using System;

​

namespace Comments

{

    public class Program

    {

        public static void Main(string[] args)

        {

            // INTEGER VALUES ARE: year, month, day, hour, minute, second

            // manually adjust as needed

            DateTime startDate = new DateTime(2016, 1, 1, 12, 1, 0);

            DateTime endDate = new DateTime(2016, 1, 2, 12, 1, 0);

            // Call the routine and display its results

            Console.Write(GetRelativeTimeBetweenDates(startDate, endDate));

        }

​

        /// <summary>

        /// Returns a string representing the relative time for when the tweet was tweeted.

        /// I started out using this as a base, but rewrote some of it: http://www.dotnetperls.com/pretty-date

        /// </summary>

        /// <param name = "startDate">The start date</param>

        /// <param name = "endDate">The end date</param>

        /// <returns>A string representing the relative time between the two dates</returns>

        public static string GetRelativeTimeBetweenDates(DateTime startDate, DateTime endDate)

        {

            const int MAXIMUM_DAYS_IN_MONTH = 31;

            const int ONE_MINUTE = 60;

            const int TWO_MINUTES = 120;

            const int ONE_HOUR = 3600;

            const int TWO_HOURS = 7200;

            const int ONE_DAY = 86400;

            const int ONE_WEEK = 7;

            const string DATE_FORMAT = "dd mmm yyyy";

            TimeSpan interval = endDate.Subtract(startDate);

            int differenceInDays = (int)interval.TotalDays;

            int differenceInSeconds = (int)interval.TotalSeconds;

            string relativeTime = "";

            if (differenceInDays >= 0 && differenceInDays < MAXIMUM_DAYS_IN_MONTH)

            {

                if (differenceInDays == 0)

                {

                    if (differenceInSeconds < ONE_MINUTE)

                    {

                        relativeTime = "just now";

                    }

                    else if (differenceInSeconds < TWO_MINUTES)

                    {

                        relativeTime = "1 minute ago";

                    }

                    else if (differenceInSeconds < ONE_HOUR)

                    {

                        relativeTime = string.Format("{0} minutes ago", Math.Floor((double)differenceInSeconds / ONE_MINUTE));

                    }

                    else if (differenceInSeconds < TWO_HOURS)

                    {

                        relativeTime = "1 hour ago";

                    }

                    else if (differenceInSeconds < ONE_DAY)

                    {

                        relativeTime = string.Format("{0} hours ago", Math.Floor((double)differenceInSeconds / ONE_HOUR));

                    }

                }

                else if (differenceInDays == 1)

                {

                    DateTime yesterday = endDate.AddDays(-1);

                    if (startDate.Date == yesterday.Date)

                    {

                        relativeTime = "yesterday";

                    }

                    else

                    {

                        relativeTime = "2 days ago";

                    }

                }

                else if (differenceInDays < ONE_WEEK)

                {

                    relativeTime = string.Format("{0} days ago", differenceInDays);

                }

                else if (differenceInDays < MAXIMUM_DAYS_IN_MONTH)

                {

                    double numberOfWeeks = Math.Ceiling((double)differenceInDays / ONE_WEEK);

                    relativeTime = string.Format("{0} week{1} ago", numberOfWeeks, numberOfWeeks > 1 ? "s" : "");

                }

                else

                {

                    DateTime oneMonthAgo = endDate.AddMonths(-1);

                    if (startDate.Year == oneMonthAgo.Year && startDate.Month == oneMonthAgo.Month)

                    {

                        relativeTime = "last month";

                    }

                    else

                    {

                        relativeTime = startDate.ToString(DATE_FORMAT);

                    }

                }

            }

​

            return relativeTime;

        }

    }

}