cg_plus-cd2025/autocrafting.lua

local add_or_create = function(t, i, n)
	t[i] = t[i] and t[i] + n or n
end

local get_group_item = function(invCache, groups)
	local maxCount = 0
	local maxItem
	local isInGroups

	for item, count in pairs(invCache) do
		isInGroups = true

		for _, group in ipairs(groups) do
			if minetest.get_item_group(item, group) == 0 then
				isInGroups = false
				break
			end
		end

		if isInGroups and count > maxCount then
			maxItem = item
			maxCount = count
		end
	end

	return maxItem
end

cg.auto_get_craftable = function(player, craft)
	local inv = player:get_inventory():get_list("main")
	local invCache = {}

	-- Create a cache of the inventory with itemName = count pairs. This speeds up searching for items.
	for _, stack in ipairs(inv) do
		if stack:get_count() > 0 then
			add_or_create(invCache, stack:get_name(), stack:get_count())
		end
	end

	local reqItems = {}
	local reqGroups = {}

	-- Find out how many of each item/group is required to craft one item.
	for _, item in pairs(craft.items) do
		if item:sub(1, 6) == "group:" then
			add_or_create(reqGroups, item, 1)
		else
			add_or_create(reqItems, item, 1)
		end
	end

	local gMaxItem

	-- For each group, find the item in that group from the player's inventory with the largest count.
	for group, count in pairs(reqGroups) do
		gMaxItem = get_group_item(invCache, group:sub(7):split(","))

		if gMaxItem then
			add_or_create(reqItems, gMaxItem, count)
		else
			return 0
		end
	end

	local craftable = 1000

	for item, count in pairs(reqItems) do
		if invCache[item] then
			craftable = math.min(craftable, math.floor(invCache[item] / count))
		else
			return 0
		end

		-- We can't craft more than the stack_max of our ingredients.
		if minetest.registered_items[item].stack_max then
			craftable = math.min(craftable, minetest.registered_items[item].stack_max)
		end
	end

	return craftable
end

cg.auto_craft = function(player, craft, num)
	inv = player:get_inventory()

	if not inv:is_empty("craft") then
		-- Attempt to move items to the player's main inventory.
		for idx, stack in ipairs(inv:get_list("craft")) do
			if not stack:is_empty() then
				stack = inv:add_item("main", stack)
				inv:set_stack("craft", idx, stack)
			end
		end

		-- Check again, and return if not all items were moved.
		if not inv:is_empty("craft") then
			minetest.chat_send_player(player:get_player_name(), cg.S("Item could not be crafted!"))
			return
		end
	end

	if craft.width > inv:get_width("craft") or table.maxn(craft.items) > inv:get_size("craft") then return end

	local width = craft.width == 0 and inv:get_width("craft") or craft.width
	local stack, invCache
	local groupCache = {}

	for idx, item in pairs(craft.items) do
		-- Shift the indices so the items in the craft go to the right spots on the crafting grid.
		idx = idx + (inv:get_width("craft") - width) * math.floor((idx - 1) / width)

		if item:sub(1, 6) == "group:" then
			-- Create an inventory cache.
			if not invCache then
				invCache = {}

				for _, stack in ipairs(inv:get_list("main")) do
					if stack:get_count() > 0 then
						add_or_create(invCache, stack:get_name(), stack:get_count())
					end
				end
			end

			-- Get the most plentiful item in the group.
			if not groupCache[item] then
				groupCache[item] = get_group_item(invCache, item:sub(7):split(","))
			end

			-- Move the selected item.
			if groupCache[item] then
				stack = inv:remove_item("main", ItemStack({name = groupCache[item], count = num}))
				inv:set_stack("craft", idx, stack)
			end
		else
			-- Move the item.
			stack = inv:remove_item("main", ItemStack({name = item, count = num}))
			inv:set_stack("craft", idx, stack)
		end
	end
end