public async Task <IActionResult> Create(ReservationInputModel model)
        {
            int ecenomyTickets           = model.Passengers.Count(p => p.TicketType == TicketType.Economy);
            int bussinesTickets          = model.Passengers.Count(p => p.TicketType == TicketType.Bussines);
            int availableEconomyTickets  = flightService.AvailableEconomyTickets(model.FlightId);
            int availableBusinessTickets = flightService.AvailableBussinesTickets(model.FlightId);

            if (availableEconomyTickets < ecenomyTickets)
            {
                ModelState.AddModelError(string.Empty, $"There are only {availableEconomyTickets} economy tickets left.");
            }
            if (availableBusinessTickets < bussinesTickets)
            {
                ModelState.AddModelError(string.Empty, $"There are only {availableBusinessTickets} business tickets left.");
            }

            if (!ModelState.IsValid)
            {
                return(View(model));
            }


            await reservationService.Create(model);

            await flightService.UpdateAvailableTickets(model.FlightId, ecenomyTickets, bussinesTickets);

            FlightViewModel flight = flightService.GetById <FlightViewModel>(model.FlightId);

            await SendConfirmationEmailsToPassengers(model.Passengers, flight);
            await SendEmailToClient(model.Client.Email, flight, model.Passengers);

            return(Redirect("/"));
        }