from django.conf import settings

NO_CACHE = -1
WHOLE_MODEL = "whole-model"

CACHE_PREFIX = getattr(settings, "CACHE_PREFIX", "")
FETCH_BY_ID = getattr(settings, "FETCH_BY_ID", False)
FLUSH = CACHE_PREFIX + ":flush:"
CACHE_EMPTY_QUERYSETS = getattr(settings, "CACHE_EMPTY_QUERYSETS", False)
TIMEOUT = getattr(settings, "CACHE_COUNT_TIMEOUT", NO_CACHE)
CACHE_INVALIDATE_ON_CREATE = getattr(settings, "CACHE_INVALIDATE_ON_CREATE", None)
CACHE_MACHINE_NO_INVALIDATION = getattr(
    settings, "CACHE_MACHINE_NO_INVALIDATION", False
)
CACHE_MACHINE_USE_REDIS = getattr(settings, "CACHE_MACHINE_USE_REDIS", False)

_invalidate_on_create_values = (None, WHOLE_MODEL)
if CACHE_INVALIDATE_ON_CREATE not in _invalidate_on_create_values:
    raise ValueError(
        "CACHE_INVALIDATE_ON_CREATE must be one of: "
        "%s" % _invalidate_on_create_values
    )