public HttpResponseMessage AddUserAndCosts(UserAndCost userAndCosts)
{
UsersAndCostStorage usersAndCostStorage = UsersAndCostStorage.GetInstance();
usersAndCostStorage.StoreUser(userAndCosts); //} catch (Exception) { return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, "Error Occurred while storing user and cost(s)"); }
return(Request.CreateResponse(HttpStatusCode.OK));
}
public List <MoneyTransferred> WhoOwesWho()
{
UsersAndCostStorage usersAndCostStorage = UsersAndCostStorage.GetInstance();
List <string> ListOfUsers = usersAndCostStorage.GetListOfUsers();
SortedDictionary <double, List <string> > TotalCostDictionary = new SortedDictionary <double, List <string> >();
double totalCost = 0.0;
foreach (string user in ListOfUsers)
{
List <string> ListOfCostUsers = new List <string>();
double totalCostForUser = usersAndCostStorage.GetUserTotalCost(user);
totalCost += totalCostForUser;
if (!TotalCostDictionary.TryGetValue(totalCostForUser, out ListOfCostUsers))
{
ListOfCostUsers = new List <string>();
ListOfCostUsers.Add(user);
TotalCostDictionary.Add(totalCostForUser, ListOfCostUsers);
}
else
{
ListOfCostUsers.Add(user);
}
}
double averageCost = totalCost / ListOfUsers.Count;
Stack <string> StackOfUsersWhoPaidMore = new Stack <string>();
Stack <double> StackOfUsersWhoPaidMoreCorrelatedTotal = new Stack <double>();
Stack <string> StackOfUsersWhoPaidLess = new Stack <string>();
Stack <double> StackOfUsersWhoPaidLessCorrelatedTotal = new Stack <double>();
foreach (KeyValuePair <double, List <string> > pair in TotalCostDictionary.Reverse())
{
if (pair.Key > averageCost)
{
foreach (string user in pair.Value)
{
StackOfUsersWhoPaidMore.Push(user);
StackOfUsersWhoPaidMoreCorrelatedTotal.Push(pair.Key);
}
}
else if (pair.Key < averageCost)
{
foreach (string user in pair.Value)
{
StackOfUsersWhoPaidLess.Push(user);
StackOfUsersWhoPaidLessCorrelatedTotal.Push(pair.Key);
}
}
}
List <MoneyTransferred> ListOfMoneyTransferred = new List <MoneyTransferred>();
while (StackOfUsersWhoPaidMore.Count > 0 && StackOfUsersWhoPaidLess.Count > 0)
{
string userWhoPaidMore = StackOfUsersWhoPaidMore.Pop();
double overPaidAmount = StackOfUsersWhoPaidMoreCorrelatedTotal.Pop() - averageCost;
while (overPaidAmount > 0 && StackOfUsersWhoPaidLess.Count > 0)
{
string userWhoPaidLess = StackOfUsersWhoPaidLess.Pop();
double paidAmount = StackOfUsersWhoPaidLessCorrelatedTotal.Pop();
double underPaidAmount = averageCost - paidAmount;
if (overPaidAmount == underPaidAmount)
{
MoneyTransferred moneyTransferred = new MoneyTransferred {
Payee = userWhoPaidMore, Payor = userWhoPaidLess, Amount = underPaidAmount
};
ListOfMoneyTransferred.Add(moneyTransferred);
overPaidAmount -= underPaidAmount;
}
else if (overPaidAmount > underPaidAmount)
{
overPaidAmount -= underPaidAmount;
StackOfUsersWhoPaidMore.Push(userWhoPaidMore);
StackOfUsersWhoPaidMoreCorrelatedTotal.Push(averageCost + overPaidAmount);
MoneyTransferred moneyTransferred = new MoneyTransferred {
Payee = userWhoPaidMore, Payor = userWhoPaidLess, Amount = underPaidAmount
};
ListOfMoneyTransferred.Add(moneyTransferred);
}
else if (overPaidAmount < underPaidAmount)
{
paidAmount += overPaidAmount;
StackOfUsersWhoPaidLess.Push(userWhoPaidLess);
StackOfUsersWhoPaidLessCorrelatedTotal.Push(paidAmount);
MoneyTransferred moneyTransferred = new MoneyTransferred {
Payee = userWhoPaidMore, Payor = userWhoPaidLess, Amount = overPaidAmount
};
ListOfMoneyTransferred.Add(moneyTransferred);
overPaidAmount = 0;
}
}
}
return(ListOfMoneyTransferred);
}
