From f66c644fceb08d1e40e8b684b3a95b0e30fd9c94 Mon Sep 17 00:00:00 2001
From: SX <50966843+S-S-X@users.noreply.github.com>
Date: Sat, 26 Sep 2020 04:37:20 +0300
Subject: [PATCH] Remove metadata for
 supply,demand,battery_count,battery_charge,battery_charge_max

Remove switching station from networks

Disable few debug prints, add removed machines to LBM

clear_networks refatoring #95

Functions remove_network_node and add_network_branch #95

Fix undef network_id, remove flatten #95
---
 technic/machines/network.lua                  | 149 ++++++++-----
 technic/machines/power_monitor.lua            |  40 ++--
 technic/machines/register/cables.lua          | 209 ++++++++++--------
 technic/machines/switching_station.lua        |  34 ++-
 .../machines/switching_station_globalstep.lua |   9 +-
 technic/spec/fixtures/minetest.lua            |  21 ++
 technic/spec/fixtures/network.lua             |  32 +++
 technic/spec/network_spec.lua                 |  11 +
 8 files changed, 299 insertions(+), 206 deletions(-)

diff --git a/technic/machines/network.lua b/technic/machines/network.lua
index 71ff05d..08182b3 100644
--- a/technic/machines/network.lua
+++ b/technic/machines/network.lua
@@ -35,6 +35,7 @@ function technic.sw_pos2tier(pos, use_vm)
 	return technic.get_cable_tier(minetest.get_node(cable_pos).name)
 end
 
+-- Destroy network data
 function technic.remove_network(network_id)
 	local cables = technic.cables
 	for pos_hash,cable_net_id in pairs(cables) do
@@ -43,7 +44,23 @@ function technic.remove_network(network_id)
 		end
 	end
 	technic.networks[network_id] = nil
-	print(string.format("NET DESTRUCT %s (%.17g)", minetest.pos_to_string(technic.network2pos(network_id)), network_id))
+	--print(string.format("NET DESTRUCT %s (%.17g)", minetest.pos_to_string(technic.network2pos(network_id)), network_id))
+end
+
+-- Remove machine or cable from network
+local network_node_tables = {"PR_nodes","BA_nodes","RE_nodes","SP_nodes","all_nodes"}
+function technic.remove_network_node(network_id, pos)
+	local network = technic.networks[network_id]
+	if not network then return end
+	technic.cables[poshash(pos)] = nil
+	for _,tblname in ipairs(network_node_tables) do
+		local table = network[tblname]
+		for id,mpos in pairs(table) do
+			if mpos.x == pos.x and mpos.y == pos.y and mpos.z == pos.z then
+				table[id] = nil
+			end
+		end
+	end
 end
 
 function technic.sw_pos2network(pos)
@@ -104,6 +121,11 @@ local overload_reset_time = tonumber(minetest.settings:get("technic.overload_res
 local overloaded_networks = {}
 
 function technic.overload_network(network_id)
+	local network = technic.networks[network_id]
+	if network then
+		network.supply = 0
+		network.battery_charge = 0
+	end
 	overloaded_networks[network_id] = minetest.get_us_time() + (overload_reset_time * 1000 * 1000)
 end
 
@@ -125,13 +147,6 @@ end
 --
 -- Functions to traverse the electrical network
 --
-local function flatten(map)
-	local list = {}
-	for key, value in pairs(map) do
-		list[#list + 1] = value
-	end
-	return list
-end
 
 local function attach_network_machine(network_id, pos)
 	local pos_hash = poshash(pos)
@@ -148,31 +163,26 @@ local function attach_network_machine(network_id, pos)
 	end
 end
 
--- Add a wire node to the LV/MV/HV network
+-- Add a machine node to the LV/MV/HV network
 local function add_network_node(nodes, pos, network_id)
+	technic.cables[poshash(pos)] = network_id
+	table.insert(nodes, pos)
+end
+
+-- Add a wire node to the LV/MV/HV network
+local function add_cable_node(nodes, pos, network_id, queue)
 	local node_id = poshash(pos)
 	technic.cables[node_id] = network_id
 	if nodes[node_id] then
 		return false
 	end
 	nodes[node_id] = pos
-	return true
-end
-
-local function add_cable_node(nodes, pos, network_id, queue)
-	if add_network_node(nodes, pos, network_id) then
-		queue[#queue + 1] = pos
-	end
+	-- Also add cables to queue
+	queue[#queue + 1] = pos
 end
 
