-- Diagnose the two reported defects:
--   (1) ramps not accessible in either direction (connectivity)
--   (2) ramps pass through buildings (clipping)
-- Uses native GetPartBoundsInBox so this stays fast on ~22k parts.
local ws = game:GetService("Workspace")
local map = ws:FindFirstChild("Map")
if not map then
	return "NO MAP"
end

local BUILDING = {
	Building = true,
	TokyoTower = true,
	TowerDeck = true,
	TowerAntenna = true,
	ShiodomeTower = true,
	TowerCrown = true,
	DietTower = true,
	RoppongiHills = true,
	TokyoStation = true,
	StationDome = true,
	Skytree = true,
	GinzaBlock = true,
	NationalDiet = true,
	BridgeTower = true,
	TowerCrossbeam = true,
	Structure = true,
	PalaceWall = true,
}

local ramp, drivable = {}, {}
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") then
		local n = d.Name
		if n:find("PAEntryRamp") or n:find("PAExitRamp") then
			table.insert(ramp, d)
		elseif n:match("^Road_%d+$") or n == "PAFloor" then
			table.insert(drivable, d)
		end
	end
end
if #ramp == 0 then
	return "no ramp parts"
end

-- ---------- (2) BUILDING CLIP CHECK ----------
local op = OverlapParams.new()
op.MaxParts = 40
local clipHits, clipNames, worst = 0, {}, {}
for _, r in ipairs(ramp) do
	local hits = ws:GetPartBoundsInBox(r.CFrame, r.Size, op)
	for _, h in ipairs(hits) do
		if h ~= r and BUILDING[h.Name] then
			clipHits += 1
			clipNames[h.Name] = (clipNames[h.Name] or 0) + 1
			if #worst < 5 then
				table.insert(worst, ("%s@%.0f,%.0f,%.0f"):format(r.Name, r.Position.X, r.Position.Y, r.Position.Z))
			end
			break
		end
	end
end

-- CONTROL: same probe against mainline Road_ parts (known-good, should be ~0)
local ctrlHits, ctrlN = 0, 0
for i = 1, #drivable, 9 do
	local d = drivable[i]
	ctrlN += 1
	local hits = ws:GetPartBoundsInBox(d.CFrame, d.Size, op)
	for _, h in ipairs(hits) do
		if h ~= d and BUILDING[h.Name] then
			ctrlHits += 1
			break
		end
	end
end

local cn = {}
for k, v in pairs(clipNames) do
	table.insert(cn, k .. "=" .. v)
end

-- ---------- (1) CONNECTIVITY ----------
-- Ramp basename groups, then endpoints of each group by trailing index.
local groups = {}
for _, r in ipairs(ramp) do
	local base, idx = r.Name:match("^(.-)_?(%d+)$")
	base = base or r.Name
	idx = tonumber(idx) or 0
	local g = groups[base]
	if not g then
		g = { lo = math.huge, hi = -math.huge, loP = nil, hiP = nil, n = 0 }
		groups[base] = g
	end
	g.n += 1
	if idx < g.lo then
		g.lo, g.loP = idx, r
	end
	if idx > g.hi then
		g.hi, g.hiP = idx, r
	end
end

-- For an endpoint, find nearest drivable surface and report gap + height delta.
local function nearestDrivable(p)
	local bd, bp = math.huge, nil
	for _, d in ipairs(drivable) do
		local dd = (d.Position - p).Magnitude
		if dd < bd then
			bd, bp = dd, d
		end
	end
	return bd, bp
end

local lines = {}
for base, g in pairs(groups) do
	if g.loP and g.hiP then
		local d1, p1 = nearestDrivable(g.loP.Position)
		local d2, p2 = nearestDrivable(g.hiP.Position)
		table.insert(
			lines,
			("%s n=%d | START gap=%.0f dY=%.1f to %s | END gap=%.0f dY=%.1f to %s"):format(
				base,
				g.n,
				d1,
				p1 and (g.loP.Position.Y - p1.Position.Y) or -999,
				p1 and p1.Name or "nil",
				d2,
				p2 and (g.hiP.Position.Y - p2.Position.Y) or -999,
				p2 and p2.Name or "nil"
			)
		)
	end
end

return ("CLIP ramp=%d/%d parts hit buildings [%s] samples=[%s] || CONTROL road %d/%d hit\n%s"):format(
	clipHits,
	#ramp,
	table.concat(cn, ", "),
	table.concat(worst, " ; "),
	ctrlHits,
	ctrlN,
	table.concat(lines, "\n")
)