"""Simple i18n for GRM console messages.

Set GRM_LANG environment variable to override the default English.
Supported: en, bg, de, ru, zh.
"""

from __future__ import annotations

import json
import os
from pathlib import Path

TRANSLATIONS: dict[str, dict[str, str]] = json.loads(
    (Path(__file__).parent / "translations.json").read_text(encoding="utf-8")
)


def _(key: str, **kwargs: object) -> str:
    """Return a translated string for the given key.

    Translation is opt-in via the ``GRM_LANG`` environment variable.
    If unset, English is always returned regardless of system locale.
    """
    lang = os.getenv("GRM_LANG", "en")
    if lang not in ("en", "bg", "de", "ru", "zh"):
        lang = "en"
    template = TRANSLATIONS.get(key, {}).get(lang, key)
    return template.format(**kwargs)