echo Alert only once based on if statement PHP - php

Question

This function scrapes my shopping cart for a particular product, and if that product exists, removes shipping services. E.G. if product id:40 is in the cart, disable shipping service values in array($shipping_services_to_hide).
I would like to display a message to customers that notifies them of the shipping restriction, in the form of an alert or preferably injecting code into the cart in a specific place (based on class -no div id available-. Also,using :before or :after with css content: would be acceptable)(no idea if this part can be done)
What would be a good way to do that?
add_filter( 'woocommerce_package_rates','hide_shipping_method_if_particular_product_available_in_cart' , 10, 2 );
function hide_shipping_method_if_particular_product_available_in_cart( $available_shipping_methods ) {
global $woocommerce;
// products_array should be filled with all the products ids
// for which shipping method (stamps) to be restricted.
$products_array = array(
40
);
// You can find the shipping service codes by doing inspect element using
// developer tools of chrome. Code for each shipping service can be obtained by
// checking 'value' of shipping option.
$shipping_services_to_hide = array(
'wf_shipping_ups:12',
'wf_shipping_ups:02',
'wf_shipping_ups:59',
'wf_shipping_ups:01',
'wf_shipping_ups:13',
'wf_shipping_ups:14',
'wf_shipping_ups:11',
'wf_shipping_ups:07',
'wf_shipping_ups:54',
'wf_shipping_ups:08',
'wf_shipping_ups:65'
);
// Get all products from the cart.
$products = $woocommerce->cart->get_cart();
// Crawl through each items in the cart.
foreach ( $products as $key => $item ) {
// If any product id from the array is present in the cart,
// unset all shipping method services part of shipping_services_to_hide array.
if( in_array( $item['product_id'], $products_array ) ) {
foreach ( $shipping_services_to_hide as &$value ) {
unset( $available_shipping_methods[ $value ] );
}
break;
}
}
// return updated available_shipping_methods;
return $available_shipping_methods;
}

Answer 1

You can trigger a notice with wc_add_notice()
if( in_array( $item['product_id'], $products_array ) ) {
foreach ( $shipping_services_to_hide as &$value ) {
unset( $available_shipping_methods[ $value ] );
// add your notice here
wc_add_notice( 'No shipping error.', 'your-plugin' ), 'notice' );
}
break;
}