Add custom promotion applicator on a subset of items

src/Promotion/Applicator/UnitsPromotionAdjustmentsApplicator.php

@@ -0,0 +1,106 @@
+<?php
+
+/*
+ * This file is part of Monsieur Biz' Advanced Promotion plugin for Sylius.
+ * (c) Monsieur Biz <[email protected]>
+ * For the full copyright and license information, please view the LICENSE.txt
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace MonsieurBiz\SyliusAdvancedPromotionPlugin\Promotion\Applicator;
+
+use Doctrine\Common\Collections\Collection;
+use Sylius\Component\Core\Distributor\IntegerDistributorInterface;
+use Sylius\Component\Core\Model\AdjustmentInterface;
+use Sylius\Component\Core\Model\ChannelInterface;
+use Sylius\Component\Core\Model\OrderInterface;
+use Sylius\Component\Core\Model\OrderItemInterface;
+use Sylius\Component\Order\Factory\AdjustmentFactoryInterface;
+use Sylius\Component\Order\Model\OrderItemUnitInterface;
+use Sylius\Component\Promotion\Model\PromotionInterface;
+use Webmozart\Assert\Assert;
+
+/**
+ * Same behaviour as the default UnitsPromotionAdjustmentsApplicator
+ * But we add the possibility to apply the promotion on a subset of items
+ * @see \Sylius\Component\Core\Promotion\Applicator\UnitsPromotionAdjustmentsApplicator
+ */
+final class UnitsPromotionAdjustmentsApplicator implements UnitsPromotionAdjustmentsApplicatorInterface
+{
+    public function __construct(private AdjustmentFactoryInterface $adjustmentFactory, private IntegerDistributorInterface $distributor)
+    {
+    }
+
+    public function apply(OrderInterface $order, PromotionInterface $promotion, array $adjustmentsAmounts, ?Collection $orderItems = null): void
+    {
+        // If no given items, promotion is on all items
+        // It will have the same behavior as the default UnitsPromotionAdjustmentsApplicator
+        // @see \Sylius\Component\Core\Promotion\Applicator\UnitsPromotionAdjustmentsApplicator
+        if (null == $orderItems) {
+            $orderItems = $order->getItems();
+        }
+
+        Assert::eq($orderItems->count(), \count($adjustmentsAmounts));
+
+        $channel = $order->getChannel();
+        Assert::isInstanceOf($channel, ChannelInterface::class);
+
+        $count = 0;
+        foreach ($orderItems as $item) {
+            /** @var OrderItemInterface $item */
+            Assert::isInstanceOf($item, OrderItemInterface::class);
+            $adjustmentAmount = $adjustmentsAmounts[$count++];
+            if (0 === $adjustmentAmount) {
+                continue;
+            }
+
+            $this->applyAdjustmentsOnItemUnits($item, $promotion, $adjustmentAmount, $channel);
+        }
+    }
+
+    private function applyAdjustmentsOnItemUnits(
+        OrderItemInterface $item,
+        PromotionInterface $promotion,
+        int $itemPromotionAmount,
+        ChannelInterface $channel,
+    ): void {
+        $splitPromotionAmount = $this->distributor->distribute($itemPromotionAmount, $item->getQuantity());
+
+        $variantMinimumPrice = $item->getVariant()?->getChannelPricingForChannel($channel)?->getMinimumPrice();
+
+        $count = 0;
+        foreach ($item->getUnits() as $unit) {
+            $promotionAmount = $splitPromotionAmount[$count++];
+            if (0 === $promotionAmount) {
+                continue;
+            }
+
+            $this->addAdjustment(
+                $promotion,
+                $unit,
+                $this->calculate($unit->getTotal(), (int) $variantMinimumPrice, $promotionAmount),
+            );
+        }
+    }
+
+    private function addAdjustment(PromotionInterface $promotion, OrderItemUnitInterface $unit, int $amount): void
+    {
+        $adjustment = $this->adjustmentFactory
+            ->createWithData(AdjustmentInterface::ORDER_PROMOTION_ADJUSTMENT, (string) $promotion->getName(), $amount)
+        ;
+        $adjustment->setOriginCode($promotion->getCode());
+
+        $unit->addAdjustment($adjustment);
+    }
+
+    private function calculate(int $itemTotal, int $minimumPrice, int $promotionAmount): int
+    {
+        if ($itemTotal + $promotionAmount <= $minimumPrice) {
+            return $minimumPrice - $itemTotal;
+        }
+
+        return $promotionAmount;
+    }
+}

src/Promotion/Applicator/UnitsPromotionAdjustmentsApplicatorInterface.php

@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of Monsieur Biz' Advanced Promotion plugin for Sylius.
+ * (c) Monsieur Biz <[email protected]>
+ * For the full copyright and license information, please view the LICENSE.txt
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace MonsieurBiz\SyliusAdvancedPromotionPlugin\Promotion\Applicator;
+
+use Doctrine\Common\Collections\Collection;
+use Sylius\Component\Core\Model\OrderInterface;
+use Sylius\Component\Promotion\Model\PromotionInterface;
+
+/**
+ * @SuppressWarnings(PHPMD.LongClassName)
+ */
+interface UnitsPromotionAdjustmentsApplicatorInterface
+{
+    /**
+     * @param array|int[] $adjustmentsAmounts
+     */
+    public function apply(OrderInterface $order, PromotionInterface $promotion, array $adjustmentsAmounts, ?Collection $orderItems = null): void;
+}