Return product stock data

app/code/Magento/CatalogInventoryGraphQl/Model/Resolver/OnlyXLeftInStockResolver.php

@@ -0,0 +1,117 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogInventoryGraphQl\Model\Resolver;
+
+use Magento\Catalog\Api\Data\ProductInterface;
+use Magento\CatalogInventory\Api\StockRegistryInterface;
+use Magento\CatalogInventory\Model\Configuration;
+use Magento\Framework\App\Config\ScopeConfigInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Query\Resolver\Value;
+use Magento\Framework\GraphQl\Query\Resolver\ValueFactory;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Store\Model\ScopeInterface;
+
+/**
+ * {@inheritdoc}
+ */
+class OnlyXLeftInStockResolver implements ResolverInterface
+{
+    /**
+     * @var ValueFactory
+     */
+    private $valueFactory;
+
+    /**
+     * @var ScopeConfigInterface
+     */
+    private $scopeConfig;
+
+    /**
+     * @var StockRegistryInterface
+     */
+    private $stockRegistry;
+
+    /**
+     * @param ValueFactory $valueFactory
+     * @param ScopeConfigInterface $scopeConfig
+     * @param StockRegistryInterface $stockRegistry
+     */
+    public function __construct(
+        ValueFactory $valueFactory,
+        ScopeConfigInterface $scopeConfig,
+        StockRegistryInterface $stockRegistry
+    ) {
+        $this->valueFactory = $valueFactory;
+        $this->scopeConfig = $scopeConfig;
+        $this->stockRegistry = $stockRegistry;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null): Value
+    {
+        if (!array_key_exists('model', $value) || !$value['model'] instanceof ProductInterface) {
+            $result = function () {
+                return null;
+            };
+
+            return $this->valueFactory->create($result);
+        }
+
+        /* @var $product ProductInterface */
+        $product = $value['model'];
+        $onlyXLeftQty = $this->getOnlyXLeftQty($product);
+
+        $result = function () use ($onlyXLeftQty) {
+            return $onlyXLeftQty;
+        };
+
+        return $this->valueFactory->create($result);
+    }
+
+    /**
+     * Get product qty left when "Catalog > Inventory > Stock Options > Only X left Threshold" is greater than 0
+     *
+     * @param ProductInterface $product
+     *
+     * @return null|float
+     */
+    private function getOnlyXLeftQty(ProductInterface $product): ?float
+    {
+        $thresholdQty = (float)$this->scopeConfig->getValue(
+            Configuration::XML_PATH_STOCK_THRESHOLD_QTY,
+            ScopeInterface::SCOPE_STORE
+        );
+        if ($thresholdQty === 0) {
+            return null;
+        }
+
+        $stockItem = $this->stockRegistry->getStockItem($product->getId());
+
+        $stockCurrentQty = $this->stockRegistry->getStockStatus(
+            $product->getId(),
+            $product->getStore()->getWebsiteId()
+        )->getQty();
+
+        $stockLeft = $stockCurrentQty - $stockItem->getMinQty();
+
+        $thresholdQty = (float)$this->scopeConfig->getValue(
+            Configuration::XML_PATH_STOCK_THRESHOLD_QTY,
+            ScopeInterface::SCOPE_STORE
+        );
+
+        if ($stockCurrentQty > 0 && $stockLeft <= $thresholdQty) {
+            return $stockLeft;
+        }
+
+        return null;
+    }
+}

app/code/Magento/CatalogInventoryGraphQl/Model/Resolver/StockStatusProvider.php

@@ -0,0 +1,69 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogInventoryGraphQl\Model\Resolver;
+
+use Magento\Catalog\Api\Data\ProductInterface;
+use Magento\CatalogInventory\Api\Data\StockStatusInterface;
+use Magento\CatalogInventory\Api\StockStatusRepositoryInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Query\Resolver\Value;
+use Magento\Framework\GraphQl\Query\Resolver\ValueFactory;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+
+/**
+ * {@inheritdoc}
+ */
+class StockStatusProvider implements ResolverInterface
+{
+    /**
+     * @var ValueFactory
+     */
+    private $valueFactory;
+
+    /**
+     * @var StockStatusRepositoryInterface
+     */
+    private $stockStatusRepository;
+
+    /**
+     * @param ValueFactory $valueFactory
+     * @param StockStatusRepositoryInterface $stockStatusRepository
+     */
+    public function __construct(ValueFactory $valueFactory, StockStatusRepositoryInterface $stockStatusRepository)
+    {
+        $this->valueFactory = $valueFactory;
+        $this->stockStatusRepository = $stockStatusRepository;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null): Value
+    {
+        if (!array_key_exists('model', $value) || !$value['model'] instanceof ProductInterface) {
+            $result = function () {
+                return null;
+            };
+
+            return $this->valueFactory->create($result);
+        }
+
+        /* @var $product ProductInterface */
+        $product = $value['model'];
+
+        $stockStatus = $this->stockStatusRepository->get($product->getId());
+        $productStockStatus = (int)$stockStatus->getStockStatus();
+
+        $result = function () use ($productStockStatus) {
+            return $productStockStatus === StockStatusInterface::STATUS_IN_STOCK ? 'IN_STOCK' : 'OUT_OF_STOCK';
+        };
+
+        return $this->valueFactory->create($result);
+    }
+}

app/code/Magento/CatalogInventoryGraphQl/README.md

@@ -0,0 +1,4 @@
+# CatalogInventoryGraphQl
+
+**CatalogInventoryGraphQl** provides type information for the GraphQl module
+to generate inventory stock fields for product information endpoints.

