/obj/machinery/duct
	name = "fluid duct"
	icon = 'icons/obj/pipes_n_cables/hydrochem/fluid_ducts.dmi'
	icon_state = "nduct"
	layer = PLUMBING_PIPE_VISIBILE_LAYER
	use_power = NO_POWER_USE

	///our ductnet, wich tracks what we're connected to
	var/datum/ductnet/net
	///the color of our duct
	var/duct_color = ATMOS_COLOR_OMNI
	///the layer of the duct
	var/duct_layer = DUCT_LAYER_DEFAULT
	///track machines we're connected to.
	var/list/atom/movable/neighbours

/obj/machinery/duct/Initialize(mapload, color_of_duct, layer_of_duct)
	if(GLOB.plumbing_layer_names["[layer_of_duct]"])
		duct_layer = layer_of_duct

	if(PERFORM_ALL_TESTS(maptest_log_mapping))
		var/datum/overlap = ducting_layer_check(src, duct_layer)
		if(!isnull(overlap))
			var/message = GLOB.plumbing_layer_names["[duct_layer]"]
			if(istype(overlap, /obj/machinery/duct))
				message = "duct on [message]"
			else
				message = "machine on [message]"
			log_mapping("Overlapping plumbing [message] detected at [AREACOORD(src)]")
			return INITIALIZE_HINT_QDEL

	. = ..()

	if(GLOB.pipe_color_name[color_of_duct])
		duct_color = color_of_duct
	add_atom_colour(duct_color, FIXED_COLOUR_PRIORITY)

	var/offset
	switch(duct_layer)
		if(FIRST_DUCT_LAYER)
			offset = -10
		if(SECOND_DUCT_LAYER)
			offset = -5
		if(THIRD_DUCT_LAYER)
			offset = 0
		if(FOURTH_DUCT_LAYER)
			offset = 5
		if(FIFTH_DUCT_LAYER)
			offset = 10
	pixel_x = offset
	pixel_y = offset
	layer = initial(layer) + duct_layer * 0.0003

	AddElement(/datum/element/undertile, TRAIT_T_RAY_VISIBLE)

	register_context()

/obj/machinery/duct/post_machine_initialize()
	. = ..()

	//can be initialized already during map init by its neighbours
	if(!net)
		net = new (src)

	LAZYINITLIST(neighbours)
	for(var/direction in GLOB.cardinals)
		//we have already connected. happens in circular connections
		var/connected = FALSE
		for(var/atom/movable/neighbour as anything in neighbours)
			if(direction & neighbours[neighbour])
				connected = TRUE
				break
		if(connected)
			continue

		for(var/atom/movable/plumbable in get_step(src, direction))
			var/opposite_dir = REVERSE_DIR(direction)

			if(istype(plumbable, /obj/machinery/duct))
				var/obj/machinery/duct/other = plumbable

				//must be same duct color
				if((duct_color != other.duct_color) && !(duct_color == ATMOS_COLOR_OMNI || other.duct_color == ATMOS_COLOR_OMNI))
					continue
				//must be same duct layer
				if(!(duct_layer & other.duct_layer))
					continue

				//connect ductnets
				if(!other.net) //will be null only for map loaded ducts
					net.ducts += other
					other.net = net
				else if(net != other.net) //merge the nets
					var/datum/ductnet/othernet = other.net
					//Take all its suppliers & demanders
					net.suppliers |= othernet.suppliers
					net.demanders |= othernet.demanders
					for(var/datum/component/plumbing/component as anything in othernet.suppliers + othernet.demanders)
						for(var/obj/machinery/duct/duct as anything in component.ducts)
							if(component.ducts[duct] == othernet)
								component.ducts[duct] = net
					othernet.suppliers.Cut()
					othernet.demanders.Cut()

					//Take all its ducts
					net.ducts |= othernet.ducts
					for(var/obj/machinery/duct/duct as anything in othernet.ducts)
						duct.net = net

					//destory it
					qdel(othernet)

				//connecting us to duct
				neighbours[other] = direction
				//connecting duct to us
				LAZYADDASSOC(other.neighbours, src, opposite_dir)
				other.update_appearance(UPDATE_ICON)

				continue

			for(var/datum/component/plumbing/plumbing as anything in plumbable.GetComponents(/datum/component/plumbing))
				//not anchored
				if(!plumbing.active())
					continue

