# -*- coding: utf-8 -*
from random import choice, shuffle
from django.db import models
from django.core.cache import cache


class BiasedManager(models.Manager):
    def by_time(self, **kwargs):
        all = super(BiasedManager, self).get_query_set().filter(**kwargs)
        result = []
        for i in all:
            for j in range(i.often):
                result.append(i)
        return result

    def one(self, **kwargs):
        return choice(self.by_time(**kwargs))

    def by_often(self, **kwargs):
        result = self.by_time(**kwargs)
        shuffle(result)
        return result

class BannerGroupCached(models.Manager):
    def all(self):
        key = 'banner_group_all'
        result = cache.get(key)
        if not result:
            result = list(self.filter())
            cache.set(key, result, 90)
        return result