from __future__ import absolute_import
from __future__ import division
from __future__ import print_function


def override(cls):
    """Annotation for documenting method overrides.

    Arguments:
        cls (type): The superclass that provides the overriden method. If this
            cls does not actually have the method, an error is raised.
    """

    def check_override(method):
        if method.__name__ not in dir(cls):
            raise NameError("{} does not override any method of {}".format(
                method, cls))
        return method

    return check_override


def PublicAPI(obj):
    """Annotation for documenting public APIs.

    Public APIs are classes and methods exposed to end users of RLlib. You
    can expect these APIs to remain stable across RLlib releases.

    Subclasses that inherit from a ``@PublicAPI`` base class can be
    assumed part of the RLlib public API as well (e.g., all trainer classes
    are in public API because Trainer is ``@PublicAPI``).

    In addition, you can assume all trainer configurations are part of their
    public API as well.
    """

    return obj


def DeveloperAPI(obj):
    """Annotation for documenting developer APIs.

    Developer APIs are classes and methods explicitly exposed to developers
    for the purposes of building custom algorithms or advanced training
    strategies on top of RLlib internals. You can generally expect these APIs
    to be stable sans minor changes (but less stable than public APIs).

    Subclasses that inherit from a ``@DeveloperAPI`` base class can be
    assumed part of the RLlib developer API as well (e.g., all policy
    optimizers are developer API because PolicyOptimizer is ``@DeveloperAPI``).
    """

    return obj