Discount Rules: Check if the user, product or cart item has discount or not

/**
 * Check user has discount or not.
 */
if (class_exists('\Wdr\App\Controllers\DiscountCalculator') && !empty(\Wdr\App\Controllers\DiscountCalculator::$applied_rules)) {
    // the user has discounts
} else {
    // the user doesn't have any discounts
}

/**
 * Check if the product has discount or not.
 */
$product = 12; // you need to pass product or its id to check
if (apply_filters('advanced_woo_discount_rules_get_product_discount_price', false, $product) !== false) {
    // the product has discounts
} else {
    // the product doesn't have any discounts
}

/**
 * Check if the cart item has discount or not.
 */
$cart_item = '23db6982caef9e9152f1a5b2589e6ca3'; // you need to pass cart item or its key to check
if (apply_filters('advanced_woo_discount_rules_get_cart_item_discount_price', false, $cart_item) !== false) {
    // the cart item has discounts
} else {
    // the cart item doesn't have any discounts
}