public async Task <IHttpActionResult> AcceptSellTransaction([FromBody] TransactionDto dto)
        {
            if (ModelState.IsValid == false)
            {
                return(BadRequest("Invalid data"));
            }
            if (dto.BuyOffer.BuyerId != (Thread.CurrentPrincipal as UserPrincipal).Id)
            {
                return(Unauthorized());
            }

            var sellOffer = _sellAssembler.DtoToEntity(dto.SellOffer);
            var buyOffer  = _buyAssembler.DtoToEntity(dto.BuyOffer);
            var rating    = dto.Rating;

            var result = await _transactionService.AcceptSellTransaction(sellOffer, buyOffer, rating);

            if (result == ErrorValue.ServerError)
            {
                return(BadRequest("Transaction error"));
            }
            else if (result == ErrorValue.TransactionAlreadyFinished)
            {
                return(BadRequest("Transaction already finished"));
            }
            return(Ok());
        }