commerce_shipping-8.x-2.0-rc2/src/Plugin/Commerce/PromotionOffer/ShipmentFixedAmountOff.php

<?php

namespace Drupal\commerce_shipping\Plugin\Commerce\PromotionOffer;

use Drupal\commerce_order\Adjustment;
use Drupal\commerce_promotion\Attribute\CommercePromotionOffer;
use Drupal\commerce_promotion\Entity\PromotionInterface;
use Drupal\commerce_promotion\Plugin\Commerce\PromotionOffer\FixedAmountOffTrait;
use Drupal\commerce_shipping\Entity\ShipmentInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;

/**
 * Provides the fixed amount off offer for shipments.
 */
#[CommercePromotionOffer(
  id: 'shipment_fixed_amount_off',
  label: new TranslatableMarkup('Fixed amount off the shipment amount'),
  entity_type: 'commerce_order',
)]
class ShipmentFixedAmountOff extends ShipmentPromotionOfferBase {

  use FixedAmountOffTrait;

  /**
   * {@inheritdoc}
   */
  public function applyToShipment(ShipmentInterface $shipment, PromotionInterface $promotion) {
    $amount = $this->getAmount();
    if ($amount->getCurrencyCode() != $shipment->getAmount()->getCurrencyCode()) {
      return;
    }
    // The offer amount can't be larger than the remaining shipment amount,
    // to avoid a negative total.
    $remaining_amount = $shipment->getAdjustedAmount();
    if ($amount->greaterThan($remaining_amount)) {
      $amount = $remaining_amount;
    }
    // Display-inclusive promotions must first be applied to the amount.
    if ($this->isDisplayInclusive()) {
      $new_shipment_amount = $shipment->getAmount()->subtract($amount);
      $shipment->setAmount($new_shipment_amount);
    }

    $shipment->addAdjustment(new Adjustment([
      'type' => 'shipping_promotion',
      'label' => $promotion->getDisplayName() ?: $this->t('Discount'),
      'amount' => $amount->multiply('-1'),
      'source_id' => $promotion->id(),
      'included' => $this->isDisplayInclusive(),
    ]));
  }

}