				//not on the same layer
				if(!(duct_layer & plumbing.ducting_layer))
					continue

				//does the duct backend connect to either supplier or demander
				if(!(opposite_dir & (plumbing.supply_connects | plumbing.demand_connects)))
					continue

				//connect duct to plumber
				if(!net.add_plumber(plumbing, opposite_dir))
					continue

				//assign neighbour
				neighbours[plumbing.parent] = direction

	update_appearance(UPDATE_ICON)

///we disconnect ourself from our neighbours. we also destroy our ductnet and tell our neighbours to make a new one
/obj/machinery/duct/on_deconstruction()
	var/obj/item/stack/ducts/duct_stack = new (drop_location())
	duct_stack.duct_color = duct_color
	duct_stack.duct_layer = duct_layer
	duct_stack.add_atom_colour(duct_color, FIXED_COLOUR_PRIORITY)

///Removes duct from ductnet
/obj/machinery/duct/proc/disconnect()
	//remove ourself from the duct
	net.ducts -= src
	if(!net.ducts.len)
		qdel(net) //destroy the pipeline. Suppliers aren't important if there aren't any ducts left
	net = null

/obj/machinery/duct/Destroy()
	//object was early deleted
	if(!net)
		return ..()

	var/list/atom/movable/visited = list(src = TRUE)
	while(neighbours.len)
		var/atom/movable/neighbour = popleft(neighbours)

		//disconnect ourself from our neighbours
		var/obj/machinery/duct/pipe = neighbour
		if(istype(pipe))
			pipe.neighbours -= src
			pipe.update_appearance(UPDATE_ICON)

		//find every node that can be reached from our neighbour making sure to not revisit it again in circles
		if(visited[neighbour])
			continue
		var/datum/ductnet/newnet
		var/list/atom/movable/queue = list(neighbour)
		while(queue.len)
			var/atom/movable/node = popleft(queue)
			if(visited[node])
				continue

			//visit all neighbours of this pipe as well
			pipe = node
			if(istype(pipe))
				//assign to new pipenet
				pipe.disconnect()
				if(!newnet)
					newnet = new
				newnet.ducts += pipe
				pipe.net = newnet

				//go through its neighbours as well
				for(var/atom/movable/subnode in pipe.neighbours)
					queue += subnode

				visited[node] = TRUE
				continue

			//assign machines to new network
			for(var/datum/component/plumbing/plumbing as anything in node.GetComponents(/datum/component/plumbing))
				//disconnect old net
				for(var/dirtext in plumbing.ducts)
					if(plumbing.ducts[dirtext] == net)
						net.remove_plumber(plumbing)
				//assign new net
				if(newnet)
					for(pipe as anything in newnet.ducts)
						var/dir = pipe.neighbours[node]
						if(dir)
							newnet.add_plumber(plumbing, REVERSE_DIR(dir))

	disconnect()

	return ..()

/obj/machinery/duct/add_context(atom/source, list/context, obj/item/held_item, mob/user)
	. = NONE
	if(held_item?.tool_behaviour == TOOL_WRENCH)
		context[SCREENTIP_CONTEXT_LMB] = "Destroy duct"
		return CONTEXTUAL_SCREENTIP_SET

/obj/machinery/duct/examine(mob/user)
	. = ..()
	. += span_notice("Its current color and layer are [GLOB.pipe_color_name[duct_color]] and [GLOB.plumbing_layer_names["[duct_layer]"]]. Use in-hand to change.")
	. += span_notice("It can be [EXAMINE_HINT("wrenched")] apart.")

/obj/machinery/duct/update_icon_state()
	var/temp_icon = initial(icon_state)

	//compute connections
	var/connects = NONE
	for(var/neighbour in neighbours)
		connects |= neighbours[neighbour]

	for(var/direction in GLOB.cardinals)
		switch(direction & connects)
			if(NORTH)
				temp_icon += "_n"
			if(SOUTH)
				temp_icon += "_s"
			if(EAST)
				temp_icon += "_e"
			if(WEST)
				temp_icon += "_w"
	icon_state = temp_icon
	return ..()

/obj/machinery/duct/wrench_act(mob/living/user, obj/item/wrench) //I can also be the RPD
	wrench.play_tool_sound(src)

	user.visible_message( \
	"[user] ununfastens \the [src].", \
	span_notice("You unfasten \the [src]."), \
	span_hear("You hear ratcheting."))