 -- Generic function to add found connected nodes to the right classification array
-local function check_node_subp(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_nodes, pos, machines, tier, sw_pos, from_below, network_id, queue)
-
-	local distance_to_switch = vector.distance(pos, sw_pos)
-	if distance_to_switch > switch_max_range then
-		-- max range exceeded
-		return
-	end
+local function check_node_subp(PR_nodes, RE_nodes, BA_nodes, all_nodes, pos, machines, tier, sw_pos, from_below, network_id, queue)
 
 	technic.get_or_load_node(pos)
 	local name = minetest.get_node(pos).name
@@ -192,10 +202,6 @@ local function check_node_subp(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_nodes
 			--attach_network_machine(network_id, pos)
 			add_network_node(PR_nodes, pos, network_id)
 			add_network_node(RE_nodes, pos, network_id)
-		elseif machines[name] == "SPECIAL" and from_below then
-			-- Another switching station -> disable it
-			attach_network_machine(network_id, pos)
-			add_network_node(SP_nodes, pos, network_id)
 		elseif machines[name] == technic.battery then
 			attach_network_machine(network_id, pos)
 			add_network_node(BA_nodes, pos, network_id)
@@ -206,7 +212,7 @@ local function check_node_subp(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_nodes
 end
 
 -- Traverse a network given a list of machines and a cable type name
-local function traverse_network(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_nodes, pos, machines, tier, sw_pos, network_id, queue)
+local function traverse_network(PR_nodes, RE_nodes, BA_nodes, all_nodes, pos, machines, tier, sw_pos, network_id, queue)
 	local positions = {
 		{x=pos.x+1, y=pos.y,   z=pos.z},
 		{x=pos.x-1, y=pos.y,   z=pos.z},
@@ -215,7 +221,7 @@ local function traverse_network(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_node
 		{x=pos.x,   y=pos.y,   z=pos.z+1},
 		{x=pos.x,   y=pos.y,   z=pos.z-1}}
 	for i, cur_pos in pairs(positions) do
-		check_node_subp(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_nodes, cur_pos, machines, tier, sw_pos, i == 3, network_id, queue)
+		check_node_subp(PR_nodes, RE_nodes, BA_nodes, all_nodes, cur_pos, machines, tier, sw_pos, i == 3, network_id, queue)
 	end
 end
 
@@ -237,6 +243,28 @@ local function get_network(network_id, tier)
 	return technic.build_network(network_id)
 end
 
+function technic.add_network_branch(queue, sw_pos, network)
+	-- Adds whole branch to network, queue positions can be used to bypass sub branches
+	local PR_nodes = network.PR_nodes -- Indexed array
+	local BA_nodes = network.BA_nodes -- Indexed array
+	local RE_nodes = network.RE_nodes -- Indexed array
+	local all_nodes = network.all_nodes -- Hash table
+	local network_id = network.id
+	local tier = network.tier
+	while next(queue) do
+		local to_visit = {}
+		for _, pos in ipairs(queue) do
+			if vector.distance(pos, sw_pos) > switch_max_range then
+				-- max range exceeded
+				return
+			end
+			traverse_network(PR_nodes, RE_nodes, BA_nodes, all_nodes, pos,
+					technic.machines[tier], tier, sw_pos, network_id, to_visit)
+		end
+		queue = to_visit
+	end
+end
+
 function technic.build_network(network_id)
 	print(string.format("NET CONSTRUCT %s (%.17g)", minetest.pos_to_string(technic.network2pos(network_id)), network_id))
 	technic.remove_network(network_id)
@@ -246,29 +274,24 @@ function technic.build_network(network_id)
 		print(string.format("Cannot build network, cannot get tier for switching station at %s", minetest.pos_to_string(sw_pos)))
 		return
 	end
-	local PR_nodes = {}
-	local BA_nodes = {}
-	local RE_nodes = {}
-	local SP_nodes = {}
-	local all_nodes = {}
+	local network = {
+		id = network_id, tier = tier, all_nodes = {},
+		SP_nodes = {}, PR_nodes = {}, RE_nodes = {}, BA_nodes = {},
+		supply = 0, demand = 0, timeout = 4, battery_charge = 0, battery_charge_max = 0,
+	}
+	-- Add first cable (one that is holding network id) and build network
 	local queue = {}
-	-- Add first cable (one that is holding network id)
-	add_cable_node(all_nodes, technic.network2pos(network_id), network_id, queue)
-	while next(queue) do
-		local to_visit = {}
-		for _, pos in ipairs(queue) do
-			traverse_network(PR_nodes, RE_nodes, BA_nodes, SP_nodes, all_nodes,
-					pos, technic.machines[tier], tier, sw_pos, network_id, to_visit)
-		end
-		queue = to_visit
-	end
-	PR_nodes = flatten(PR_nodes)
-	BA_nodes = flatten(BA_nodes)
-	RE_nodes = flatten(RE_nodes)
-	--SP_nodes = flatten(SP_nodes) -- can this be removed from network data?
-	technic.networks[network_id] = {tier = tier, all_nodes = all_nodes, SP_nodes = SP_nodes,
-			PR_nodes = PR_nodes, RE_nodes = RE_nodes, BA_nodes = BA_nodes, timeout = 4}
-	return PR_nodes, BA_nodes, RE_nodes
+	add_cable_node(network.all_nodes, technic.network2pos(network_id), network_id, queue)
+	technic.add_network_branch(queue, sw_pos, network)
+	-- Flatten hashes to optimize iterations
+	--network.PR_nodes = flatten(network.PR_nodes) -- Already processed as indexed array
+	--network.BA_nodes = flatten(network.BA_nodes) -- Already processed as indexed array
+	--network.RE_nodes = flatten(network.RE_nodes) -- Already processed as indexed array
+	network.battery_count = #network.BA_nodes
+	-- Add newly built network to cache array
+	technic.networks[network_id] = network
+	-- And return producers, batteries and receivers (should this simply return network?)
+	return network.PR_nodes, network.BA_nodes, network.RE_nodes
 end
 
