NSLocale *locale = [NSLocale currentLocale];
//    NSLocale *locale = [[[NSLocale alloc] initWithLocaleIdentifier:@"fr_FR"] autorelease];

NSDateFormatter *relativeDateFormatter = [[NSDateFormatter alloc] init];
[relativeDateFormatter setTimeStyle:NSDateFormatterNoStyle];
[relativeDateFormatter setDateStyle:NSDateFormatterMediumStyle];
[relativeDateFormatter setDoesRelativeDateFormatting:YES];
[relativeDateFormatter setLocale:locale];

NSDateFormatter *normalDateFormatter = [[NSDateFormatter alloc] init];
[normalDateFormatter setTimeStyle:NSDateFormatterNoStyle];
[normalDateFormatter setDateStyle:NSDateFormatterMediumStyle];
[normalDateFormatter setDoesRelativeDateFormatting:NO];
[normalDateFormatter setLocale:locale];

NSString * lastUniqueString = nil;

for ( NSTimeInterval timeInterval = -60*60*24*400; timeInterval < 60*60*24*400; timeInterval += 60.0*60.0*24.0 )
{
    NSDate * date = [NSDate dateWithTimeIntervalSinceNow:timeInterval];

    NSString * relativeFormattedString = [relativeDateFormatter stringForObjectValue:date];
    NSString * formattedString = [normalDateFormatter stringForObjectValue:date];

    if ( [relativeFormattedString isEqualToString:lastUniqueString] || [relativeFormattedString isEqualToString:formattedString] )
        continue;

    NSLog( @"%@", relativeFormattedString );
    lastUniqueString = relativeFormattedString;
}

# File vendor/rails/actionpack/lib/action_view/helpers/date_helper.rb, line 59
def distance_of_time_in_words(from_time, to_time = 0, include_seconds = false, options = {})
 from_time = from_time.to_time if from_time.respond_to?(:to_time)
 to_time = to_time.to_time if to_time.respond_to?(:to_time)
 distance_in_minutes = (((to_time - from_time).abs)/60).round
 distance_in_seconds = ((to_time - from_time).abs).round

 I18n.with_options :locale => options[:locale], :scope => 'datetime.distance_in_words''datetime.distance_in_words' do |locale|
   case distance_in_minutes
     when 0..1
       return distance_in_minutes == 0 ?
              locale.t(:less_than_x_minutes, :count => 1) :
              locale.t(:x_minutes, :count => distance_in_minutes) unless include_seconds

       case distance_in_seconds
         when 0..4   then locale.t :less_than_x_seconds, :count => 5
         when 5..9   then locale.t :less_than_x_seconds, :count => 10
         when 10..19 then locale.t :less_than_x_seconds, :count => 20
         when 20..39 then locale.t :half_a_minute
         when 40..59 then locale.t :less_than_x_minutes, :count => 1
         else             locale.t :x_minutes,           :count => 1
       end

     when 2..44           then locale.t :x_minutes,      :count => distance_in_minutes
     when 45..89          then locale.t :about_x_hours,  :count => 1
     when 90..1439        then locale.t :about_x_hours,  :count => (distance_in_minutes.to_f / 60.0).round
     when 1440..2879      then locale.t :x_days,         :count => 1
     when 2880..43199     then locale.t :x_days,         :count => (distance_in_minutes / 1440).round
     when 43200..86399    then locale.t :about_x_months, :count => 1
     when 86400..525599   then locale.t :x_months,       :count => (distance_in_minutes / 43200).round
     when 525600..1051199 then locale.t :about_x_years,  :count => 1
     else                      locale.t :over_x_years,   :count => (distance_in_minutes / 525600).round
   end
 end
end

public static class DateTimePretty
{
    private const int SECOND = 1;
    private const int MINUTE = 60 * SECOND;
    private const int HOUR = 60 * MINUTE;
    private const int DAY = 24 * HOUR;
    private const int WEEK = 7 * DAY;
    private const int MONTH = 30 * DAY;

    private const int YEAR = 365;

