--[[
	diag_bootcheck.luau -- decide facing using the BOOT/SPOILER cue, which is
	directly interpretable, and verify it survives the build.

	Findings so far:
	  * gtr_r34 template: wheels -10.27, hood -6.22, boot +6.64 -> all three
	    cues AGREE, nose at -Z. So wheel labels are NOT swapped.
	  * bodywork "asym" gave gtr_r34 -0.37 while rx7_fc/silv_s15 were
	    positive, yet all three have boot at +Z. asym is therefore a poor
	    proxy (it is dominated by whichever big slab a given shell happens to
	    have) and its verdicts must be discarded.

	The boot/spoiler is unambiguous: it belongs at the TAIL. On a correctly
	faced car (chassis forward = -Z) the boot must land at POSITIVE body-local
	Z. Measure that on the BUILT car, per shell, and compare to the template.
	Shells with no named boot get a fallback: the tail is the end furthest
	from the front wheels, per that shell's own wheel cue.
]]

local ServerScriptService = game:GetService("ServerScriptService")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local RunService = game:GetService("RunService")

local out = {}
local function log(...)
	local parts = {}
	for i = 1, select("#", ...) do
		parts[#parts + 1] = tostring((select(i, ...)))
	end
	table.insert(out, table.concat(parts, " "))
end

local Shared = ReplicatedStorage:FindFirstChild("Shared")
local Cars = require(Shared.Cars)
local Chassis = require(Shared.Chassis)
local orig = ServerScriptService:FindFirstChild("Server", true):FindFirstChild("CarManager")
local cm = orig:Clone()
cm.Parent = orig.Parent
local CarManager = require(cm)

local TAIL = { boot = true, spoiler = true, trunk = true, taillight = true, exhaust = true, diffuser = true }
local NOSE = { hood = true, windshield = true, bonnet = true, grille = true, headlight = true, splitter = true }

local function cueZ(root: Instance, frame: CFrame)
	local inv = frame:Inverse()
	local tS, tN, nS, nN = 0, 0, 0, 0
	for _, p in ipairs(root:GetDescendants()) do
		if p:IsA("BasePart") then
			local nm = p.Name:lower()
			local z = (inv * p.Position).Z
			if TAIL[nm] then
				tS, tN = tS + z, tN + 1
			elseif NOSE[nm] then
				nS, nN = nS + z, nN + 1
			end
		end
	end
	return (tN > 0 and tS / tN or nil), (nN > 0 and nS / nN or nil), tN, nN
end

log("chassis forward = -Z, so TAIL parts must land at POSITIVE body-local Z.")
log("")
log(string.format("%-14s %22s %30s", "car", "TEMPLATE (tail/nose)", "BUILT (tail/nose)  verdict"))
log(string.rep("-", 74))

for _, t in ipairs(ReplicatedStorage.CarModels:GetChildren()) do
	local id = t.Name
	local tT, tNz, tCount, nCount = cueZ(t, t:GetPivot())

	local bT, bN = nil, nil
	local car = Cars.Get(id)
	if car then
		local m = CarManager._buildForDiag(car, Chassis.tuningFor(car))
		m.Parent = workspace
		m:PivotTo(CFrame.new(0, 5010, 0))
		for _ = 1, 3 do
			RunService.Heartbeat:Wait()
		end
		local sh = m:FindFirstChild("Shell")
		if sh then
			bT, bN = cueZ(sh, m.PrimaryPart.CFrame)
		end
		m:Destroy()
	end

	local verdict
	if bT then
		verdict = bT > 0 and "CORRECT" or "*** BACKWARDS ***"
	elseif bN then
		verdict = bN < 0 and "CORRECT" or "*** BACKWARDS ***"
	else
		verdict = "no named cue - cannot judge"
	end

	log(
		string.format(
			"%-14s   tail %8s nose %7s    tail %8s nose %7s   %s",
			id,
			tT and string.format("%+.2f", tT) or "n/a",
			tNz and string.format("%+.2f", tNz) or "n/a",
			bT and string.format("%+.2f", bT) or "n/a",
			bN and string.format("%+.2f", bN) or "n/a",
			verdict
		)
	)
end

cm:Destroy()
return table.concat(out, "\n")