// Load tax config if available, otherwise define fallback class
if (file_exists(_PS_CONFIG_DIR_ . 'tax_eu_config.php')) {
require_once(_PS_CONFIG_DIR_ . 'tax_eu_config.php');
} else {
// Fallback class if config file doesn't exist
class TaxEUConfig
{
public static function getVATRate($country_iso) {
return 0.0;
}

public static function isEUCountry($country_iso) {
return false;
}
}
}

class Cart extends CartCore
{
    /**
     * Override getOrderTotal to fix tax calculation for EU customers with BaseLinker integration
     */
    public function getOrderTotal(
        $withTaxes = true,
        $type = Cart::BOTH,
        $products = null,
        $id_carrier = null,
        $use_cache = false,
        bool $keepOrderPrices = false
    )
    {
        // Fix context issue - ensure cart is set in context
        if (!Context::getContext()->cart || Context::getContext()->cart->id != $this->id) {
            Context::getContext()->cart = $this;
        }

        // Fix for BaseLinker VAT EU 0% export issue
        if ($withTaxes && $this->isEUCustomer()) {
            $this->ensureCorrectTaxCalculation();
        }

        try {
            return parent::getOrderTotal($withTaxes, $type, $products, $id_carrier, $use_cache, $keepOrderPrices);
        } catch (Exception $e) {
            // Log error and return 0 to prevent fatal errors
            PrestaShopLogger::addLog(
                'Cart Override: Error calculating order total for cart ID ' . $this->id . ': ' . $e->getMessage(),
                3,
                null,
                'Cart',
                $this->id
            );
            return 0;
        }
    }

    /**
     * Check if customer is from EU
     */
    private function isEUCustomer()
    {
        if (!$this->id_address_delivery) {
            return false;
        }

        $address = new Address($this->id_address_delivery);
        if (!$address->id_country) {
            return false;
        }

        $country = new Country($address->id_country);
        return TaxEUConfig::isEUCountry($country->iso_code);
    }

    /**
     * Ensure correct tax calculation for EU customers
     */
    private function ensureCorrectTaxCalculation()
    {
        // Force tax calculation method for EU customers
        $this->setTaxCalculationMethod();

        // Apply correct VAT rates for EU countries
        $address = new Address($this->id_address_delivery);
        $country = new Country($address->id_country);

        $vat_rate = TaxEUConfig::getVATRate($country->iso_code);
        if ($vat_rate > 0) {
            Context::getContext()->cookie->__set('customer_vat_rate', $vat_rate);
        }
    }

    /**
     * Override getAverageProductsTaxRate to ensure correct tax calculation
     */
    public function getAverageProductsTaxRate(&$cartAmountTaxExcluded = null, &$cartAmountTaxIncluded = null)
    {
        // Fix context issue
        if (!Context::getContext()->cart || Context::getContext()->cart->id != $this->id) {
            Context::getContext()->cart = $this;
        }

        // If we have a stored VAT rate for EU customer, use it
        if ($this->isEUCustomer() && isset(Context::getContext()->cookie->customer_vat_rate)) {
            $vat_rate = (float)Context::getContext()->cookie->customer_vat_rate;

            try {
                $cartAmountTaxExcluded = $this->getOrderTotal(false, Cart::ONLY_PRODUCTS);
                $cartAmountTaxIncluded = $cartAmountTaxExcluded * (1 + ($vat_rate / 100));

                return $vat_rate / 100;
            } catch (Exception $e) {
                // Log error and fall back to parent method
                PrestaShopLogger::addLog(
                    'Cart Override: Error in getAverageProductsTaxRate for cart ID ' . $this->id . ': ' . $e->getMessage(),
                    3,
                    null,
                    'Cart',
                    $this->id
                );
                return parent::getAverageProductsTaxRate($cartAmountTaxExcluded, $cartAmountTaxIncluded);
            }
        }

        return parent::getAverageProductsTaxRate($cartAmountTaxExcluded, $cartAmountTaxIncluded);
    }
}
<br />
<b>Fatal error</b>:  Uncaught Error: Class 'Cart' not found in /home/tsgduwfxmk/domains/tsgduwfxmk.cfolks.pl/public_html/classes/controller/FrontController.php:467
Stack trace:
#0 /home/tsgduwfxmk/domains/tsgduwfxmk.cfolks.pl/public_html/controllers/front/listing/CategoryController.php(81): FrontControllerCore-&gt;init()
#1 /home/tsgduwfxmk/domains/tsgduwfxmk.cfolks.pl/public_html/classes/controller/Controller.php(300): CategoryControllerCore-&gt;init()
#2 /home/tsgduwfxmk/domains/tsgduwfxmk.cfolks.pl/public_html/classes/Dispatcher.php(510): ControllerCore-&gt;run()
#3 /home/tsgduwfxmk/domains/tsgduwfxmk.cfolks.pl/public_html/index.php(28): DispatcherCore-&gt;dispatch()
#4 {main}
  thrown in <b>/home/tsgduwfxmk/domains/tsgduwfxmk.cfolks.pl/public_html/classes/controller/FrontController.php</b> on line <b>467</b><br />