/// <summary>
        /// Adds new transaction to table storage or updates an existing item.
        /// Throws exception when item is not valid, resolving customer external ID failed or if table storage operation fails.
        /// </summary>
        /// <param name="t">Transaction item to add/update</param>
        public void AddOrUpdateTransaction(Transaction t)
        {
            EnsureTransactionHasCustomerInternalID(t);
            t.EnsureEntityValidForStorage();

            var ent = new TransactionTableEntity(t.ID.Value, t.Date.Value, t.InternalRef.Value)
            {
                MvaNumber = t.MvaNumber,
                Amount = t.Amount,
                Description = t.Description,
                CustomerNumber = t.CustomerNumber,
                AccountID = t.AccountID,
                ProductID = t.ProductID,
                NotInvoiceable = t.NotInvoiceable,
                ExternalRecordID = t.ExternalRecordID,
            };

            AddOrUpdateTransaction(ent);
        }
        /// <summary>
        /// Adds the transaction item to search index. Can also be used for updating existing items by specifying the Transaction.ID value.
        /// Throws exception when item is not valid, resolving customer external ID failed or if search index operation fails.
        /// </summary>
        /// <param name="t"></param>
        public void AddToIndex(Transaction t)
        {
            t.EnsureEntityValidForStorage();

            Guid internalID;
            if (t.InternalRef.HasValue)
            {
                internalID = t.InternalRef.Value;
            }
            else
            {
                Customer c = new CustomerRepository().GetCustomerByExternalID(t.MvaNumber.Value, t.ExternalRef);
                if (c == null)
                {
                    throw new Exception(string.Format("Failed to resolve customer external ID ({0}) to internal", t.ExternalRef));
                }
                internalID = c.InternalID.Value;
            }
            
            var tableEnt = new TransactionTableEntity(t.ID.Value, t.Date.Value, internalID)
            {
                Amount = t.Amount,
                CustomerNumber = t.CustomerNumber,
                AccountID = t.AccountID,
                Description = t.Description,
                MvaNumber = t.MvaNumber,
                ProductID = t.ProductID
            };

            AddToIndex(tableEnt);
        }
        /// <summary>
        /// Adds the transaction item to WebJob queues. Workers process each queue item and add them to transaction table and search index.
        /// Can also be used for updating existing items if Transaction.ID is specified.
        /// Also generates ID if it's null and sets Date to DateTime.Now if it isn't set.
        /// </summary>
        /// <param name="t">Transaction item to add/update</param>
        /// <returns>The item that was added to queue. Throws exception when item is not valid or if adding to queue failed.</returns>
        public Transaction AddTransactionToUpdateQueue(Transaction t)
        {
            t.EnsureEntityValidForStorage(true);
            SerializeTransactionAndAddToQueue(t);

            return t;
        }