#!/usr/bin/env lua
-- i love build scripts i love build scripts i love build scripts scripts build love i script build love me i love script build i script love build
local isBlendi = os.getenv("USER") == "blendi"
local separator = package.config:sub(1,1)

local function filename(path)
	local s,e = 1, #path
	for i = 1,#path do
		if path:sub(i,i) == '/' then s = i+1 end;
		if path:sub(i,i) == '.' then e = i-1 end;
	end

	return path:sub(s,e)
end

local function runCommand(cmd, ignore_fail)
	print("> " .. cmd)
	local result = os.execute(cmd)
	if (result ~= true and result ~= 0) and (not ignore_fail) then
		os.exit(1)
	end
end

local function fixPath(path)
	local new = ""
	for i = 1,#path do
		local ch = path:sub(i,i)
		if ch == '/' then new = new .. separator
		else new = new .. ch end
	end
	return new
end

if arg[1] == "clean" then
	if separator == '\\' then
		runCommand("rmdir /s /q build 2>nul", true)
	else
		runCommand("rm -rf build")
	end
	return
end

local needsDir = false

if separator == '\\' then
	needsDir = true
else
	-- TODO: maybe use exit code instead of the first return value?
	local ok, _, code = os.execute('test -d build');

	local exists = (ok == 0 or (ok == true and code == 0))

	needsDir = not exists;
end

if needsDir then
	if separator == '\\' then
		runCommand('mkdir build 2>nul')
	else
		runCommand('mkdir -p build')
	end
end

local files = {
	'src/error.c',
	'src/helper.c',
	'src/lexer.c',
	'src/parser.c',
	'src/compiler.c',
	'src/vm.c',
	'src/main.c',
}

local objects = {}

local coolArgs = {}

local function getTime(path)
	local handle = assert(io.popen('stat -c %Y "' .. path .. '" 2>/dev/null'))
	local result = handle:read("*a")
	handle:close()
	return tonumber(result) or 0
end

local function needsRebuild(src, obj)
	if separator == '\\' then return true end
	local srcTime = getTime(src)
	local objTime = getTime(obj)
	return srcTime > objTime
end

if not isBlendi then table.insert(coolArgs, '-fsanitize=undefined,address') end

local needsLinking = false

for i = 1,#files do
	local fname = files[i]
	local out = "build/" .. filename(fname) .. '.o'

	fname = fixPath(fname)
	out = fixPath(out)

	if needsRebuild(fname, out) then
		needsLinking = true
		runCommand('clang -g -c -o ' .. out .. ' ' .. fname .. ' ' .. table.concat(coolArgs, ' '))
	end

	objects[#objects+1] = out;
end

local exe = separator == '\\' and ".\\noom.exe" or "./noom"

if needsLinking then
	runCommand('clang -g -o ' .. exe .. ' ' .. table.concat(objects, ' ') .. ' ' .. table.concat(coolArgs, ' '))
end

if arg[1] == "run" then
	runCommand(exe)
end