 --
@@ -315,9 +338,11 @@ function technic.network_run(network_id)
 	local RE_nodes
 
 	local tier = technic.sw_pos2tier(pos)
+	local network
 	if tier then
 		PR_nodes, BA_nodes, RE_nodes = get_network(network_id, tier)
 		if technic.is_overloaded(network_id) then return end
+		network = technic.networks[network_id]
 	else
 		--dprint("Not connected to a network")
 		technic.network_infotext(network_id, S("%s Has No Network"):format(S("Switching Station")))
@@ -400,13 +425,12 @@ function technic.network_run(network_id)
 			S("Switching Station"), technic.EU_string(PR_eu_supply),
 			technic.EU_string(RE_eu_demand)))
 
-	local meta = minetest.get_meta(pos)
-
 	-- If mesecon signal and power supply or demand changed then
 	-- send them via digilines.
 	if mesecons_path and digilines_path and mesecon.is_powered(pos) then
-		if PR_eu_supply ~= meta:get_int("supply") or
-				RE_eu_demand ~= meta:get_int("demand") then
+		if PR_eu_supply ~= network.supply or
+				RE_eu_demand ~= network.demand then
+			local meta = minetest.get_meta(pos)
 			local channel = meta:get_string("channel")
 			digilines.receptor_send(pos, technic.digilines.rules, channel, {
 				supply = PR_eu_supply,
@@ -416,11 +440,11 @@ function technic.network_run(network_id)
 	end
 
 	-- Data that will be used by the power monitor
-	meta:set_int("supply",PR_eu_supply)
-	meta:set_int("demand",RE_eu_demand)
-	meta:set_int("battery_count",#BA_nodes)
-	meta:set_int("battery_charge",BA_charge)
-	meta:set_int("battery_charge_max",BA_charge_max)
+	network.supply = PR_eu_supply
+	network.demand = RE_eu_demand
+	network.battery_count = #BA_nodes
+	network.battery_charge = BA_charge
+	network.battery_charge_max = BA_charge_max
 
 	-- If the PR supply is enough for the RE demand supply them all
 	if PR_eu_supply >= RE_eu_demand then
@@ -533,13 +557,16 @@ if false then
 		nodenames = {
 			"group:technic_machine",
 			"group:technic_all_tiers",
+			"technic:switching_station",
+			"technic:power_monitor",
 		},
 		action = function(pos, node)
 			-- Delete all listed metadata key/value pairs from technic machines
 			local keys = {
 				"LV_EU_timeout", "MV_EU_timeout", "HV_EU_timeout",
 				"LV_network", "MV_network", "HV_network",
-				"active_pos",
+				"active_pos", "supply", "demand",
+				"battery_count", "battery_charge", "battery_charge_max",
 			}
 			local meta = minetest.get_meta(pos)
 			for _,key in ipairs(keys) do
diff --git a/technic/machines/power_monitor.lua b/technic/machines/power_monitor.lua
index e17a790..3618cf8 100644
--- a/technic/machines/power_monitor.lua
+++ b/technic/machines/power_monitor.lua
@@ -13,6 +13,7 @@ local function get_cable(pos)
 end
 
 -- return the position of connected cable or nil
+-- TODO: Make it support every possible orientation
 local function get_connected_cable_network(pos)
 	local param2 = minetest.get_node(pos).param2
 	-- should probably also work sideways or upside down but for now it wont
@@ -26,18 +27,16 @@ local function get_connected_cable_network(pos)
 	-- Behind?
 	checkpos = vector.add(minetest.facedir_to_dir(param2),pos)
 	network_id = get_cable(checkpos) and technic.pos2network(checkpos)
-	if network_id then
-		return network_id
-	end
+	return network_id
 end
 