	deconstruct()
	return ITEM_INTERACT_SUCCESS

/obj/item/stack/ducts
	name = "stack of duct"
	desc = "A stack of fluid ducts."
	singular_name = "duct"
	icon = 'icons/obj/pipes_n_cables/hydrochem/fluid_ducts.dmi'
	icon_state = "ducts"
	mats_per_unit = list(/datum/material/iron=SMALL_MATERIAL_AMOUNT*5)
	w_class = WEIGHT_CLASS_TINY
	novariants = FALSE
	max_amount = 50
	item_flags = NOBLUDGEON
	merge_type = /obj/item/stack/ducts
	matter_amount = 1
	///Color of our duct
	var/duct_color = ATMOS_COLOR_OMNI
	///Default layer of our duct
	var/duct_layer = THIRD_DUCT_LAYER

/obj/item/stack/ducts/Initialize(mapload, new_amount, merge, list/mat_override, mat_amt)
	. = ..()

	//when wrench is over us
	register_context()

	//when we are over pipe
	register_item_context()

/obj/item/stack/ducts/add_context(atom/source, list/context, obj/item/held_item, mob/user)
	. = NONE
	if(held_item?.tool_behaviour == TOOL_WRENCH && isopenturf(loc))
		context[SCREENTIP_CONTEXT_LMB] = "Wrench duct"
		return CONTEXTUAL_SCREENTIP_SET

/obj/item/stack/ducts/add_item_context(obj/item/source, list/context, atom/target, mob/living/user)
	. = NONE
	if(istype(target, /obj/machinery/duct))
		context[SCREENTIP_CONTEXT_LMB] = "Pick duct"
		return CONTEXTUAL_SCREENTIP_SET

/obj/item/stack/ducts/examine(mob/user)
	. = ..()
	. += span_notice("Its current color and layer are [GLOB.pipe_color_name[duct_color]] and [GLOB.plumbing_layer_names["[duct_layer]"]]. Use in-hand to change.")
	. += span_notice("Place on ground & [EXAMINE_HINT("wrench")] to create duct.")

/obj/item/stack/ducts/attack_self(mob/user)
	var/new_layer = tgui_input_list(user, "Select a layer", "Layer", GLOB.plumbing_layers, GLOB.plumbing_layer_names["[duct_layer]"])
	if(!user.is_holding(src))
		return
	if(new_layer)
		duct_layer = GLOB.plumbing_layers[new_layer]
	var/new_color = tgui_input_list(user, "Select a color", "Color", GLOB.pipe_paint_colors, GLOB.pipe_color_name[duct_color])
	if(!user.is_holding(src))
		return
	if(new_color)
		duct_color = GLOB.pipe_paint_colors[new_color]
		add_atom_colour(duct_color, FIXED_COLOUR_PRIORITY)

/obj/item/stack/ducts/wrench_act(mob/living/user, obj/item/tool)
	return check_attach_turf(loc)

/obj/item/stack/ducts/interact_with_atom(atom/interacting_with, mob/living/user, list/modifiers)
	// Turn into a duct stack and then merge to the in-hand stack.
	if(istype(interacting_with, /obj/machinery/duct))
		if(amount == max_amount)
			balloon_alert(user, "stack full!")
			return ITEM_INTERACT_FAILURE
		qdel(interacting_with)
		add(1)
		return ITEM_INTERACT_SUCCESS

	return check_attach_turf(interacting_with, user)

/obj/item/stack/ducts/proc/check_attach_turf(turf/open_turf, mob/user)
	. = NONE
	if(isopenturf(open_turf))
		var/datum/overlap = ducting_layer_check(open_turf, duct_layer)
		if(!isnull(overlap))
			if(user)
				open_turf.balloon_alert(user, "overlapping [istype(overlap, /obj/machinery/duct) ? "duct" : "machine"] detected!")
			return ITEM_INTERACT_FAILURE

		new /obj/machinery/duct(open_turf, duct_color, duct_layer)
		playsound(open_turf, 'sound/machines/click.ogg', 50, TRUE)
		use(1)
		return ITEM_INTERACT_SUCCESS

/obj/item/stack/ducts/fifty
	amount = 50