"""Example authentication module."""


def authenticate(username: str, password: str) -> dict | None:
    """Authenticate a user and return session info."""
    user = find_user(username)
    if user and verify_password(password, user["password_hash"]):
        return create_session(user)
    return None


def create_session(user: dict) -> dict:
    """Create a new session for the authenticated user."""
    import secrets
    return {
        "user_id": user["id"],
        "token": secrets.token_urlsafe(32),
        "expires_in": 3600,
    }


def find_user(username: str) -> dict | None:
    """Find a user by username (stub)."""
    return None


def verify_password(password: str, password_hash: str) -> bool:
    """Verify a password against its hash (stub)."""
    return False