 -- return the position of the associated switching station or nil
-local function get_swpos(pos)
+local function get_network(pos)
 	local network_id = get_connected_cable_network(pos)
 	local network = network_id and technic.networks[network_id]
 	local swpos = network and technic.network2sw_pos(network_id)
 	local is_powermonitor = swpos and minetest.get_node(swpos).name == "technic:switching_station"
-	return (is_powermonitor and network.all_nodes[network_id]) and swpos
+	return (is_powermonitor and network.all_nodes[network_id]) and network
 end
 
 minetest.register_craft({
@@ -97,19 +96,16 @@ minetest.register_node("technic:power_monitor",{
 					return
 				end
 
-				local sw_pos = get_swpos(pos)
-				if not sw_pos then
-					return
-				end
+				local network = get_network(pos)
+				if not network then return end
 
-				local sw_meta = minetest.get_meta(sw_pos)
 				digilines.receptor_send(pos, technic.digilines.rules, channel, {
-					supply = sw_meta:get_int("supply"),
-					demand = sw_meta:get_int("demand"),
-					lag = sw_meta:get_int("lag"),
-					battery_count = sw_meta:get_int("battery_count"),
-					battery_charge = sw_meta:get_int("battery_charge"),
-					battery_charge_max = sw_meta:get_int("battery_charge_max"),
+					supply = network.supply,
+					demand = network.demand,
+					lag = network.lag,
+					battery_count = network.battery_count,
+					battery_charge = network.battery_charge,
+					battery_charge_max = network.battery_charge_max,
 				})
 			end
 		},
@@ -123,14 +119,10 @@ minetest.register_abm({
 	chance     = 1,
 	action = function(pos, node, active_object_count, active_object_count_wider)
 		local meta = minetest.get_meta(pos)
-		local sw_pos = get_swpos(pos)
-		if sw_pos then
-			local sw_meta = minetest.get_meta(sw_pos)
-			local supply = sw_meta:get_int("supply")
-			local demand = sw_meta:get_int("demand")
-			meta:set_string("infotext",
-					S("Power Monitor. Supply: @1 Demand: @2",
-					technic.EU_string(supply), technic.EU_string(demand)))
+		local network = get_network(pos)
+		if network then
+			meta:set_string("infotext", S("Power Monitor. Supply: @1 Demand: @2",
+					technic.EU_string(network.supply), technic.EU_string(network.demand)))
 		else
 			meta:set_string("infotext",S("Power Monitor Has No Network"))
 		end
diff --git a/technic/machines/register/cables.lua b/technic/machines/register/cables.lua
index 768c54f..e625422 100644
--- a/technic/machines/register/cables.lua
+++ b/technic/machines/register/cables.lua
@@ -13,6 +13,9 @@ end
 
 local function check_connections(pos)
 	-- Build a table of all machines
+	-- TODO: Move this to network.lua
+	-- TODO: Build table for current tier only, we do not want to test other tiers.
+	-- Make sure that multi tier machines work (currently supply converter).
 	local machines = {}
 	for tier,list in pairs(technic.machines) do
 		for k,v in pairs(list) do
@@ -36,81 +39,94 @@ local function check_connections(pos)
 	return connections
 end
 
-local function clear_networks(pos)
-	local node = minetest.get_node(pos)
-	local placed = node.name ~= "air"
+local function connect_networks(pos, positions)
+	-- TODO: Allow connecting networks:
+	-- If neighbor branch does not belong to any network attach it to this network
+	-- If neighbor branch belongs to another network check which one has least #all_nodes and rebuild that
+	for _,connected_pos in pairs(positions) do
+		local net = technic.pos2network(connected_pos)
+		if net and technic.networks[net] then
+			-- Not a dead end, so the whole network needs to be recalculated
+			technic.remove_network(net)
+		end
+	end
+end
+
+local function place_network_node(pos, node)
 	local positions = check_connections(pos)
 	if #positions < 1 then return end
 	local dead_end = #positions == 1
-	for _,connected_pos in pairs(positions) do
-		local net = technic.cables[minetest.hash_node_position(connected_pos)]
-		if net and technic.networks[net] then
-			if dead_end and placed then
-				-- Dead end placed, add it to the network
-				-- Get the network
-				local network_id = technic.cables[minetest.hash_node_position(positions[1])]
-				if not network_id then
-					-- We're evidently not on a network, nothing to add ourselves to
-					return
-				end
-				local sw_pos = minetest.get_position_from_hash(network_id)
-				sw_pos.y = sw_pos.y + 1
-				local network = technic.networks[network_id]
-				local tier = network.tier
 
