using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        //###Static variables

        double rent = 2000000;

        double kpiRate = 0.025;

        double kpiShare = 0.5;

        int optionYears = 5;

        //Number of years to calculate data for

        int yearsToShow = 10;

        //Dates for contract duration

        DateTime contractStart = new DateTime(2017,07,01);

        DateTime contractEnd = new DateTime(2025,07,01);

        //Date for first KPI adjustment

        DateTime kpiStart = new DateTime(2023,07,01);

        //Current date used for comparing

        DateTime dateNow = DateTime.Now;

        //Dynamic variables

        DateTime optionStartDate = contractEnd.AddDays(1);

        //How many days is the duration of the contract?

        System.TimeSpan contractDaysDiff = contractEnd - contractStart;

        int contractDays = contractDaysDiff.Days;

        //How many days of first year the contract is valid for. E.g. does it start in middle of year?

        DateTime contractStartLastDay = new DateTime(contractStart.Year, 12 , 31);

        System.TimeSpan contractFirstYearDiff = (contractStartLastDay - contractStart);

        double contractFirstYearDays = contractFirstYearDiff.Days;

        //How many days of last year the contract is valid for. E.g. does it start in middle of year?

        DateTime contractEndLastDay = new DateTime(contractEnd.Year, 12 , 31);

        System.TimeSpan contractEndYearDiff = (contractEndLastDay - contractEnd);

        double contractEndYearDays = contractEndYearDiff.Days;

        double tempRent = rent;

        double tempOption = 0;

        List<double> rentResults = new List<double>();

        List<double> optionResults = new List<double>();

        //Variables to be used for keeping track of date within loop

        DateTime loopDate = dateNow;

        DateTime loopKPIDate = kpiStart;

        //###Loop for rental period

        bool firstRun = true;

        while(loopDate.Year <= contractEnd.Year) {

            //First run, only calculate rent for remaining days of current year

            if(firstRun) {

                //If kpiStart date has occured

                if(kpiStart <= loopDate) {

                        tempRent = (tempRent * (1+kpiRate*kpiShare))*contractFirstYearDays/365;

                        rentResults.Add(tempRent);

                        loopKPIDate = loopKPIDate.AddYears(1);

                        loopDate = loopDate.AddYears(1);

                    //If kpiStart has not occured

                    } else {

                        tempRent = rent*((contractFirstYearDays)/365);

                        rentResults.Add(tempRent);

                        loopKPIDate = loopKPIDate.AddYears(1);

                        loopDate = loopDate.AddYears(1);

                    }

                firstRun = false;

                continue;

            }

            //If we are in last year of contract, which might end in the middle of year we need to calculate for number of days

            if(loopDate.Year == contractEnd.Year) {

                //Standard loop, running whole contract period except first and last run.

                if(kpiStart <= loopDate) {

                    tempRent = (tempRent * (1+kpiRate*kpiShare))*(365-contractFirstYearDays)/365;

                    rentResults.Add(tempRent);

                    loopKPIDate = loopKPIDate.AddYears(1);

                    loopDate = loopDate.AddYears(1);

                } else {

                    tempRent = rent*(365-contractFirstYearDays)/365;

                    rentResults.Add(tempRent);

                    loopKPIDate = loopKPIDate.AddYears(1);

                    loopDate = loopDate.AddYears(1);

                }

                continue;

            }

            //Standard loop, running whole contract period except first and last run.

            if(kpiStart <= loopDate) {

                tempRent = (tempRent * (1+kpiRate*kpiShare));

                rentResults.Add(tempRent);

                loopKPIDate = loopKPIDate.AddYears(1);

                loopDate = loopDate.AddYears(1);

            } else {

                tempRent = rent;

                rentResults.Add(tempRent);

                loopKPIDate = loopKPIDate.AddYears(1);

                loopDate = loopDate.AddYears(1);

            }

        }

        //###Loop for option period

        firstRun = true;

        int i=0;

        while(i < optionYears) {

            //First run, only calculate option for remaining days of current year

            if(firstRun) {

                //If kpiStart date has occured

                if(kpiStart <= loopDate) {

                        tempOption = (tempOption * (1+kpiRate*kpiShare))*contractEndYearDays/365;

                        optionResults.Add(tempOption);

                        loopKPIDate = loopKPIDate.AddYears(1);

                        loopDate = loopDate.AddYears(1);    

                    //If kpiStart has not occured

                    } else {

                        tempOption = rent*((contractEndYearDays)/365);

                        optionResults.Add(tempOption);

                        loopKPIDate = loopKPIDate.AddYears(1);

                        loopDate = loopDate.AddYears(1);

                    }

                firstRun = false;

                continue;

            }

​

            //Standard loop, running whole contract period except first and last run.

            if(kpiStart <= loopDate) {

                tempOption = (tempOption * (1+kpiRate*kpiShare));

                optionResults.Add(tempOption);

                loopKPIDate = loopKPIDate.AddYears(1);

                loopDate = loopDate.AddYears(1);

            } else {

                tempOption = rent;

                optionResults.Add(tempOption);

                loopKPIDate = loopKPIDate.AddYears(1);

                loopDate = loopDate.AddYears(1);

            }

            i++;

        }

        //Reference code

        Console.WriteLine("Rent results");

        Console.WriteLine(rentResults.Count);

        i=0;

        foreach (var temp in rentResults) {

            if(i>=yearsToShow) {break;}

            Console.WriteLine(temp);

            i++;

        }

        Console.WriteLine("Option results");

        Console.WriteLine(optionResults.Count);

        foreach (var temp in optionResults) {

            if(i>=yearsToShow) {break;}

            Console.WriteLine(temp);

            i++;

        }

    }

}