    const string now ="just now";
    const string secondsFuture ="in {0} seconds", secondsPast ="{0} seconds ago";
    const string minuteFuture ="in about a minute", minutePast ="about a minute ago";
    const string minutesFuture ="in about {0} minutes", minutesPast ="about {0} minutes ago";
    const string hourFuture ="in about an hour", hourPast ="about an hour ago";
    const string hoursFuture ="in about {0} hours", hoursPast ="about {0} hours ago";
    const string tomorrow ="tomorrow, {0}", yesterday ="yesterday, {0}";
    const string nextDay ="{0}", nextWeekDay ="next {0}", lastDay ="last {0}";
    //const string daysFuture ="in about {0} days", daysPast ="about {0} days ago";
    const string weekFuture ="in about a week", weekPast ="about a week ago";
    const string weeksFuture ="in about {0} weeks", weeksPast ="about {0} weeks ago";
    const string monthFuture ="in about a month", monthPast ="about a month ago";
    const string monthsFuture ="in about {0} months", monthsPast ="about {0} months ago";
    const string yearFuture ="in about a year", yearPast ="about a year ago";
    const string yearsFuture ="in about {0} years", yearsPast ="about {0} years ago";
    const string centuryFuture ="in about a century", centuryPast ="about a century ago";
    const string centuriesFuture ="in about {0} centuries", centuriesPast ="about {0} centuries ago";

    /// <summary>
    /// Returns a pretty version of the provided DateTime:"42 years ago", or"in 9 months".
    /// </summary>
    /// <param name="dateTime">DateTime in local time format, not Utc</param>
    /// <returns>A pretty string</returns>
    public static string GetPrettyDate(DateTime dateTime)
    {
        DateTime dateTimeNow = DateTime.Now;
        bool isFuture = (dateTimeNow.Ticks < dateTime.Ticks);
        var ts = isFuture ? new TimeSpan(dateTime.Ticks - dateTimeNow.Ticks) : new TimeSpan(dateTimeNow.Ticks - dateTime.Ticks);

        double delta = ts.TotalSeconds;

        if (delta < 10)
            return now;
        if (delta < 1 * MINUTE)
            return isFuture ? string.Format(secondsFuture, ts.Seconds) : string.Format(secondsPast, ts.Seconds);
        if (delta < 2 * MINUTE)
            return isFuture ? minuteFuture : minutePast;
        if (delta < 45 * MINUTE)
            return isFuture ? string.Format(minutesFuture, ts.Minutes) : string.Format(minutesPast, ts.Minutes);
        if (delta < 2 * HOUR)
            return isFuture ? hourFuture : hourPast;
        if (delta < 7 * DAY)
        {
            string shortTime = DateTimeFormatInfo.CurrentInfo.ShortTimePattern;
            string shortWeekdayTime ="dddd," + shortTime;
            int dtDay = (int) dateTime.DayOfWeek;
            int nowDay = (int) dateTimeNow.DayOfWeek;
            if (isFuture)
            {
                if (dtDay == nowDay)
                {
                    if (delta < DAY)
                        return string.Format(hoursFuture, ts.Hours);
                    else
                        return string.Format(nextWeekDay, dateTime.ToString(shortWeekdayTime));
                }
                else if (dtDay - nowDay == 1 || dtDay - nowDay == -6)
                    return string.Format(tomorrow, dateTime.ToString(shortTime));
                else
                    return string.Format(nextDay, dateTime.ToString(shortWeekdayTime));
            }
            else
            {
                if (dtDay == nowDay)
                {
                    if (delta < DAY)
                        return string.Format(hoursPast, ts.Hours);
                    else
                        return string.Format(lastDay, dateTime.ToString(shortWeekdayTime));
                }
                else if (nowDay - dtDay == 1 || nowDay - dtDay == -6)
                    return string.Format(yesterday, dateTime.ToString(shortTime));
                else
                    return string.Format(lastDay, dateTime.ToString(shortWeekdayTime));
            }
        }
        //if (delta < 7 * DAY)
        //    return isFuture ? string.Format(daysFuture, ts.Days) : string.Format(daysPast, ts.Days);
        if (delta < 4 * WEEK)
        {
            int weeks = Convert.ToInt32(Math.Floor((double) ts.Days / 30));
            if (weeks <= 1)
                return isFuture ? weekFuture : weekPast;
            else
                return isFuture ? string.Format(weeksFuture, weeks) : string.Format(weeksPast, weeks);
        }
        if (delta < 12 * MONTH)
        {
            int months = Convert.ToInt32(Math.Floor((double) ts.Days / 30));
            if (months <= 1)
                return isFuture ? monthFuture : monthPast;
            else
                return isFuture ? string.Format(monthsFuture, months) : string.Format(monthsPast, months);
        }

