Cart and Checkout Block alert messages

add_action( 'template_redirect', function() {

	// Skip Logged In
	if( get_current_user_id() ) {
		return;
	}

	// Carts With Subscriptions Only
	if(
		! class_exists( 'WC_Subscriptions_Cart' )
		|| ! WC_Subscriptions_Cart::cart_contains_subscription()
	) {
		return;
	}

	// Get Current Page
	global $post;
	$post_slug = isset( $post->post_name ) ? $post->post_name : '';

	switch( $post_slug ) {

		case 'cart':
		case 'checkout':
			$message = '
				<p>
					<strong>Apple Pay notice:</strong>
					If you already have an account with us using your Apple ID email address,
					please <a href="/my-account/">log-in</a> first before using Apple Pay.
				</p>
			';
			wc_add_notice( $message, 'notice' );
			break;

	}

} );