-				-- Actually add it to the (cached) network
-				-- This is similar to check_node_subp
-				local pos_hash = minetest.hash_node_position(pos)
-				technic.cables[pos_hash] = network_id
-				pos.visited = 1
-				if technic.is_tier_cable(name, tier) then
-					network.all_nodes[pos_hash] = pos
-				elseif technic.machines[tier][node.name] then
-					if     technic.machines[tier][node.name] == technic.producer then
-						table.insert(network.PR_nodes,pos)
-					elseif technic.machines[tier][node.name] == technic.receiver then
-						table.insert(network.RE_nodes,pos)
-					elseif technic.machines[tier][node.name] == technic.producer_receiver then
-						table.insert(network.PR_nodes,pos)
-						table.insert(network.RE_nodes,pos)
-					elseif technic.machines[tier][node.name] == "SPECIAL" and
-							(pos.x ~= sw_pos.x or pos.y ~= sw_pos.y or pos.z ~= sw_pos.z) and
-							from_below then
-						network.SP_nodes[pos_hash] = pos
-					elseif technic.machines[tier][node.name] == technic.battery then
-						table.insert(network.BA_nodes,pos)
-					end
-				end
-			elseif dead_end and not placed then
-				-- Dead end removed, remove it from the network
-				-- Get the network
-				local network_id = technic.cables[minetest.hash_node_position(positions[1])]
-				if not network_id then
-					-- We're evidently not on a network, nothing to add ourselves to
-					return
-				end
-				local network = technic.networks[network_id]
+	-- Dead end placed, add it to the network
+	-- Get the network
+	local network_id = technic.pos2network(positions[1])
+	if not network_id then
+		-- We're evidently not on a network, nothing to add ourselves to
+		return
+	end
+	local network = technic.networks[network_id]
+	local tier = network.tier
 
-				-- Search for and remove machine
-				technic.cables[minetest.hash_node_position(pos)] = nil
-				for tblname,table in pairs(network) do
-					if tblname ~= "tier" then
-						for machinenum,machine in pairs(table) do
-							if machine.x == pos.x
-							and machine.y == pos.y
-							and machine.z == pos.z then
-								table[machinenum] = nil
-							end
-						end
-					end
+	if not dead_end then
+		return connect_networks(pos, positions)
+	end
+
+	-- Actually add it to the (cached) network
+	-- This is similar to check_node_subp
+	local pos_hash = minetest.hash_node_position(pos)
+	technic.cables[pos_hash] = network_id
+	pos.visited = 1
+	if technic.is_tier_cable(name, tier) then
+		network.all_nodes[pos_hash] = pos
+	elseif technic.machines[tier][node.name] then
+		if     technic.machines[tier][node.name] == technic.producer then
+			table.insert(network.PR_nodes,pos)
+		elseif technic.machines[tier][node.name] == technic.receiver then
+			table.insert(network.RE_nodes,pos)
+		elseif technic.machines[tier][node.name] == technic.producer_receiver then
+			table.insert(network.PR_nodes,pos)
+			table.insert(network.RE_nodes,pos)
+		elseif technic.machines[tier][node.name] == technic.battery then
+			table.insert(network.BA_nodes,pos)
+		end
+	end
+end
+
+local function remove_network_node(pos)
+	-- Get the network
+	local network_id = technic.pos2network(pos)
+	if not network_id then
+		-- We're evidently not on a network, nothing to add ourselves to
+		return
+	end
+
+	local positions = check_connections(pos)
+	if #positions < 1 then return end
+	local dead_end = #positions == 1
+
+	if not dead_end then
+		-- TODO: Check branches around and switching stations for branches:
+		--   remove branches that do not have switching station.
+		--   remove branches not connected to another branch.
+		--   do not rebuild networks here, leave that for ABM to reduce unnecessary cache building.
+		-- For now remove network like how it was done before:
+		technic.remove_network(network_id)
+		return
+	end
+
+	-- Dead end removed, remove it from the network
+	local network = technic.networks[network_id]
+	technic.cables[minetest.hash_node_position(pos)] = nil
+	-- TODO: Looping over all keys in network is not right way to do this, should fix to use known machine types.
+	-- Better to add network function that knows what to remove, something like technic.remove_node(network_id, pos)
+	for tblname,table in pairs(network) do
+		if type(table) == "table" then
+			for machinenum,machine in pairs(table) do
+				if machine.x == pos.x
+				and machine.y == pos.y
+				and machine.z == pos.z then
+					table[machinenum] = nil
 				end
-			else
-				-- Not a dead end, so the whole network needs to be recalculated
-				for _,v in pairs(technic.networks[net].all_nodes) do
-					local pos1 = minetest.hash_node_position(v)
-					technic.cables[pos1] = nil
-				end
-				technic.networks[net] = nil
 			end
 		end
 	end
@@ -142,7 +158,8 @@ function technic.register_cable(tier, size, description, prefix, override_cable,
 	prefix = prefix or ""
 	override_cable_plate = override_cable_plate or override_cable
 	local ltier = string.lower(tier)
-	cable_tier["technic:"..ltier..prefix.."_cable"] = tier
+	local node_name = "technic:"..ltier..prefix.."_cable"
+	cable_tier[node_name] = tier
 
