public sealed class CashChequePrintingHandler : IDisposable
{
    private readonly IDisposable subscription;

    public CashChequePrintingHandler()
    {
        subscription = PluginContext.Notifications.CashChequePrinting.Subscribe(OnCashChequePrinting);
    }

    private static CashCheque OnCashChequePrinting(Guid orderId)
    {
        PluginContext.Log.Info("On cash cheque printing subscription.");

        var order = PluginContext.Operations.GetOrderById(orderId);
        var message = order.Status == OrderStatus.Closed
            ? $"Zamówienie #{order.Number} storno."
            : $"Zamówienie #{order.Number} zapłata.";
        
        return new CashCheque
        {
            BeforeCheque = new XElement(Tags.Center, message),
            AfterCheque = new XElement(Tags.QRCode, message)
        };
    }

    public void Dispose()
    {
        try
        {
            subscription.Dispose();
        }
        catch (RemotingException)
        {
            // nic do zrobienia przy utracie połączenia
        }
    }
}

private void StornoPastOrder()
{
    var pastOrder = PluginContext.Operations.GetPastOrders().First();
    var paymentType = pastOrder.Payments.First();

    // rt.WriteoffType.HasFlag(WriteoffType.Cafe) - storno z odpisem
    // rt.WriteoffType == WriteoffType.None - storno bez odpisu
    var removalType = PluginContext.Operations.GetRemovalTypesToStornoPastOrderItems().First(rt => rt.WriteoffType.HasFlag(WriteoffType.Cafe));
    var section = pastOrder.RestaurantSection;
    var orderType = pastOrder.OrderType;
    var taxationSystem = PluginContext.Operations.GetTaxationSystemsToStornoPastOrderItems().Select(ts => (TaxationSystem?)ts).FirstOrDefault();

    PluginContext.Operations.StornoPastOrder(
        PluginContext.Operations.GetCredentials(),
        pastOrder,
        paymentType,
        removalType,
        section,
        orderType,
        null,
        taxationSystem,
        null);
}

private void StornoProducts()
{
    var paymentType = PluginContext.Operations.GetPaymentTypesToStornoPastOrderItems().First(pt => pt.Name.Contains("SampleApiPayment"));

    // rt.WriteoffType.HasFlag(WriteoffType.Cafe) - storno z odpisem
    // rt.WriteoffType == WriteoffType.None - storno bez odpisu
    var removalType = PluginContext.Operations.GetRemovalTypesToStornoPastOrderItems().First(rt => rt.WriteoffType.HasFlag(WriteoffType.Cafe));
    var section = PluginContext.Operations.GetTerminalsGroupRestaurantSections(PluginContext.Operations.GetHostTerminalsGroup()).First();
    var orderType = PluginContext.Operations.GetOrderTypes().FirstOrDefault(ot => ot.OrderServiceType == OrderServiceTypes.Common);
    var taxationSystem = PluginContext.Operations.GetTaxationSystemsToStornoPastOrderItems().Select(ts => (TaxationSystem?)ts).FirstOrDefault();

    var activeProducts = PluginContext.Operations.GetActiveProducts()
        .Where(product => product.Template == null &&
            (product.Type == ProductType.Dish || product.Type == ProductType.Modifier || product.Type == ProductType.Goods || product.Type == ProductType.ForPurchase))
        .ToList();

    PluginContext.Operations.StornoPastOrderItems(
        PluginContext.Operations.GetCredentials(),
        GetPastOrderItems(activeProducts).ToList(),
        paymentType,
        removalType,
        section,
        orderType,
        null,
        taxationSystem,
        null);
}

private IEnumerable<PastOrderItem> GetPastOrderItems(IReadOnlyList<IProduct> activeProducts)
{
    var product = activeProducts.First(p => p.Name.Contains("Tea"));
    yield return new PastOrderItem
    {
        IsMainDish = true,
        Product = product,
        ProductSize = PluginContext.Operations.GetProductSizes().FirstOrDefault(ps => ps.Name.Contains("S")),
        Amount = 2,
        SumWithDiscounts = 100.5m,
        Price = 0, // nieużywane w StornoPastOrderItems
        SumWithoutDiscounts = 0, // nieużywane w StornoPastOrderItems
    };

    product = activeProducts.First(p => p.Name.Contains("Cream"));
    yield return new PastOrderItem
    {
        IsMainDish = false,
        Product = product,
        ProductSize = null,
        Amount = 2,
        SumWithDiscounts = 0m,
        Price = 0, // nieużywane w StornoPastOrderItems
        SumWithoutDiscounts = 0, // nieużywane w StornoPastOrderItems
    };

    product = activeProducts.First(p => p.Name.Contains("Puree"));
    yield return new PastOrderItem
    {
        IsMainDish = true,
        Product = product,
        ProductSize = null,
        Amount = 1,
        SumWithDiscounts = 90m,
        Price = 0, // nieużywane w StornoPastOrderItems
        SumWithoutDiscounts = 0, // nieużywane w StornoPastOrderItems
    };

    product = activeProducts.First(p => p.Name.Contains("Bottle"));
    yield return new PastOrderItem
    {
        IsMainDish = true,
        Product = product,
        ProductSize = null,
        Amount = 2,
        SumWithDiscounts = -15m,
        Price = 0, // nieużywane w StornoPastOrderItems
        SumWithoutDiscounts = 0, // nieużywane w StornoPastOrderItems
    };
}