add_action( 'woocommerce_before_calculate_totals', 'vandaal_quantity_based_pricing', 9999 );
 
function vandaal_quantity_based_pricing( $cart ) {
 
    if ( is_admin() && ! defined( 'DOING_AJAX' ) ) return;
 
    if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 ) return;
 
    // Define discount rules and thresholds
    $threshold1 = 101; // Když je počet kusů vyšší než > 100
    $discount1 = 0.05; // Slevnit kus o 5%
    $threshold2 = 1001; // Když je počet kusů vyšší než > 1000
    $discount2 = 0.1; // Slevnit kus o 10%
 
    foreach ( $cart->get_cart() as $cart_item_key => $cart_item ) {
      $product_id = $cart_item['product_id'];
      if ( $cart_item['quantity'] >= $threshold1 && $cart_item['quantity'] < $threshold2 ) {
         $price = round( $cart_item['data']->get_price() * ( 1 - $discount1 ), 2 );
         $cart_item['data']->set_price( $price );
      } elseif ( $cart_item['quantity'] >= $threshold2 ) {
         $price = round( $cart_item['data']->get_price() * ( 1 - $discount2 ), 2 );
         $cart_item['data']->set_price( $price );
      }    
    }
    
 }