AI Assistants

from __future__ import annotations

import hashlib
import hmac


def normalize_whatsapp_number(raw: str) -> str:
    return "".join(ch for ch in raw if ch.isdigit())


def verify_meta_signature(raw_body: bytes, signature_header: str | None, app_secret: str) -> bool:
    if not signature_header or not app_secret:
        return False
    prefix = "sha256="
    if not signature_header.startswith(prefix):
        return False
    expected = hmac.new(app_secret.encode("utf-8"), raw_body, hashlib.sha256).hexdigest()
    provided = signature_header[len(prefix) :]
    return hmac.compare_digest(expected, provided)


def hash_nonce(value: str) -> str:
    return hashlib.sha256(value.encode("utf-8")).hexdigest()