technic/technic/machines/other/constructor.lua

local S = technic.getter

local function deploy_node(inv, slot_name, pos, node, machine_node)
	if node.name ~= "air" then
		if node.name == "ignore" or
				node.name == "default:lava_source" or
				node.name == "default:lava_flowing" or
				node.name == "default:water_source" or
				node.name == "default:water_flowing" then
			return
		end
		local drops = minetest.get_node_drops(node.name, "")
		local remove_to = false
		for i, item in ipairs(drops) do
			if not inv:room_for_item(slot_name, item) then
				remove_to = i - 1
				break
			end
			inv:add_item(slot_name, item)
		end
		if remove_to then
			for i = 1, remove_to do
				inv:remove_item(slot_name, drops[i])
			end
		else
			minetest.remove_node(pos)
		end
		return
	end
	if not inv:is_empty(slot_name) then
		local stack = inv:get_list(slot_name)[1]
		local def = stack:get_definition()
		if def.type == "node" then
			minetest.set_node(pos, {
				name = stack:get_name(),
				param2 = machine_node.param2
			})
			stack:take_item()
			inv:set_stack(slot_name, 1, stack)
		elseif def.type == "craft" then
			if def.on_place then
				-- Use pcall to avoid nil placer errors.
				-- TODO: Do without pcall.
				local ok, stk = pcall(def.on_place, stack, nil, {
					-- Fake pointed_thing
					type = "node",
					above = pos,
					under = { x = pos.x, y = pos.y - 1, z = pos.z },
				})
				if ok then
					inv:set_stack(slot_name, 1, stk or stack)
					return
				end
			end
			minetest.item_place_object(stack, nil, {
				-- Fake pointed_thing
				type = "node",
				above = pos,
				under = pos,
			})
			inv:set_stack(slot_name, 1, nil)
		end
	end
end

minetest.register_craft({
	type = "shapeless",
	output = 'technic:constructor_mk1_off 1',
	recipe = { "technic:nodebreaker_off", "technic:deployer_off" },
})
minetest.register_craft({
	type = "shapeless",
	output = 'technic:constructor_mk2_off 1',
	recipe = { "technic:constructor_mk1_off", "technic:constructor_mk1_off" },
})

minetest.register_craft({
	type = "shapeless",
	output = 'technic:constructor_mk3_off 1',
	recipe = { "technic:constructor_mk2_off", "technic:constructor_mk2_off" },
})

local function make_on(mark, length)
	return function(pos, node)
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		local dir = vector.new()
		if node.param2 == 3 then dir.x = 1 end
		if node.param2 == 2 then dir.z = 1 end
		if node.param2 == 1 then dir.x = -1 end
		if node.param2 == 0 then dir.z = -1 end

		local place_pos = vector.new(pos)

		if node.name == "technic:constructor_mk"..mark.."_off" then
			technic.swap_node(pos, "technic:constructor_mk"..mark.."_on")
			nodeupdate(pos)
			for i = 1, length do
				place_pos = vector.add(place_pos, dir)
				local place_node = minetest.get_node(place_pos)
				deploy_node(inv, "slot"..i, place_pos, place_node, node)
			end
		end
	end
end

local function make_off(mark)
	return function(pos, node)
		if node.name == "technic:constructor_mk"..mark.."_on" then
			technic.swap_node(pos, "technic:constructor_mk"..mark.."_off")
			nodeupdate(pos)
		end
	end
end


local function make_constructor(mark, length)
	minetest.register_node("technic:constructor_mk"..mark.."_off", {
		description = S("Constructor Mk%d"):format(mark),
		tiles = {
			"technic_constructor_mk"..mark.."_top_off.png",
			"technic_constructor_mk"..mark.."_bottom_off.png",
			"technic_constructor_mk"..mark.."_side2_off.png",
			"technic_constructor_mk"..mark.."_side1_off.png",
			"technic_constructor_back.png",
			"technic_constructor_front_off.png"
		},
		paramtype2 = "facedir",
		groups = { snappy = 2, choppy = 2, oddly_breakable_by_hand = 2, mesecon = 2 },
		mesecons = { effector = { action_on = make_on(mark, length) } },
		sounds = default.node_sound_stone_defaults(),
		on_construct = function(pos)
			local meta = minetest.get_meta(pos)
			local formspec = "size[8,9;]"..
					"label[0,0;"..S("Constructor Mk%d"):format(mark).."]"..
					"list[current_player;main;0,5;8,4;]"
			for i = 1, length do
				formspec = formspec
						.. "label[5,"..(i - 1)..";"..S("Slot %d"):format(i).."]"
						.. "list[current_name;slot"..i
						.. ";6,"..(i - 1)..";1,1;]"
			end
			meta:set_string("formspec", formspec)
			meta:set_string("infotext", S("Constructor Mk%d"):format(mark))
			local inv = meta:get_inventory()
			for i = 1, length do
				inv:set_size("slot"..i, 1)
			end
		end,
		can_dig = function(pos, player)
			local meta = minetest.get_meta(pos)
			local inv = meta:get_inventory()
			for i = 1, length do
				if not inv:is_empty("slot"..i) then
					return false
				end
			end
			return true
		end,
		allow_metadata_inventory_put = technic.machine_inventory_put,
		allow_metadata_inventory_take = technic.machine_inventory_take,
		allow_metadata_inventory_move = technic.machine_inventory_move,
	})

	minetest.register_node("technic:constructor_mk"..mark.."_on", {
		tiles = {
			"technic_constructor_mk"..mark.."_top_on.png",
			"technic_constructor_mk"..mark.."_bottom_on.png",
			"technic_constructor_mk"..mark.."_side2_on.png",
			"technic_constructor_mk"..mark.."_side1_on.png",
			"technic_constructor_back.png",
			"technic_constructor_front_on.png"
		},
		paramtype2 = "facedir",
		drop = "technic:constructor_mk"..mark.."_off",
		groups = {
			snappy = 2,
			choppy = 2,
			oddly_breakable_by_hand = 2,
			mesecon = 2,
			not_in_creative_inventory = 1
		},
		mesecons = { effector = { action_off = make_off(mark) } },
		sounds = default.node_sound_stone_defaults(),
		allow_metadata_inventory_put = technic.machine_inventory_put,
		allow_metadata_inventory_take = technic.machine_inventory_take,
		allow_metadata_inventory_move = technic.machine_inventory_move,
	})
end

make_constructor(1, 1)
make_constructor(2, 2)
make_constructor(3, 4)