using System;

using System.Linq;

using Gtt.InterestCalculator;

​

public class Program

{

    public static void Main()

    {

        var accounts = new Account[]

        {

            new Account("Citi", 98.57m, 3566.74m, 16.99m),

            new Account("Chase 4128", 92m, 3931.37m, 15.24m),

            new Account("Fnbo", 48.02m, 1187.42m, 9.99m),

            new Account("Capital One", 54m, 2391.14m, 14.99m),

            new Account("Chase 2457", 85m, 4224.76m, 14.99m),

            new Account("Syf", 15.78m, 387.66m, 0m),

            new Account("UMB Cardcenter", 61m, 3178.06m, 11.15m)

        };

        accounts.ProcessAvalanche(1212.85m);

        accounts.ProcessAvalanche(1712.85m);

    }

}

​

public static class AccountsExtensions

{

    public static void ProcessAvalanche(this Account[] accounts, decimal avalancheAmount, bool printAvalanches = false)

    {

        Console.WriteLine("\nProcessing avalance of " + avalancheAmount);

        var orderedAccounts = accounts.OrderByDescending(a => a.APR);

        int month = 0;

        foreach (var account in orderedAccounts) { account.RemainingBalance = account.Balance; }

        while (accounts.Any(a => a.RemainingBalance > 0))

        {

            month++;

            var monthlyAvalanche = avalancheAmount;

            // First pay down all the monthly minimums and add interest

            foreach (var account in orderedAccounts)

            {

                if (account.RemainingBalance <= 0) continue;

                var monthlyPayment = account.Minimum > account.RemainingBalance ? account.RemainingBalance : account.Minimum;

                account.RemainingBalance -= monthlyPayment;

                if (account.APR > 0) 

                {

                    decimal interest = Gtt.InterestCalculator.CompoundInterestCalculator.CalculateInterest(account.RemainingBalance, account.APR / 100m, 1d/12d);

                    account.RemainingBalance += interest;

                }

                monthlyAvalanche -= monthlyPayment;

                if (account.RemainingBalance <= 0) Console.WriteLine("\tPaid off " + account.Name + " in month " + month);

            }

            // Now pay all the remaining avalanche toward the highest APR card

            foreach (var account in orderedAccounts)

            {

                if (account.RemainingBalance <= 0) continue;

                var avalanchePayment = account.RemainingBalance > monthlyAvalanche ? monthlyAvalanche : account.RemainingBalance;

                account.RemainingBalance -= avalanchePayment; // All the avalanche goes here, no interest to worry about

                monthlyAvalanche -= avalanchePayment;

                if (account.RemainingBalance <= 0) Console.WriteLine("\tPaid off " + account.Name + " in month " + month);

                if (monthlyAvalanche <= 0) break;

            }

        }

    }

}

​

public class Account

{

    public string Name { get; set; }

    public decimal Minimum { get; set; }

    public decimal Balance { get; set; }

    public decimal APR { get; set; }

    public decimal RemainingBalance { get; set; }

    public Account(string name, decimal minimum, decimal balance, decimal apr)

    {

        Name = name;

        Minimum = minimum;

        Balance = balance;

        APR = apr;

    }

}