MC-24043: "Apply discount to Shipping Amount" disabled for "Fixed amo…

…unt discount for whole cart" action

app/code/Magento/SalesRule/Helper/CartFixedDiscount.php

@@ -0,0 +1,223 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\SalesRule\Helper;
+
+use Magento\Framework\Pricing\PriceCurrencyInterface;
+use Magento\Quote\Api\Data\AddressInterface;
+use Magento\Quote\Model\Quote;
+use Magento\SalesRule\Model\DeltaPriceRound;
+use Magento\SalesRule\Model\Rule;
+
+/**
+ * Helper for CartFixed Available Discount and Quote Totals
+ */
+class CartFixedDiscount
+{
+    /**
+     * @var DeltaPriceRound
+     */
+    private $deltaPriceRound;
+
+    /**
+     * @var PriceCurrencyInterface
+     */
+    private $priceCurrency;
+
+    /**
+     * @param DeltaPriceRound $deltaPriceRound
+     * @param PriceCurrencyInterface $priceCurrency
+     */
+    public function __construct(
+        DeltaPriceRound $deltaPriceRound,
+        PriceCurrencyInterface $priceCurrency
+    ) {
+        $this->deltaPriceRound = $deltaPriceRound;
+        $this->priceCurrency = $priceCurrency;
+    }
+
+    /**
+     * Retrieve shipping amount by quote address and shipping method
+     *
+     * @param AddressInterface $address
+     * @return float
+     */
+    public function calculateShippingAmountWhenAppliedToShipping(
+        AddressInterface $address
+    ): float {
+        $shippingAmount = (float) $address->getShippingAmount();
+        if ($shippingAmount == 0.0) {
+            $address->setCollectShippingRates(true);
+            $address->collectShippingRates();
+            $shippingRates = $address->getAllShippingRates();
+            foreach ($shippingRates as $shippingRate) {
+                if ($shippingRate->getCode() === $address->getShippingMethod()
+                ) {
+                    $shippingAmount = (float) $shippingRate->getPrice();
+                    break;
+                }
+            }
+        }
+        return $shippingAmount;
+    }
+
+    /**
+     * Get the available discount amount calculated from the ration
+     *
+     * @param float $ruleDiscount
+     * @param float $qty
+     * @param float $baseItemPrice
+     * @param float $baseRuleTotals
+     * @param string $discountType
+     * @return float
+     */
+    public function getDiscountAmount(
+        float $ruleDiscount,
+        float $qty,
+        float $baseItemPrice,
+        float $baseRuleTotals,
+        string $discountType
+    ): float {
+        $ratio = $baseItemPrice * $qty / $baseRuleTotals;
+        return $this->deltaPriceRound->round(
+            $ruleDiscount * $ratio,
+            $discountType
+        );
+    }
+
+    /**
+     * Get shipping discount amount
+     *
+     * @param Rule $rule
+     * @param float $shippingAmount
+     * @param float $quoteBaseSubtotal
+     * @return float
+     */
+    public function getShippingDiscountAmount(
+        Rule $rule,
+        float $shippingAmount,
+        float $quoteBaseSubtotal
+    ): float {
+        $ratio = $shippingAmount / $quoteBaseSubtotal;
+        return $this->priceCurrency
+            ->roundPrice(
+                $rule->getDiscountAmount() * $ratio
+            );
+    }
+
+    /**
+     * Check if the current quote is multi shipping or not
+     *
+     * @param Quote $quote
+     * @return bool
+     */
+    public function checkMultiShippingQuote(Quote $quote): bool
+    {
+        $isMultiShipping = false;
+        $extensionAttributes = $quote->getExtensionAttributes();
+        if (!$quote->isVirtual() &&
+            $extensionAttributes &&
+            $extensionAttributes->getShippingAssignments()) {
+            $shippingAssignments = $extensionAttributes->getShippingAssignments();
+            if (count($shippingAssignments) > 1) {
+                $isMultiShipping = true;
+            }
+        }
+        return $isMultiShipping;
+    }
+
+    /**
+     * Get base rule totals for multi shipping addresses
+     *
+     * @param Quote $quote
+     * @return float
+     */
+    public function getQuoteTotalsForMultiShipping(Quote $quote): float
+    {
+        $quoteTotal = $quote->getBaseSubtotal();
+        $extensionAttributes = $quote->getExtensionAttributes();
+        $shippingAssignments = $extensionAttributes->getShippingAssignments();
+        $totalShippingPrice = 0.0;
+        foreach ($shippingAssignments as $assignment) {
+            $totalShippingPrice += $assignment->getShipping()->getAddress()->getBaseShippingInclTax();
+        }
+        return $quoteTotal + $totalShippingPrice;
+    }
+
+    /**
+     * Get base rule totals for regular shipping address
+     *
+     * @param Quote\Address $address
+     * @param float $baseRuleTotals
+     * @return float
+     */
+    public function getQuoteTotalsForRegularShipping(
+        Quote\Address $address,
+        float $baseRuleTotals
+    ): float {
+        $baseRuleTotals += $this->calculateShippingAmountWhenAppliedToShipping(
+            $address
+        );
+        return $baseRuleTotals;
+    }
+
+    /**
+     * Get base rule totals
+     *
+     * @param int $isAppliedToShipping
+     * @param Quote $quote
+     * @param bool $isMultiShipping
+     * @param Quote\Address $address
+     * @param float $baseRuleTotals
+     * @return float
+     */
+    public function getBaseRuleTotals(
+        int $isAppliedToShipping,
+        Quote $quote,
+        bool $isMultiShipping,
+        Quote\Address $address,
+        float $baseRuleTotals
+    ): float {
+        if ($isAppliedToShipping) {
+            $baseRuleTotals = ($quote->getIsMultiShipping() && $isMultiShipping) ?
+                $this->getQuoteTotalsForMultiShipping($quote) :
+                $this->getQuoteTotalsForRegularShipping($address, $baseRuleTotals);
+        } else {
+            if ($quote->getIsMultiShipping() && $isMultiShipping) {
+                $baseRuleTotals = $quote->getBaseSubtotal();
+            }
+        }
+        return (float) $baseRuleTotals;
+    }
+
+    /**
+     * Get available discount amount
+     *
+     * @param Rule $rule
+     * @param Quote $quote
+     * @param bool $isMultiShipping
+     * @param array $cartRules
+     * @param float $baseDiscountAmount
+     * @param float $availableDiscountAmount
+     * @return float
+     */
+    public function getAvailableDiscountAmount(
+        Rule $rule,
+        Quote $quote,
+        bool $isMultiShipping,
+        array $cartRules,
+        float $baseDiscountAmount,
+        float $availableDiscountAmount
+    ): float {
+        if ($quote->getIsMultiShipping() && $isMultiShipping) {
+            $availableDiscountAmount = (float)$cartRules[$rule->getId()] - $baseDiscountAmount;
+        } else {
+            $availableDiscountAmount -= $baseDiscountAmount;
+        }
+        return $availableDiscountAmount;
+    }
+}