Refactors intercom code to not process , adds signals for area power changes and area apc deletion , removes .src from fire alarm code

code/__DEFINES/components.dm

@@ -92,6 +92,8 @@
 
 //machinery
 #define COMSIG_AREA_APC_OPERATING "area_operating"  //from apc process()
+#define COMSIG_AREA_APC_DELETED "area_apc_gone"
+#define COMSIG_AREA_APC_POWER_CHANGE "area_apc_power_change"
 #define COMSING_DESTRUCTIVE_ANALIZER "destructive_analizer"
 #define COMSIG_TURRENT "create_turrent"
 

code/game/area/areas.dm

@@ -205,6 +205,7 @@
 /area/proc/power_change()
 	for(var/obj/machinery/M in src)	// for each machine in the area
 		M.power_change()			// reverify power status (to update icons etc.)
+	SEND_SIGNAL(src, COMSIG_AREA_APC_POWER_CHANGE)
 	if (fire || eject || party)
 		updateicon()
 

code/game/machinery/alarm.dm

@@ -1084,15 +1084,15 @@ FIRE ALARM
 	if(stat & (NOPOWER|BROKEN))
 		return
 
-	if(src.timing)
-		if(src.time > 0)
-			src.time = src.time - ((world.timeofday - last_process)/10)
+	if(timing)
+		if(time > 0)
+			time -= (world.timeofday - last_process)/10
 		else
-			src.alarm()
-			src.time = 0
-			src.timing = 0
+			alarm()
+			time = 0
+			timing = 0
 			STOP_PROCESSING(SSmachines, src)
-		src.updateDialog()
+		updateDialog()
 	last_process = world.timeofday
 
 	if(locate(/obj/fire) in loc)
@@ -1304,4 +1304,3 @@ Just a object used in constructing fire alarms
 		var/tp = text2num(href_list["tp"])
 		time += tp
 		time = min(max(round(time), 0), 120)
-

code/game/objects/items/devices/radio/intercom.dm

@@ -9,7 +9,7 @@
 	canhear_range = 2
 	flags = CONDUCT | NOBLOODY
 	var/number = 0
-	var/last_tick //used to delay the powercheck
+	var/area/linked_area
 
 /obj/item/device/radio/intercom/custom
 	name = "station intercom (Custom)"
@@ -39,7 +39,7 @@
 
 /obj/item/device/radio/intercom/New()
 	..()
-	START_PROCESSING(SSobj, src)
+	loop_area_check()
 
 /obj/item/device/radio/intercom/department/medbay/New()
 	..()
@@ -64,10 +64,6 @@
 	..()
 	internal_channels[num2text(SYND_FREQ)] = list(access_syndicate)
 
-/obj/item/device/radio/intercom/Destroy()
-	STOP_PROCESSING(SSobj, src)
-	. = ..()
-
 /obj/item/device/radio/intercom/attack_ai(mob/user as mob)
 	src.add_fingerprint(user)
 	spawn (0)
@@ -93,23 +89,28 @@
 
 	return canhear_range
 
-/obj/item/device/radio/intercom/Process()
-	if(((world.timeofday - last_tick) > 30) || ((world.timeofday - last_tick) < 0))
-		last_tick = world.timeofday
-
-		if(!src.loc)
-			on = FALSE
-		else
-			var/area/A = get_area(src)
-			if(!A)
-				on = FALSE
-			else
-				on = A.powered(EQUIP) // set "on" to the power status
-
-		if(!on)
-			icon_state = "intercom-p"
-		else
-			icon_state = "intercom"
+/obj/item/device/radio/intercom/proc/change_status()
+	on = linked_area.powered(EQUIP)
+	icon_state = on ? "intercom" : "intercom-p"
+
+/obj/item/device/radio/intercom/proc/loop_area_check()
+	var/area/target_area = get_area(src)
+	if(!target_area)
+		addtimer(CALLBACK(src, .proc/loop_area_check), 30 SECONDS)
+		return FALSE
+	if(!target_area.apc)
+		addtimer(CALLBACK(src, .proc/loop_area_check), 30 SECONDS) // We don't proces if there is no APC , no point in doing so is there ?
+		return FALSE
+	linked_area = target_area
+	RegisterSignal(target_area, COMSIG_AREA_APC_DELETED, .proc/on_apc_removal)
+	RegisterSignal(target_area, COMSIG_AREA_APC_POWER_CHANGE, .proc/change_status)
+
+/obj/item/device/radio/intercom/proc/on_apc_removal()
+	UnregisterSignal(linked_area , COMSIG_AREA_APC_DELETED)
+	UnregisterSignal(linked_area, COMSIG_AREA_APC_POWER_CHANGE)
+	linked_area = null
+	on = FALSE
+	addtimer(CALLBACK(src, .proc/loop_area_check), 30 SECONDS)
 
 /obj/item/device/radio/intercom/broadcasting
 	broadcasting = 1

code/modules/power/apc.dm

@@ -188,6 +188,7 @@
 /obj/machinery/power/apc/Destroy()
 	update()
 	area.apc = null
+	SEND_SIGNAL(area, COMSIG_AREA_APC_DELETED)
 	area.power_light = 0
 	area.power_equip = 0
 	area.power_environ = 0