from json import load
from os import path

from flask import request


CATALOG_CACHE = {}


def current_lang():
    return request.accept_languages.best_match(["en", "fr"])


def i18n(string: str, *args: str) -> str:
    lang = current_lang()

    if lang != "en" and lang not in CATALOG_CACHE:
        catalog_file = f"{path.dirname(__file__)}/{lang}.json"
        if path.exists(catalog_file):
            with open(catalog_file) as catalog_json:
                catalog = load(catalog_json)
                CATALOG_CACHE[lang] = catalog

    if lang in CATALOG_CACHE and string in CATALOG_CACHE[lang]:
        return CATALOG_CACHE[lang][string] % args

    return string % args