--[[
	verify_fixes.luau -- build all five cars with the NEWLY PUSHED code and
	measure whether the two fixes actually work. Runs in the EDIT datamodel,
	where require() is fresh (no Play-session cache pin), so this is the first
	honest test of these fixes.

	Checks, per car:

	FIX 1 -- FACING (hatch_junk, hyper_x rendered backwards)
	  Compare mean Z of F* wheel groups vs R* groups in the model's own frame.
	  Chassis convention: front axle is built at NEGATIVE Z. So frontZ < rearZ
	  means the car faces the right way. hatch_junk / hyper_x previously came
	  out reversed because their shell wheel LABELS are swapped, which fooled
	  the auto-solver into a 180 degree rotation; SHELL_YAW_OVERRIDE pins them
	  to yaw 0.

	FIX 2 -- WHEEL STANCE (rx7_fc wheels protruding from the bodywork)
	  For each wheel, measure |X| of the wheel's visual centre against |X| of
	  the axle it hangs from. The old code picked an arbitrary BasePart as the
	  wheel root (often a rotor/caliper ~0.96 studs inboard of the tyre) and
	  made THAT concentric with the axle, shoving the tyre outboard by the
	  difference. Now it picks the largest-volume part (the tyre). Residual
	  offset should be near zero; anything > 0.35 studs is a visible protrusion.

	Everything is measured from the built model, not inferred from source.
	Models are destroyed afterwards so Edit is left clean.
]]

local ServerScriptService = game:GetService("ServerScriptService")

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 serverFolder = ServerScriptService:FindFirstChild("Server", true)
local cmMod = serverFolder and serverFolder:FindFirstChild("CarManager")
if not cmMod then
	return "FATAL: no CarManager module found"
end

log(
	string.format(
		"CarManager source: %d bytes, SHELL_YAW_OVERRIDE=%s",
		#cmMod.Source,
		tostring(cmMod.Source:find("SHELL_YAW_OVERRIDE", 1, true) ~= nil)
	)
)

local okCM, CarManager = pcall(require, cmMod)
if not okCM then
	return "FATAL: require(CarManager) failed: " .. tostring(CarManager)
end
if typeof(CarManager._buildForDiag) ~= "function" then
	return "FATAL: _buildForDiag is "
		.. typeof(CarManager._buildForDiag)
		.. " -- require() served STALE code, results would be meaningless"
end
log("_buildForDiag present -> NEW code is genuinely running")

-- find Cars + Tuning modules
local function findModule(name)
	for _, svc in ipairs({ game:GetService("ReplicatedStorage"), ServerScriptService }) do
		local m = svc:FindFirstChild(name, true)
		if m and m:IsA("ModuleScript") then
			return m
		end
	end
	return nil
end

local carsMod = findModule("Cars")
local chassisMod = findModule("Chassis")
if not carsMod then
	return "FATAL: Cars module not found"
end
if not chassisMod then
	return "FATAL: Chassis module not found (needed for tuningFor)"
end
local Cars = require(carsMod)
local Chassis = require(chassisMod)
if typeof(Chassis.tuningFor) ~= "function" then
	return "FATAL: Chassis.tuningFor is " .. typeof(Chassis.tuningFor)
end

local FRONT_NEG_Z = true -- chassis builds front axle at -Z
local PROTRUDE_TOL = 0.35

log("")
log(string.format("%-10s %8s %8s %-12s | %8s %-10s", "car", "frontZ", "rearZ", "FACING", "maxOff", "STANCE"))
log(string.rep("-", 74))

local built = {}
local anyFail = false

local carList = Cars.List or Cars.All
if typeof(carList) ~= "table" or #carList == 0 then
	return "FATAL: could not find a non-empty car list (Cars.List). " .. "Refusing to report a vacuous pass."
end
log(string.format("car list: %d entries", #carList))

for _, car in ipairs(carList) do
	if typeof(car) == "table" and car.Id then
		local tuning = Chassis.tuningFor(car)
		local ok, model = pcall(CarManager._buildForDiag, car, tuning)
		if not ok or typeof(model) ~= "Instance" then
			log(string.format("%-10s  BUILD FAILED: %s", car.Id, tostring(model)))
			anyFail = true
		else
			model.Parent = workspace
			built[#built + 1] = model
			local pivotInv = model:GetPivot():Inverse()

			-- ---- FACING: mean Z of front vs rear wheel groups
			local fS, fN, rS, rN = 0, 0, 0, 0
			-- ---- STANCE: wheel centre |X| vs its axle |X|
			local maxOff = 0

			for _, d in ipairs(model:GetDescendants()) do
				if d:IsA("BasePart") and d.Name:match("^Wheel_") then
					local lbl = d.Name:sub(7, 7):upper()
					local z = (pivotInv * d.CFrame).Z
					if lbl == "F" then
						fS, fN = fS + z, fN + 1
					elseif lbl == "R" then
						rS, rN = rS + z, rN + 1
					end

					-- visual tyre centre = centroid of the attached shell parts
					local axleX = (pivotInv * d.CFrame).X
					local sum, n = Vector3.zero, 0
					for _, c in ipairs(d:GetDescendants()) do
						if c:IsA("BasePart") then
							sum, n = sum + c.Position, n + 1
						end
					end
					if n > 0 then
						local visX = (pivotInv * CFrame.new(sum / n)).X
						local off = math.abs(math.abs(visX) - math.abs(axleX))
						if off > maxOff then
							maxOff = off
						end
					end
				end
			end

			local facing, stance = "n/a", "n/a"
			if fN > 0 and rN > 0 then
				local fz, rz = fS / fN, rS / rN
				local good = FRONT_NEG_Z and (fz < rz) or (fz > rz)
				facing = good and "OK" or "BACKWARDS"
				if not good then
					anyFail = true
				end
				stance = (maxOff <= PROTRUDE_TOL) and "OK" or "PROTRUDING"
				if maxOff > PROTRUDE_TOL then
					anyFail = true
				end
				log(string.format("%-10s %8.2f %8.2f %-12s | %8.3f %-10s", car.Id, fz, rz, facing, maxOff, stance))
			else
				log(string.format("%-10s   (no Wheel_* parts found)", car.Id))
				anyFail = true
			end
		end
	end
end

for _, m in ipairs(built) do
	m:Destroy()
end

local tested = #built
log("")
if tested == 0 then
	log(">>> NOTHING WAS TESTED -- no cars built. This is a FAILURE, not a pass.")
elseif anyFail then
	log(string.format(">>> SOME CHECKS FAILED (%d cars tested)", tested))
else
	log(string.format(">>> ALL CHECKS PASSED (%d cars tested)", tested))
end
return table.concat(out, "\n")