symposion_app/registrasion/controllers/flag.py
2016-05-01 14:56:51 +10:00

257 lines
8 KiB
Python

import itertools
import operator
from collections import defaultdict
from collections import namedtuple
from django.db.models import Count
from django.db.models import Q
from .batch import BatchController
from .conditions import ConditionController
from registrasion.models import conditions
from registrasion.models import inventory
class FlagController(object):
SINGLE = True
PLURAL = False
NONE = True
SOME = False
MESSAGE = {
NONE: {
SINGLE:
"%(items)s is no longer available to you",
PLURAL:
"%(items)s are no longer available to you",
},
SOME: {
SINGLE:
"Only %(remainder)d of the following item remains: %(items)s",
PLURAL:
"Only %(remainder)d of the following items remain: %(items)s"
},
}
@classmethod
def test_flags(
cls, user, products=None, product_quantities=None):
''' Evaluates all of the flag conditions on the given products.
If `product_quantities` is supplied, the condition is only met if it
will permit the sum of the product quantities for all of the products
it covers. Otherwise, it will be met if at least one item can be
accepted.
If all flag conditions pass, an empty list is returned, otherwise
a list is returned containing all of the products that are *not
enabled*. '''
if products is not None and product_quantities is not None:
raise ValueError("Please specify only products or "
"product_quantities")
elif products is None:
products = set(i[0] for i in product_quantities)
quantities = dict((product, quantity)
for product, quantity in product_quantities)
elif product_quantities is None:
products = set(products)
quantities = {}
if products:
# Simplify the query.
all_conditions = cls._filtered_flags(user)
else:
all_conditions = []
# All disable-if-false conditions on a product need to be met
do_not_disable = defaultdict(lambda: True)
# At least one enable-if-true condition on a product must be met
do_enable = defaultdict(lambda: False)
# (if either sort of condition is present)
# Count the number of conditions for a product
dif_count = defaultdict(int)
eit_count = defaultdict(int)
messages = {}
for condition in all_conditions:
cond = ConditionController.for_condition(condition)
remainder = cond.user_quantity_remaining(user, filtered=True)
# Get all products covered by this condition, and the products
# from the categories covered by this condition
ids = [product.id for product in products]
# TODO: This is re-evaluated a lot.
all_products = inventory.Product.objects.filter(id__in=ids)
cond = (
Q(flagbase_set=condition) |
Q(category__in=condition.categories.all())
)
all_products = all_products.filter(cond)
all_products = all_products.select_related("category")
if quantities:
consumed = sum(quantities[i] for i in all_products)
else:
consumed = 1
met = consumed <= remainder
if not met:
items = ", ".join(str(product) for product in all_products)
base = cls.MESSAGE[remainder == 0][len(all_products) == 1]
message = base % {"items": items, "remainder": remainder}
for product in all_products:
if condition.is_disable_if_false:
do_not_disable[product] &= met
dif_count[product] += 1
else:
do_enable[product] |= met
eit_count[product] += 1
if not met and product not in messages:
messages[product] = message
total_flags = FlagCounter.count(user)
valid = {}
# the problem is that now, not every condition falls into
# do_not_disable or do_enable '''
# You should look into this, chris :)
for product in products:
if quantities:
if quantities[product] == 0:
continue
f = total_flags.get(product)
if f.dif > 0 and f.dif != dif_count[product]:
do_not_disable[product] = False
if product not in messages:
messages[product] = "Some disable-if-false " \
"conditions were not met"
if f.eit > 0 and product not in do_enable:
do_enable[product] = False
if product not in messages:
messages[product] = "Some enable-if-true " \
"conditions were not met"
for product in itertools.chain(do_not_disable, do_enable):
f = total_flags.get(product)
if product in do_enable:
# If there's an enable-if-true, we need need of those met too.
# (do_not_disable will default to true otherwise)
valid[product] = do_not_disable[product] and do_enable[product]
elif product in do_not_disable:
# If there's a disable-if-false condition, all must be met
valid[product] = do_not_disable[product]
error_fields = [
(product, messages[product])
for product in valid if not valid[product]
]
return error_fields
@classmethod
@BatchController.memoise
def _filtered_flags(cls, user):
'''
Returns:
Sequence[flagbase]: All flags that passed the filter function.
'''
types = list(ConditionController._controllers())
flagtypes = [i for i in types if issubclass(i, conditions.FlagBase)]
all_flags = conditions.FlagBase.objects.all()
all_subsets = []
for flagtype in flagtypes:
flags = flagtype.objects.filter(id__in=all_flags)
ctrl = ConditionController.for_type(flagtype)
flags = ctrl.pre_filter(flags, user)
all_subsets.append(flags)
return list(itertools.chain(*all_subsets))
ConditionAndRemainder = namedtuple(
"ConditionAndRemainder",
(
"condition",
"remainder",
),
)
_FlagCounter = namedtuple(
"_FlagCounter",
(
"products",
"categories",
),
)
_ConditionsCount = namedtuple(
"ConditionsCount",
(
"dif",
"eit",
),
)
class FlagCounter(_FlagCounter):
@classmethod
@BatchController.memoise
def count(cls, user):
# Get the count of how many conditions should exist per product
flagbases = conditions.FlagBase.objects
types = (
conditions.FlagBase.ENABLE_IF_TRUE,
conditions.FlagBase.DISABLE_IF_FALSE,
)
keys = ("eit", "dif")
flags = [
flagbases.filter(
condition=condition_type
).values(
'products', 'categories'
).annotate(
count=Count('id')
)
for condition_type in types
]
cats = defaultdict(lambda: defaultdict(int))
prod = defaultdict(lambda: defaultdict(int))
for key, flagcounts in zip(keys, flags):
for row in flagcounts:
if row["products"] is not None:
prod[row["products"]][key] = row["count"]
if row["categories"] is not None:
cats[row["categories"]][key] = row["count"]
return cls(products=prod, categories=cats)
def get(self, product):
p = self.products[product.id]
c = self.categories[product.category.id]
eit = p["eit"] + c["eit"]
dif = p["dif"] + c["dif"]
return _ConditionsCount(dif=dif, eit=eit)