-- Triage the obstacle hits: WHAT is hit, on WHICH segments, and how far
-- through the run. Contact with the apron at the ring mouth and with the
-- carriageway at the merge is intended; contact with a pier is never.
-- SAFETY: MapBuilder.build() destroys Workspace.Map first. Stash the live map
-- aside and restore it afterwards -- see verify_shared_ramps.luau.
local ServerScriptService = game:GetService("ServerScriptService")
local live = workspace:FindFirstChild("Map")
local stash = nil
if live then
	stash = Instance.new("Folder")
	stash.Name = "__MAP_STASH__"
	stash.Parent = ServerScriptService
	live.Parent = stash
end
local function restoreLive()
	if stash then
		local held = stash:FindFirstChild("Map")
		local rebuilt = workspace:FindFirstChild("Map")
		if rebuilt then
			rebuilt:Destroy()
		end
		if held then
			held.Parent = workspace
		end
		stash:Destroy()
	end
end

local out = {}
local function log(...)
	table.insert(out, table.concat({ ... }, " "))
end

local src = ServerScriptService:FindFirstChild("Server")
src = src and src:FindFirstChild("MapBuilder") or ServerScriptService:FindFirstChild("MapBuilder", true)
local MapBuilder = require(src:Clone())
local map = MapBuilder.build and MapBuilder.build() or MapBuilder.Build()
map.Name = "TRIAGE_CLONE"
map.Parent = workspace

local RUNS = {
	"PAEntryRampTrunk",
	"PAEntryRampNear",
	"PAEntryRampCross",
	"PAEntryRampMerge",
	"PAExitRampTrunk",
	"PAExitRampNear",
	"PAExitRampCross",
	"PAExitRampMerge",
}
local deckOf = {}
for _, r in ipairs(RUNS) do
	deckOf[r] = {}
end
for _, d in ipairs(map:GetDescendants()) do
	if d:IsA("BasePart") then
		for _, r in ipairs(RUNS) do
			local idx = d.Name:match("^" .. r .. "_(%d+)$")
			if idx then
				table.insert(deckOf[r], { i = tonumber(idx), p = d })
			end
		end
	end
end
for _, r in ipairs(RUNS) do
	table.sort(deckOf[r], function(a, b)
		return a.i < b.i
	end)
end

local function isRampPart(p)
	local n = p.Name
	if n:find("PARamp") or n:find("PARing") then
		return true
	end
	for _, r in ipairs(RUNS) do
		if n:sub(1, #r) == r then
			return true
		end
	end
	return false
end

-- Normalise an obstacle name to its class (Road_537 -> Road_).
local function klass(n)
	if n:sub(1, 5) == "Road_" then
		return "Road_*"
	end
	return (n:gsub("_%d+$", "_*"))
end

for _, r in ipairs(RUNS) do
	local segs = deckOf[r]
	local byClass = {}
	for k, e in ipairs(segs) do
		local params = OverlapParams.new()
		params.FilterType = Enum.RaycastFilterType.Include
		params.FilterDescendantsInstances = { map }
		params.MaxParts = 60
		for _, o in ipairs(workspace:GetPartsInPart(e.p, params)) do
			if o ~= e.p and not isRampPart(o) then
				local c = klass(o.Name)
				local rec = byClass[c]
				if not rec then
					rec = { lo = k, hi = k, n = 0 }
					byClass[c] = rec
				end
				rec.lo = math.min(rec.lo, k)
				rec.hi = math.max(rec.hi, k)
				rec.n += 1
			end
		end
	end
	local any = false
	for c, rec in pairs(byClass) do
		any = true
		log(
			string.format(
				"%-18s %-16s segs %d..%d of %d  (%.0f%%..%.0f%% along)  %d contacts",
				r,
				c,
				rec.lo,
				rec.hi,
				#segs,
				rec.lo / #segs * 100,
				rec.hi / #segs * 100,
				rec.n
			)
		)
	end
	if not any then
		log(string.format("%-18s CLEAN", r))
	end
end

map:Destroy()
restoreLive()
log(string.format("live map restored: %s", tostring(workspace:FindFirstChild("Map") ~= nil)))
return table.concat(out, "\n")