/**
* Determine the cost of a given number of an item and calculate a new value for the item
* accordingly.
*
* @param oper 1 for buying, 0 for selling.
* @param commodity the commodity in question
* @param amount the desired amount of the item in question
* @return the total cost and the calculated new value as an Invoice
*/
public Invoice generateInvoice(int oper, Commodities commodity, int amount) {
// get the initial value of the item, 0 for not found
Invoice inv = new Invoice(0.0, 0.0);
inv.value = commodity.getValue();
// get the spread so we can do one initial decrement of the value if we are selling
BigDecimal spread = BigDecimal.valueOf(commodity.getSpread());
// determine the total cost
inv.total = 0.0;
for (int x = 1; x <= amount; x++) {
BigDecimal minValue = BigDecimal.valueOf(commodity.getMinValue());
BigDecimal maxValue = BigDecimal.valueOf(commodity.getMaxValue());
BigDecimal changeRate = BigDecimal.valueOf(commodity.getChangeRate());
// work the spread on the first one.
if ((oper == 0) && (x == 1)) {
inv.subtractValue(spread.doubleValue());
} else if ((oper == 0) && (x > 1)) { // otherwise, do the usual decriment.
inv.subtractValue(changeRate.doubleValue());
}
// check the current value
if (inv.getValue() >= minValue.doubleValue()) { // current value is @ or above minValue
// be sure value is not above maxValue
if (inv.getValue() < maxValue.doubleValue()) { // current value is "just right"
inv.addTotal(inv.getValue()); // add current value to total
} else { // current value is above the max
inv.addTotal(maxValue.doubleValue()); // add maxValue to total
}
} else { // current value is below the minimum
inv.addTotal(minValue.doubleValue()); // add the minimum to total
if ((oper == 0) && (x == 1)) {
inv.subtractTotal(
spread
.doubleValue()); // subtract the spread if we're selling and this is the first run
}
}
// Change our stored value for the item
// we don't care about min/maxValue here because we don't want the value to 'bounce' off of
// them.
if (oper == 1) {
inv.addValue(changeRate.doubleValue());
}
}
return inv;
}
