woocommerce-paypal-payments/modules/ppcp-compat/src/CompatModule.php

<?php
/**
 * The compatibility module.
 *
 * @package WooCommerce\PayPalCommerce\Compat
 */

declare(strict_types=1);

namespace WooCommerce\PayPalCommerce\Compat;

use Dhii\Container\ServiceProvider;
use Dhii\Modular\Module\ModuleInterface;
use Interop\Container\ServiceProviderInterface;
use Psr\Container\ContainerInterface;
use WooCommerce\PayPalCommerce\Compat\PPEC\PpecHelper;

/**
 * Class CompatModule
 */
class CompatModule implements ModuleInterface {

	/**
	 * Setup the compatibility module.
	 *
	 * @return ServiceProviderInterface
	 */
	public function setup(): ServiceProviderInterface {
		return new ServiceProvider(
			require __DIR__ . '/../services.php',
			require __DIR__ . '/../extensions.php'
		);
	}

	/**
	 * Run the compatibility module.
	 *
	 * @param ContainerInterface|null $container The Container.
	 */
	public function run( ContainerInterface $container ): void {
		$this->initialize_ppec_compat_layer( $container );
	}

	/**
	 * Returns the key for the module.
	 *
	 * @return string|void
	 */
	public function getKey() {
	}

	/**
	 * Sets up the PayPal Express Checkout compatibility layer.
	 *
	 * @param ContainerInterface|null $container The Container.
	 * @return void
	 */
	private function initialize_ppec_compat_layer( $container ): void {
		// Process PPEC subscription renewals through PayPal Payments.
		$handler = $container->get( 'compat.ppec.subscriptions-handler' );
		$handler->maybe_hook();

		// Settings.
		$ppec_import = $container->get( 'compat.ppec.settings_importer' );
		$ppec_import->maybe_hook();

		// Inbox note inviting merchant to disable PayPal Express Checkout.
		add_action(
			'woocommerce_init',
			function() {
				if ( is_callable( array( WC(), 'is_wc_admin_active' ) ) && WC()->is_wc_admin_active() && class_exists( 'Automattic\WooCommerce\Admin\Notes\Notes' ) ) {
					PPEC\DeactivateNote::init();
				}
			}
		);

	}

}