 	local groups = {snappy=2, choppy=2, oddly_breakable_by_hand=2,
 			["technic_"..ltier.."_cable"] = 1}
@@ -158,22 +175,22 @@ function technic.register_cable(tier, size, description, prefix, override_cable,
 		connect_right  = {-size, -size, -size, 0.5,   size, size}, -- x+
 	}
 
-	minetest.register_node("technic:"..ltier..prefix.."_cable", override_table({
+	minetest.register_node(node_name, override_table({
 		description = S("%s Cable"):format(tier),
 		tiles = {"technic_"..ltier..prefix.."_cable.png"},
 		inventory_image = "technic_"..ltier..prefix.."_cable_wield.png",
 		wield_image = "technic_"..ltier..prefix.."_cable_wield.png",
 		groups = groups,
 		sounds = default.node_sound_wood_defaults(),
-		drop = "technic:"..ltier..prefix.."_cable",
+		drop = node_name,
 		paramtype = "light",
 		sunlight_propagates = true,
 		drawtype = "nodebox",
 		node_box = node_box,
 		connects_to = {"group:technic_"..ltier.."_cable",
 			"group:technic_"..ltier, "group:technic_all_tiers"},
-		on_construct = clear_networks,
-		on_destruct = clear_networks,
+		on_construct = function(pos) place_network_node(pos, node_name) end,
+		on_destruct = remove_network_node,
 	}, override_cable))
 
 	local xyz = {
@@ -205,15 +222,15 @@ function technic.register_cable(tier, size, description, prefix, override_cable,
 			tiles = {"technic_"..ltier..prefix.."_cable.png"},
 			groups = table.copy(groups),
 			sounds = default.node_sound_wood_defaults(),
-			drop = "technic:"..ltier..prefix.."_cable_plate_1",
+			drop = node_name .. "_plate_1",
 			paramtype = "light",
 			sunlight_propagates = true,
 			drawtype = "nodebox",
 			node_box = table.copy(node_box),
 			connects_to = {"group:technic_"..ltier.."_cable",
 				"group:technic_"..ltier, "group:technic_all_tiers"},
-			on_construct = clear_networks,
-			on_destruct = clear_networks,
+			on_construct = function(pos) place_network_node(pos, node_name.."_plate_"..i) end,
+			on_destruct = remove_network_node,
 		}
 		def.node_box.fixed = {
 			{-size, -size, -size, size, size, size},
@@ -254,7 +271,7 @@ function technic.register_cable(tier, size, description, prefix, override_cable,
 				if num == nil then num = 1 end
 				return item_place_override_node(
 					itemstack, placer, pointed_thing,
-					{name = "technic:"..ltier..prefix.."_cable_plate_"..num}
+					{name = node_name.."_plate_"..num}
 				)
 			end
 		else
@@ -271,39 +288,41 @@ function technic.register_cable(tier, size, description, prefix, override_cable,
 			num = num + dir
 			num = (num >= 1 and num) or num + 6
 			num = (num <= 6 and num) or num - 6
-			minetest.swap_node(pos, {name = "technic:"..ltier..prefix.."_cable_plate_"..num})
+			minetest.swap_node(pos, {name = node_name.."_plate_"..num})
 		end
-		minetest.register_node("technic:"..ltier..prefix.."_cable_plate_"..i, override_table(def, override_cable_plate))
-		cable_tier["technic:"..ltier..prefix.."_cable_plate_"..i] = tier
+		minetest.register_node(node_name.."_plate_"..i, override_table(def, override_cable_plate))
+		cable_tier[node_name.."_plate_"..i] = tier
 	end
 
-	local c = "technic:"..ltier..prefix.."_cable"
 	minetest.register_craft({
-		output = "technic:"..ltier..prefix.."_cable_plate_1 5",
+		output = node_name.."_plate_1 5",
 		recipe = {
-			{"", "", c},
-			{c , c , c},
-			{"", "", c},
+			{""       , ""       , node_name},
+			{node_name, node_name, node_name},
+			{""       , ""       , node_name},
 		}
 	})
 
 	minetest.register_craft({
-		output = c,
+		output = node_name,
 		recipe = {
-			{"technic:"..ltier..prefix.."_cable_plate_1"},
+			{node_name.."_plate_1"},
 		}
 	})
 end
 
