-- The rebuild was interrupted mid-flight; its effect is UNKNOWN. Establish
-- ground truth before touching anything else.
--   (a) Did the build run? part count vs 16714 (user-edited) / 16820 (source).
--   (b) Is the aux lane back? user's edited workspace had 30 aux parts,
--       source produces 52 -- so they deleted ~22.
--   (c) Did the smoothing pass actually land on the east slip?
local out = {}
local function say(s) table.insert(out, s) end

local map = workspace:FindFirstChild("Map")
if not map then return "workspace.Map MISSING" end

local parts = 0
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") then parts += 1 end
end
say(("parts=%d   (16714=user-edited, 16820=source rebuild)"):format(parts))

-- Aux lane inventory, with index range + position so I can tell WHICH lane.
local aux = {}
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") then
		local k = d.Name:match("^AuxLane_(%d+)$")
		if k then table.insert(aux, { i = tonumber(k), p = d.Position, inst = d }) end
	end
end
table.sort(aux, function(a, b) return a.i < b.i end)
say(("AuxLane parts=%d   (30=after user deletion, 52=source)"):format(#aux))
if #aux > 0 then
	-- group into contiguous runs so each physical lane shows up separately
	local runs, cur = {}, nil
	for _, a in ipairs(aux) do
		if cur and a.i - cur.last <= 2 then cur.last = a.i; cur.n += 1
		else
			if cur then table.insert(runs, cur) end
			cur = { first = a.i, last = a.i, n = 1, p = a.p }
		end
	end
	if cur then table.insert(runs, cur) end
	for _, r in ipairs(runs) do
		say(("   aux run idx %d..%d  n=%d  at (%.0f,%.0f,%.0f)"):format(
			r.first, r.last, r.n, r.p.X, r.p.Y, r.p.Z))
	end
end

-- Slip smoothness: did the relaxation take effect?
for _, s in ipairs({ "PAWestSlip", "PAEastSlip" }) do
	local segs = {}
	for _, d in ipairs(map:GetDescendants()) do
		if d:IsA("BasePart") then
			local k = d.Name:match("^" .. s .. "_Deck_(%d+)$")
			if k then table.insert(segs, { i = tonumber(k), p = d.Position, cf = d.CFrame }) end
		end
	end
	table.sort(segs, function(a, b) return a.i < b.i end)
	if #segs == 0 then say(s .. ": ABSENT") continue end
	local total, worst, worstAt, over = 0, 0, -1, 0
	for j = 2, #segs do
		local a, b = segs[j - 1].cf.LookVector, segs[j].cf.LookVector
		local d = math.deg(math.acos(math.clamp(a:Dot(b), -1, 1)))
		total += d
		if d > worst then worst = d; worstAt = segs[j].i end
		if d > 5 then over += 1 end
	end
	local topY, level = segs[1].p.Y, 0
	for _, sg in ipairs(segs) do
		if math.abs(sg.p.Y - topY) < 0.5 then level += 1 else break end
	end
	say(("%s: segs=%d total=%.1fdeg worst=%.1f@%d over5=%d level=%d"):format(
		s, #segs, total, worst, worstAt, over, level))
end

return table.concat(out, "\n")