Add: Cross-sells for the Store API Cart response.

src/StoreApi/SchemaController.php

@@ -42,6 +42,7 @@ public function __construct( ExtendSchema $extend ) {
 				Schemas\V1\CartCouponSchema::IDENTIFIER    => Schemas\V1\CartCouponSchema::class,
 				Schemas\V1\CartFeeSchema::IDENTIFIER       => Schemas\V1\CartFeeSchema::class,
 				Schemas\V1\CartItemSchema::IDENTIFIER      => Schemas\V1\CartItemSchema::class,
+				Schemas\V1\CrossSellsItemSchema::IDENTIFIER => Schemas\V1\CrossSellsItemSchema::class,
 				Schemas\V1\CartSchema::IDENTIFIER          => Schemas\V1\CartSchema::class,
 				Schemas\V1\CartExtensionsSchema::IDENTIFIER => Schemas\V1\CartExtensionsSchema::class,
 				Schemas\V1\CheckoutSchema::IDENTIFIER      => Schemas\V1\CheckoutSchema::class,

src/StoreApi/Schemas/ExtendSchema.php

@@ -4,6 +4,7 @@
 use Automattic\WooCommerce\StoreApi\Schemas\V1\CartItemSchema;
 use Automattic\WooCommerce\StoreApi\Schemas\V1\CartSchema;
 use Automattic\WooCommerce\StoreApi\Schemas\V1\CheckoutSchema;
+use Automattic\WooCommerce\StoreApi\Schemas\V1\CrossSellsItemSchema;
 use Automattic\WooCommerce\StoreApi\Schemas\V1\ProductSchema;
 use Automattic\WooCommerce\StoreApi\Formatters;
 
@@ -25,6 +26,7 @@ final class ExtendSchema {
 	 */
 	private $endpoints = [
 		CartItemSchema::IDENTIFIER,
+		CrossSellsItemSchema::IDENTIFIER,
 		CartSchema::IDENTIFIER,
 		CheckoutSchema::IDENTIFIER,
 		ProductSchema::IDENTIFIER,

src/StoreApi/Schemas/V1/CartSchema.php

@@ -40,6 +40,13 @@ class CartSchema extends AbstractSchema {
 	 */
 	public $coupon_schema;
 
+	/**
+	 * Cross-sells item schema instance.
+	 *
+	 * @var CrossSellsItemSchema
+	 */
+	public $cross_sells_item_schema;
+
 	/**
 	 * Fee schema instance.
 	 *
@@ -84,6 +91,7 @@ class CartSchema extends AbstractSchema {
 	public function __construct( ExtendSchema $extend, SchemaController $controller ) {
 		parent::__construct( $extend, $controller );
 		$this->item_schema             = $this->controller->get( CartItemSchema::IDENTIFIER );
+		$this->cross_sells_item_schema = $this->controller->get( CrossSellsItemSchema::IDENTIFIER );
 		$this->coupon_schema           = $this->controller->get( CartCouponSchema::IDENTIFIER );
 		$this->fee_schema              = $this->controller->get( CartFeeSchema::IDENTIFIER );
 		$this->shipping_rate_schema    = $this->controller->get( CartShippingRateSchema::IDENTIFIER );
@@ -155,6 +163,16 @@ public function get_properties() {
 				'context'     => [ 'view', 'edit' ],
 				'readonly'    => true,
 			],
+			'cross_sells'             => [
+				'description' => __( 'List of cross-sells items related to cart items.', 'woo-gutenberg-products-block' ),
+				'type'        => 'array',
+				'context'     => [ 'view', 'edit' ],
+				'readonly'    => true,
+				'items'       => [
+					'type'       => 'object',
+					'properties' => $this->force_schema_readonly( $this->cross_sells_item_schema->get_properties() ),
+				],
+			],
 			'needs_payment'           => [
 				'description' => __( 'True if the cart needs payment. False for carts with only free products and no shipping costs.', 'woo-gutenberg-products-block' ),
 				'type'        => 'boolean',
@@ -323,6 +341,9 @@ public function get_item_response( $cart ) {
 		// Get shipping packages to return in the response from the cart.
 		$shipping_packages = $has_calculated_shipping ? $controller->get_shipping_packages() : [];
 
+		// Get visible cross sells products.
+		$cross_sells = array_filter( array_map( 'wc_get_product', $cart->get_cross_sells() ), 'wc_products_array_filter_visible' );
+
 		return [
 			'coupons'                 => $this->get_item_responses_from_schema( $this->coupon_schema, $cart->get_applied_coupons() ),
 			'shipping_rates'          => $this->get_item_responses_from_schema( $this->shipping_rate_schema, $shipping_packages ),
@@ -331,6 +352,7 @@ public function get_item_response( $cart ) {
 			'items'                   => $this->get_item_responses_from_schema( $this->item_schema, $cart->get_cart() ),
 			'items_count'             => $cart->get_cart_contents_count(),
 			'items_weight'            => wc_get_weight( $cart->get_cart_contents_weight(), 'g' ),
+			'cross_sells'             => $this->get_item_responses_from_schema( $this->cross_sells_item_schema, $cross_sells ),
 			'needs_payment'           => $cart->needs_payment(),
 			'needs_shipping'          => $cart->needs_shipping(),
 			'has_calculated_shipping' => $has_calculated_shipping,

src/StoreApi/Schemas/V1/CrossSellsItemSchema.php

@@ -0,0 +1,62 @@
+<?php
+namespace Automattic\WooCommerce\StoreApi\Schemas\V1;
+
+/**
+ * CrossSellsItemSchema class.
+ */
+class CrossSellsItemSchema extends ProductSchema {
+
+	/**
+	 * The schema item name.
+	 *
+	 * @var string
+	 */
+	protected $title = 'cart_cross_sells_item';
+
+	/**
+	 * The schema item identifier.
+	 *
+	 * @var string
+	 */
+	const IDENTIFIER = 'cart-cross-sells-item';
+
+	/**
+	 * Cross-sells schema properties.
+	 *
+	 * @return array
+	 */
+	public function get_properties() {
+		$properties = parent::get_properties();
+
+		return [
+			'id'                => $properties['id'],
+			'name'              => $properties['name'],
+			'permalink'         => $properties['permalink'],
+			'prices'            => $properties['prices'],
+			'images'            => $properties['images'],
+			'average_rating'    => $properties['average_rating'],
+			self::EXTENDING_KEY => $this->get_extended_schema( self::IDENTIFIER ),
+		];
+	}
+
+	/**
+	 * Converts a WooCommerce product into an object suitable for the response.
+	 *
+	 * @param \WC_Product $product Cross-sell product.
+	 *
+	 * @return array
+	 */
+	public function get_item_response( $product ) {
+
+		return [
+			'id'                => $product->get_id(),
+			'name'              => $this->prepare_html_response( $product->get_title() ),
+			'permalink'         => $product->get_permalink(),
+			'prices'            => (object) $this->prepare_product_price_response( $product ),
+			'average_rating'    => (string) $product->get_average_rating(),
+			'images'            => $this->get_images( $product ),
+			self::EXTENDING_KEY => $this->get_extended_data( self::IDENTIFIER ),
+		];
+	}
+
+}