/// <summary>
/// call all machine item categories to try and find the item you are looking for.
/// </summary>
/// <param name="position">The position in the vending macine of the item.</param>
/// <returns><see cref="MachineItem"/></returns>
private MachineItem TryFindMachineItem(MachineItemPosition position)
{
var chipsTask = Task.Run(() => tryChips(position));
var chocolatesTask = Task.Run(() => tryChocolates(position));
var sweetsTask = Task.Run(() => trySweets(position));
var drinksTask = Task.Run(() => tryDrinks(position));
Task.WaitAll(chipsTask, chocolatesTask, sweetsTask, drinksTask);
if (chipsTask.Result != null)
{
return(chipsTask.Result);
}
if (chocolatesTask.Result != null)
{
return(chocolatesTask.Result);
}
if (sweetsTask.Result != null)
{
return(sweetsTask.Result);
}
if (drinksTask.Result != null)
{
return(drinksTask.Result);
}
return(null);
}
private MachineItem tryChocolates(MachineItemPosition position)
{
var chipsItem = _vendingMachineItems.Chocolates.ToList().Find(x => x.Position.Equals(position));
if (chipsItem == null)
{
return(null);
}
return(chipsItem);
}
/// <summary>
/// get the item from the machine based on the position in the machine it is in.
/// </summary>
/// <param name="position">The position of the item in the vending machine,</param>
/// <param name="tenderAmount">The amount an individual has put in the vending machine.</param>
/// <returns>decimal</returns>
public decimal ProcessPurchase(MachineItemPosition position, decimal tenderAmount)
{
MachineItem item = TryFindMachineItem(position);
if (item == null)
{
throw new ApplicationException($"Unable to find the vending machine item at position: {position.ToString()}.");
}
if (tenderAmount < item.Price)
{
throw new ApplicationException($"The amount provided: {_currencySymbol} {tenderAmount}, is less than the required amount of: {_currencySymbol} {item.Price} for the {item.Item}");
}
return(calculateChange(item.Price, tenderAmount));
}
