init.luau

--!strict

local process = require("@lune/process")

local inverted = require("Icid")

export type inverted = inverted.icid

local function replace(str, pattern, replacement: ((string) -> string) | string | { [string]: string }?)
	return string.gsub(str, pattern, if replacement then replacement else "")
end

local defaultOptions = true
local defaultLocale = "en-US"

local osLocale = {}

function osLocale.getStdOut(command, args)
	return process.spawn(command, args).stdout
end

function osLocale.getEnvLocale(env: { LANG: any?, LANGUAGE: any?, LC_ALL: any?, LC_MESSAGES: any? }?)
	local resultEnv = if env == nil then process.env else env :: any
	return resultEnv.LC_ALL or resultEnv.LC_MESSAGES or resultEnv.LANG or resultEnv.LANGUAGE
end

function osLocale.parseLocale(str: string)
	local env = process.env
	for _, v in str:split("\n") do
		local result = v.split("=")
		env[result[1]] = replace(result[2], '^"|"$')
	end
	return osLocale.getEnvLocale(env)
end

function osLocale.getLocale(str: string)
	return if str then replace(str, "[.:].*") else nil
end

function osLocale.getLocales()
	return osLocale.getStdOut("locale", { "-a" })
end

function osLocale.getSupportedLocale(locale, locales)
	locales = if locales == nil then "" else locales :: string
	return if locales:find(locale) then locale else defaultLocale
end

function osLocale.getAppleLocale()
	local results = {
		osLocale.getStdOut("defaults", { "read", "-globalDomain", "AppleLocale" }),
		osLocale.getLocales(),
	}

	return osLocale.getSupportedLocale(results[1], results[2])
end

function osLocale.getUnixLocale()
	return osLocale.getLocale(osLocale.parseLocale(osLocale.getStdOut("locale")))
end

function osLocale.getWinLocale()
	local stdout = osLocale.getStdOut("wmic", { "os", "get", "locale" })
	local lcidCode = tonumber(replace(stdout, "Locale"), 16) :: number

	return inverted[lcidCode]
end

function normalise(input)
	return replace(input, "_", "-")
end

local cache = {}

return function(spawn: boolean?): inverted
	spawn = if spawn == nil then defaultOptions else spawn
	if cache[spawn] then
		return cache[spawn]
	end

	local locale

	local envLocale = osLocale.getEnvLocale()

	if envLocale or spawn == false then
		locale = osLocale.getLocale(envLocale)
	elseif process.os == "windows" then
		locale = osLocale.getWinLocale()
	elseif process.os == "macos" then
		locale = osLocale.getAppleLocale()
	else
		locale = osLocale.getUnixLocale()
	end

	local normalised = normalise(locale or defaultLocale)
	cache[spawn] = normalised

	return normalised :: inverted
end