How to create timer in swift using (NStimer) - swift

Question

I am trying to make countdown (NSTimer).
for example:- count down timer 2d:21h:50m:20s
I used some code:-
override func viewDidLoad() {
super.viewDidLoad()
self.timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.UpdateTime), userInfo: nil, repeats: true)
}
#objc func UpdateTime() {
let userCalendar = Calendar.current
// Set Current Date
let date = Date()
let components = userCalendar.dateComponents([.hour, .minute, .month, .year, .day, .second], from: date)
let currentDate = userCalendar.date(from: components)!
// Set Event Date
var eventDateComponents = DateComponents()
eventDateComponents.year = 2020
eventDateComponents.month = 07
eventDateComponents.day = 2
eventDateComponents.hour = 0
eventDateComponents.minute = 0
eventDateComponents.second = 0
eventDateComponents.timeZone = TimeZone(abbreviation: "GMT")
// Convert eventDateComponents to the user's calendar
let eventDate = userCalendar.date(from: eventDateComponents)!
// Change the seconds to days, hours, minutes and seconds
let timeLeft = userCalendar.dateComponents([.day, .hour, .minute, .second], from: currentDate, to: eventDate)
// Display Countdown
timerLabel.text = "\(timeLeft.day!)d \(timeLeft.hour!)h \(timeLeft.minute!)m \ (timeLeft.second!)s"
// Show diffrent text when the event has passed
}
My API Response:-
func callForTimerApi(){
let url = "\(ApiLink.HOST_URL)/wp/v2/getDeadline"
Alamofire.request(url, method: .get, parameters: nil, encoding: URLEncoding.default, headers: nil).responseJSON { response in
switch response.result {
case .success:
if let value = response.result.value {
print(value)
let dict = value as! [String:Any]
let userData = dict.validatedValue("data", expected:[[String:Any]]() as AnyObject) as! [[String:Any]]
for item in userData {
let length = item.validatedValue("length", expected: String() as AnyObject) as! String
print(length)
self.counters = Int(length)!
}
}
case .failure(let error):
print(error)
presentAlert("", msgStr: "Could not connect to the server.", controller: self)
}
}
}
I got it 48 length in hours from API,and my coutdown timer starts 2d:24h:45m:20s and my starts timer is over than show countdown timer is 0d:0h:0m:0s