"Time ago" function for Swift (based on MatthewYork's DateTools for Objective-C)

timeago.swift

func timeAgoSinceDate(date:NSDate, numericDates:Bool) -> String {
    let calendar = NSCalendar.currentCalendar()
    let unitFlags = NSCalendarUnit.CalendarUnitMinute | NSCalendarUnit.CalendarUnitHour | NSCalendarUnit.CalendarUnitDay | NSCalendarUnit.CalendarUnitWeekOfYear | NSCalendarUnit.CalendarUnitMonth | NSCalendarUnit.CalendarUnitYear | NSCalendarUnit.CalendarUnitSecond
    let now = NSDate()
    let earliest = now.earlierDate(date)
    let latest = (earliest == now) ? date : now
    let components:NSDateComponents = calendar.components(unitFlags, fromDate: earliest, toDate: latest, options: nil)
    
    if (components.year >= 2) {
        return "\(components.year) years ago"
    } else if (components.year >= 1){
        if (numericDates){
            return "1 year ago"
        } else {
            return "Last year"
        }
    } else if (components.month >= 2) {
        return "\(components.month) months ago"
    } else if (components.month >= 1){
        if (numericDates){
            return "1 month ago"
        } else {
            return "Last month"
        }
    } else if (components.weekOfYear >= 2) {
        return "\(components.weekOfYear) weeks ago"
    } else if (components.weekOfYear >= 1){
        if (numericDates){
            return "1 week ago"
        } else {
            return "Last week"
        }
    } else if (components.day >= 2) {
        return "\(components.day) days ago"
    } else if (components.day >= 1){
        if (numericDates){
            return "1 day ago"
        } else {
            return "Yesterday"
        }
    } else if (components.hour >= 2) {
        return "\(components.hour) hours ago"
    } else if (components.hour >= 1){
        if (numericDates){
            return "1 hour ago"
        } else {
            return "An hour ago"
        }
    } else if (components.minute >= 2) {
        return "\(components.minute) minutes ago"
    } else if (components.minute >= 1){
        if (numericDates){
            return "1 minute ago"
        } else {
            return "A minute ago"
        }
    } else if (components.second >= 3) {
        return "\(components.second) seconds ago"
    } else {
        return "Just now"
    }
    
}