local LOG = give_initial_enderchest.log
local enable_bags = give_initial_enderchest.bags_enable

---@param n bagSlot
---@return (mt.ItemStack|string)[]?
local function getSlot(n)
	local items = give_initial_enderchest.bags_items[n]
	if items == nil then
		LOG("error", ("slot %s is out of range!"):format(n))
	end
	return items
end

---@param player mt.PlayerObjectRef
---@return nil
local function bags_give_fallback(player)
	for i = 1, 4 do
		if give_initial_enderchest.bags_type[i] then
			give_initial_enderchest._give_common(player, "main",
					give_initial_enderchest.bags_items[i])
		end
	end
end

---@param player mt.PlayerObjectRef
---@return nil
local function bags_give(player)
	if not enable_bags then  -- safeguard
		LOG("error", "bags_give: bags are disabled!")
		return
	end

	local bags_inv_name = player:get_player_name() .. "_bags"
	local bags_inv = core.get_inventory({
		type = "detached", name = bags_inv_name
	})
	for i = 1, 4 do
		local bag_item = give_initial_enderchest.bags_type[i]
		if bag_item then
			local list = "bag" .. i
			if bags_inv:is_empty(list) then
				bag_item = ItemStack(bag_item)
				local left = bags_inv:add_item(list, bag_item)

				-- Manually trigger callback to create player inventory lists
				-- https://github.com/luanti-org/luanti/issues/8390
				if left:get_count() == 0 then
					core.detached_inventories[bags_inv_name].on_put(bags_inv,
							list, 1, bag_item, player)
				end
			end

			give_initial_enderchest._give_common(player,
					"bag" .. i .. "contents",
					give_initial_enderchest.bags_items[i])
		end
	end
end

---@param slot bagSlot
---@param stack mt.ItemStack|string
---@return nil
function give_initial_enderchest.bags_add(slot, stack)
	local items = getSlot(slot)
	if items == nil then return end

	table.insert(items, stack)
end

---@param slot bagSlot
---@param csv string
---@return nil
function give_initial_enderchest.bags_add_from_csv(slot, csv)
	local items = getSlot(slot)
	if items == nil then return end

	for _, stack in ipairs(csv:split(",")) do
		give_initial_enderchest.bags_add(slot, stack)
	end
end

---@param slot bagSlot
---@return  (mt.ItemStack|string)[]
function give_initial_enderchest.bags_get_list(slot)
	return getSlot(slot)
end

---@param slot bagSlot
---@param list (mt.ItemStack|string)[]
---@return nil
function give_initial_enderchest.bags_set_list(slot, list)
	if give_initial_enderchest.bags_items[slot] == nil then
		LOG("error", ("slot %s is out of range!"):format(slot))
	end
	give_initial_enderchest.bags_items[slot] = list
end

---@param slot bagSlot
---@return nil
function give_initial_enderchest.bags_clear(slot)
	give_initial_enderchest.bags_set_list(slot, {})
end


-- TODO: check if unified_inventory version is too old
if core.get_modpath("unified_inventory") and
		core.settings:get_bool("unified_inventory_bags", true) then
	give_initial_enderchest.bags_give = bags_give
else
	LOG("warning",
			"Initial bags are enabled but unified_inventory is not found. Using main inv instead")
	give_initial_enderchest.bags_give = bags_give_fallback
end

if enable_bags then
	for i = 1, 4 do
		local type = core.settings:get("give_initial_enderchest_bag" .. i) or "none"
		if type == "bag_small" or type == "bag_medium" or type == "bag_large" then
			give_initial_enderchest.bags_type[i] = "unified_inventory:" .. type
		end

		local csv = core.settings:get("give_initial_enderchest_bag" .. i .. "_items") or ""
		give_initial_enderchest.bags_add_from_csv(i, csv)
	end
end