esun3d/app/code/Esun/Cart/Model/ShippingEstimate.php

<?php
declare(strict_types=1);

namespace Esun\Cart\Model;

use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Framework\Pricing\PriceCurrencyInterface;
use Magento\Quote\Model\Quote;
use Magento\Quote\Model\Quote\Item\AbstractItem;
use Magento\SalesRule\Model\ResourceModel\Rule\CollectionFactory as RuleCollectionFactory;
use Magento\Store\Model\ScopeInterface;

class ShippingEstimate
{
    private const XML_PATH_FLATRATE_ACTIVE = 'carriers/flatrate/active';
    private const XML_PATH_FLATRATE_PRICE = 'carriers/flatrate/price';
    private const XML_PATH_FLATRATE_TITLE = 'carriers/flatrate/title';
    private const XML_PATH_FLATRATE_NAME = 'carriers/flatrate/name';

    public function __construct(
        private readonly ScopeConfigInterface $scopeConfig,
        private readonly PriceCurrencyInterface $priceCurrency,
        private readonly RuleCollectionFactory $ruleCollectionFactory
    ) {
    }

    public function getData(Quote $quote): array
    {
        $storeId = (int)$quote->getStoreId();
        $available = $this->hasPhysicalItems($quote)
            && $this->scopeConfig->isSetFlag(
                self::XML_PATH_FLATRATE_ACTIVE,
                ScopeInterface::SCOPE_STORE,
                $storeId
            );
        $freeShipping = $available && $this->isFreeShipping($quote);
        $baseAmount = $available && !$freeShipping
            ? (float)$this->scopeConfig->getValue(
                self::XML_PATH_FLATRATE_PRICE,
                ScopeInterface::SCOPE_STORE,
                $storeId
            )
            : 0.0;
        $amount = $available
            ? (float)$this->priceCurrency->convertAndRound($baseAmount, $quote->getStore())
            : 0.0;

        return [
            'available' => $available,
            'free_shipping' => $freeShipping,
            'quantity' => $this->getPhysicalQuantity($quote),
            'base_amount' => $baseAmount,
            'amount' => $amount,
            'description' => $available ? $this->getDescription($storeId, $freeShipping) : '',
        ];
    }

    public function isFreeShipping(Quote $quote): bool
    {
        if (!$this->hasPhysicalItems($quote) || !$quote->getStoreId()) {
            return false;
        }

        $address = clone $quote->getShippingAddress();
        $address->setTotalQty($this->getPhysicalQuantity($quote))
            ->setSubtotal((float)$quote->getSubtotal())
            ->setBaseSubtotal((float)$quote->getBaseSubtotal());

        $collection = $this->ruleCollectionFactory->create();
        $collection->setValidationFilter(
            (int)$quote->getStore()->getWebsiteId(),
            (int)$quote->getCustomerGroupId(),
            (string)$quote->getCouponCode(),
            null,
            $address
        );

        foreach ($collection as $rule) {
            if ((int)$rule->getSimpleFreeShipping() > 0
                && $rule->getConditions()->validate($address)
            ) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param AbstractItem[] $items
     */
    public function isFreeShippingForItems(array $items): bool
    {
        foreach ($items as $item) {
            $quote = $item->getQuote();
            if ($quote instanceof Quote) {
                return $this->isFreeShipping($quote);
            }

            $addressQuote = $item->getAddress()?->getQuote();
            if ($addressQuote instanceof Quote) {
                return $this->isFreeShipping($addressQuote);
            }
        }

        return false;
    }

    private function hasPhysicalItems(Quote $quote): bool
    {
        return $this->getPhysicalQuantity($quote) > 0;
    }

    private function getPhysicalQuantity(Quote $quote): float
    {
        $quantity = 0.0;
        foreach ($quote->getAllVisibleItems() as $item) {
            if ($item->getProduct()->isVirtual()) {
                continue;
            }
            $quantity += (float)$item->getQty();
        }

        return $quantity;
    }

    private function getDescription(int $storeId, bool $freeShipping): string
    {
        if ($freeShipping) {
            return (string)__('Free Shipping');
        }

        $title = (string)$this->scopeConfig->getValue(
            self::XML_PATH_FLATRATE_TITLE,
            ScopeInterface::SCOPE_STORE,
            $storeId
        );
        $name = (string)$this->scopeConfig->getValue(
            self::XML_PATH_FLATRATE_NAME,
            ScopeInterface::SCOPE_STORE,
            $storeId
        );

        return trim($title . ($title !== '' && $name !== '' ? ' - ' : '') . $name);
    }
}