Woocommerce sale flash in percentage

woo-hooks.php

<?php
/**
* shows percentage in flash sales
*/

add_filter( 'woocommerce_sale_flash', 'ask_percentage_sale', 11, 3 );
function ask_percentage_sale( $text, $post, $product ) {
    $discount = 0;
    if ( $product->get_type() == 'variable' ) {
        $available_variations = $product->get_available_variations();								
        $maximumper = 0;
        for ($i = 0; $i < count($available_variations); ++$i) {
            $variation_id=$available_variations[$i]['variation_id'];
            $variable_product1= new WC_Product_Variation( $variation_id );
            $regular_price = $variable_product1->get_regular_price();
            $sales_price = $variable_product1->get_sale_price();
            if( $sales_price ) {
                $percentage= round( ( ( $regular_price - $sales_price ) / $regular_price ) * 100 ) ;
                if ($percentage > $maximumper) {
                    $maximumper = $percentage;
                }
            }        
        }
        $text = '<span class="onsale">' . $maximumper  . '%</span>';
    } elseif ( $product->get_type() == 'simple' ) {
        $percentage = round( ( ( $product->get_regular_price() - $product->get_sale_price() ) / $product->get_regular_price() ) * 100 );
        $text = '<span class="onsale">' . $percentage . '%</span>';
    }   

    return $text;
}

I used my own custom code works super nice then you can add css to change the appearance of the badge

`/* Replace text of Sale! badge with percentage */
add_filter( 'woocommerce_sale_flash', 'ds_replace_sale_text' );

function ds_replace_sale_text($text) {
global $product;
$stock = $product->get_stock_status();
$product_type = $product->get_type();
$sale_price = 0;
$regular_price = 0;
if($product_type == 'variable'){
$product_variations = $product->get_available_variations();
foreach ($product_variations as $kay => $value){
if($value['display_price'] < $value['display_regular_price']){
$sale_price = $value['display_price'];
$regular_price = $value['display_regular_price'];
}
}
if($regular_price > $sale_price && $stock != 'outofstock') {
$product_sale = intval(((intval($regular_price) - floatval($sale_price)) / floatval($regular_price)) * 100);
if ($product_sale > 5 ) {
return ' - ' . esc_html($product_sale) . '% Sonderpreis!';
}
if ($product_sale <= 5 ) {
return ' Sale!';
}
}else{
return '';
}
}else{
$regular_price = get_post_meta( get_the_ID(), '_regular_price', true);
$sale_price = get_post_meta( get_the_ID(), '_sale_price', true);
if($regular_price > 5) {
$product_sale = intval(((floatval($regular_price) - floatval($sale_price)) / floatval($regular_price)) * 100);
return ' -' . esc_html($product_sale) . '% Sonderpreis!';
}
if($regular_price >= 0 && $regular_price <= 5 ) {
$product_sale = intval(((floatval($regular_price) - floatval($sale_price)) / floatval($regular_price)) * 100);
return ' Sale!';
}
else{
return '';
}
}
}`