package SeqWorker
import public TimerUtils
import public ClosureTimers

/**
Sequentially executes the given closure, as long as the 
	abstract function onExecute(PayloadCallback cb) returns boolean
-closure returns true. 
On returning false the callback ends and the closure is destroyed.
*/
public function doSeq(SeqCallback cb)
	cb.ref = getTimer()..setData(cb castTo int)
	cb.ref..start(0.001, () -> onSeq())

function onSeq() 
	let time = GetExpiredTimer()
	let rcb = (time.getData() castTo SeqCallback)
	if not rcb.done and rcb.ref != null
		if rcb.doStep()
			time.start(0.001, () -> onSeq())
		else
			rcb.terminate()

public abstract class PayloadCallback
	int customData = 0
	
	function doStep()
		onExecute(this)

	abstract function onExecute(PayloadCallback cb)

public abstract class SeqCallback
	int customData = 0
	boolean done = false
	timer ref = null

	construct()

	function terminate()
		if not done or ref != null
			done = true
			destroy this

	function doStep() returns boolean
		if not done
			return onExecute(this)
		return false

	abstract function onExecute(SeqCallback cb) returns boolean

	ondestroy
		if ref != null
			ref.release()
			ref = null