TimedActionRepeater.swift

//
//  TimedActionRepeater.swift
//
//  Created by Stephan Cilliers on 2018/06/26.
//  Copyright © 2018 Stephan Cilliers. All rights reserved.
//

import Foundation

class TimedActionRepeater {
	var delegate: TimedActionRepeaterDelegate?
	private(set) var repetitions: Int
	private(set) var repetitionsCompleted = 0
    var repetitionsRemaining: Int {
        return max(0, repetitions - repetitionsCompleted)
    }
	private var timer: Timer!
	private var callback: (Int, Bool) -> ()
	private var repetitionTime: TimeInterval
    private var delayTimer: Timer?
    
    var isActive: Bool {
        return timer != nil || delayTimer != nil
    }
    
	init(repetitionTime: TimeInterval, repetitions: Int, callback: @escaping (Int, Bool) -> ()) {
		self.repetitionTime = repetitionTime
		self.callback = callback
		self.repetitions = repetitions
	}
	
	func start() {
		stop()
		timer = Timer.scheduledTimer(withTimeInterval: repetitionTime, repeats: true, block: { (timer) in
			self.repetitionsCompleted += 1
			self.callback(self.repetitionsCompleted, self.repetitionsRemaining == 0)
			if self.repetitionsRemaining == 0 {
				self.delegate?.timerCompleted()
				self.stop()
			}
		})
	}
    
    func startImmediately() {
        start()
        self.repetitionsCompleted += 1
        self.callback(self.repetitionsCompleted, self.repetitionsRemaining == 0)
        if self.repetitionsRemaining == 0 {
            self.delegate?.timerCompleted()
            self.stop()
        }
    }
    
    func start(after delay: TimeInterval) {
        delayTimer = Timer.scheduledTimer(withTimeInterval: delay, repeats: false, block: { (timer) in
            self.startImmediately()
        })
    }
	
	func stop() {
        delayTimer?.invalidate()
        delayTimer = nil
		repetitionsCompleted = 0
		if let _ = timer {
			self.timer.invalidate()
			self.timer = nil
		}
	}
}

protocol TimedActionRepeaterDelegate {
	func timerCompleted()
}