The_End/mods/gameplay_mechanics/crafting/stations.lua

-- Crafting Mod - semi-realistic crafting in minetest
-- Copyright (C) 2018 rubenwardy <rw@rubenwardy.com>
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public
-- License as published by the Free Software Foundation; either
-- version 2.1 of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-- Lesser General Public License for more details.
--
-- You should have received a copy of the GNU Lesser General Public
-- License along with this library; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

crafting.register_type("inv")

if minetest.global_exists("sfinv") then
	local player_inv_hashes = {}


	sfinv.override_page("sfinv:crafting", {
		get = function(self, player, context)
			player_inv_hashes[player:get_player_name()] =
					crafting.calc_inventory_list_hash(player:get_inventory(), "main")

			local formspec = crafting.make_result_selector(player, "inv", 1, { x = 8, y = 3 }, context)
			return sfinv.make_formspec(player, context, formspec, true)
		end,
		on_player_receive_fields = function(self, player, context, fields)
			if crafting.result_select_on_receive_results(player, "inv", 1, context, fields) then
				sfinv.set_player_inventory_formspec(player)
			end
			return true
		end
	})

	local function check_for_changes()
		for _, player in pairs(minetest.get_connected_players()) do
			if sfinv.get_or_create_context(player).page == "sfinv:crafting" then
				local hash = crafting.calc_inventory_list_hash(player:get_inventory(), "main")
				local old_hash = player_inv_hashes[player:get_player_name()]
				if hash ~= old_hash then
					sfinv.set_page(player, "sfinv:crafting")
				end
			end
		end

		minetest.after(1, check_for_changes)
	end
	check_for_changes()
end