Cart Message for specific shipping class, minimum amount and geolocated country in WooCommerce

I tried to make the code from Cart Message for a specific shipping class and a minimal cart total in Woocommerce coexist with my recent code Free shipping cart message for a specific shipping class, a minimal amount and a specific Country in Woocommerce, with additional multiple conditions:

add_action( 'woocommerce_before_calculate_totals', 'cart_items_shipping_class_message', 20, 1 );
function cart_items_shipping_class_message( $cart ){
    if ( ! is_cart() || ( is_admin() && ! defined('DOING_AJAX') ) )
        return;    
    $shipping_class = 'supplier';
    $min_amout      = 20;
    $free_shipping  = 50;
    $amout_incl_tax = 0;
    foreach( $cart->get_cart() as $cart_item ){     
        if( $cart_item['data']->get_shipping_class() === $shipping_class ){            
            $amout_incl_tax += $cart_item['line_subtotal'] + $cart_item['line_subtotal_tax'];
        }       
    }
    if( $amout_incl_tax > 0 && $amout_incl_tax < $min_amout && is_cart() && WC_Geolocation::geolocate_ip()['country'] === 'IT' ){               
        remove_action( 'woocommerce_proceed_to_checkout', 'woocommerce_button_proceed_to_checkout', 20 );       
        wc_add_notice( sprintf( '<p><strong><font color="#cc1602">20 € of minimum amount on products SUPPLIER</font></strong></p><a href="/brand/supplier-slug" class="button">Add %s of products</a><span class="sub-button">' . wc_price($free_shipping - $amout_incl_tax) . 'for free shipping!</span>',
            wc_price($min_amout - $amout_incl_tax) ), 'error' );
    }
    elseif( $amout_incl_tax > 0 && $amout_incl_tax < $min_amout && is_cart() && ! WC_Geolocation::geolocate_ip()['country'] === 'IT' ){             
        remove_action( 'woocommerce_proceed_to_checkout', 'woocommerce_button_proceed_to_checkout', 20 );       
        wc_add_notice( sprintf( '<p><strong><font color="#cc1602">20 € of minimum amount on products SUPPLIER</font></strong></p><a href="/brand/supplier-slug" class="button">Add %s of products</a>',
            wc_price($min_amout - $amout_incl_tax) ), 'error' );
    }
    elseif( $amout_incl_tax >= $min_amout && $amout_incl_tax < $free_shipping && is_cart() && WC_Geolocation::geolocate_ip()['country'] === 'IT' ){             
        wc_add_notice( sprintf( '<p><strong><font color="green">FREE SHIPPING on products SUPPLIER width at least 50 €</font></strong></p><a href="/brand/supplier-slug" class="button free">Add %s of products for free shipping!</a>',
            wc_price($free_shipping - $amout_incl_tax) ), 'notice' );
    }
}

The cart "Ajax update" seems to be slowed down. Maybe it is possible to lighten the code?

I replaced old <font> html tag, make the code translatable and more modular.

The "ajax update" slow down is due to the remove_action() execution when "supplier" items subtotal is less than the minimal required amount, and can't be improved.

Your revisited code:

add_action( 'woocommerce_before_calculate_totals', 'cart_items_shipping_class_message', 20, 1 );
function cart_items_shipping_class_message( $cart ){
    if ( ( is_admin() && ! defined('DOING_AJAX' ) ) || ! is_cart() )
        return;

    $shipping_class = 'supplier';
    $min_amount      = 20;
    $free_shipping  = 50;
    $items_subtotal = 0;

    // Getting non discounted "supplier" cart items subtotal including taxes 
    foreach( $cart->get_cart() as $cart_item ){
        // Targeting our defined shipping class only
        if( $cart_item['data']->get_shipping_class() === $shipping_class ){
            // Add each subtotal from our defined shipping class only
            $items_subtotal += $cart_item['line_subtotal'] + $cart_item['line_subtotal_tax'];
        }
    }

    $is_geo_ip_italy = WC_Geolocation::geolocate_ip()['country'] === 'IT';

    if( $items_subtotal > 0 && $items_subtotal < $min_amount ){
        remove_action( 'woocommerce_proceed_to_checkout', 'woocommerce_button_proceed_to_checkout', 20 );

        $free_message =  sprintf( ' <span class="sub-button">%s %s</span>',
            wc_price( $free_shipping - $items_subtotal ),
            __('for free shipping!', 'woocommerce')
        );

        wc_add_notice( sprintf( '<p><strong style="color:#cc1602;">%s %s</strong></p><a href="%s" class="button">%s</a>%s',
            wc_price( $min_amout ),
            __('of minimum amount on products SUPPLIER', 'woocommerce'),
            home_url('/brand/supplier-slug'),
            sprintf( __('Add %s of products', 'woocommerce'), wc_price($min_amount - $items_subtotal) ),
            $is_geo_ip_italy ? $free_message : '',
        ), 'error' );
    }
    elseif( $items_subtotal >= $min_amount && $items_subtotal < $free_shipping && $is_geo_ip_italy ){
        wc_add_notice( sprintf( '<p><strong style="color:green">%s %s</strong></p><a href="%s" class="button free">%s</a>',
            __('FREE SHIPPING on products SUPPLIER width at least', 'woocommerce'),
            wc_price( $free_shipping ),
            home_url('/brand/supplier-slug'),
            sprintf( __('Add %s of products for free shipping!', 'woocommerce'), wc_price($free_shipping - $items_subtotal) ),
        ), 'notice' );
    }
}

Code goes in functions.php file of the active child theme (or active theme). Tested and works.