Extend payment gateways REST endpoint (https://github.com/woocommerce/woocommerce-admin/pull/6919)

* Extend the existing REST endpoint with gateway status data

* Add settings URL to response

* Add setup specific fields to response

* Fix controller class name

* Only pass required setting keys instead of fields

* Add changelog entry

plugins/woocommerce-admin/readme.txt

@@ -79,6 +79,7 @@ Release and roadmap notes are available on the [WooCommerce Developers Blog](htt
 - Add: Consume remote payment methods on frontend #6867
 - Add: Add plugin installer to allow installation of plugins via URL #6805
 - Add: Optional children prop to SummaryNumber component #6748
+- Add: Extend payment gateways REST endpoint #6919
 - Dev: Add data source filter to remote inbox notification system #6794
 - Dev: Add A/A test #6669
 - Dev: Add support for nonces in note actions #6726

plugins/woocommerce-admin/src/Features/RemotePaymentMethods/Init.php

@@ -8,6 +8,7 @@ namespace Automattic\WooCommerce\Admin\Features\RemotePaymentMethods;
 defined( 'ABSPATH' ) || exit;
 
 use Automattic\WooCommerce\Admin\RemoteInboxNotifications\SpecRunner;
+use Automattic\WooCommerce\Admin\Features\RemotePaymentMethods\PaymentGatewaysController;
 
 /**
  * Remote Payment Methods engine.
@@ -21,6 +22,7 @@ class Init {
 	 */
 	public function __construct() {
 		add_action( 'change_locale', array( __CLASS__, 'delete_specs_transient' ) );
+		PaymentGatewaysController::init();
 	}
 
 	/**

plugins/woocommerce-admin/src/Features/RemotePaymentMethods/PaymentGatewaysController.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * Logic for extending WC_REST_Payment_Gateways_Controller.
+ */
+
+namespace Automattic\WooCommerce\Admin\Features\RemotePaymentMethods;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * PaymentGateway class
+ */
+class PaymentGatewaysController {
+
+	/**
+	 * Initialize payment gateway changes.
+	 */
+	public static function init() {
+		add_filter( 'woocommerce_rest_prepare_payment_gateway', array( __CLASS__, 'extend_response' ), 10, 3 );
+	}
+
+	/**
+	 * Add necessary fields to REST API response.
+	 *
+	 * @param  WP_REST_Response   $response   Response data.
+	 * @param  WC_Payment_Gateway $gateway    Payment gateway object.
+	 * @param  WP_REST_Request    $request    Request object.
+	 * @return WP_REST_Response
+	 */
+	public static function extend_response( $response, $gateway, $request ) {
+		$data = $response->get_data();
+
+		$data['needs_setup'] = $gateway->needs_setup();
+
+		if ( method_exists( $gateway, 'get_oauth_connection_url' ) ) {
+			$data['oauth_connection_url'] = $gateway->get_oauth_connection_url();
+		}
+
+		if ( method_exists( $gateway, 'get_required_settings_keys' ) ) {
+			$data['required_settings_keys'] = $gateway->get_required_settings_keys();
+		}
+
+		$data['settings_url'] = admin_url( 'admin.php?page=wc-settings&tab=checkout&section=' . strtolower( $gateway->id ) );
+
+		$response->set_data( $data );
+
+		return $response;
+	}
+}