if getgenv().__SA_LightingLock_Running then
	local existing = getgenv().__SA_LightingLock_Running
	existing.token = existing.token + 1
	local myToken = existing.token

	if existing.Conn then pcall(function() existing.Conn:Disconnect() end) end
	if existing.SkyConn then pcall(function() existing.SkyConn:Disconnect() end) end
	existing.Conn = nil
	existing.SkyConn = nil
	getgenv().__SA_LightingLock_Running = nil

	local ok, StarterGui = pcall(game.GetService, game, "StarterGui")
	if ok then
		pcall(function()
			StarterGui:SetCore("SendNotification", {
				Title = "Lighting Lock",
				Text = "Unlocked",
				Duration = 1
			})
		end)
	end
	return
end

local Lighting = game:GetService("Lighting")
local RunService = game:GetService("RunService")
local StarterGui = game:GetService("StarterGui")

local LOCK_PROPS = {
	"Ambient", "OutdoorAmbient", "Brightness", "ClockTime",
	"ColorShift_Bottom", "ColorShift_Top", "EnvironmentDiffuseScale",
	"EnvironmentSpecularScale", "ExposureCompensation", "FogColor",
	"FogEnd", "FogStart", "GeographicLatitude", "GlobalShadows",
	"ShadowSoftness", "Technology"
}

local function notify(text)
	pcall(function()
		StarterGui:SetCore("SendNotification", {
			Title = "Lighting Lock",
			Text = text,
			Duration = 1
		})
	end)
end

local function snapshot()
	local snap = {}
	for _, prop in ipairs(LOCK_PROPS) do
		local ok, val = pcall(function() return Lighting[prop] end)
		if ok then snap[prop] = val end
	end
	return snap
end

local function cloneSky()
	local sky = Lighting:FindFirstChildOfClass("Sky")
	return sky and sky:Clone()
end

local state = {token = 1}
getgenv().__SA_LightingLock_Running = state

local snap = snapshot()
local skyClone = cloneSky()

state.Conn = RunService.Heartbeat:Connect(function()
	if getgenv().__SA_LightingLock_Running ~= state then return end
	for prop, val in pairs(snap) do
		local ok, cur = pcall(function() return Lighting[prop] end)
		if ok and cur ~= val then
			pcall(function() Lighting[prop] = val end)
		end
	end
end)

if skyClone then
	state.SkyConn = Lighting.ChildAdded:Connect(function(child)
		if getgenv().__SA_LightingLock_Running ~= state then return end
		if child:IsA("Sky") and child ~= skyClone then
			task.defer(function()
				if getgenv().__SA_LightingLock_Running ~= state then return end
				pcall(function() child:Destroy() end)
				if not Lighting:FindFirstChildOfClass("Sky") then
					local restored = skyClone:Clone()
					restored.Parent = Lighting
				end
			end)
		end
	end)

	if not Lighting:FindFirstChildOfClass("Sky") then
		skyClone:Clone().Parent = Lighting
	end
end

notify("Lighting + skybox locked")