#!/usr/bin/env lua

local function usage()
	print ([[Lua static checker
Usage: ]] .. arg[0]:match('/?([^/]+)$') .. [[ LUASOURCE

Detects read/write accesses to undeclared globals.]])
end

if #arg < 1 then
	usage()
	os.exit()
end

local globals = {
	assert = true,
	collectgarbage = true,
	dofile = true,
	error = true,
	_G = true,
	getfenv = true,
	getmetatable = true,
	ipairs = true,
	load = true,
	loadfile = true,
	loadstring = true,
	next = true,
	pairs = true,
	pcall = true,
	print = true,
	rawequal = true,
	rawget = true,
	rawset = true,
	select = true,
	setfenv = true,
	setmetatable = true,
	tonumber = true,
	tostring = true,
	type = true,
	unpack = true,
	_VERSION = true,
	xpcall = true,

	module = true,
	package = true,
	require = true,

	coroutine = true,
	debug = true,
	io = true,
	math = true,
	os = true,
	string = true,
	table = true,
}

for _, v in ipairs(arg) do
	print('==> ' .. v)
	local p = io.popen('luac -p -l -- ' .. v)

	for m in p:lines() do
		if m:match('ETTABUP.*_ENV') then
			local line, op, field = m:match('(%[[%d]+%]).*(.)ETTABUP.*"([_%w]+)"')
			if not globals[field] then
				if op == 'G' then
					op = '<-'
				else
					op = '->'
				end
				print(line, op, field)
			end
		end
	end

	p:close()
end