IMMREX7

# -*- coding: utf-8 -*-

from functools import lru_cache, wraps
from datetime import datetime, timedelta

DEFAULT_MAXSIZE = 128


def memoize(obj):
    """A general-use memoizer decorator for class, object, function; supports kwargs"""
    cache = obj.cache = {}

    @wraps(obj)
    def memoizer(*args, **kwargs):
        """Actual implementation"""
        key = str(args) + str(kwargs)
        if key not in cache:
            cache[key] = obj(*args, **kwargs)
        return cache[key]

    return memoizer


def timed_lru_cache(seconds: int, maxsize: int = DEFAULT_MAXSIZE):
    """A decorator that wraps lru_cache and allows the setting of a
    lifetime in seconds, after which the cache will expire
    :param seconds: The number of seconds after which the cache will expire
    :param maxsize: The maximum number of entries in the cache before it will start dropping old entries
    """
    def wrapper_cache(func):
        func = lru_cache(maxsize=maxsize)(func)
        func.lifetime = timedelta(seconds=seconds)
        func.expiration = datetime.utcnow() + func.lifetime

        @wraps(func)
        def wrapped_func(*args, **kwargs):
            if datetime.utcnow() >= func.expiration:
                func.cache_clear()
                func.expiration = datetime.utcnow() + func.lifetime

            return func(*args, **kwargs)

        return wrapped_func

    return wrapper_cache