show persian times ago e.x input method String date format : "yyyy-MM-dd HH:mm:ss"

PrettyTime.swift

import Foundation

class PrettyTime {
    
    // example uses : PrettyTime.timesAgo(strDate : "2018-03-10 13:19:13" , numericDates : false)
    
    static func timesAgo(strDate:String, numericDates:Bool) -> String {
        
        
        var stringDate = strDate
        
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
        dateFormatter.locale = NSLocale(localeIdentifier: "en_US_ POSIX") as Locale?
        
        if stringDate.isEmpty {
            let date = Date()
            stringDate = dateFormatter.string(from: date)
        }
        
        let date = dateFormatter.date(from: stringDate)
        
        if date == nil {
            return "invalid date string"
        }
        
        let calendar = NSCalendar.current
        let now = NSDate()
        let earliest = now.earlierDate(date!)
        let latest =  (earliest == now as Date) ? date : now as Date
        
        let components = calendar.dateComponents([.minute, .hour, .day, .weekOfYear, .month, .year, .second], from: date! , to: latest!)
        
        if (components.year! >= 2) {
            return "\(String(describing: components.year!)) سال قبل"
        } else if (components.year! >= 1){
            if (numericDates){
                return "۱ سال قبل"
            } else {
                return "سال قبل"
            }
        } else if (components.month! >= 2) {
            return "\(String(describing: components.month!)) ماه پیش"
        } else if (components.month! >= 1){
            if (numericDates){
                return "۱ ماه پیش"
            } else {
                return "یک ماه قبل"
            }
        } else if (components.weekOfYear! >= 2) {
            return "\(String(describing: components.weekOfYear!)) هفته پیش"
        } else if (components.weekOfYear! >= 1){
            if (numericDates){
                return "۱ هفته پیش"
            } else {
                return "یک هفته پیش"
            }
        } else if (components.day! >= 2) {
            return "\(String(describing: components.day!)) روز قبل"
        } else if (components.day! >= 1){
            if (numericDates){
                return "۱ روز قبل"
            } else {
                return "دیروز"
            }
        } else if (components.hour! >= 2) {
            return "\(String(describing: components.hour!)) ساعت قبل"
        } else if (components.hour! >= 1){
            if (numericDates){
                return "۱ ساعت قبل"
            } else {
                return "یک ساعت پیش"
            }
        } else if (components.minute! >= 2) {
            return "\(String(describing: components.minute!)) دقیقه پیش"
        } else if (components.minute! >= 1){
            if (numericDates){
                return "۱ دقیقه پیش"
            } else {
                return "یک دقیقه پیش"
            }
        } else if (components.second! >= 3) {
            return "\(String(describing: components.second!)) ثانیه پیش"
        } else {
            return "چند لحظه پیش"
        }
        
    }
       
}