(defrule init
	(true null)
=>
	(add (sensor-active none))
	(add (sensor-working sensor1))
	(add (sensor-working sensor2))
	(add (mode failure))
	(enable (timer 1 10))
	(print ("default rule fired!"))
	(disable (self))
)



(defrule sensor-failed
	(sensor-working ?)
	(sensor-failed ?)
=>
	(delete (sensor-working ?))
)

(defule check-active
	(sensor-active ?)
	(sensor-failed ?)
=>
	(delete (sensor-active ?))
	(add (sensor-active none))
)

(defrule make-working
	(sensor-active none)
	(sensor-working ?)
=>
	(add (sensor-active ?))
	(delete (mode failure))
	(add (mode normal))
	(delete (sensor-active none))
)

(defrule failure
	(mode normal)
	(sensor-active none)
	(sensor-failed sensor1)
	(sensor-failed sensor2)
=>
	(add (mode failure))
	(delete (mode safe))
	(delete (mode normal))
)

(defrule trigger1
	(timer-triggered 1)
=>
	(print ("Sensor 1 failure."))
	(add (sensor-failed sensor1))
	(enable (timer 2 10))
	(delete (timer-triggered 1))
	(disable (self))
)

(defrule trigger2
	(timer-triggered 2)
=>
	(print ("Sensor 2 failure."))
	(add (sensor-failed sensor2))
	(enable (timer 3 10))
	(delete (timer-triggered 2))
	(disable (self))
)

(defrule trigger3
	(timer-triggered 3)
=>
	(print ("Sensor 1 is now working."))
	(delete (sensor-failed sensor1))
	(add (sensor-working sensor1))
	(enable (timer 4 10))
	(delete (timer-triggered 3)
	(disable (self))
)

(defrule trigger4
	(timer-triggered 4)
=>
	(print ("Sensor 2 is now working."))
	(delete (sensor-failed sensor2))
	(add (sensor-working sensor2))
	(enable (timer 1 10))
	(delete (timer-triggered 4))
	(disable (self))
)