from django.core.exceptions import ImproperlyConfigured
try:
    from importlib import import_module
except ImportError:
    from django.utils.importlib import import_module

from .conf import settings


def get_update_task(task_path=None):
    import_path = task_path or settings.CELERY_HAYSTACK_DEFAULT_TASK
    module, attr = import_path.rsplit('.', 1)
    try:
        mod = import_module(module)
    except ImportError as e:
        raise ImproperlyConfigured('Error importing module %s: "%s"' %
                                   (module, e))
    try:
        task = getattr(mod, attr)
    except AttributeError:
        raise ImproperlyConfigured('Module "%s" does not define a "%s" '
                                   'class.' % (module, attr))
    return task