--[[
	diag_shellyaw2.luau -- corrected. The first attempt looked in the wrong
	place (CarShells/Shells/Cars) and then measured the CHASSIS wheels, so it
	reported an identical -11.80 wheelbase for every car and proved nothing.

	Shells actually live in ReplicatedStorage.CarModels[car.Id] (CarManager
	line 347). This inspects those templates directly and reports the exact
	cue the auto-aligner uses, plus the resulting yaw.
]]

local ReplicatedStorage = game:GetService("ReplicatedStorage")

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 models = ReplicatedStorage:FindFirstChild("CarModels")
if not models then
	log("ReplicatedStorage.CarModels: MISSING -> every car uses the procedural")
	log("CarBody shell, which is authored nose-toward -Z and cannot be backwards.")
	return table.concat(out, "\n")
end

log("ReplicatedStorage.CarModels children:")
for _, t in ipairs(models:GetChildren()) do
	log(string.format("   %-14s (%s)", t.Name, t.ClassName))
end
log("")

for _, template in ipairs(models:GetChildren()) do
	if template:IsA("Model") then
		local wf = template:FindFirstChild("Wheels")
		if not wf then
			log(
				string.format(
					"%-14s Wheels folder MISSING -> shellYaw = 0 (fails soft, keeps authored yaw)",
					template.Name
				)
			)
		else
			local pivotInv = template:GetPivot():Inverse()
			local fSum, fN, rSum, rN = Vector3.zero, 0, Vector3.zero, 0
			local names = {}
			for _, w in ipairs(wf:GetChildren()) do
				table.insert(names, w.Name)
				local part = w:IsA("BasePart") and w or w:FindFirstChildWhichIsA("BasePart", true)
				if part then
					local h = w.Name:sub(1, 1):upper()
					local lp = pivotInv * part.Position
					if h == "F" then
						fSum, fN = fSum + lp, fN + 1
					elseif h == "R" then
						rSum, rN = rSum + lp, rN + 1
					end
				end
			end
			if fN > 0 and rN > 0 then
				local nose = (fSum / fN) - (rSum / rN)
				local usable = (math.abs(nose.X) + math.abs(nose.Z)) > 0.05
				local yaw = usable and -math.atan2(nose.X, -nose.Z) or 0
				log(
					string.format(
						"%-14s [%s] F=%d R=%d nose=(%.2f,%.2f,%.2f) -> yaw %+.1f deg %s",
						template.Name,
						table.concat(names, ","),
						fN,
						rN,
						nose.X,
						nose.Y,
						nose.Z,
						math.deg(yaw),
						usable and "" or "*** DEGENERATE -> yaw 0 ***"
					)
				)
			else
				log(
					string.format(
						"%-14s [%s] F=%d R=%d -> *** NO F/R CUE, shellYaw = 0, stays as authored ***",
						template.Name,
						table.concat(names, ","),
						fN,
						rN
					)
				)
			end
		end
	end
end

return table.concat(out, "\n")