/// <summary>
/// Buys good via barter.
/// </summary>
/// <param name="buyerStock">The buyer's goods up for trade.</param>
/// <param name="good">The good being traded for.</param>
/// <param name="amount">The amount of the good being bought.</param>
/// <param name="market">The market that the barter is taking place in.</param>
/// <returns>The resulting change in goods for the buyer.</returns>
public IProductAmountCollection BarterGood(IProductAmountCollection buyerStock,
IProduct good, double amount, IMarket market)
{
// TODO, update to use the coincidence of wants,
// it will discourage barter more than anything.
if (buyerStock == null)
{
throw new ArgumentNullException(nameof(buyerStock));
}
if (good == null)
{
throw new ArgumentNullException(nameof(good));
}
if (market == null)
{
throw new ArgumentNullException(nameof(market));
}
if (amount <= 0)
{
throw new ArgumentOutOfRangeException(nameof(amount));
}
// the return result of the barter
var result = new ProductAmountCollection();
// TODO a barter modifier, to discourage or encourage bartering.
// This should become more flexible later.
var BarterMod = 1;
// Get how much we can or want to get
amount = Math.Min(amount, ForSale.GetProductValue(good));
// get the price of the good.
var totalPrice = GetPrice(good, market.GetPrice(good)) * amount * BarterMod;
// get the total price of what's offered.
double barterVal = 0;
foreach (var product in buyerStock)
{
barterVal += market.GetPrice(product.Item1) * product.Item2;
}
// the barter we're trading for the goods.
IProductAmountCollection barter;
// if the available barter is greater than the price, begin bartering
if (barterVal >= totalPrice)
{
// Use get change for the easiest option.
barter = market.ChangeForPrice(buyerStock, totalPrice);
// don't go more accurate, barter isn't supposed to be more accurate to coins,
// no one would accept change in bits of wheat.
// Add the goods being bought
result.AddProducts(good, amount);
// Remove the goods being traded.
result.AddProducts(barter.Multiply(-1));
}
else
{
// if it's not enough, throw it all in, and buy what you can.
double buyableUnits = 0;
// if the good is fractional
if (good.Fractional)
{
// just divide
buyableUnits = barterVal / (market.GetPrice(good) * BarterMod);
}
else
{
// round down
buyableUnits = Math.Floor(barterVal / (market.GetPrice(good) * BarterMod));
}
// If we can buy anything, do so.
if (buyableUnits > 0)
{
// add the goods
result.AddProducts(good, buyableUnits);
// subtract the goods
result.AddProducts(buyerStock.Multiply(-1));
}
}
// No change, this is bartering.
// We've done what we can, move on.
return(result);
}
public IProductAmountCollection BuyGood(IProductAmountCollection cash,
IProduct good, double amount, IMarket market)
{
// Sanity check for nulls.
if (cash is null)
{
throw new ArgumentNullException(nameof(cash));
}
if (good is null)
{
throw new ArgumentNullException(nameof(good));
}
if (market is null)
{
throw new ArgumentNullException(nameof(market));
}
if (amount <= 0)
{
throw new ArgumentOutOfRangeException(nameof(amount));
}
// The collection we're returning.
var result = new ProductAmountCollection();
// get how much to buy, what's available, or what's desired.
var available = Math.Min(amount, ForSale.GetProductValue(good));
// get the price of that good
var totalPrice = GetPrice(good, market.GetPrice(good)) * available;
// get the cash needed for the goods
var money = market.ChangeForPrice(cash, totalPrice);
// get our available money total
var totalMoney = money.Sum(x => market.GetPrice(x.Item1, x.Item2));
// if the money is enough, just buy outright
if (totalMoney >= totalPrice)
{
// Add what they're buying.
result.AddProducts(good, available);
// remove what they spent
result.AddProducts(money.Multiply(-1));
}
else if (!good.Fractional && totalMoney < market.GetPrice(good))
{// If the total money is not enough for a single unit, and the good can't be divided
// we can't actually buy anything, so just return an empty transaction
return(new ProductAmountCollection());
}
else // if it's not enough
{
// get the buyable units of the good
double buyableUnits = 0;
// if we can buy fractionally
if (good.Fractional)
{
// just do the math straight.
buyableUnits = totalMoney / market.GetPrice(good);
}
else // if we can't
{
// take what we can and round down, seller should always make more than the buyer here.
buyableUnits = Math.Floor(totalMoney / market.GetPrice(good));
}
// if we can buy any units
if (buyableUnits > 0)
{
// buy them add the units to the results
result.AddProducts(good, buyableUnits);
// subtract the cash.
result.AddProducts(money.Multiply(-1));
}
}
// Get change, if any.
var change = totalMoney - market.GetPrice(good) * result.GetProductValue(good);
// get the change, if any
IProductAmountCollection buyersChange = new ProductAmountCollection();
// if change is greater than 0.
if (change > 0) // Make said change.
{
buyersChange = market.ChangeForPrice(GetCash(market.AcceptedCurrencies), change);
}
// add back the buyer's change
result.AddProducts(buyersChange);
// TODO, maybe add check to see if the seller shortchanged the buyer.
// complete the transaction for the seller, and subtract the result.
CompleteTransaction(result.Multiply(-1));
// we're done, return the change in the buyer's goods.
return(result);
}