        // Switch to days to avoid overflow
        delta = ts.TotalDays;
        if (delta < 100 * YEAR)
        {
            int years = Convert.ToInt32(Math.Floor((double) ts.TotalDays / 365.25));
            if (years <= 1)
                return isFuture ? yearFuture : yearPast;
            else
                return isFuture ? string.Format(yearsFuture, years) : string.Format(yearsPast, years);
        }
        else
        {
            int centuries = Convert.ToInt32(Math.Floor((double) ts.TotalDays / 365.2425));
            if (centuries <= 1)
                return isFuture ? centuryFuture : centuryPast;
            else
                return isFuture ? string.Format(centuriesFuture, centuries) : string.Format(centuriesPast, centuries);
        }
    }
}

NSTimeInterval const kTenSeconds = (10.0f );
NSTimeInterval const kOneMinute = (60.0f);
NSTimeInterval const kFiveMinutes = (5.0f*60.0f);
NSTimeInterval const kFifteenMinutes = (15.0f*60.0f) ;
NSTimeInterval const kHalfAnHour = (30.0f*60.0f) ;
NSTimeInterval const kOneHour = 3600.0f;    // (60.0f * 60.0f);
NSTimeInterval const kHalfADay = (3600.0f * 12.0f);
NSTimeInterval const kOneDay = (3600.0f * 24.0f);
NSTimeInterval const kOneWeek = (3600.0f * 24.0f * 7.0f);

@implementation NSDate (Fuzzy)

-(NSString*)fuzzyStringRelativeToNow;
{
    static NSArray* secondsStrings;
    static NSArray* minuteStrings;
    static NSArray* fiveMinuteStrings;
    static NSArray* halfHourStrings;
    static NSArray* earlyMonthStrings;

    NSTimeInterval timeFromNow = [self timeIntervalSinceNow];
    if((timeFromNow < 0))       // In the past
    {
        timeFromNow = - timeFromNow;

        if ( (timeFromNow <  kTenSeconds))
        {
            if(!secondsStrings)
            {  
                secondsStrings = [[NSArray arrayWithObjects:@"just now",
                                                            //@"a few seconds ago",
                                                            //@"right this instant",
                                                            @"moments ago",
                                                            nil] retain];
            }

            unsigned int index = random() % ([secondsStrings count] - 1);
            return [secondsStrings objectAtIndex:index];
        }

        if ( (timeFromNow < kOneMinute))
        {
            if(!minuteStrings)
            {

                minuteStrings = [[NSArray arrayWithObjects:@"just now",
                                  @"very recently",
                                  @"in the last minute",
                                  nil] retain];
            }

            unsigned int index = random() % ([minuteStrings count] - 1);
            return [minuteStrings objectAtIndex:index];
        }

        if (timeFromNow < kFiveMinutes)
        {
            if(!fiveMinuteStrings)
            {
                fiveMinuteStrings = [[NSArray arrayWithObjects:@"just now",
                                      @"very recently",
                                      //@"in the last minute",
                                      @"a few minutes ago",
                                      //@"in the last five minutes",
                                      nil] retain];
            }
            unsigned int index = random() % ([fiveMinuteStrings count] - 1);
            return [fiveMinuteStrings objectAtIndex:index];
        }

        if (timeFromNow < kFifteenMinutes)
        {
            return @"in the last 15 minutes";
        }

        if (timeFromNow < kHalfAnHour)
        {
            if(!halfHourStrings)
            {
                halfHourStrings = [[NSArray arrayWithObjects:@"in the last half hour",
                                                            //@"in the last half an hour",
                                                            @"in the last 30 minutes",
                                                            //@"about half an hour ago",
                                                            @"fairly recently",
                                                            nil] retain];
            }
            unsigned int index = random() % ([halfHourStrings count] - 1);
            return [halfHourStrings objectAtIndex:index];
        }

        if (timeFromNow < kOneHour)
        {
            return @"in the last hour";
        }

        if ((timeFromNow < (kOneHour + kFiveMinutes)) && (timeFromNow > (kOneHour - kFiveMinutes)))
        {
            return @"about an hour ago";
        }

        if((timeFromNow < ((kOneHour*2.0f) + kFiveMinutes ))&& (timeFromNow > ((kOneHour*2.0f) - kFiveMinutes)))
        {
            return @"a couple of hours ago";
        }

