Call update procs instead of directly setting idle_power_usage or active_power_usage.

- Adds the update_idle_power_usage() and update_active_power_usage() procs for the respective vars.
- Switches all places modifying those vars directly to call the procs instead.
- This will let us react to the change appropriately, paving the way towards static area power.
- Adds update_power_channel proc for the sake of completeness, but no machines actually modify it so far.

code/modules/overmap/ships/computers/computer_shims.dm

@@ -20,9 +20,9 @@
 /obj/machinery/proc/change_power_consumption(new_power_consumption, use_power_mode = USE_POWER_IDLE)
 	switch(use_power_mode)
 		if(USE_POWER_IDLE)
-			idle_power_usage = new_power_consumption
+			update_idle_power_usage(new_power_consumption)
 		if(USE_POWER_ACTIVE)
-			active_power_usage = new_power_consumption
+			update_active_power_usage(new_power_consumption)
 	// No need to do anything else in our power scheme.
 
 // Defining directly here to avoid conflicts with existing set_broken procs in our codebase that behave differently.

code/modules/power/fusion/core/_core.dm

@@ -60,7 +60,7 @@ var/list/fusion_cores = list()
 	if(href_list["str"])
 		var/dif = text2num(href_list["str"])
 		field_strength = min(max(field_strength + dif, MIN_FIELD_STR), MAX_FIELD_STR)
-		active_power_usage = 500 * field_strength
+		update_active_power_usage(500 * field_strength)
 		if(owned_field)
 			owned_field.ChangeFieldStrength(field_strength)
 
@@ -96,7 +96,7 @@ var/list/fusion_cores = list()
 /obj/machinery/power/fusion_core/proc/set_strength(var/value)
 	value = CLAMP(value, MIN_FIELD_STR, MAX_FIELD_STR)
 	field_strength = value
-	active_power_usage = 5 * value
+	update_active_power_usage(5 * value)
 	if(owned_field)
 		owned_field.ChangeFieldStrength(value)
 

code/modules/power/fusion/gyrotron/gyrotron.dm

@@ -22,7 +22,7 @@ var/list/gyrotrons = list()
 
 /obj/machinery/power/emitter/gyrotron/Initialize()
 	gyrotrons += src
-	active_power_usage = mega_energy * 50000
+	update_active_power_usage(mega_energy * 50000)
 	default_apply_parts()
 	. = ..()
 
@@ -31,7 +31,7 @@ var/list/gyrotrons = list()
 	return ..()
 
 /obj/machinery/power/emitter/gyrotron/process()
-	active_power_usage = mega_energy * 50000
+	update_active_power_usage(mega_energy * 50000)
 	. = ..()
 
 /obj/machinery/power/emitter/gyrotron/get_rand_burst_delay()

code/modules/power/fusion/gyrotron/gyrotron_control.dm

@@ -75,7 +75,7 @@
 			to_chat(usr, "<span class='warning'>That's not a valid number.</span>")
 			return 1
 		G.mega_energy = CLAMP(new_val, 1, 50)
-		G.active_power_usage = G.mega_energy * 1500
+		G.update_active_power_usage(G.mega_energy * 1500)
 		updateUsrDialog()
 		return 1
 

code/modules/power/lighting.dm

@@ -445,7 +445,7 @@ var/global/list/light_type_cache = list()
 		update_use_power(USE_POWER_IDLE)
 		set_light(0)
 
-	active_power_usage = ((light_range * light_power) * LIGHTING_POWER_FACTOR)
+	update_active_power_usage((light_range * light_power) * LIGHTING_POWER_FACTOR)
 
 
 /obj/machinery/light/attack_generic(var/mob/user, var/damage)

code/modules/power/singularity/particle_accelerator/particle_control.dm

@@ -24,7 +24,7 @@
 /obj/machinery/particle_accelerator/control_box/New()
 	wires = new(src)
 	connected_parts = list()
-	active_power_usage = initial(active_power_usage) * (strength + 1)
+	update_active_power_usage(initial(active_power_usage) * (strength + 1))
 	..()
 
 /obj/machinery/particle_accelerator/control_box/Destroy()

code/modules/research/server.dm

@@ -31,7 +31,7 @@
 	var/tot_rating = 0
 	for(var/obj/item/weapon/stock_parts/SP in src)
 		tot_rating += SP.rating
-	idle_power_usage /= max(1, tot_rating)
+	update_idle_power_usage(initial(idle_power_usage) / max(1, tot_rating))
 
 /obj/machinery/r_n_d/server/Initialize()
 	. = ..()

code/modules/shieldgen/emergency_shield.dm

@@ -153,9 +153,10 @@
 
 	create_shields()
 
-	idle_power_usage = 0
+	var/new_power_usage = 0
 	for(var/obj/machinery/shield/shield_tile in deployed_shields)
-		idle_power_usage += shield_tile.shield_idle_power
+		new_power_usage += shield_tile.shield_idle_power
+	update_idle_power_usage(new_power_usage)
 	update_use_power(USE_POWER_IDLE)
 
 /obj/machinery/shieldgen/proc/shields_down()
@@ -205,7 +206,7 @@
 				new_power_usage += shield_tile.shield_idle_power
 
 			if (new_power_usage != idle_power_usage)
-				idle_power_usage = new_power_usage
+				update_idle_power_usage(new_power_usage)
 				use_power(0)
 
 			check_delay = 60