dotnet-cqrs/Svrnty.Sample/Sagas/OrderFulfillmentSaga.cs

using Svrnty.CQRS.Events.Abstractions.Sagas;

namespace Svrnty.Sample.Sagas;

/// <summary>
/// Sample saga demonstrating compensation pattern for order fulfillment.
/// </summary>
/// <remarks>
/// This saga orchestrates:
/// 1. Reserve Inventory
/// 2. Authorize Payment
/// 3. Ship Order
///
/// If any step fails, all completed steps are compensated in reverse order.
/// </remarks>
public sealed class OrderFulfillmentSaga : ISaga
{
    public string SagaId { get; set; } = string.Empty;
    public string CorrelationId { get; set; } = string.Empty;
    public string SagaName { get; set; } = "order-fulfillment";
}

/// <summary>
/// Saga steps for order fulfillment.
/// </summary>
public static class OrderFulfillmentSteps
{
    /// <summary>
    /// Step 1: Reserve inventory for the order.
    /// </summary>
    public static async Task ReserveInventoryAsync(ISagaContext context, CancellationToken cancellationToken)
    {
        var orderId = context.Get<string>("OrderId");
        var items = context.Get<List<OrderItem>>("Items") ?? new List<OrderItem>();

        Console.WriteLine($"[SAGA] Reserving inventory for order {orderId}...");

        // Simulate inventory reservation
        await Task.Delay(100, cancellationToken);

        var reservationId = Guid.NewGuid().ToString();
        context.Set("ReservationId", reservationId);

        Console.WriteLine($"[SAGA] Inventory reserved: {reservationId}");
    }

    /// <summary>
    /// Compensation: Release inventory reservation.
    /// </summary>
    public static async Task CompensateReserveInventoryAsync(ISagaContext context, CancellationToken cancellationToken)
    {
        var reservationId = context.Get<string>("ReservationId");

        Console.WriteLine($"[SAGA] COMPENSATING: Releasing inventory reservation {reservationId}...");

        // Simulate inventory release
        await Task.Delay(100, cancellationToken);

        Console.WriteLine($"[SAGA] COMPENSATING: Inventory released");
    }

    /// <summary>
    /// Step 2: Authorize payment for the order.
    /// </summary>
    public static async Task AuthorizePaymentAsync(ISagaContext context, CancellationToken cancellationToken)
    {
        var orderId = context.Get<string>("OrderId");
        var amount = context.Get<decimal>("Amount");

        Console.WriteLine($"[SAGA] Authorizing payment for order {orderId}: ${amount}...");

        // Simulate payment authorization (could fail based on saga data)
        await Task.Delay(100, cancellationToken);

        var shouldFail = context.Get<bool>("FailPayment");
        if (shouldFail)
        {
            throw new InvalidOperationException("Payment authorization failed: Insufficient funds");
        }

        var authorizationCode = Guid.NewGuid().ToString();
        context.Set("AuthorizationCode", authorizationCode);

        Console.WriteLine($"[SAGA] Payment authorized: {authorizationCode}");
    }

    /// <summary>
    /// Compensation: Void payment authorization.
    /// </summary>
    public static async Task CompensateAuthorizePaymentAsync(ISagaContext context, CancellationToken cancellationToken)
    {
        var authorizationCode = context.Get<string>("AuthorizationCode");

        Console.WriteLine($"[SAGA] COMPENSATING: Voiding payment authorization {authorizationCode}...");

        // Simulate payment void
        await Task.Delay(100, cancellationToken);

        Console.WriteLine($"[SAGA] COMPENSATING: Payment voided");
    }

    /// <summary>
    /// Step 3: Ship the order.
    /// </summary>
    public static async Task ShipOrderAsync(ISagaContext context, CancellationToken cancellationToken)
    {
        var orderId = context.Get<string>("OrderId");
        var address = context.Get<string>("ShippingAddress");

        Console.WriteLine($"[SAGA] Shipping order {orderId} to {address}...");

        // Simulate shipping
        await Task.Delay(100, cancellationToken);

        var trackingNumber = $"TRACK-{Guid.NewGuid().ToString()[..8].ToUpper()}";
        context.Set("TrackingNumber", trackingNumber);

        Console.WriteLine($"[SAGA] Order shipped: Tracking #{trackingNumber}");
    }

    /// <summary>
    /// Compensation: Cancel shipment.
    /// </summary>
    public static async Task CompensateShipOrderAsync(ISagaContext context, CancellationToken cancellationToken)
    {
        var trackingNumber = context.Get<string>("TrackingNumber");

        Console.WriteLine($"[SAGA] COMPENSATING: Canceling shipment {trackingNumber}...");

        // Simulate shipment cancellation
        await Task.Delay(100, cancellationToken);

        Console.WriteLine($"[SAGA] COMPENSATING: Shipment cancelled");
    }
}

/// <summary>
/// Order item for saga.
/// </summary>
public sealed class OrderItem
{
    public required string ProductId { get; init; }
    public required string ProductName { get; init; }
    public int Quantity { get; init; }
    public decimal Price { get; init; }
}