Helper class that provides most commonly used Extension Methods for DateTime object

using System;
using System.Collections.Generics;

namespace Utilities
{
    /// <summary>
    /// DayExtensions
    /// </summary>
    public static class DayExtensions
    {

         /// <summary>
        /// Determines whether the specified current date is future date.
        /// </summary>
        /// <param name="date">The date.</param>
        /// <returns>
        ///     <c>true</c> if [is future date] [the specified date]; otherwise, <c>false</c>.
        /// </returns>
        public static bool IsFutureDate(this DateTime date)
        {
             int currentYear = DateTime.Now.Year;
             bool isFutureDate = false;

             //Future Year.
            if (date.Year > currentYear)
            {
                isFutureDate = true;
            }
            else
            {
                 if (date.Year < currentYear)
                 {
                      //Earlier Year.
                    isFutureDate = false;

                 }
                 else
                 {
                     //Current Year.
                    isFutureDate = date.DayOfYear > DateTime.Now.DayOfYear ? true : false;
                 }
             }
             return isFutureDate;
        }


        /// <summary>
        /// Determines whether [is weekend date] [the specified date].
        /// </summary>
        /// <param name="date">The date.</param>
        /// <returns>
        ///     <c>true</c> if [is weekend date] [the specified date]; otherwise, <c>false</c>.
        /// </returns>
        public static bool IsWeekendDate(this DateTime date)
        {
             if ((date.DayOfWeek == DayOfWeek.Saturday) || (date.DayOfWeek == DayOfWeek.Sunday))
            {
                 return true;
            }
            else
            {
                 return false;
            }
        }

         /// <summary>
        /// Lasts the day.
        /// </summary>
        /// <param name="date">The date.</param>
        /// <returns></returns>
        public static DateTime LastDay(this DateTime date)
        {
             int daysInMonth = DateTime.DaysInMonth(date.Year, date.Month);

            DateTime lastDay = date.FirstDay().AddDays(daysInMonth - 1);

             return lastDay;
        }

         /// <summary>
        /// Returns a DateTime representing the first day in the current month
        /// </summary>
        /// <param name="date">The date</param>
        /// <returns></returns>
        public static DateTime FirstDay(this DateTime date)
        {
            DateTime firstday = date.AddDays(1 - date.Day);
             return firstday;
        }

        /// <summary>
        /// Returns a DateTime representing the first specified day in the current month
        /// </summary>
        /// <param name="date">The day</param>
        /// <param name="dayOfWeek">The current day of week</param>
        /// <returns></returns>
        public static DateTime FirstDayofWeek(this DateTime date, DayOfWeek dayOfWeek)
        {
            DateTime first = date.FirstDay();

             if (first.DayOfWeek != dayOfWeek)
            {
                first = first.Next(dayOfWeek);
             }

             return first;
        }


        /// <summary>
        /// Returns a DateTime representing the last specified day in the current month
        /// </summary>
        /// <param name="date">The date</param>
        /// <param name="dayOfWeek">The current day of week</param>
        /// <returns></returns>
        public static DateTime Last(this DateTime date, DayOfWeek dayOfWeek)
        {
            DateTime last = date.LastDay();

            last = last.AddDays(Math.Abs(dayOfWeek - last.DayOfWeek) * -1);

             return last;
        }

         /// <summary>
        /// Returns aDateTime representing the first date following the current date which falls on the given day of the week
        /// </summary>
        /// <param name="date">The date</param>
        /// <param name="dayOfWeek">The day of week for the next date to get</param>
        /// <returns></returns>
        public static DateTime Next(this DateTime date, DayOfWeek dayOfWeek)
         {
             int offsetDays = dayOfWeek - date.DayOfWeek;

             if (offsetDays <= 0)
            {
                offsetDays += 7;
            }

           return date.AddDays(offsetDays);
        }

        /// <summary>
        /// Gets the Previous/Last occured Friday's Date. Returns this friday if the date is in current week. or the
        /// </summary>
        /// <param name="current">The current.</param>
        /// <param name="defaultDate">The default date.</param>
        /// <returns></returns>
        public static DateTime LastFriday(this DateTime current, DateTime? defaultDate)
        {

            DayOfWeek today         = DateTime.Now.DayOfWeek;
            int days                = today - DayOfWeek.Sunday;
            DateTime weekStartDate  = DateTime.Now.AddDays(-days);
            DateTime weekEndDate    = weekStartDate.AddDays(6);

            double offset = 0;

             if ((current.Ticks > weekStartDate.Ticks) && (current.Ticks < weekEndDate.Ticks))
            {
                 //Selected date is in current week. Adjust the offset and send it back.
                 switch (current.DayOfWeek)
                 {
                      case DayOfWeek.Monday:
                        offset = -3;
                         break;
                     case DayOfWeek.Tuesday:
                        offset = -4;
                         break;
                     case DayOfWeek.Wednesday:
                        offset = -5;
                         break;
                     case DayOfWeek.Thursday:
                        offset = -6;
                         break;
                     case DayOfWeek.Friday:
                        offset = -7;
                         break;
                     case DayOfWeek.Saturday:
                        offset = -1;
                         break;
                     case DayOfWeek.Sunday:
                        offset = -2;
                         break;
                 }
             }
             else
            {
                 //return friday of selected day's week.
                 switch (current.DayOfWeek)
                 {
                      case DayOfWeek.Monday:
                        offset = 4;
                         break;
                     case DayOfWeek.Tuesday:
                        offset = 3;
                         break;
                     case DayOfWeek.Wednesday:
                        offset = 2;
                         break;
                     case DayOfWeek.Thursday:
                        offset = 1;
                         break;
                     case DayOfWeek.Friday:
                        offset = 0;
                         break;
                     case DayOfWeek.Saturday:
                        offset = -1;
                         break;
                     case DayOfWeek.Sunday:
                        offset = 5;
                         break;
                }
            }
          
            return current.AddDays(offset);
        }
    }