/**
 * Set discount for bulk buying
 */

add_action('woocommerce_before_calculate_totals', 'cc_quantity_based_pricing', 9999);

function cc_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 = 10; // Change price if items > 10
  $discount1 = 0.05; // Reduce unit price by 5%
  $threshold2 = 100; // Change price if items > 100
  $discount2 = 0.1; // Reduce unit price by 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);
    }
  }

}