Replaces Subsystems (mostly) with internal computing device (#7798)

This is for robots.

code/modules/modular_computers/computers/modular_computer/core.dm

@@ -31,7 +31,7 @@
 		else
 			idle_threads.Remove(P)
 
-	working = hard_drive && processor_unit && damage < broken_damage && (apc_power(0) || battery_power(0))
+	working = hard_drive && processor_unit && damage < broken_damage && computer_use_power()
 	check_update_ui_need()
 
 	if (working && enabled && world.time > ambience_last_played + 30 SECONDS && prob(3))
@@ -125,7 +125,7 @@
 		else
 			to_chat(user, "You press the power button, but the computer fails to boot up, displaying variety of errors before shutting down again.")
 		return
-	if(processor_unit && (apc_power(0) || battery_power(0))) // Battery-run and charged or non-battery but powered by APC.
+	if(processor_unit && computer_use_power()) // Battery-run and charged or non-battery but powered by APC.
 		if(issynth)
 			to_chat(user, "You send an activation signal to \the [src], turning it on")
 		else

code/modules/modular_computers/computers/modular_computer/power.dm

@@ -38,6 +38,16 @@
 	A.use_power(power_usage, EQUIP)
 	return TRUE
 
+
+// Tries to use power in general (Abstraction)
+/obj/item/modular_computer/proc/computer_use_power(var/power_usage = 0)
+	// First tries to charge from an APC, if APC is unavailable switches to battery power. If neither works the computer fails.
+	if(apc_power(power_usage))
+		return TRUE
+	if(battery_power(power_usage))
+		return TRUE
+	return FALSE
+
 // Handles power-related things, such as battery interaction, recharging, shutdown when it's discharged
 /obj/item/modular_computer/proc/handle_power()
 	var/power_usage = screen_on ? base_active_power_usage : base_idle_power_usage
@@ -47,13 +57,8 @@
 				power_usage += H.power_usage
 		last_power_usage = power_usage
 
-	// First tries to charge from an APC, if APC is unavailable switches to battery power. If neither works the computer fails.
-	if(apc_power(power_usage))
-		if (power_has_failed)
-			power_has_failed = FALSE
-			update_icon()
-		return
-	if(battery_power(power_usage))
+	
+	if(computer_use_power(power_usage))
 		if (power_has_failed)
 			power_has_failed = FALSE
 			update_icon()

code/modules/modular_computers/computers/modular_computer/ui.dm

@@ -5,7 +5,7 @@
 		if(ui)
 			ui.close()
 		return
-	if(!apc_power(0) && !battery_power(0))
+	if(!computer_use_power())
 		if(ui)
 			ui.close()
 		return