-
-local function clear_nets_if_machine(pos, node)
+minetest.register_on_placenode(function(pos, node)
 	for tier, machine_list in pairs(technic.machines) do
 		if machine_list[node.name] ~= nil then
-			return clear_networks(pos)
+			return place_network_node(pos, node)
 		end
 	end
-end
-
-minetest.register_on_placenode(clear_nets_if_machine)
-minetest.register_on_dignode(clear_nets_if_machine)
+end)
 
+minetest.register_on_dignode(function(pos, node)
+	for tier, machine_list in pairs(technic.machines) do
+		if machine_list[node.name] ~= nil then
+			return remove_network_node(pos)
+		end
+	end
+end)
diff --git a/technic/machines/switching_station.lua b/technic/machines/switching_station.lua
index 2953219..0bd8ef1 100644
--- a/technic/machines/switching_station.lua
+++ b/technic/machines/switching_station.lua
@@ -92,11 +92,19 @@ minetest.register_node("technic:switching_station",{
 				if channel ~= meta:get_string("channel") then
 					return
 				end
-				digilines.receptor_send(pos, technic.digilines.rules, channel, {
-					supply = meta:get_int("supply"),
-					demand = meta:get_int("demand"),
-					lag = meta:get_int("lag")
-				})
+				local network_id = technic.sw_pos2network(pos)
+				local network = network_id and technic.networks[network_id]
+				if network then
+					digilines.receptor_send(pos, technic.digilines.rules, channel, {
+						supply = network.supply,
+						demand = network.demand,
+						lag = network.lag
+					})
+				else
+					digilines.receptor_send(pos, technic.digilines.rules, channel, {
+						error = "No network",
+					})
+				end
 			end
 		},
 	},
@@ -106,14 +114,6 @@ minetest.register_node("technic:switching_station",{
 -- The action code for the switching station --
 -----------------------------------------------
 
-function technic.switching_station_run(pos)
-	local network_id = technic.sw_pos2network(pos)
-	if network_id then
-		return technic.network_run(network_id)
-	end
-	--print(string.format("technic.switching_station_run(%s) failed, no network available", minetest.pos_to_string(pos)))
-end
-
 -- Timeout ABM
 -- Timeout for a node in case it was disconnected from the network
 -- A node must be touched by the station continuously in order to function
@@ -168,9 +168,6 @@ minetest.register_abm({
 				local remaining = technic.reset_overloaded(network_id)
 				if remaining > 0 then
 					infotext = S("%s Network Overloaded, Restart in %dms"):format(S("Switching Station"), remaining / 1000)
-					-- Set switching station supply value to zero to clean up power monitor supply info
-					-- TODO: This should be saved with network and removed from metadata
-					meta:set_int("supply",0)
 				else
 					infotext = S("%s Restarting Network"):format(S("Switching Station"))
 				end
@@ -187,8 +184,3 @@ minetest.register_abm({
 		end
 	end,
 })
-
-for tier, machines in pairs(technic.machines) do
-	-- SPECIAL will not be traversed
-	technic.register_machine(tier, "technic:switching_station", "SPECIAL")
-end
diff --git a/technic/machines/switching_station_globalstep.lua b/technic/machines/switching_station_globalstep.lua
index e83f0df..bed6f07 100644
--- a/technic/machines/switching_station_globalstep.lua
+++ b/technic/machines/switching_station_globalstep.lua
@@ -86,12 +86,13 @@ minetest.register_globalstep(function(dtime)
 
 	for network_id, switch in pairs(switches) do
 		local pos = technic.network2sw_pos(network_id)
+		local network = technic.networks[network_id]
 		local diff = now - switch.time
 
 		minetest.get_voxel_manip(pos, pos)
 		local node = minetest.get_node(pos)
 
-		if node.name ~= "technic:switching_station" then
+		if network == nil or node.name ~= "technic:switching_station" then
 			-- station vanished
 			switches[network_id] = nil
 
@@ -102,13 +103,11 @@ minetest.register_globalstep(function(dtime)
 			if switch.skip < 1 then
 
 				local start = minetest.get_us_time()
-				technic.switching_station_run(pos)
+				technic.network_run(network_id)
 				local switch_diff = minetest.get_us_time() - start
 
-				local meta = minetest.get_meta(pos)
-
 				-- set lag in microseconds into the "lag" meta field
-				meta:set_int("lag", switch_diff)
+				network.lag = switch_diff
 
