namespace DistanceOfTimeInWordsDemo
{
public static class DateTimeExtension
{
private class RangePair { public int Lower { get; set; } public int Upper { get; set; } }
private class KeyArgPair { public string ResourceKey { get; set; } public int DivideBy { get; set; } }
private static Dictionary<RangePair, KeyArgPair> WordsRange;
static DateTimeExtension()
{
WordsRange = new Dictionary<RangePair, KeyArgPair>();
WordsRange.Add(new RangePair { Lower = 0, Upper = 4 }, new KeyArgPair { ResourceKey = “LessThanFiveSeconds”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = 5, Upper = 9 }, new KeyArgPair { ResourceKey = “LessThanTenSeconds”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = 10, Upper = 19 }, new KeyArgPair { ResourceKey = “LessThanTwentySeconds”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = 20, Upper = 39 }, new KeyArgPair { ResourceKey = “HalfAMinute”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = 40, Upper = 59 }, new KeyArgPair { ResourceKey = “LessThanAMinute”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(2).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(44).TotalSeconds }, new KeyArgPair { ResourceKey = “MultipleMinutes”, DivideBy = 1 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(45).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(89).TotalSeconds }, new KeyArgPair { ResourceKey = “AboutOneHour”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(90).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(1439).TotalSeconds }, new KeyArgPair { ResourceKey = “AboutMultipleHours”, DivideBy = 60 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(1440).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(2879).TotalSeconds }, new KeyArgPair { ResourceKey = “OneDay”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(2880).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(43199).TotalSeconds }, new KeyArgPair { ResourceKey = “MultipleDays”, DivideBy = 1440 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(43200).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(86399).TotalSeconds }, new KeyArgPair { ResourceKey = “AboutOneMonth”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(86400).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(525599).TotalSeconds }, new KeyArgPair { ResourceKey = “MultipleMonths”, DivideBy = 43200 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(525600).TotalSeconds, Upper = (int)TimeSpan.FromMinutes(1051199).TotalSeconds }, new KeyArgPair { ResourceKey = “AboutOneYear”, DivideBy = 0 });
WordsRange.Add(new RangePair { Lower = (int)TimeSpan.FromMinutes(1051200).TotalSeconds, Upper = Int32.MaxValue }, new KeyArgPair { ResourceKey = “MultipleYears”, DivideBy = 525600 });
}

public static string TimeAgoInWords(this DateTime fromTime)
{
return DistanceOfTimeInWords(fromTime, DateTime.Now);
}

public static string TimeAgoInWords(this DateTime fromTime, bool includeSeconds)
{
return DistanceOfTimeInWords(fromTime, DateTime.Now, includeSeconds);
}

public static string DistanceOfTimeInWords(this DateTime fromTime, DateTime toTime)
{
return DistanceOfTimeInWords(fromTime, toTime, false);
}

public static string DistanceOfTimeInWords(this DateTime fromTime, DateTime toTime, bool includeSeconds)
{
Func<int, double, int> RoundedDistance = (value, dividedBy) => (int)Decimal.Round(Convert.ToDecimal(value / dividedBy), MidpointRounding.AwayFromZero);
Func<int, int, int, bool> InRange = (value, low, high) => (value >= low && value <= high);
Func<string, int?, string> InWords = (name, args) => (!String.IsNullOrEmpty(name)) ? (args.HasValue) ? String.Format(Resources.ResourceManager.GetString(name), args.Value) : Resources.ResourceManager.GetString(name) : String.Empty;

TimeSpan ts = (toTime - fromTime).Duration();
int distanceInMinutes = (int)ts.TotalMinutes;
int distanceInSeconds = (int)ts.TotalSeconds;

if (distanceInMinutes <= 1)
{
var query = (from s in WordsRange
where InRange(distanceInSeconds, s.Key.Lower, s.Key.Upper)
select s.Value.ResourceKey).FirstOrDefault();
if (includeSeconds)
{
if (!String.IsNullOrEmpty(query)) { return InWords(query, null); }
else { return InWords(”OneMinute”, null); }
}
else { return InWords((distanceInMinutes.Equals(0)) ? “LessThanAMinute” : “OneMinute”, null); }
}
else
{
var query = (from s in WordsRange
where InRange(distanceInSeconds, s.Key.Lower, s.Key.Upper)
select s.Value).FirstOrDefault();
if (query != null) { return InWords(query.ResourceKey, (query.DivideBy > 0) ? new Nullable<int>(RoundedDistance(distanceInMinutes, query.DivideBy)) : null); }
}
return String.Empty;
}
}
}