"""Standalone language detection used by app.py routing logic."""
from langdetect import detect, DetectorFactory, LangDetectException
DetectorFactory.seed = 42

SUPPORTED = {"en", "fr"}

def detect_language(text: str, hint: str = "auto") -> str:
    if hint in SUPPORTED:
        return hint
    if not text or not text.strip():
        return "en"
    try:
        lang = detect(text[:500])
        return lang if lang in SUPPORTED else "en"
    except LangDetectException:
        return "en"