"""The two settings every service must declare, and their fallbacks."""

from __future__ import annotations

from django.conf import settings

DEFAULT_SERVICE = "yksa"


def service() -> str:
    """Short service slug: ``tdas``, ``odms``, ``ops``.

    Namespaces every cache key this package writes. The services share one Redis,
    so a wrong or missing value silently merges two rate-limit budgets.
    """
    return getattr(settings, "YKSA_SERVICE", DEFAULT_SERVICE)


def user_agent() -> str:
    """Identifies us to the upstreams we poll; several ban unattributed clients."""
    return getattr(
        settings,
        "YKSA_USER_AGENT",
        f"yksa-{service()}/0.1 (+https://{service()}.tmtc.yksa.space)",
    )


def cache_key(*parts: str) -> str:
    return ":".join((service(), *parts))