import json
from pathlib import Path
from flask import session

LanguageMapping = dict[str, str]

def load_language(lang_code: str) -> LanguageMapping:
    with open(Path("kanken_online/static/lang", f"{lang_code}.json")) as f:
        return json.load(f)

LANGUAGES = {}

def update_languages():
    ENGLISH = load_language("en")
    JAPANESE = load_language("ja")

    global LANGUAGES
    LANGUAGES = {
        "en": ENGLISH,
        "ja": JAPANESE
    }

update_languages()

# assert all(all(key in lang for key in EXISTING_STRINGS) for lang in LANGUAGES)  # Ensure all strings are mapped for all existing languages
# assert not [key for lang in LANGUAGES for key in lang if ((key in lang) and (key not in EXISTING_STRINGS))]
# assert not any((((key in lang) and (key not in EXISTING_STRINGS)) for key in lang) for lang in LANGUAGES)  # Ensure no languages have strings not specified by the main index


def localize(text_id: str, language: dict[str, str] = None) -> str:
    if language is None:
        preference = session.get("language", "ja")
        language = LANGUAGES.get(preference)
    return language[text_id]