Choose layers for circulator and engine heater (#2977)

## About The Pull Request

Lets you choose pipe layer for circulator and engine heater by using
multitool on circuitboard. I literally just copy-pasted freezers code.

Unfortunately, sprites aren't compatible with these changes, so this
problem needs to be solved by brave spriters.

## Why It's Good For The Game

Makes engine heaters and circulators more flexible and easier to place
for both mappers and players.

## Changelog

:cl:
add: Layer changing to engine heaters and freezers

code/game/machinery/shuttle/shuttle_heater.dm

@@ -25,7 +25,7 @@
 	layer = OBJ_LAYER
 	showpipe = TRUE
 
-	pipe_flags = PIPING_ONE_PER_TURF | PIPING_DEFAULT_LAYER_ONLY
+	pipe_flags = PIPING_ONE_PER_TURF
 
 	var/efficiency_multiplier = 1
 	var/gas_capacity = 0
@@ -34,6 +34,13 @@
 	///The internals tank to draw from
 	var/obj/item/tank/fuel_tank
 
+/obj/machinery/atmospherics/components/unary/shuttle/heater/on_construction(obj_color, set_layer)
+	var/obj/item/circuitboard/machine/shuttle/heater/board = circuit
+	if(board)
+		piping_layer = board.pipe_layer
+		set_layer = piping_layer
+	..()
+
 /obj/machinery/atmospherics/components/unary/shuttle/heater/New()
 	. = ..()
 	SetInitDirections()

code/game/objects/items/circuitboards/machine_circuitboards.dm

@@ -201,8 +201,19 @@
 	name = "Circulator/Heat Exchanger (Machine Board)"
 	icon_state = "engineering"
 	build_path = /obj/machinery/atmospherics/components/binary/circulator
+	var/pipe_layer = PIPING_LAYER_DEFAULT
 	req_components = list()
 
+/obj/item/circuitboard/machine/circulator/attackby(obj/item/I, mob/user, params)
+	if(I.tool_behaviour == TOOL_MULTITOOL)
+		pipe_layer = (pipe_layer >= PIPING_LAYER_MAX) ? PIPING_LAYER_MIN : (pipe_layer + 1)
+		to_chat(user, "<span class='notice'>You change the circuitboard to layer [pipe_layer].</span>")
+		return
+
+/obj/item/circuitboard/machine/circulator/examine()
+	. = ..()
+	. += "<span class='notice'>It is set to layer [pipe_layer].</span>"
+
 /obj/item/circuitboard/machine/emitter
 	name = "Emitter (Machine Board)"
 	icon_state = "engineering"
@@ -1470,10 +1481,22 @@
 
 /obj/item/circuitboard/machine/shuttle/heater
 	name = "Fueled Engine Heater (Machine Board)"
+	desc = "You can use mulitool to switch pipe layers"
 	build_path = /obj/machinery/atmospherics/components/unary/shuttle/heater
+	var/pipe_layer = PIPING_LAYER_DEFAULT
 	req_components = list(/obj/item/stock_parts/micro_laser = 2,
 		/obj/item/stock_parts/matter_bin = 1)
 
+/obj/item/circuitboard/machine/shuttle/heater/attackby(obj/item/I, mob/user, params)
+	if(I.tool_behaviour == TOOL_MULTITOOL)
+		pipe_layer = (pipe_layer >= PIPING_LAYER_MAX) ? PIPING_LAYER_MIN : (pipe_layer + 1)
+		to_chat(user, "<span class='notice'>You change the circuitboard to layer [pipe_layer].</span>")
+		return
+
+/obj/item/circuitboard/machine/shuttle/heater/examine()
+	. = ..()
+	. += "<span class='notice'>It is set to layer [pipe_layer].</span>"
+
 /obj/item/circuitboard/machine/shuttle/smes
 	name = "Electric Engine Precharger (Machine Board)"
 	build_path = /obj/machinery/power/smes/shuttle

code/modules/atmospherics/machinery/components/binary_devices/circulator.dm

@@ -15,12 +15,19 @@
 	var/active = FALSE
 
 	var/last_pressure_delta = 0
-	pipe_flags = PIPING_ONE_PER_TURF | PIPING_DEFAULT_LAYER_ONLY
+	pipe_flags = PIPING_ONE_PER_TURF
 
 	var/flipped = 0
 	var/mode = CIRCULATOR_HOT
 	var/obj/machinery/power/generator/generator
 
+/obj/machinery/atmospherics/components/unary/shuttle/heater/on_construction(obj_color, set_layer)
+	var/obj/item/circuitboard/machine/circulator/board = circuit
+	if(board)
+		piping_layer = board.pipe_layer
+		set_layer = piping_layer
+	..()
+
 //for mappers
 /obj/machinery/atmospherics/components/binary/circulator/cold
 	mode = CIRCULATOR_COLD