Prevent Wholesale Customer to Add Product to the Cart If The Product is Low on Stock

// Prevent wholesale customer to add to cart if the product is low on stock

add_filter('woocommerce_is_purchasable', 'wwpp_disable_cart_lowstock', 10, 2 );

add_filter('woocommerce_variation_is_purchasable', 'wwpp_disable_cart_lowstock', 10, 2 );

function wwpp_disable_cart_lowstock( $purchasable, $product ) {

	global $wc_wholesale_prices_premium;

  	$user_wholesale_role = $wc_wholesale_prices_premium->wwpp_wholesale_roles->getUserWholesaleRole();

    if( !empty( $user_wholesale_role ) ) {

		if ( wwpp_is_product_low_stock($product) ) {

			return false;

		}

	}

   return $purchasable;

}

// Disable 'Read More' button

add_filter('woocommerce_loop_add_to_cart_link', 'wwpp_lowstock_disable_read_more_button',10,2);

function wwpp_lowstock_disable_read_more_button( $add_to_cart_html, $product ) {

    global $wc_wholesale_prices_premium;

  	$user_wholesale_role = $wc_wholesale_prices_premium->wwpp_wholesale_roles->getUserWholesaleRole();

    if( !empty( $user_wholesale_role ) ) {

        if ( wwpp_is_product_low_stock($product) ) { 

            return '';

        }

    }

    return $add_to_cart_html;

}

// Display a message for low stock product

add_action('woocommerce_single_product_summary', 'wwpp_disable_cart_lowstock_message', 10);

add_action('woocommerce_after_shop_loop_item', 'wwpp_disable_cart_lowstock_message', 10);

function wwpp_disable_cart_lowstock_message(){

    global $product,$wc_wholesale_prices_premium;

  	$user_wholesale_role = $wc_wholesale_prices_premium->wwpp_wholesale_roles->getUserWholesaleRole();

    if( !empty( $user_wholesale_role ) ) {

        if ( wwpp_is_product_low_stock($product) ) { 

            // Feel free to change the message below if the product is low on stock

            echo __('Product is not available for wholesale customer at the moment.<br>Contact us for more information.');

        }

    }

}

// Function to check if the product is low on stock

function wwpp_is_product_low_stock($product){

    $stock_manage_stock = $product->get_manage_stock();

    $stock_quantity = $product->get_stock_quantity();

    // If the low stock treshold doen't set in the product setting, then use the woo setting in WooCommerce > Product > Inventory

    $low_stock_threshold = $product->get_low_stock_amount() ? $product->get_low_stock_amount() : get_option( 'woocommerce_notify_low_stock_amount', 2 ) ;

    // Check if manage stock is enabled on the product setting, then check if it's low on stock

    if ($stock_manage_stock && $stock_quantity <= $low_stock_threshold ) { 

        return true;

    }

    return false;

}