import datetime

from cache.key import KEY
from cache.lru import LRU

"""MIT License

Copyright (c) 2020 Rajat Singh

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE."""
"""Modified code from https://github.com/iamsinghrajat/async-cache"""


class AsyncConditionalTTL:
    class _TTL(LRU):
        def __init__(self, time_to_live, maxsize):
            super().__init__(maxsize=maxsize)

            self.time_to_live = (
                datetime.timedelta(seconds=time_to_live) if time_to_live else None
            )

            self.maxsize = maxsize

        def __contains__(self, key):
            if key not in self.keys():
                return False
            key_expiration = super().__getitem__(key)[1]
            if key_expiration and key_expiration < datetime.datetime.now():
                del self[key]
                return False
            return True

        def __getitem__(self, key):
            value = super().__getitem__(key)[0]
            return value

        def __setitem__(self, key, value):
            value, ignore_ttl = value  # unpack tuple
            ttl_value = (
                (datetime.datetime.now() + self.time_to_live)
                if (self.time_to_live and not ignore_ttl)
                else None
            )  # ignore ttl if ignore_ttl is True
            super().__setitem__(key, (value, ttl_value))

    def __init__(self, time_to_live=60, maxsize=1024, skip_args: int = 0):
        """

        :param time_to_live: Use time_to_live as None for non expiring cache
        :param maxsize: Use maxsize as None for unlimited size cache
        :param skip_args: Use `1` to skip first arg of func in determining cache key
        """
        self.ttl = self._TTL(time_to_live=time_to_live, maxsize=maxsize)
        self.skip_args = skip_args

    def __call__(self, func):
        async def wrapper(*args, **kwargs):
            key = KEY(args[self.skip_args :], kwargs)
            if key in self.ttl:
                val = self.ttl[key]
            else:
                self.ttl[key] = await func(*args, **kwargs)
                val = self.ttl[key]

            return val

        wrapper.__name__ += func.__name__

        return wrapper