Shipping method set concept

app/code/Magento/QuoteGraphQl/Model/Resolver/ShippingMethod/SetShippingMethodsOnCart.php

@@ -0,0 +1,105 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Model\Resolver\ShippingMethod;
+
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\Framework\Stdlib\ArrayManager;
+use Magento\Quote\Api\CartRepositoryInterface;
+use Magento\Quote\Api\Data\CartInterface;
+use Magento\Quote\Model\MaskedQuoteIdToQuoteIdInterface;
+
+class SetShippingMethodsOnCart implements ResolverInterface
+{
+    /**
+     * @var CartRepositoryInterface
+     */
+    private $cartRepository;
+
+    /**
+     * @var MaskedQuoteIdToQuoteIdInterface
+     */
+    private $maskedQuoteIdToQuoteId;
+
+    /**
+     * @var ArrayManager
+     */
+    private $arrayManager;
+
+    /**
+     * SetShippingMethodsOnCart constructor.
+     * @param ArrayManager $arrayManager
+     * @param MaskedQuoteIdToQuoteIdInterface $maskedQuoteIdToQuoteId
+     */
+    public function __construct(
+        ArrayManager $arrayManager,
+        MaskedQuoteIdToQuoteIdInterface $maskedQuoteIdToQuoteId,
+        CartRepositoryInterface $cartRepository
+    ) {
+        $this->arrayManager = $arrayManager;
+        $this->maskedQuoteIdToQuoteId = $maskedQuoteIdToQuoteId;
+        $this->cartRepository = $cartRepository;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
+    {
+        $shippingMethods = $this->arrayManager->get('input/shipping_methods', $args);
+        $maskedCartId = $this->arrayManager->get('input/cart_id', $args);
+
+        if (!$maskedCartId) {
+            // TODO: throw an exception
+        }
+
+        if (!$shippingMethods) {
+            // TODO: throw an exception?
+        }
+
+        foreach ($shippingMethods as $shippingMethod) {
+            if (empty($shippingMethod['cart_address_id'])) {
+                // TODO: throw input exception
+            }
+
+            if (empty($shippingMethod['shipping_method_code'])) {
+                // TODO: throw input exception
+            }
+
+            // TODO: move to a separate class
+            // TODO: check current customer can apply operations on specified cart
+        }
+
+        $quoteId = $this->maskedQuoteIdToQuoteId->execute($maskedCartId);
+        $quote = $this->cartRepository->get($quoteId); // TODO: catch no such entity exception
+        $this->setShippingMethods($shippingMethods, $quote);
+
+        $quote->collectTotals();
+        $quote->save();
+        //$this->cartRepository->save($quote);
+
+        return 'Success!';
+    }
+
+    private function setShippingMethods($shippingMethods, CartInterface $quote)
+    {
+        $addresses = $quote->getAllShippingAddresses();
+        /** @var  \Magento\Quote\Model\Quote\Address $address */
+        foreach ($addresses as $address) {
+            $addressId = $address->getId();
+            $shippingMethodForAddress = array_search($addressId, array_column($shippingMethods, 'cart_address_id'));
+            if ($shippingMethodForAddress !== false) {
+                $address->setShippingMethod($shippingMethods[$shippingMethodForAddress]['shipping_method_code']);
+//                $address->setCollectShippingRates(1);
+                $address->save();
+            }
+        }
+        // TODO: make sure that shipping method is assigned for all addresses
+    }
+}

app/code/Magento/QuoteGraphQl/etc/schema.graphqls

@@ -11,7 +11,7 @@ type Mutation {
     removeCouponFromCart(input: RemoveCouponFromCartInput): RemoveCouponFromCartOutput @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\Coupon\\RemoveCouponFromCart")
     setShippingAddressesOnCart(input: SetShippingAddressesOnCartInput): SetShippingAddressesOnCartOutput
     setBillingAddressOnCart(input: SetBillingAddressOnCartInput): SetBillingAddressOnCartOutput
-    setShippingMethodsOnCart(input: SetShippingMethodsOnCartInput): SetShippingMethodsOnCartOutput
+    setShippingMethodsOnCart(input: SetShippingMethodsOnCartInput): SetShippingMethodsOnCartOutput @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\ShippingMethod\\SetShippingMethodsOnCart")
 }
 
 input SetShippingAddressesOnCartInput {
@@ -47,11 +47,12 @@ input CartAddressInput {
 }
 
 input SetShippingMethodsOnCartInput {
+    cart_id: String!
     shipping_methods: [ShippingMethodForAddressInput!]!
 }
 
 input ShippingMethodForAddressInput {
-    cart_address_id: String!
+    cart_address_id: String! # todo: int?
     shipping_method_code: String!
 }
 
@@ -64,12 +65,12 @@ type SetShippingAddressesOnCartOutput {
 }
 
 type SetShippingMethodsOnCartOutput {
-    cart: Cart!
+    cart: String
 }
 
 # If no address is provided, the system get address assigned to a quote
 # If there's no address at all - the system returns all shipping methods
-type AvailableShippingMethodsOnCartInput {
+input AvailableShippingMethodsOnCartInput {
     cart_id: String!
     customer_address_id: Int
     address: CartAddressInput