-- Is the fused aux run genuine continuous pavement (a weaving section), or
-- overlapping/duplicated parts? Checks per-sample coverage, duplicate indices,
-- and the width profile across both mouths.
local ws = game:GetService("Workspace")
local map = ws:FindFirstChild("Map")
if not map then return "NOMAP" end

local seen, dupes = {}, 0
local byIdx = {}
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") then
		local i = tonumber(d.Name:match("^AuxLane_(%d+)$") or "")
		if i then
			if seen[i] then dupes += 1 end
			seen[i] = true
			byIdx[i] = d
		end
	end
end

local out = {}
local function say(s) table.insert(out, s) end
say(("duplicate AuxLane indices: %d -> %s"):format(dupes, dupes == 0 and "PASS" or "FAIL"))

-- Walk 505..570 and report which samples have lane and how wide.
local missing = {}
local prof = {}
for i = 505, 570 do
	local p = byIdx[i]
	if p then
		table.insert(prof, ("%d:%.0f"):format(i, p.Size.X))
	else
		table.insert(missing, i)
		table.insert(prof, ("%d:--"):format(i))
	end
end
say("width profile (sample:width, -- = no lane):")
say("  " .. table.concat(prof, " "))
say("gaps in 505..570: " .. (#missing > 0 and table.concat(missing, ",") or "none"))

-- The only gaps should be the ramp noses (the ramp deck covers those).
-- Derive coverage from the ACTUAL ramp deck parts, but test the point where
-- the AUX LANE would sit (deck edge + half lane width) -- NOT the mainline
-- centreline. Testing proximity to the centreline marked 26 samples as "nose"
-- because the ramp spirals past them at other heights, which would mask any
-- real hole and make this check vacuously pass. The nose test must also match
-- in HEIGHT: a ramp 50 studs below the deck does not cover the deck's edge.
local samples = require(game:GetService("ReplicatedStorage")
	:WaitForChild("Shared"):WaitForChild("Circuit")).samples
local decks = {}
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") and d.Name:match("Slip_Deck_") then
		table.insert(decks, d)
	end
end

local HALF, AUXW, SIDE = 30, 26, -1
local function auxPointAt(i)
	local n = #samples
	local a = samples[((i - 1) % n) + 1]
	local b = samples[(i % n) + 1]
	local f = b.pos - a.pos
	f = Vector3.new(f.X, 0, f.Z).Unit
	local r = Vector3.new(-f.Z, 0, f.X)
	return a.pos + r * (SIDE * (HALF + AUXW / 2)), a.pos.Y
end

local NOSE, noseWhy = {}, {}
for _, i in ipairs(missing) do
	local p, deckY = auxPointAt(i)
	for _, d in ipairs(decks) do
		local flat = (Vector3.new(d.Position.X, 0, d.Position.Z)
			- Vector3.new(p.X, 0, p.Z)).Magnitude
		local dy = math.abs(d.Position.Y - deckY)
		-- Must overlap the lane footprint horizontally AND be at deck level.
		if flat <= AUXW and dy <= 6 then
			NOSE[i] = true
			noseWhy[i] = ("%s flat=%.0f dy=%.0f"):format(d.Name, flat, dy)
			break
		end
	end
end
local noseList = {}
for i in pairs(NOSE) do table.insert(noseList, i) end
table.sort(noseList)
say(("ramp-nose-covered gaps (%d): %s"):format(#noseList, table.concat(noseList, ",")))
for _, i in ipairs(noseList) do
	say(("    %d covered by %s"):format(i, noseWhy[i]))
end

local lo, hi = math.huge, -1
for k in pairs(byIdx) do
	lo = math.min(lo, k); hi = math.max(hi, k)
end
local bad = {}
for _, i in ipairs(missing) do
	-- Samples outside the lane's own extent are not holes; only flag gaps that
	-- sit strictly between the first and last aux segment.
	if i > lo and i < hi and not NOSE[i] then table.insert(bad, i) end
end
say(("lane run extent: %d..%d"):format(lo, hi))
say(("non-nose gaps inside the lane run: %s -> %s"):format(#bad > 0 and table.concat(bad, ",") or "none",
	#bad == 0 and "PASS (only ramp noses uncovered)" or "FAIL (hole in pavement)"))

-- Between the two mouths, is the lane continuously full width (a real weaving
-- section) rather than tapering out and back in?
local weaveMin = math.huge
local weaveTested = 0
for i = 528, 548 do
	local p = byIdx[i]
	if p then
		weaveTested += 1
		weaveMin = math.min(weaveMin, p.Size.X)
	end
end
if weaveTested == 0 then
	say("weave section: FAIL nothing tested")
else
	say(("weave section 528..548: %d segs, min width %.1f -> %s")
		:format(weaveTested, weaveMin,
			weaveMin >= 24 and "PASS (continuous full-width weaving lane)" or "TAPERS"))
end
return table.concat(out, "\n")