Bugfix: Add Magento Discount to order lines

Service/Order/Lines/Generator/MagentoDiscount.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mollie\Payment\Service\Order\Lines\Generator;
+
+use Magento\Sales\Api\Data\OrderInterface;
+use Mollie\Api\Types\OrderLineType;
+use Mollie\Payment\Helper\General;
+
+class MagentoDiscount implements GeneratorInterface
+{
+    /**
+     * @var General
+     */
+    private $mollieHelper;
+
+    public function __construct(
+        General $mollieHelper
+    ) {
+        $this->mollieHelper = $mollieHelper;
+    }
+
+    public function process(OrderInterface $order, array $orderLines): array
+    {
+        if (!$order->getBaseDiscountAmount()) {
+            return $orderLines;
+        }
+
+        $forceBaseCurrency = (bool)$this->mollieHelper->useBaseCurrency($order->getStoreId());
+        $currency = $forceBaseCurrency ? $order->getBaseCurrencyCode() : $order->getOrderCurrencyCode();
+        $amount = (float)$order->getData(($forceBaseCurrency ? 'base_' : '') . 'discount_amount');
+
+        $orderLines[] = [
+            'type' => OrderLineType::TYPE_DISCOUNT,
+            'name' => __('Magento Discount'),
+            'quantity' => 1,
+            'unitPrice' => $this->mollieHelper->getAmountArray($currency, $amount),
+            'totalAmount' => $this->mollieHelper->getAmountArray($currency, $amount),
+            'vatRate' => '0.00',
+            'vatAmount' => $this->mollieHelper->getAmountArray($currency, 0),
+        ];
+
+        return $orderLines;
+    }
+}

etc/di.xml

@@ -158,6 +158,7 @@
     <type name="Mollie\Payment\Service\Order\Lines\OrderLinesGenerator">
         <arguments>
             <argument name="generators" xsi:type="array">
+                <item name="magento_discount" xsi:type="object">Mollie\Payment\Service\Order\Lines\Generator\MagentoDiscount</item>
                 <item name="fooman_totals" xsi:type="object">Mollie\Payment\Service\Order\Lines\Generator\FoomanTotals</item>
                 <item name="weee_fee" xsi:type="object">Mollie\Payment\Service\Order\Lines\Generator\WeeeFeeGenerator</item>
                 <item name="mageworx_rewardpoints" xsi:type="object">Mollie\Payment\Service\Order\Lines\Generator\MageWorxRewardPoints</item>