# src/explainability.py
# -----------------------------------------------------------------------------
# Minimal helpers kept for guideline rerun logic (hash-based staleness).
# -----------------------------------------------------------------------------

from __future__ import annotations
import hashlib
import re

def normalize_text(s: str) -> str:
    return re.sub(r"\s+", " ", (s or "").strip())

def text_hash(s: str) -> str:
    s_norm = normalize_text(s)
    return hashlib.sha256(s_norm.encode("utf-8")).hexdigest()[:16]

def is_stale(current_text: str, baseline_hash: str | None) -> bool:
    if not baseline_hash:
        return False
    return text_hash(current_text) != baseline_hash