minetest-mod-sparktech/sparkfurnace/metalfurnace.lua

local NAME = minetest.get_current_modname()
local modifier = 10 -- Cooking cost modifier
local time_modifier = 1.5 -- Cooking time modifier

local formspec =
	"size[8,6.5]"..
	"list[current_name;source;0,0;1,2;]" ..
	"list[current_name;product;7,0;1,2;]" ..
	"list[current_player;main;0,2.5;8,3;8]" ..
	"list[current_player;main;0,5.7;8,1;]"..
	"bgcolor[#FC05E344;false]" ..
	"listcolors[#fc059db0;#fc059dd0]"

local function is_smeltable(items)
	local cooked
	local aftercooked
	cooked, aftercooked = minetest.get_craft_result({method = "cooking", width = 1, items = items})
	return cooked.time ~= 0
end

local function is_item_allowed(pos, target, _, stack)
	if target == "product" then return 0 end --so no items get moved into the souce inventory by the user

	if stack == nil or not is_smeltable({stack}) then --invalid or unsmeltable items dont get in
		return 0
	else
		return stack:get_count()
	end
end

local function is_item_allowed_move(pos, src, sidx, target, tidx, c, p)
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	local stack = inv:get_stack(src, sidx)
	return is_item_allowed(pos, target, tidx, stack, p)
end

local function ongetitem(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

local function update_formspec(pos)
  local meta = minetest.get_meta(pos)
  	local inventory = meta:get_inventory()
	local cfmsp = formspec

	local energy = meta:get_int("energy")
	
	cfmsp = cfmsp ..
	  sparktech.makebar("energy2.png", 0, 2.1, 9.75, 0.25,
			    energy, minetest.get_item_group(minetest.get_node(pos).name, "sparktech_energy_max")
			    , 0)

	for item=1, 2 do -- Later this should only be done when a player looks into the block
	  local cooked
	  local aftercooked
	  local progress = meta:get_int("progress_" .. item)	
	  cooked, aftercooked = minetest.get_craft_result({method = "cooking", width = 1, items = {inventory:get_stack("source", item)}})
	  
	  cfmsp = cfmsp ..
	    sparktech.makebar("progress2.png", 0, -1 + item, 1, 1,
			      progress, math.ceil(cooked.time * time_modifier), 0)
	end
	
	meta:set_string("formspec", cfmsp)
end

local function mytime(pos, elapsed)
	local meta = minetest.get_meta(pos)
	local energy = meta:get_int("energy")
	local inventory = meta:get_inventory()
	local source = inventory:get_list("source")
	local product = inventory:get_list("product")
	local counter = 0
	local newcycle = true -- set to false if not new cycle is required
  
	for item=1,2 do
		if energy == 0 then return end --if no energy is available return, rest of the function doesnt matter
		local cooked
		local aftercooked
		local progress = meta:get_int("progress_" .. item)	
		cooked, aftercooked = minetest.get_craft_result({method = "cooking", width = 1, items = {inventory:get_stack("source", item)}})
		--source and product assigned
		if progress >= math.ceil(cooked.time * time_modifier) then
			if inventory:room_for_item("product", cooked.item) then
				inventory:add_item("product", cooked.item)
				inventory:set_stack("source", item, aftercooked.items[1])
				meta:set_int("progress_" .. item, 0)
			else
				counter = counter +1
			end
		else
			meta:set_int("progress_" .. item, progress + 1)
			energy = energy - 1 * modifier
			meta:set_int("energy", energy)
		end
		-- minetest.debug(dump(pos) .. " : " .. dump(item))
	end

	update_formspec(pos)
	
	if counter == 2 then
		newcycle = false -- this meens that both finished cooking and the other inventory is full
	end
	--TODO: for the formspec code, if it is marked as active update it here
	if (newcycle) then
		minetest.get_node_timer(pos):start(1.0) -- it was determined that a new cycle is required, this is the case if energy and material to cook is available
	end
	return
end

local function maytake(pos, listname, index, stack, player)
	local meta = minetest.get_meta(pos)
	if listname == "product" then 
		return tonumber(stack:get_count()) --sure, take the stuff that the furnace has cooked for you :D
	end
	-- TODO: code to stop people from taking halfcooked items, they'd burn their fingers
end

minetest.register_node( NAME .. ":lv_furnace", {
	description = "Electric furnace",

	tiles = {
		"furnace2.png",
		"furnace2.png",
		"furnace2.png",
		"furnace2.png",
		"furnace2.png",
		"furnace.png"
	},
	paramtype2 = "facedir",

	groups = {
		sparktech_techy = 1,
		sparktech_energy_type = 4,
		sparktech_net_trigger = 1,
		sparktech_energy_max = 300,
		spark_energy_timer = 2
	},

	on_timer = mytime, -- add a mytimer function
	 allow_metadata_inventory_take = maytake,

	--on_righclick = function(pos, node, player, itemstack, pointed_thing)
	--TODO show formspec here, and store that a formspec is open in meta, the mytimer function schould update the formspec if it is open, recievefields schould mark it as closed

	--end,

	on_construct = function(pos, placer)
	  local meta = minetest.get_meta(pos)
	  meta:set_string("formspec",formspec) --gonna replace this with crafting the formspec on rightclick instead
	  local inventory = meta:get_inventory()
	  inventory:set_size('source',2)
	  inventory:set_size('product',2)
	end,

	on_rightclick = function(pos, clicker) -- Requires Version >0.4.16 to trigger because a custom formspec is set
	  minetest.debug("Ping!")
	  return false
	end,

	allow_metadata_inventory_put = is_item_allowed,
	allow_metadata_inventory_move = is_item_allowed_move,
	--on_metadata_inventory_move = ongetitem, --doesnt seem necesarry to me, if the item moves in the inventory schould not change the cooking process
	on_metadata_inventory_put = ongetitem
})

minetest.register_craft({
	output = NAME .. ":lv_furnace",
	recipe = { 	{ 'group:steelplate', 'group:steelplate', 'group:steelplate' },
				{ 'group:steelplate', 'default:copper_ingot', 'group:steelplate' },
				{ 'group:steelplate', 'group:steelplate', 'group:steelplate' }}
})