[*] refactoring preselect plugin

 + quote address assignment
 + method separation

Author: sfritzsche

composer.json

@@ -34,7 +34,7 @@
         }
     ],
     "require": {
-        "php": "~7.3||~7.4",
+        "php": "~7.4",
         "magento/framework": "^103.0.0",
         "magento/module-quote": "^101.2",
         "magento/module-customer": "^103.0"

src/Plugin/PreselectShipping.php

@@ -0,0 +1,114 @@
+<?php
+declare(strict_types=1);
+
+namespace IntegerNet\ShippingPreselection\Plugin;
+
+use IntegerNet\ShippingPreselection\Service\AddressSetMockdata;
+use IntegerNet\ShippingPreselection\Service\AddressResetConditions;
+use Magento\Checkout\Model\Session;
+use Magento\Quote\Model\Quote;
+use Magento\Quote\Model\Quote\Address;
+use Magento\Quote\Model\Quote\Address\Rate;
+use Magento\Quote\Model\ShippingMethodManagement;
+use Magento\Quote\Model\ShippingAddressAssignment;
+
+class PreselectShipping
+{
+    private ShippingMethodManagement $methodManagement;
+    private AddressSetMockdata $addressSetMockData;
+    private AddressResetConditions $addressReset;
+    private ShippingAddressAssignment $addressAssignment;
+
+    public function __construct(
+        ShippingMethodManagement $methodManagement,
+        AddressResetConditions $addressReset,
+        AddressSetMockdata $addressSetMockdata,
+        ShippingAddressAssignment $addressAssignment
+    ) {
+        $this->methodManagement = $methodManagement;
+        $this->addressSetMockData = $addressSetMockdata;
+        $this->addressReset = $addressReset;
+        $this->addressAssignment = $addressAssignment;
+    }
+
+    /**
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
+     */
+    public function afterGetQuote(Session $subject, Quote $result): Quote
+    {
+        if (!$this->isPreselectionAllowed($result)) {
+            return $result;
+        }
+        $address = $result->getShippingAddress();
+        if ($this->shouldMockAddress($address)) {
+            $this->addressSetMockData->setMockDataOnAddress($address);
+            $this->addressAssignment->setAddress($result, $address);
+        }
+        $this->preselectShippingMethod($result);
+        return $result;
+    }
+    
+    public function shouldMockAddress(Address $address): bool
+    {
+        return (true !== $address->validate());
+    }
+    
+    public function preselectShippingMethod(Quote $quote): void
+    {
+        $quote->getShippingAddress()->requestShippingRates(); // load new rates
+        if (!$rate = $this->getCheapestShippingRate($quote)) {
+            return;
+        }
+        try {
+            $this->methodManagement->set(
+                $quote->getId(),
+                $rate->getCarrier(),
+                $rate->getMethod()
+            );
+        } catch (\Exception $e) {
+            $quote->addErrorInfo('error', null, $e->getCode(), $e->getMessage());
+        }
+    }
+    
+    public function getCheapestShippingRate(Quote $quote): ?Rate
+    {
+        $selectedRate = null;
+        foreach ($this->getShippingRates($quote) as $rate) {
+            /** @var Rate $rate */
+            if ($selectedRate === null || $rate->getPrice() < $selectedRate->getPrice()) {
+                $selectedRate = $rate;
+            }
+        }
+        return $selectedRate;
+    }
+    
+    public function getShippingRates(Quote $quote)
+    {
+        return $quote->getShippingAddress()->getShippingRatesCollection();
+    }
+    
+    public function isPreselectionAllowed(Quote $quote): bool
+    {
+        return $this->validateShippingResetConditions() &&
+            $this->validateQuoteConditions($quote) &&
+            $this->validateShippingConditions($quote);
+    }
+    
+    public function validateShippingResetConditions(): bool
+    {
+        return !$this->addressReset->isAddressResetRequest() &&
+            !$this->addressReset->isAddressIgnoreRequest();
+    }
+    
+    public function validateQuoteConditions(Quote $quote): bool
+    {
+        return !$quote->getIsVirtual() && $quote->getItemsCount();
+    }
+    
+    public function validateShippingConditions(Quote $quote): bool
+    {
+        $address = $quote->getShippingAddress();
+        $shippingIsFine = $address->validate() && !empty($address->getShippingMethod());
+        return !$shippingIsFine;
+    }
+}

src/Plugin/PreselectShippingMethod.php

@@ -3,7 +3,7 @@
         xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
         <type name="Magento\Checkout\Model\Session">
             <plugin name="integernet_shippingpreselection_preselectshippingmethod"
-                    type="IntegerNet\ShippingPreselection\Plugin\PreselectShippingMethod" sortOrder="20"/>
+                    type="IntegerNet\ShippingPreselection\Plugin\PreselectShipping" sortOrder="20"/>
             <plugin name="integernet_shippingpreselection_resetshippingaddress"
                     type="IntegerNet\ShippingPreselection\Plugin\ResetShippingAddress" sortOrder="30"/>
         </type>