public GoodsBuyedEvent BuyGoods(IReadOnlyCollection <Coin> depositedAmount, GoodsIdentity goods)
{
Contract.Requires(depositedAmount != null);
var availableGoods = _availableGoods.Retrieve(goods);
var depositWallet = new Wallet(depositedAmount);
var depositTotal = depositWallet.TotalFunds();
if (depositTotal < availableGoods.Price)
{
throw new InsufficientAmountForBuyingGoodsException(availableGoods.Price, depositTotal, goods);
}
var refundAmount = depositTotal - availableGoods.Price;
_vendingMachineWallet = _vendingMachineWallet.Put(depositedAmount);
_buyerWallet = _buyerWallet.Retrieve(depositedAmount);
var refundCoins = Refund(refundAmount);
var refundWallet = new Wallet(refundCoins);
if (refundWallet.TotalFunds() != refundAmount)
{
throw new VendingMachineDoesNotHaveCoinsForRefundException(_vendingMachineWallet, refundAmount);
}
_vendingMachineWallet = _vendingMachineWallet.Retrieve(refundCoins);
_buyerWallet = _buyerWallet.Put(refundCoins);
return(new GoodsBuyedEvent(_vendingMachineWallet, _buyerWallet, availableGoods, refundCoins));
}
public Goods(GoodsIdentity identity, decimal price, int count)
{
Contract.Requires(price > decimal.Zero);
Contract.Requires(count >= 0);
Identity = identity;
Price = price;
Count = count;
}
public Goods Retrieve(GoodsIdentity goods, int count = 1)
{
Contract.Requires(count > 0);
var availableGoods = _bag.SingleOrDefault(g => g.Identity.Equals(goods));
if (availableGoods == null || availableGoods.Count < count)
{
throw new GoodsShortageException(availableGoods, count);
}
_bag.Remove(availableGoods);
availableGoods = new Goods(goods, availableGoods.Price, availableGoods.Count - count);
if (availableGoods.Count > count)
{
_bag.Add(availableGoods);
}
return(availableGoods);
}