Added the Stockable interface

Changelog.md

@@ -27,6 +27,7 @@
 - Added `isZoneRestricted()` & `isNotZoneRestricted()` helper methods to the `ShippingMethod` class
 - Added the payment dependent shipping fee calculator
 - Added the `units_sold` and the `last_sale_at` attributes to the master product model (SUM/MAX from variants)
+- Added the `Stockable` interface (Contracts)
 - Fixed possible null return type on Billpayer::getName() when is_organization is true but the company name is null
 
 ## 3.x Series

src/Contracts/Changelog.md

@@ -7,6 +7,7 @@
 
 - Dropped PHP 8.0 & PHP 8.1 Support
 - Dropped Laravel 9 Support
+- Added the `Stockable` interface
 
 ## 3.x Series
 

src/Contracts/Stockable.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Contains the Stockable interface.
+ *
+ * @copyright Copyright (c) 2023 Vanilo UG
+ * @author Attila Fulop
+ * @license MIT
+ * @since 2023-11-23
+ *
+ */
+
+namespace Vanilo\Contracts;
+
+interface Stockable
+{
+ public function isOnStock(): bool;
+
+ public function onStockQuantity(): float;
+
+ public function isBackorderUnrestricted(): bool;
+
+ public function backorderQuantity(): ?float;
+
+ public function totalAvailableQuantity(): float;
+}