        // Now we're over an hour, we need to calculate a few specific dates to compare against

        NSDate *today = [NSDate date];

        NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];

        NSUInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit;
        NSDateComponents* todayComponents = [gregorian components:unitFlags fromDate:today];

        todayComponents.hour = 12;

        NSDate* noonToday = [gregorian dateFromComponents:todayComponents];


        NSTimeInterval timeSinceNoonToday = [self timeIntervalSinceDate:noonToday];

        if (timeSinceNoonToday > 0)                         // sometime since noon
        {
            if (timeSinceNoonToday > kOneHour * 9)          // i.e. after 9pm today
                return @"earlier tonight";
            if (timeSinceNoonToday > kOneHour * 7)          // i.e. after 7pm today
                return @"earlier this evening";
            if (timeSinceNoonToday < kOneHour * 1)          // between noon and 1pm
                return @"early this afternoon";

            return @"this afternoon";
        }


        NSTimeInterval timeSinceMidnight = kHalfADay -timeSinceNoonToday;   // Note sign is reversed.  

        if ((timeSinceNoonToday < 0) & (timeSinceNoonToday > -kHalfADay))       // between midnight and noon today
        {
            if (timeSinceMidnight < kFiveMinutes)
                return @"around midnight";
            if (timeSinceMidnight < kOneHour * 2)           // up to 2am
                return @"very early this morning";
            if (timeSinceMidnight < kOneHour * 5)           // up to 5am
                return @"early this morning";
            else if (timeSinceMidnight < kOneHour * 11)
                return @"late this morning";
            else
                return @"this morning";
        }


        // NSTimeInterval timeSinceNoonYesterday = timeSinceNoonToday - kOneDay;

        // timeSinceMidnight = -timeSinceMidnight;

        if (timeSinceMidnight < kOneHour * 24)      // not the day before...
        {

            if (timeSinceMidnight < kFiveMinutes)
                return @"around midnight";
            if (timeSinceMidnight < kFifteenMinutes)
                return @"just before midnight";
            if (timeSinceMidnight < kOneHour * 2)           // after 10pm
                return @"late last night";
            if (timeSinceMidnight < kOneHour * 5)           // After 7
                return @"yesterday evening";
            else if (timeSinceMidnight < kOneHour * 7)
                return @"yesterday evening";                // after 5pm
            else if (timeSinceMidnight < kOneHour * 7)
                return @"yesterday evening";                // after 5pm
            else if (timeSinceMidnight < kOneHour * 10)
                return @"yesterday afternoon";              // after 5pm
            else if (timeSinceMidnight < kOneHour * 12)
                return @"early yesterday afternoon";        // before 1pm
            else if (timeSinceMidnight < kOneHour * 13)
                return @"late yesterday morning";           // after 11m
            else if (timeSinceMidnight < kOneHour * 17)
                return @"yesterday morning";                
            else
                return @"early yesterday morning";
        }

        NSDateFormatter* formatter = [[[NSDateFormatter alloc] init] autorelease];

        int integerSeconds = timeSinceMidnight;
        int integerDay = kOneDay;
        int secondsIntoDay = integerSeconds % integerDay;
        NSString* formatString = @"last %@";

        if (timeFromNow < kOneWeek)
        {
            if (secondsIntoDay < kFifteenMinutes)
                formatString = @"around midnight on %@";
            //else if (secondsIntoDay < kFifteenMinutes)
            //  formatString = @"just before midnight on %@";
            else if (secondsIntoDay < kOneHour * 2)         // after 10pm
                formatString = @"late on %@ night";
            else if (secondsIntoDay < kOneHour * 5)         // After 7
                formatString = @"on %@ evening";
            else if (secondsIntoDay < kOneHour * 10)
                formatString = @"on %@ afternoon";              // after 5pm
            else if (secondsIntoDay < kOneHour * 12)
                formatString = @"early on %@ afternoon";        // before 1pm
            else if (secondsIntoDay < kOneHour * 13)
                formatString = @"late on %@ morning";           // after 11am
            else if (secondsIntoDay < kOneHour * 17)
                formatString = @"on %@ morning";                
            else if (secondsIntoDay < kOneHour * 24)        // not the day before...
                formatString = @"early on %@ morning";

            [formatter setDateFormat:@"EEEE"];  /// EEEE is long format of day of the week see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
            return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]];
        }

