EC-CUBE4 で割引明細を追加するカスタマイズの例
以下のPHPファイルを作成する。
app/Customize/Service/PurchaseFlow/Processor/TestDiscountProcessor.php
app/Customize/Service/PurchaseFlow/Processor/TestDiscountProcessor.php
<?php


namespace Customize\Service\PurchaseFlow\Processor;


use Doctrine\ORM\EntityManagerInterface;
use Eccube\Annotation\OrderFlow;
use Eccube\Annotation\ShoppingFlow;
use Eccube\Entity\ItemHolderInterface;
use Eccube\Entity\Master\OrderItemType;
use Eccube\Entity\Master\TaxDisplayType;
use Eccube\Entity\Master\TaxType;
use Eccube\Entity\OrderItem;
use Eccube\Service\PurchaseFlow\PurchaseContext;
use Eccube\Service\PurchaseFlow\DiscountProcessor;

/**
 * 値引きを追加する.
 *
 * ここでフローを指定
 * @ShoppingFlow
 * @OrderFlow
 */
class TestDiscountProcessor implements DiscountProcessor
{
    /**
     * @var EntityManagerInterface
     */
    protected $entityManager;

    /**
     * TestDiscountProcessor constructor.
     *
     * @param EntityManagerInterface $entityManager
     */
    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->entityManager = $entityManager;
    }

    public function removeDiscountItem(ItemHolderInterface $itemHolder, PurchaseContext $context)
    {
        foreach ($itemHolder->getItems() as $item) {
            if ($item->getProcessorName() == TestDiscountProcessor::class) {
                $itemHolder->removeOrderItem($item);
                $this->entityManager->remove($item);
            }
        }
    }

    public function addDiscountItem(ItemHolderInterface $itemHolder, PurchaseContext $context)
    {
        /* 必要であればここで適応条件の制御をする
         * if...
         */
        
        // 課税/不課税や税込/税抜はここで作成
        $DiscountType = $this->entityManager->find(OrderItemType::class, OrderItemType::DISCOUNT);
        $TaxInclude = $this->entityManager->find(TaxDisplayType::class, TaxDisplayType::EXCLUDED);
        $Taxation = $this->entityManager->find(TaxType::class, TaxType::TAXATION);

        $OrderItem = new OrderItem();
        $OrderItem->setProductName($DiscountType->getName())
            ->setPrice(-100)
            ->setQuantity(1)
            ->setTax(-10)
            ->setTaxRate(10)
            ->setRoundingType(null)
            ->setOrderItemType($DiscountType)
            ->setTaxDisplayType($TaxInclude)
            ->setTaxType($Taxation)
            ->setOrder($itemHolder)
            ->setProcessorName(TestDiscountProcessor::class);
        $itemHolder->addItem($OrderItem);
    }
}