Leaderstats + Saving (DataStore)

--[[
	Leaderstats + Saving (DataStore)  ·  by Cube Burst Studios  ·  CC0
	Shows Coins and Wins on the leaderboard and saves them safely.

	SETUP
	1. Put this Script in ServerScriptService.
	2. Publish the game, then Game Settings > Security > turn ON "Enable Studio Access to API Services"
	   (only needed to test saving inside Studio).
	3. Change other scripts' stats like this:  player.leaderstats.Coins.Value += 10

	WHY IT'S SAFE
	- UpdateAsync (not SetAsync) so two servers never overwrite each other blindly.
	- Retries with back-off when Roblox's DataStore service hiccups.
	- Autosaves every 2 minutes and saves everyone when the server shuts down.
	- Never saves a player whose data failed to load (so a bad load can't wipe their progress).
]]

local Players = game:GetService("Players")
local DataStoreService = game:GetService("DataStoreService")
local RunService = game:GetService("RunService")

local STORE = DataStoreService:GetDataStore("PlayerData_v1") -- change the name to reset everyone's data
local AUTOSAVE_SECONDS = 120
local MAX_TRIES = 4

-- every stat you want: name = starting value
local DEFAULTS = {
	Coins = 0,
	Wins = 0,
}

local loaded = {} -- [player] = true once their data loaded OK

local function withRetries(fn)
	local lastErr
	for attempt = 1, MAX_TRIES do
		local ok, result = pcall(fn)
		if ok then
			return true, result
		end
		lastErr = result
		task.wait(2 ^ attempt) -- 2, 4, 8, 16 seconds
	end
	return false, lastErr
end

local function keyFor(player)
	return "player_" .. player.UserId
end

local function load(player)
	local folder = Instance.new("Folder")
	folder.Name = "leaderstats"
	for name, default in pairs(DEFAULTS) do
		local value = Instance.new("IntValue")
		value.Name = name
		value.Value = default
		value.Parent = folder
	end
	folder.Parent = player

	local ok, data = withRetries(function()
		return STORE:GetAsync(keyFor(player))
	end)
	if not ok then
		warn("Couldn't load data for " .. player.Name .. ": " .. tostring(data))
		return -- not marked loaded, so we will never save over their real data
	end
	if type(data) == "table" then
		for name in pairs(DEFAULTS) do
			if type(data[name]) == "number" then
				folder[name].Value = data[name]
			end
		end
	end
	loaded[player] = true
end

local function save(player)
	if not loaded[player] then
		return
	end
	local folder = player:FindFirstChild("leaderstats")
	if not folder then
		return
	end
	local snapshot = {}
	for name in pairs(DEFAULTS) do
		local value = folder:FindFirstChild(name)
		snapshot[name] = value and value.Value or DEFAULTS[name]
	end
	local ok, err = withRetries(function()
		STORE:UpdateAsync(keyFor(player), function()
			return snapshot
		end)
	end)
	if not ok then
		warn("Couldn't save data for " .. player.Name .. ": " .. tostring(err))
	end
end

Players.PlayerAdded:Connect(load)
for _, player in ipairs(Players:GetPlayers()) do -- players who joined before this script ran
	task.spawn(load, player)
end

Players.PlayerRemoving:Connect(function(player)
	save(player)
	loaded[player] = nil
end)

task.spawn(function()
	while true do
		task.wait(AUTOSAVE_SECONDS)
		for _, player in ipairs(Players:GetPlayers()) do
			task.spawn(save, player)
		end
	end
end)

game:BindToClose(function()
	if RunService:IsStudio() then
		task.wait(1)
	end
	local pending = 0
	for _, player in ipairs(Players:GetPlayers()) do
		pending += 1
		task.spawn(function()
			save(player)
			pending -= 1
		end)
	end
	local started = os.clock()
	while pending > 0 and os.clock() - started < 25 do
		task.wait(0.1)
	end
end)