        //formatString = @"on %@ the week before last";
        /*if (secondsIntoDay < kOneHour * 2)            // after 10pm
            formatString = @"early on %@ the week before last";
        else if (timeSinceMidnight > kOneHour * 13)
            formatString = @"late on %@ the week before last";          // after 11m*/

        //if (timeFromNow < kOneWeek * 2)
        //{
        //  [formatter setDateFormat:@"EEE"];           /// EEE is short format of day of the week see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
        //  return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]];
        //}

        if (timeFromNow < kOneWeek * 2)
            {
            return @"the week before last";
            }

        NSDateComponents* myComponents = [gregorian components:unitFlags fromDate:self];

        int monthsAgo = myComponents.month - todayComponents.month;

        int yearsAgo = myComponents.year - todayComponents.year;
        if (yearsAgo == 0)
        {
            if (monthsAgo == 0)
            {
                if(myComponents.day > 22)
                    return @"late this month";
                if(myComponents.day < 7)
                {

                    if(!earlyMonthStrings)
                    {  
                        earlyMonthStrings = [[NSArray arrayWithObjects:@"earlier this month",
                                                                       //@"at the beginning of the month",
                                                                       @"early this month",
                                                                       nil] retain];
                    }

                    unsigned int index = random() % ([earlyMonthStrings count] - 1);
                    return [earlyMonthStrings objectAtIndex:index];
                }
                return @"earlier this month";
            }

            if (monthsAgo == 1)
            {
                if(myComponents.day > 22)
                    return @"late last month";
                if(myComponents.day < 7)
                    return @"early last month";
                return @"last month";
            }

            formatString  = @"in %@ this year";
            /*if(myComponents.day > 22)
                formatString  = @"late in %@ this year";
            if(myComponents.day < 7)
                formatString  = @"early in %@ this year";*/


            [formatter setDateFormat:@"MMMM"];          /// MMM is longformat of month see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
            return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]];  
        }

        if (yearsAgo == 1)
        {
            formatString  = @"in %@ last year";
            /*if(myComponents.day > 22)
                formatString  = @"late in %@ last year";
            if(myComponents.day < 7)
                formatString  = @"late in %@ last year";*/


            [formatter setDateFormat:@"MMM"];           /// MMM is longformat of month see: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns
            return [NSString stringWithFormat:formatString, [formatter stringFromDate: self]];  
        }

        // int daysAgo = integerSeconds / integerDay;

    // Nothing yet...
        [formatter setDateStyle:kCFDateFormatterMediumStyle];
        //[formatter setTimeStyle:kCFDateFormatterShortStyle];

        return [NSString stringWithFormat:@"on %@",[formatter stringFromDate: self]];

    }
    else
    if(timeFromNow > 0) // The future
    {
        AICLog(kErrorLogEntry, @"FuzzyDates: Time marked as in the future: referenced date is %@, local time is %@", self, [NSDate date]);
        return @"moments ago";

    }
    else
        return @"right now";    // this seems unlikely.

    return [self description];  // should never get here.
}

if timestamp < 5sec
   "A moment ago"
elseif timestamp < 5min
   "Few minutes ago"
elseif timestamp < 12hr && timestamp < noon
   "Today Morning"
...
elseif timestamp < 1week
   "Few days ago"
elseif timestamp < 1month
   "Few weeks ago"
elseif timestamp < 6month
   "Few Months ago"
...
else
   "Really really long time ago"

DateTime now = DateTime.Now;

long nowticks = now.Ticks;
long thenticks = dt.Ticks;

long diff = nowticks - thenticks;

DateTime n = new DateTime(diff);

if (n.Year > 1)
{
    return n.Year.ToString() +" years ago";
}
else if (n.Month > 1)
{
    return n.Month.ToString() +" months ago";
}
else if (n.Day > 1)
{
    return n.Day.ToString() +" days ago";
}
else if (n.Hour > 1)
{
    return n.Hour.ToString() +" hours ago";
}
else if (n.Minute > 1)
{
    return n.Minute.ToString() +" minutes ago";
}
else
{
    return n.Second.ToString() +" seconds ago";
}

Today, Tomorrow, Yesterday, Last Friday, etc
17 August 2013 - 19 August 2013
This Friday from 13:00 - 16.00
5 days ago
Sat Aug 17 2013 18:40:39 GMT+0900 (JST)
2014-11-30T08:15:30-05:30