minetest-mod-sparktech/sparktool/lua/charger.lua

local NAME = minetest.get_current_modname()
local MAX_ENERGY = 200

local formspec = sparktech.add_inventory(8,1.5,
	"list[current_name;charge;0,0;1,1;]")

local SPEED = 10

minetest.register_node(NAME ..":charger", {
	description = "Electric Charger",
	tiles = {
		NAME .. "_steel_sideplate.png",
		NAME .. "_steel_sideplate.png",
		NAME .. "_steel_sideplate.png",
		NAME .. "_steel_sideplate.png",
		NAME .. "_steel_backplate.png",
		NAME .. "_charger_frontplate.png",
	},
	groups = {
		sparktech_techy = WRENCHABLE,
		sparktech_energy_type = ENERGY_CONSUMER,
		sparktech_energy_storeonbreak = TRUE,
		sparktech_net_trigger = TRUE,
		sparktech_energy_max = MAX_ENERGY,
		sparktech_energy_wakeup = 10 
	},
	allow_metadata_inventory_put = function (_, _, _, itemstack)
		if minetest.get_item_group(itemstack:get_name(), "sparktech_chargable") > 0 then
			return 1
		else
			return 0
		end
	end,
	on_metadata_inventory_put = function (pos)
		local meta = minetest.get_meta(pos)
		if meta:get_int("energy") <= 0 then return end
		local timer = minetest.get_node_timer(pos)
		timer:start(1.0)
	end,
	on_timer = function (pos, elapsed)
		local meta = minetest.get_meta(pos)
		local energy = meta:get_int("energy")

		local inv = meta:get_inventory()
		local chgitem = inv:get_stack("charge", 1)
		local item_meta = chgitem:get_meta()
		local max = minetest.get_item_group(chgitem:get_name(),
			"sparktech_chargable")
		local curr = item_meta:get_int("energy")
		local diff = math.min(max - curr, SPEED)

		if energy >= diff then
			item_meta:set_int("energy", curr + diff)
			energy = energy - diff
			meta:set_int("energy", energy)

			local f = chgitem:get_definition()._sparktech_update_energy
			if f then
				chgitem = f(chgitem)
			end
			inv:set_stack("charge", 1, chgitem)
		end

		if diff ~= 0 then
			local timer = minetest.get_node_timer(pos)
			timer:start(1.0)
		end

	meta:set_string("formspec", formspec ..
		sparktech.makebar("energy2.png",
		1.25, 0.0, 8, 1,
		energy, minetest.get_item_group(minetest.get_node(pos).name,
		"sparktech_energy_max"), 0))
	end,
	on_construct = function(pos, placer)
		local meta = minetest.get_meta(pos)
		meta:set_string("formspec", formspec)
		local inventory = meta:get_inventory()
		inventory:set_size('charge', 1)
	end,
})

minetest.register_craft({
	output = NAME .. ":charger",
		recipe = {
			{ "", "sparkcore:cable", "" },
			{ "default:copper_ingot", "sparkcomponent:steel_chasis", "default:copper_ingot" },
			{ "", "sparkcore:cable", "" },
		}
})