--[[
	diag_whatami.luau -- answer three questions the user's report raises, with
	no assumptions:

	  Q1. Is the module in THIS DataModel the source I edited on disk?
	      (compare length + marker strings; disk file is 41650 bytes and
	      contains SHELL_YAW_OVERRIDE and bestVol)

	  Q2. Is the require() cache still pinned to pre-push code?
	      (_buildForDiag present in source but nil after require == pinned,
	      meaning NO fix can be in effect yet this session)

	  Q3. Are the cars the user is looking at STALE STAGED PROPS?
	      workspace.ShellReview was populated by tools/shot_shells.luau in an
	      earlier run. Those models are a frozen snapshot -- they are inert
	      Instances, not live rebuilds, so they will look identical forever
	      regardless of what CarManager says. Report whether ShellReview
	      exists, what is in it, and how each car is oriented RIGHT NOW so we
	      can tell "stale props" from "fix genuinely not working".

	For Q3 the facing is read from the staged model directly: compare the mean
	Z of the F* wheel groups against the R* groups in the model's own frame.
	Front should sit at NEGATIVE Z (chassis convention: front axle built at
	Z = -WHEELBASE/2). If front is at +Z the car is backwards.
]]

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

-- ------------------------------------------------------------------ Q1 + Q2
log("=== Q1: is the live module my edited source? ===")
local mods = {}
for _, d in ipairs(ServerScriptService:GetDescendants()) do
	if d:IsA("ModuleScript") and d.Name == "CarManager" then
		mods[#mods + 1] = d
	end
end
log(string.format("  instances: %d", #mods))
for _, m in ipairs(mods) do
	local src = ""
	pcall(function()
		src = m.Source
	end)
	log(
		string.format(
			"  %s  len=%d (disk 41650) SHELL_YAW_OVERRIDE=%s bestVol=%s",
			m:GetFullName(),
			#src,
			tostring(src:find("SHELL_YAW_OVERRIDE", 1, true) ~= nil),
			tostring(src:find("bestVol", 1, true) ~= nil)
		)
	)
end

log("")
log("=== Q2: is require() still pinned to old code? ===")
if #mods == 1 then
	local ok, mod = pcall(require, mods[1])
	if ok and typeof(mod) == "table" then
		local fresh = typeof(mod._buildForDiag) == "function"
		log("  _buildForDiag after require: " .. typeof(mod._buildForDiag))
		log(
			fresh and "  => NEW code is live; fixes CAN take effect"
				or "  => STILL PINNED to pre-push code; NO fix can be in effect yet"
		)
	end
end

-- ---------------------------------------------------------------------- Q3
log("")
log("=== Q3: what is actually sitting in workspace.ShellReview? ===")
local review = workspace:FindFirstChild("ShellReview")
if not review then
	log("  ShellReview does NOT exist -- user must be looking at something else")
	log("  (spawned cars in-game, or the templates in ReplicatedStorage)")
else
	log("  ShellReview EXISTS with " .. #review:GetChildren() .. " children.")
	log("  These are FROZEN PROPS from an earlier shot_shells.luau run.")
	log("  They do not rebuild themselves -- code fixes cannot change them.")
	log("")
	log(string.format("  %-14s %10s %10s  %s", "model", "frontZ", "rearZ", "verdict"))
	for _, m in ipairs(review:GetChildren()) do
		if m:IsA("Model") then
			local shell = m:FindFirstChild("Shell")
			local wg = shell and shell:FindFirstChild("Wheels")
			if not wg then
				local f = m:FindFirstChild("Wheels", true)
				wg = f
			end
			if wg then
				local pivot = m:GetPivot()
				local inv = pivot:Inverse()
				local fS, fN, rS, rN = 0, 0, 0, 0
				for _, w in ipairs(wg:GetChildren()) do
					local sum, n = Vector3.zero, 0
					if w:IsA("BasePart") then
						sum, n = w.Position, 1
					end
					for _, d in ipairs(w:GetDescendants()) do
						if d:IsA("BasePart") then
							sum, n = sum + d.Position, n + 1
						end
					end
					if n > 0 then
						local z = (inv * (sum / n)).Z
						local head = w.Name:sub(1, 1):upper()
						if head == "F" then
							fS, fN = fS + z, fN + 1
						elseif head == "R" then
							rS, rN = rS + z, rN + 1
						end
					end
				end
				if fN > 0 and rN > 0 then
					local fz, rz = fS / fN, rS / rN
					log(
						string.format(
							"  %-14s %10.3f %10.3f  %s",
							m.Name,
							fz,
							rz,
							fz < rz and "front at -Z  OK" or "front at +Z  BACKWARDS"
						)
					)
				end
			end
		end
	end
end

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