local module = {}
local DataStoreService = game:GetService("DataStoreService")
local playerData = DataStoreService:GetDataStore("PlayerData")
local AUTOSAVE_INTERVAL = 120

--empty table to add player data to
local sessionData = {}


--function for changing a specific stat
function module:ChangeStat(player, statName, value)
    local key = "Player_"..player.UserId
    assert(typeof(sessionData[key][statName]) == typeof(value), "ChangeStat error: types do not match")

    if typeof(sessionData[key][statName]) == "number" then
        sessionData[key][statName] = sessionData[key][statName] + value
    else
        sessionData[key][statName] = value
    end
end

local function savePlayerData(key)
    if sessionData[key] then
        playerData:SetAsync(key, sessionData[key])
    end
end

function module.setupPlayerData(player)
	local key = "Player_"..player.UserId
	print(key)
	local dataFromDS = playerData:GetAsync(key)

	if dataFromDS then
		sessionData[key] = dataFromDS
		print("loaded data from datastore")
	else
		--no data from DS, give default value
		sessionData[key] = {Cash=0, Subscribers=0}

		--save default data to datastore
		savePlayerData(key)
		print("created new data for player")
	end
end

local function saveOnExit(player)
    local key = "Player_"..player.UserId
    savePlayerData(key)
end

local function autoSave()
	print("started autosave function...")
    while wait(AUTOSAVE_INTERVAL) do
		print("autosaving...")
        for index, playerData in pairs(sessionData) do
            savePlayerData(index)
        end
    end
end

spawn(autoSave)
return module