functional-reactive-intuition-1.swift

var panPresent = false
var pinchPresent = false
var gestureTimer: NSTimer?
var secondsLeft = 3

func handlePan(panGesture: UIPanGestureRecognizer) {
  if panGesture.state == .Began && self.panPresent == false {
    self.panPresent = true
    self.checkIfBothGesturesPresent()
  } else if panGesture.state == .Ended {
    self.panPresent = false
    self.stopTimerIfNeeded()
  }
}

func handlePinch(pinchGesture: UIPinchGestureRecognizer) {
  if pinchGesture.state == .Began && self.pinchPresent == false {
    self.pinchPresent = true
    self.checkIfBothGesturesPresent()
  } else if pinchGesture.state == .Ended {
    self.pinchPresent = false
    self.stopTimerIfNeeded()
  }
}

func checkIfBothGesturesPresent() {
  if self.pinchPresent == true && self.panPresent == true && self.gestureTimer == nil {
    self.secondsLeft = 3
    self.gestureTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: “tick:”...
    print("started")
  }
}

func stopTimerIfNeeded() {
  if let gestureTimer = gestureTimer {
    gestureTimer.invalidate()
    self.gestureTimer = nil
    print("completed")
  }
}

func tick(timer: NSTimer) {
  if self.secondsLeft <= 0 {
    self.stopTimerIfNeeded()
    return
  }
  self.secondsLeft--
  print("tick")
}