"""Common utility helpers for the server package."""
from __future__ import annotations

import uuid
from typing import Iterable, List


def normalize_recipients(value: str | None) -> List[str]:
    """Split a comma separated string of emails into a clean list."""
    if not value:
        return []
    return [item.strip() for item in value.split(",") if item.strip()]


def is_valid_email(value: str) -> bool:
    """Perform a very small sanity check for email addresses."""
    value = value.strip()
    return bool(value and "@" in value)


def generate_request_id() -> str:
    """Return a UUID4 string for request correlation."""
    return str(uuid.uuid4())