 				-- overload detection
 				if switch_diff > 250000 then
diff --git a/technic/spec/fixtures/minetest.lua b/technic/spec/fixtures/minetest.lua
index f035b28..b759cda 100644
--- a/technic/spec/fixtures/minetest.lua
+++ b/technic/spec/fixtures/minetest.lua
@@ -1,6 +1,13 @@
 local function noop(...) end
 local function dummy_coords(...) return { x = 123, y = 123, z = 123 } end
 
+_G.world = { nodes = {} }
+local world = _G.world
+_G.world.set_node = function(pos, node)
+	local hash = minetest.hash_node_position(pos)
+	world.nodes[hash] = node
+end
+
 _G.core = {}
 _G.minetest = _G.core
 
@@ -64,12 +71,26 @@ _G.minetest.register_lbm = noop
 _G.minetest.register_abm = noop
 _G.minetest.register_chatcommand = noop
 _G.minetest.chat_send_player = noop
+_G.minetest.register_alias = noop
 _G.minetest.register_craftitem = noop
 _G.minetest.register_craft = noop
+_G.minetest.register_node = noop
 _G.minetest.register_on_placenode = noop
 _G.minetest.register_on_dignode = noop
 _G.minetest.item_drop = noop
 
+_G.minetest.get_node = function(pos)
+	local hash = minetest.hash_node_position(pos)
+	return world.nodes[hash] or {name="IGNORE",param2=0}
+end
+
 _G.minetest.get_modpath = function(...) return "./unit_test_modpath" end
 
 _G.minetest.get_pointed_thing_position = dummy_coords
+
+--
+-- Minetest default noop table
+--
+local default = { __index = function(...) return function(...)end end }
+_G.default = {}
+setmetatable(_G.default, default)
diff --git a/technic/spec/fixtures/network.lua b/technic/spec/fixtures/network.lua
index 7f1af94..ef06a92 100644
--- a/technic/spec/fixtures/network.lua
+++ b/technic/spec/fixtures/network.lua
@@ -1,5 +1,37 @@
 
+local world = {
+	{{x=100,y=100,z=100}, "technic:lv_cable"},
+	{{x=101,y=100,z=100}, "technic:lv_cable"},
+	{{x=102,y=100,z=100}, "technic:lv_cable"},
+	{{x=103,y=100,z=100}, "technic:lv_cable"},
+	{{x=100,y=101,z=100}, "technic:switching_station"},
+
+	{{x=100,y=200,z=100}, "technic:mv_cable"},
+	{{x=101,y=200,z=100}, "technic:mv_cable"},
+	{{x=102,y=200,z=100}, "technic:mv_cable"},
+	{{x=103,y=200,z=100}, "technic:mv_cable"},
+	{{x=100,y=201,z=100}, "technic:switching_station"},
+
+	{{x=100,y=300,z=100}, "technic:hv_cable"},
+	{{x=101,y=300,z=100}, "technic:hv_cable"},
+	{{x=102,y=300,z=100}, "technic:hv_cable"},
+	{{x=103,y=300,z=100}, "technic:hv_cable"},
+	{{x=100,y=301,z=100}, "technic:switching_station"},
+}
+
+-- Build world for tests
+for _,node in ipairs(world) do
+	_G.world.set_node(node[1], {name=node[2], param2=0})
+end
+
 _G.technic = {}
 _G.technic.S = string.format
+_G.technic.getter = function(...) return "" end
 
 sourcefile("register")
+
+sourcefile("machines/register/cables")
+
+sourcefile("machines/LV/cables")
+sourcefile("machines/MV/cables")
+sourcefile("machines/HV/cables")
diff --git a/technic/spec/network_spec.lua b/technic/spec/network_spec.lua
index ffe1c23..575b150 100644
--- a/technic/spec/network_spec.lua
+++ b/technic/spec/network_spec.lua
@@ -37,6 +37,17 @@ describe("Power network helper", function()
 			assert.same(net_id, technic.sw_pos2network(sw_pos) )
 		end)
 
+		it("returns nil tier for empty position", function()
+			assert.is_nil(technic.sw_pos2tier({x=9999,y=9999,z=9999}))
+		end)
+
+		it("returns correct tier for switching station position", function()
+			-- World is defined in fixtures/network.lua
+			assert.same("LV", technic.sw_pos2tier({x=100,y=101,z=100}))
+			assert.same("MV", technic.sw_pos2tier({x=100,y=201,z=100}))
+			assert.same("HV", technic.sw_pos2tier({x=100,y=301,z=100}))
+		end)
+
 	end)
 
 	--[[ TODO: