init.lua

local tool_enabled = minetest.settings:get_bool("item_magnet.tool_enabled", true)
local control_enabled = minetest.global_exists("controls") and minetest.settings:get_bool("item_magnet.control_enabled", true)

if not (tool_enabled or control_enabled) then return end

local tool_strength = tonumber(minetest.settings:get("item_magnet.tool_strength")) or 4
local tool_radius = math.max(1,
		   tonumber(minetest.settings:get("item_magnet.tool_radius"))
		or tonumber(minetest.settings:get("item_magnet.radius"))
		or 5)
local control_radius = math.max(1,
		   tonumber(minetest.settings:get("item_magnet.control_radius"))
		or tonumber(minetest.settings:get("item_magnet.radius"))
		or 1)

local function pick_up_items(player, radius)
	if not player or not player:is_player() or player.is_fake_player then return end
	local pos = player:get_pos()
	local inv = player:get_inventory()
	local stuff_was_picked_up = false
	for _, obj in ipairs(minetest.get_objects_inside_radius(pos, radius)) do
		local ent = obj:get_luaentity()
		if ent and ent.name == "__builtin:item" then
			local item = ItemStack(ent.itemstring)
			if inv:room_for_item("main", item) then
				ent:on_punch(player)
				stuff_was_picked_up = true
			end
		end
	end
	return stuff_was_picked_up
end

local function attract_items(player, radius, strength)
	if not player or not player:is_player() or player.is_fake_player then return end
	local pos = player:get_pos()
	local stuff_was_attracted = false
	for _, obj in ipairs(minetest.get_objects_inside_radius(pos, radius)) do
		local ent = obj:get_luaentity()
		if ent and ent.name == "__builtin:item" then
			local tool_pos = vector.add(pos, {x=0,y=1.5,z=0})
			local dir = vector.direction(obj:get_pos(), tool_pos) -- normalised direction to player
			local dist = math.min(vector.distance(tool_pos, obj:get_pos()), 1) -- distance to player
			local vel = vector.divide(dir, dist/strength) -- Make attraction weaker when further away
			obj:add_velocity(vel)
			stuff_was_attracted = true
		end
	end
	return stuff_was_attracted
end

if tool_enabled then
	minetest.register_tool("item_magnet:magnet", {
		description = "Item Magnet",
		inventory_image = "item_magnet_magnet.png",
		on_use = function(itemstack, player, pointed_thing)
			if control_enabled then
				local stuff_was_attracted = attract_items(player, tool_radius, tool_strength)
				if stuff_was_attracted then
					itemstack:add_wear(655)
					return itemstack
				end
			else
				local stuff_was_picked_up = pick_up_items(player, tool_radius)
				if stuff_was_picked_up then
					itemstack:add_wear(655)
					return itemstack
				end
			end
		end,
	})

	if minetest.get_modpath("default") then
		minetest.register_craft({
			output = "item_magnet:magnet",
			recipe = {
				{"default:iron_lump", "", "default:iron_lump"},
				{"default:iron_lump", "", "default:iron_lump"},
				{"", "default:iron_lump", ""},
			}
		})
	end
end

if control_enabled then
	controls.register_on_press(function(player, key)
		if key ~= "sneak" then return end

		pick_up_items(player, control_radius)
	end)
end