $maxSendAttempts = $this->globalConfig->getValue(self::XML_PATH_ASYNC_SENDING_ATTEMPTS);

            /** @var \Magento\Store\Model\Store $store */
            foreach ($stores as $store) {
                $this->identityContainer->setStore($store);
                if (!$this->identityContainer->isEnabled()) {
                    continue;
                }
                $entityCollection = clone $this->entityCollection;
                $entityCollection->addFieldToFilter('store_id', $store->getId());

                /** @var \Magento\Sales\Model\AbstractModel $item */
                foreach ($entityCollection->getItems() as $item) {
                    $sendAttempts = $item->getEmailSent() ?? -$maxSendAttempts;
                    $isEmailSent = $this->emailSender->send($item, true);

                    if ($isEmailSent) {
                        $sendAttempts = 1;
                    } else {
                        $sendAttempts++;
                    }

                    $this->entityResource->saveAttribute(
                        $item->setEmailSent($sendAttempts),
                        'email_sent'
                    );
                }
            }
        }
    }

    /**
     * Get stores for given entities.
     *
     * @param ResourceModel\Collection\AbstractCollection $entityCollection
     * @return \Magento\Store\Api\Data\StoreInterface[]
     * @throws \Magento\Framework\Exception\NoSuchEntityException
     */
    private function getStores(
        AbstractCollection $entityCollection
    ): array {
        $stores = [];

        $entityCollection->addAttributeToSelect('store_id')->getSelect()->group('store_id');
        /** @var \Magento\Sales\Model\EntityInterface $item */
        foreach ($entityCollection->getItems() as $item) {
            /** @var StoreManagerInterface $store */
            $store = $this->storeManager->getStore($item->getStoreId());
            $stores[$item->getStoreId()] = $store;
        }

        return $stores;
    }

    /**
     * Filter collection by start from date
     *
     * @param AbstractCollection $collection
     * @return void
     */
    private function filterCollectionByStartFromDate(AbstractCollection $collection): void
    {
        /** @var $configValue ValueInterface */
        $configValue = $this->configValueFactory->create();
        $configValue->load('sales_email/general/async_sending', 'path');

        if ($configValue->getId()) {
            $startFromDate = date(
                'Y-m-d H:i:s',
                strtotime($configValue->getUpdatedAt() . ' ' . $this->modifyStartFromDate)
            );

            $collection->addFieldToFilter('created_at', ['from' => $startFromDate]);
        }
    }
}