-- CONTROL + CONNECTIVITY.
-- 1. Control: deliberately test a part known to intersect structure, so a
--    0-hit result on the ramps means "clear", not "probe is broken".
-- 2. Connectivity: largest gap between consecutive deck segments within each
--    run, and the trunk->near handoff distance.
local ws = game:GetService("Workspace")
local map = ws:FindFirstChild("Map")
if not map then
	return "no Map"
end

local structural, runs = {}, {}
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") then
		local nm = d.Name
		if nm:find("PierColumn") or nm:find("PAMast") or nm:find("GirderRib") then
			table.insert(structural, d)
		end
		for _, base in ipairs({
			"PAEntryRampTrunk",
			"PAEntryRampCross",
			"PAEntryRampNear",
			"PAExitRampTrunk",
			"PAExitRampCross",
			"PAExitRampNear",
		}) do
			if nm:sub(1, #base + 1) == base .. "_" then
				runs[base] = runs[base] or {}
				table.insert(runs[base], d)
			end
		end
	end
end

local function overlaps(p, s)
	local d1, d2 = p.Position, s.Position
	return math.abs(d1.X - d2.X) < (p.Size.X + s.Size.X) / 2
		and math.abs(d1.Z - d2.Z) < (p.Size.Z + s.Size.Z) / 2
		and math.abs(d1.Y - d2.Y) < (p.Size.Y + s.Size.Y) / 2
end

local out = {}

-- CONTROL: a probe box placed exactly on the first structural part must hit.
local ctrl = structural[1]
local fake = { Position = ctrl.Position, Size = Vector3.new(4, 4, 4) }
local ctrlHits = 0
for _, s in ipairs(structural) do
	if overlaps(fake, s) then
		ctrlHits += 1
	end
end
table.insert(
	out,
	("CONTROL (box on a known pier): hits=%d  -> probe %s"):format(
		ctrlHits,
		ctrlHits > 0 and "WORKS" or "IS BROKEN/VACUOUS"
	)
)
table.insert(out, "structuralParts=" .. #structural)

-- CONNECTIVITY
local function sortKey(p)
	return tonumber(p.Name:match("_(%d+)$")) or 0
end
for _, base in ipairs({
	"PAEntryRampTrunk",
	"PAEntryRampCross",
	"PAEntryRampNear",
	"PAExitRampTrunk",
	"PAExitRampCross",
	"PAExitRampNear",
}) do
	local parts = runs[base]
	if not parts then
		table.insert(out, base .. ": MISSING")
	else
		table.sort(parts, function(a, b)
			return sortKey(a) < sortKey(b)
		end)
		local maxGap = 0
		for i = 2, #parts do
			local g = (parts[i].Position - parts[i - 1].Position).Magnitude
			maxGap = math.max(maxGap, g)
		end
		table.insert(out, ("%s: n=%d maxSegGap=%.1f"):format(base, #parts, maxGap))
	end
end

-- Handoffs along the flyover chain: Trunk -> Cross -> Near. The ramps now
-- cross OVER the mainline, so `Cross` sits between the spiral and the
-- descent; checking Trunk->Near directly would report a false gap.
for _, pair in ipairs({
	{ "PAEntryRampTrunk", "PAEntryRampCross" },
	{ "PAEntryRampCross", "PAEntryRampNear" },
	{ "PAExitRampTrunk", "PAExitRampCross" },
	{ "PAExitRampCross", "PAExitRampNear" },
}) do
	local t, nr = runs[pair[1]], runs[pair[2]]
	if t and nr then
		table.sort(t, function(a, b)
			return sortKey(a) < sortKey(b)
		end)
		table.sort(nr, function(a, b)
			return sortKey(a) < sortKey(b)
		end)
		local best = math.huge
		for _, a in ipairs({ t[1], t[#t] }) do
			for _, b in ipairs({ nr[1], nr[#nr] }) do
				best = math.min(best, (a.Position - b.Position).Magnitude)
			end
		end
		table.insert(out, ("HANDOFF %s->%s closestEnd=%.1f"):format(pair[1], pair[2], best))
	end
end
return table.concat(out, "\n")