That'll do pig, that'll do. (#10144)

* Fixes TEG processing not being synchronized.

Fixes #10034

* ugh

code/_hooks/events.dm

@@ -45,4 +45,4 @@
 			continue
 		args["event"] = src
 		if(call(objRef,procName)(args, holder)) //An intercept value so whatever code section knows we mean business
-			. = 1
+			. = 1

code/controllers/Processes/pipenet.dm

@@ -1,14 +1,16 @@
 var/global/list/datum/pipe_network/pipe_networks = list()
 var/global/list/obj/machinery/atmospherics/atmos_machines = list()
+var/event/on_pipenet_tick = new()
 
 /datum/controller/process/pipenet
 	schedule_interval = 29 // every 2 seconds
 
 /datum/controller/process/pipenet/setup()
 	name = "pipenet"
-
+	global.on_pipenet_tick.holder = src
 
 /datum/controller/process/pipenet/doWork()
+	INVOKE_EVENT(global.on_pipenet_tick, list())
 	for(var/obj/machinery/atmospherics/atmosmachinery in atmos_machines)
 		if(istype(atmosmachinery))
 			if(!atmosmachinery.disposed && !atmosmachinery.timestopped)

code/modules/power/generator.dm

@@ -20,6 +20,7 @@
 	machine_flags = WRENCHMOVE | FIXED2WORK
 
 	var/tmp/datum/html_interface/nanotrasen/interface
+	var/tmp/on_pipenet_tick_key
 
 /obj/machinery/power/generator/New()
 	..()
@@ -48,6 +49,7 @@
 	interface = new(src, name, 450, 410, head)
 
 	html_machines += src
+	on_pipenet_tick_key = global.on_pipenet_tick.Add(src, "pipenet_process")
 
 	init_ui()
 
@@ -65,6 +67,7 @@
 	interface = null
 
 	html_machines -= src
+	global.on_pipenet_tick.Remove(on_pipenet_tick_key)
 
 /obj/machinery/power/generator/proc/init_ui()
 	interface.updateLayout({"
@@ -260,7 +263,8 @@
 	if(lastgenlev != 0)
 		overlays += "teg-op[lastgenlev]"
 
-/obj/machinery/power/generator/process()
+// We actually tick power gen on the pipenet process to make sure we're synced with pipenet updates.
+/obj/machinery/power/generator/proc/pipenet_process(var/list/event_args, var/datum/controller/process/pipenet/owner)
 	if(!operable())
 		return
 
@@ -295,8 +299,6 @@
 	if(circ2.network2)
 		circ2.network2.update = TRUE
 
-	add_avail(last_gen)
-
 	//Update icon overlays and power usage only if displayed level has changed.
 	var/genlev = Clamp(round(11 * last_gen / max_power), 0, 11)
 
@@ -309,6 +311,10 @@
 
 	updateUsrDialog()
 
+/obj/machinery/power/generator/process()
+	if (operable())
+		add_avail(last_gen)
+
 /obj/machinery/power/generator/attack_ai(mob/user)
 	return attack_hand(user)