public async Task CheckoutConfirmed()

in src/Relecloud.Web.CallCenter/Controllers/CartController.cs [140:187]
43 lines of code
7 McCabe index (conditional complexity)

        public async Task<IActionResult> CheckoutConfirmed(CheckoutViewModel model)
        {
            try
            {
                if (model == null || model.PaymentDetails is null)
                {
                    ModelState.AddModelError(string.Empty, "Invalid form state data");
                    return View(nameof(Checkout), model);
                }
                if (ModelState.IsValid)
                {
                    var cartData = await GetCartAsync();
                    var serializableDictionary = MapToSerializableDictionary(cartData.Concerts);

                    var purchaseResult = await this.ticketPurchaseService.PurchaseTicketAsync(new PurchaseTicketsRequest
                    {
                        ConcertIdsAndTicketCounts = serializableDictionary,
                        PaymentDetails = model.PaymentDetails,
                        UserId = User.GetUniqueId(),
                    });

                    if (purchaseResult.Status == PurchaseTicketsResultStatus.Success)
                    {
                        // Remove all items from the cart.
                        SetCartData(new Dictionary<int, int>());
                        this.telemetryClient.TrackEvent("CheckoutCart");
                        return RedirectToAction(nameof(Index), "Ticket");
                    }

                    if (purchaseResult.ErrorMessages is null)
                    {
                        ModelState.AddModelError(string.Empty, "We're sorry but the purchasing service is unavailable at this time.");
                    }
                    else
                    {
                        ModelState.AddErrorMessages(purchaseResult.ErrorMessages);
                    }
                }
            }
            catch (Exception ex)
            {
                this.logger.LogError(ex, $"Unable to perform checkout for ${User.Identity!.Name}");
                ModelState.AddModelError(string.Empty, "We're sorry for the iconvenience but there was an error while trying to process your order. Please try again later.");
            }

            model.Cart = await GetCartAsync();
            return View(nameof(Checkout), model);
        }