app/code/Magento/CatalogInventoryGraphQl/composer.json

@@ -0,0 +1,24 @@
+{
+  "name": "magento/module-catalog-inventory-graph-ql",
+  "description": "N/A",
+  "type": "magento2-module",
+  "require": {
+    "php": "~7.1.3||~7.2.0",
+    "magento/framework": "*",
+    "magento/module-store": "*",
+    "magento/module-catalog": "*",
+    "magento/module-catalog-inventory": "*"
+  },
+  "license": [
+    "OSL-3.0",
+    "AFL-3.0"
+  ],
+  "autoload": {
+    "files": [
+      "registration.php"
+    ],
+    "psr-4": {
+      "Magento\\CatalogInventoryGraphQl\\": ""
+    }
+  }
+}

app/code/Magento/CatalogInventoryGraphQl/etc/module.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<!--
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+-->
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
+    <module name="Magento_CatalogInventoryGraphQl">
+        <sequence>
+            <module name="Magento_Store"/>
+            <module name="Magento_Catalog"/>
+            <module name="Magento_CatalogInventory"/>
+        </sequence>
+    </module>
+</config>

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

@@ -0,0 +1,12 @@
+# Copyright © Magento, Inc. All rights reserved.
+# See COPYING.txt for license details.
+
+interface ProductInterface {
+    only_x_left_in_stock: Float @doc(description: "Product stock only x left count") @resolver(class: "Magento\\CatalogInventoryGraphQl\\Model\\Resolver\\OnlyXLeftInStockResolver")
+    stock_status: ProductStockStatus @doc(description: "Stock status of the product") @resolver(class: "Magento\\CatalogInventoryGraphQl\\Model\\Resolver\\StockStatusProvider")
+}
+
+enum ProductStockStatus @doc(description: "This enumeration states whether a product stock status is in stock or out of stock") {
+    IN_STOCK
+    OUT_OF_STOCK
+}

app/code/Magento/CatalogInventoryGraphQl/registration.php

@@ -0,0 +1,10 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+use Magento\Framework\Component\ComponentRegistrar;
+
+ComponentRegistrar::register(ComponentRegistrar::MODULE, 'Magento_CatalogInventoryGraphQl', __DIR__);

composer.json

@@ -112,6 +112,7 @@
         "magento/module-catalog-analytics": "*",
         "magento/module-catalog-import-export": "*",
         "magento/module-catalog-inventory": "*",
+        "magento/module-catalog-inventory-graph-ql": "*",
         "magento/module-catalog-rule": "*",
         "magento/module-catalog-rule-configurable": "*",
         "magento/module-catalog-search": "*",

dev/tests/api-functional/testsuite/Magento/GraphQl/CatalogInventory/ProductOnlyXLeftInStockTest.php

@@ -0,0 +1,64 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\GraphQl\CatalogInventory;
+
+use Magento\TestFramework\TestCase\GraphQlAbstract;
+
+class ProductOnlyXLeftInStockTest extends GraphQlAbstract
+{
+    /**
+     * @magentoApiDataFixture Magento/Catalog/_files/product_simple_with_all_fields.php
+     */
+    public function testQueryProductOnlyXLeftInStockDisabled()
+    {
+        $this->cleanCache();
+        $productSku = 'simple';
+
+        $query = <<<QUERY
+        {
+            products(filter: {sku: {eq: "{$productSku}"}})
+            {
+                items {
+                    only_x_left_in_stock
+                }
+            }
+        }
+QUERY;
+
+        $response = $this->graphQlQuery($query);
+
+        $this->assertArrayHasKey(0, $response['products']['items']);
+        $this->assertArrayHasKey('only_x_left_in_stock', $response['products']['items'][0]);
+        $this->assertNull($response['products']['items'][0]['only_x_left_in_stock']);
+    }
+
+    /**
+     * @magentoApiDataFixture Magento/Catalog/_files/product_simple_with_all_fields.php
+     * @magentoConfigFixture default_store cataloginventory/options/stock_threshold_qty 120
+     */
+    public function testQueryProductOnlyXLeftInStockEnabled()
+    {
+        $productSku = 'simple';
+
+        $query = <<<QUERY
+        {
+            products(filter: {sku: {eq: "{$productSku}"}})
+            {
+                items {
+                    only_x_left_in_stock            
+                }
+            }
+        }
+QUERY;
+        $response = $this->graphQlQuery($query);
+
+        $this->assertArrayHasKey(0, $response['products']['items']);
+        $this->assertArrayHasKey('only_x_left_in_stock', $response['products']['items'][0]);
+        $this->assertEquals(100, $response['products']['items'][0]['only_x_left_in_stock']);
+    }
+}