public async Task <PurchaseModel> OrderItem(int id, string sessionId)
{
//by default you can buy the item
var result = new PurchaseModel
{
CanBuy = true,
SellableItem = _mapper.Map <SellableItemModel>(await _sellableItemRepository.Find(id)),
InsertedTokens = await _tokenService.GetCollection(sessionId)
};
//always deduct only one item per purchase
//no stock available
if (result.SellableItem.Quantity == 0)
{
result.Message = "The item is out of stock";
result.CanBuy = false;
}
//define 1 to be deducted later from the stock
result.SellableItem.Quantity = 1;
//not enough money to buy
if (result.InsertedTokens.Total < result.SellableItem.Price)
{
double remainingMoney = result.SellableItem.Price - result.InsertedTokens.Total;
result.Message =
$"Insufficient money. You need to add at least {remainingMoney / 100} eur to buy this item";
result.CanBuy = false;
}
if (!result.CanBuy)
{
return(result);
}
if (result.InsertedTokens.Total != result.SellableItem.Price)
{
var exchangeTokens = await _ledgerRepository.GetExchangeTokens();
var giveBack = result.InsertedTokens.Total - result.SellableItem.Price;
var tokensToExchange = new List <ExchangeToken>();
while (giveBack > 0 && result.CanBuy)
{
foreach (var t in exchangeTokens)
{
if (giveBack / t.Value <= 0)
{
continue;
}
if (t.Quantity == 0)
{
result.CanBuy = false;
result.Message = "The machine doesn't have enough exchange tokens, ask for help.";
}
giveBack -= t.Value;
t.Quantity--;
tokensToExchange.Add(t);
break;
}
}
result.ExchangeTokens = _mapper.Map <TokenModelCollection>(tokensToExchange);
await _ledgerRepository.AddExchangeTokens(sessionId, tokensToExchange);
}
var subtracted = await _ledgerRepository.Subtract(sessionId, result.SellableItem.Price);
var subtractedTokens = subtracted.Select(p => p.Token);
await _sellableItemRepository.DeductStock(_mapper.Map <SellableItem>(result.SellableItem));
result.Message = "Thanks for your order";
result.SubtractedTokens = _mapper.Map <TokenModelCollection>(subtractedTokens);
return(result);
}