How do I stop my timers at 0 automatically in SpriteKit? - swift

Question

Keep in mind this is in Sprite Kit. Basically I want a way to have my in-game upgrades on a timer that allows the user to get the upgrade after the timer has finished. The user would touch the button once to start the timer, and once it gets to zero, it stops itself. I can't get it to stop, however.
import Foundation
import SpriteKit
var timer1Cycle = 0
var timer1Time = 10000
var timer1 = Timer()
var timer1IsOn = false
class SkillPointsScene: SKScene{
func updateTimer1() {
timer1Time -= 1
timer1Label.text = " \(timer1Time) :Kepler-22b units"
}
func startTimer1(){
if timer1IsOn == false {
timer1 = Timer.scheduledTimer(timeInterval: 0.0004, target: self, selector: #selector(SkillPointsScene.updateTimer1), userInfo: nil, repeats: true)
timer1IsOn = true
}
}
func stopTimer1() {
timer1.invalidate()
timer1Time = 0
timer1Label.text = "Research Complete"
timer1IsOn = false
}
Here is the image button to start counting down from 10000:
let oneLifeImage = SKSpriteNode(imageNamed: "gun1")
let timer1Label = SKLabelNode(fontNamed: "theBoldFontt")
// runs as soon as the screen loads every time
override func didMove(to view: SKView) {
if timer1Time <= 0 {
self.stopTimer1()
}
let background = SKSpriteNode(imageNamed: "background")
background.position = CGPoint(x: self.size.width/2, y: self.size.height/2)
background.zPosition = 0
self.addChild(background)
timer1Label.text = " "
timer1Label.fontSize = 35
timer1Label.fontColor = SKColor.white
timer1Label.position = CGPoint(x: self.size.width*0.5, y: self.size.height*0.82)
timer1Label.zPosition = 100
self.addChild(timer1Label)
oneLifeImage.setScale(1)
oneLifeImage.position = CGPoint(x: self.size.width/2, y: self.size.height*0.75)
oneLifeImage.zPosition = 2
self.addChild(oneLifeImage)
And here is where the button is touched:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch: AnyObject in touches{
let pointOfTouch = touch.location(in: self)
let wait = SKAction.wait(forDuration: 1.5)
if oneLifeImage.contains(pointOfTouch){
if timer1Cycle == 0 {
timer1Time = 10000
}
if timer1Cycle == 1 {
timer1Time = 25000
}
if timer1IsOn == false {
startTimer1()
timer1Cycle -= 1
}
I get it to start the count down, but it never stops on its own. I don't know what to do now; I can't find any information on this because it is in Swift 3 with Sprite Kit, not the normal single view that everybody seems to know how to use.