using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        const int DIGITS_BEFORE_COMPLEX_RANDOM = 9;

        long unixMs = (long)DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;

        // difference between 1.00ba and 6.00ba: 

        double differenceBetweenMinAndMax = 12860928449;//11000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000d;

        int power = (int)Math.Ceiling(Math.Log10(differenceBetweenMinAndMax));

        if (differenceBetweenMinAndMax / Math.Pow(10, power) == 1)

            power++;

        Console.WriteLine("Possible Range: " + differenceBetweenMinAndMax);

        Console.WriteLine("Num digits before we only apply random to the left most digits of this length: " + DIGITS_BEFORE_COMPLEX_RANDOM);

        Console.WriteLine("Power for base 10: " + power);

        if (power > DIGITS_BEFORE_COMPLEX_RANDOM)

        {

            long unixMsSwapped = MakeUnixTimestampSignificant(unixMs, DIGITS_BEFORE_COMPLEX_RANDOM);

            double divisor = Math.Pow(10, power - DIGITS_BEFORE_COMPLEX_RANDOM);

            double toRandom = Math.Floor(differenceBetweenMinAndMax / divisor);

            double randomed = unixMsSwapped % (long)toRandom;

            double finalVal = randomed * divisor;

            string toSwap = unixMs.ToString();

            Console.WriteLine("Max amount possible to add to Min: " + differenceBetweenMinAndMax);

            Console.WriteLine("Num to divide by: " + divisor);

            Console.WriteLine("Num to random after dividing: " + toRandom);

            Console.WriteLine("Randomed Number: " + randomed);

            Console.WriteLine("Num after multiplying by the previous divisor: " + finalVal);

        }

        else

        {

            long unixMsSwapped = MakeUnixTimestampSignificant(unixMs, power);

            double finalVal = unixMsSwapped % differenceBetweenMinAndMax;

            Console.WriteLine("Randomed Number with full precision: " + finalVal);

        }

    }

    static long MakeUnixTimestampSignificant(long ms, int significantDigits)

    {

        // this is within 1 second, we'll be fine.

        if (significantDigits <= 4)

            return ms;

        StringBuilder swapper = new StringBuilder(ms.ToString());

        int maxIndex = swapper.Length - significantDigits;

        char first = swapper[swapper.Length - 1];

        char second = swapper[swapper.Length - 2];

        swapper[swapper.Length - 1] = swapper[maxIndex];

        swapper[swapper.Length - 2] = swapper[maxIndex + 1];

        swapper[maxIndex] = first;

        swapper[maxIndex + 1] = second;

        Console.WriteLine("Timestamp Before Swap = " + ms);

        Console.WriteLine("Timestamp After Swap = " + swapper.ToString());

        return long.Parse(swapper.ToString());

    }

}