Merge pull request 'Refactored idempotency check to observe completed status' (#116) from payments into master

Reviewed-on: #116

LiteCharms.Features.MidrandBooks/Payments/PaymentService.cs

@@ -123,8 +123,7 @@ public sealed class PaymentService(IDbContextFactory<MidrandBooksDbContext> cont
             await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);
 
             var exists = await context.Ledger.AnyAsync(l =>
-                l.OrderId == orderId &&
+                l.OrderId == orderId && l.PaymentId == paymentId && l.Status == LedgerStatuses.Completed, cancellationToken);
-                l.PaymentId == paymentId, cancellationToken);
 
             return Result.Ok(exists);
         }
@@ -162,6 +161,7 @@ public sealed class PaymentService(IDbContextFactory<MidrandBooksDbContext> cont
                 CustomerId = request.CustomerId,
                 OrderId = request.OrderId,
                 PaymentId = request.PaymentId,
+                MerchantPaymentId = request.PaymentGatewayReference,
                 Status = request.Status,                
             });