"""Modulo que contiene la clase/decorador Cache"""
import json
import logging
from blake3 import blake3  # pylint: disable=no-name-in-module
from django.core.cache import cache

_log = logging.getLogger(__name__)
_log.addHandler(logging.NullHandler())


class Cache:
    """ Decorator that caches the result of a function

    It works by generating a key given the function signature and uses it to store the result
    of the function on redis, so if the function is called with the same parameters again it
    will be cached and will retrieve the data from redis and will not execute the function.

    It is assumed that the function will returns a dictionary that can be formatted to json.
    """

    # Time to expire, by default a week
    expire = 60 * 60 * 24 * 7

    def __init__(self, function):
        self.function = function

    def __call__(self, *args, **kwargs):
        _log.info('Caching function %s with argument list %s and dictionary %s',
                  self.function.__name__, args, kwargs)

        key = f'{self.function.__name__}:{self.create_hash_key(args, kwargs)}'
        _log.debug('Resolved key for function is "%s"', key)

        if cache.ttl(key) != 0:
            _log.info('Key was in cache')
            result = json.loads(cache.get(key))
            return result

        _log.info('Key was not in cache')
        result = self.function(*args, **kwargs)
        cache.set(key, json.dumps(result), timeout=self.expire)
        return result

    @staticmethod
    def create_hash_key(args, kwargs):
        """Crea la key dados unos argumentos arbitrarios"""
        return blake3((str(args) + str(kwargs)).encode('utf-8')).hexdigest()