# -*- coding: utf-8 -*-
# !/usr/bin/env python

import pickle

from django.core.cache.backends.base import DEFAULT_TIMEOUT

from django.core.cache.backends.memcached import BaseMemcachedCache

from library import memcache


class CustomizedMemcachedCacheBackend(BaseMemcachedCache):
    """为了使用修改过的兼容的memcache客户端，这里做django的适配层"""

    def __init__(self, server, params):
        super(CustomizedMemcachedCacheBackend, self).__init__(server, params,
                                                              library = memcache,
                                                              value_not_found_exception = ValueError)

    @property
    def _cache(self):
        # type:()->memcache.Client
        if getattr(self, '_client', None) is None:
            self._client = self._lib.Client(self._servers, pickleProtocol = pickle.HIGHEST_PROTOCOL, debug = False,
                                            cache_cas = True)
        return self._client

    def cas(self, key, value, cas = None, timeout = DEFAULT_TIMEOUT):
        key = self.make_key(key)
        return self._cache.cas(key, value, self.get_backend_timeout(timeout))

    def get(self, key, default = None, version = None, ignore_exc = True):
        key = self.make_key(key, version = version)
        val = self._cache.get(key, ignore_exc)
        if val is None:
            return default
        return val

    def gets(self, key, ignore_exc = True):
        key = self.make_key(key)
        value = self._cache.gets(key, ignore_exc)
        return value, None

    def delete(self, key, version = None):
        key = self.make_key(key, version = version)
        return self._cache.delete(key)


__all__ = ['CustomizedMemcachedCacheBackend']