<?php

global $product;

if (!$product->is_in_stock()) {
  $showText = '<span class="out">Out of stock</span>';
  echo $showText;
}

if ($product->is_on_sale()){

  if ( $product->get_type() == 'variable' ) {
    $vars = $product->get_available_variations();

    $var_cero = $vars[0]['variation_id'];
    $variable_product = wc_get_product($var_cero);
    $regular_price = $variable_product->get_regular_price();
    $sale_price = $variable_product->get_sale_price();
    if($sale_price){
      $percent_max=round( ( ( $regular_price - $sale_price ) / $regular_price ) * 100 );
    }else{
      $percent_max=0;
    }

    $cont_percent=0;
    foreach ($vars as $varID) {
      $variable_product = wc_get_product($varID['variation_id']);
      $regular_price = $variable_product->get_regular_price();
      $sale_price = $variable_product->get_sale_price();
      if($sale_price){
        $percent = round( ( ( $regular_price - $sale_price ) / $regular_price ) * 100 );
      }else{
        $percent=0;
      }

      if($percent_max!=$percent){
        if($percent_max>$percent){
          $percent_max=$percent_max;
        }else{
          $percent_max=$percent;
        }			 
      }else{
        $cont_percent++;
      }

      #echo $regular_price." - ".$sale_price."%".$percent_max."<br>";

    }

    if($cont_percent==count($vars)){
      $showText = '<span class="onsale">'. __('-', 'woocommerce' ). $percent_max. '%</span>';
    }else{
      $showText = '<span class="onsale">'. __('Up to -', 'woocommerce' ). $percent_max. '%</span>';
    }

  }
  else{
    $regular_price = $product->regular_price;
    $sale_price = $product->sale_price;
    $percent = round( ( ( $regular_price - $sale_price ) / $regular_price ) * 100 );

    $showText = '<span class="onsale">'. __('-', 'woocommerce' ). $percent . '%</span>';
  }

  echo $showText;
}

?>