gestioCOF/kfet/statistic.py

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from datetime import date, datetime, time, timedelta
import pytz
from dateutil.parser import parse as dateutil_parse
from dateutil.relativedelta import relativedelta
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from django.db.models import Sum
from django.utils import timezone
KFET_WAKES_UP_AT = time(7, 0)
def kfet_day(year, month, day, start_at=KFET_WAKES_UP_AT):
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"""Étant donné une date, renvoie un objet `datetime`
correspondant au début du 'jour K-Fêt' correspondant."""
naive = datetime.combine(date(year, month, day), start_at)
return pytz.timezone("Europe/Paris").localize(naive, is_dst=None)
def to_kfet_day(dt, start_at=KFET_WAKES_UP_AT):
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"""
Retourne le 'jour K-Fêt' correspondant à un objet `datetime` donné
"""
kfet_dt = kfet_day(year=dt.year, month=dt.month, day=dt.day)
if dt.time() < start_at:
kfet_dt -= timedelta(days=1)
return kfet_dt
class Scale(object):
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"""
Classe utilisée pour subdiviser un QuerySet (e.g. des opérations) sur
une échelle de temps donnée, avec un pas de temps fixe.
Cette échelle peut être spécifiée :
- par un début et une fin,
- par un début/une fin et un nombre de subdivisions.
Si le booléen `std_chunk` est activé, les subdivisions sont standardisées :
on appelle `get_chunk_start` sur toutes les subdivisions (enfin, sur la première).
"""
name = None
step = None
def __init__(self, n_steps=0, begin=None, end=None, last=False, std_chunk=True):
self.std_chunk = std_chunk
if last:
end = timezone.now()
if std_chunk:
if begin is not None:
begin = self.get_chunk_start(begin)
if end is not None:
end = self.do_step(self.get_chunk_start(end))
if begin is not None and n_steps != 0:
self.begin = begin
self.end = self.do_step(self.begin, n_steps=n_steps)
elif end is not None and n_steps != 0:
self.end = end
self.begin = self.do_step(self.end, n_steps=-n_steps)
elif begin is not None and end is not None:
self.begin = begin
self.end = end
else:
raise Exception(
"Two of these args must be specified: "
"n_steps, begin, end; "
"or use last and n_steps"
)
self.datetimes = self.get_datetimes()
@staticmethod
def by_name(name):
for cls in Scale.__subclasses__():
if cls.name == name:
return cls
return None
def get_from(self, dt):
return self.std_chunk and self.get_chunk_start(dt) or dt
def __getitem__(self, i):
return self.datetimes[i], self.datetimes[i + 1]
def __len__(self):
return len(self.datetimes) - 1
def do_step(self, dt, n_steps=1):
return dt + self.step * n_steps
def get_datetimes(self):
datetimes = [self.begin]
tmp = self.begin
while tmp < self.end:
tmp = self.do_step(tmp)
datetimes.append(tmp)
return datetimes
def get_labels(self, label_fmt=None):
if label_fmt is None:
label_fmt = self.label_fmt
return [
begin.strftime(label_fmt.format(i=i, rev_i=len(self) - i))
for i, (begin, end) in enumerate(self)
]
def chunkify_qs(self, qs, field=None):
if field is None:
field = "at"
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"""
Découpe un queryset en subdivisions, avec agrégation optionnelle des résultats
NB : on pourrait faire ça en une requête, au détriment de la lisibilité...
"""
begin_f = "{}__gte".format(field)
end_f = "{}__lte".format(field)
return [qs.filter(**{begin_f: begin, end_f: end}) for begin, end in self]
def get_by_chunks(self, qs, field_callback=None, field_db="at"):
"""Objects of queryset ranked according to the scale.
Returns a generator whose each item, corresponding to a scale chunk,
is a generator of objects from qs for this chunk.
Args:
qs: Queryset of source objects, must be ordered *first* on the
same field returned by `field_callback`.
field_callback: Callable which gives value from an object used
to compare against limits of the scale chunks.
Default to: lambda obj: getattr(obj, field_db)
field_db: Used to filter against `scale` limits.
Default to 'at'.
Examples:
If queryset `qs` use `values()`, `field_callback` must be set and
could be: `lambda d: d['at']`
If `field_db` use foreign attributes (eg with `__`), it should be
something like: `lambda obj: obj.group.at`.
"""
if field_callback is None:
def field_callback(obj):
return getattr(obj, field_db)
begin_f = "{}__gte".format(field_db)
end_f = "{}__lte".format(field_db)
qs = qs.filter(**{begin_f: self.begin, end_f: self.end})
obj_iter = iter(qs)
last_obj = None
def _objects_until(obj_iter, field_callback, end):
"""Generator of objects until `end`.
Ends if objects source is empty or when an object not verifying
field_callback(obj) <= end is met.
If this object exists, it is stored in `last_obj` which is found
from outer scope.
Also, if this same variable is non-empty when the function is
called, it first yields its content.
Args:
obj_iter: Source used to get objects.
field_callback: Returned value, when it is called on an object
will be used to test ordering against `end`.
end
"""
nonlocal last_obj
if last_obj is not None:
yield last_obj
last_obj = None
for obj in obj_iter:
if field_callback(obj) <= end:
yield obj
else:
last_obj = obj
return
for begin, end in self:
# forward last seen object, if it exists, to the right chunk,
# and fill with empty generators for intermediate chunks of scale
if last_obj is not None:
if field_callback(last_obj) > end:
yield iter(())
continue
# yields generator for this chunk
# this set last_obj to None if obj_iter reach its end, otherwise
# it's set to the first met object from obj_iter which doesn't
# belong to this chunk
yield _objects_until(obj_iter, field_callback, end)
class DayScale(Scale):
name = "day"
step = timedelta(days=1)
label_fmt = "%A"
@classmethod
def get_chunk_start(cls, dt):
return to_kfet_day(dt)
class WeekScale(Scale):
name = "week"
step = timedelta(days=7)
label_fmt = "Semaine %W"
@classmethod
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def get_chunk_start(cls, dt):
dt_kfet = to_kfet_day(dt)
offset = timedelta(days=dt_kfet.weekday())
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return dt_kfet - offset
class MonthScale(Scale):
name = "month"
step = relativedelta(months=1)
label_fmt = "%B"
@classmethod
def get_chunk_start(cls, dt):
return to_kfet_day(dt).replace(day=1)
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def stat_manifest(
scales_def=None, scale_args=None, scale_prefix=None, **other_url_params
):
if scale_prefix is None:
scale_prefix = "scale_"
if scales_def is None:
scales_def = []
if scale_args is None:
scale_args = {}
manifest = []
for label, cls in scales_def:
url_params = {scale_prefix + "name": cls.name}
url_params.update(
{scale_prefix + key: value for key, value in scale_args.items()}
)
url_params.update(other_url_params)
manifest.append(dict(label=label, url_params=url_params))
return manifest
def last_stats_manifest(
scales_def=None, scale_args=None, scale_prefix=None, **url_params
):
scales_def = [
("Derniers mois", MonthScale),
("Dernières semaines", WeekScale),
("Derniers jours", DayScale),
]
if scale_args is None:
scale_args = {}
scale_args.update(dict(last=True, n_steps=7))
return stat_manifest(
scales_def=scales_def,
scale_args=scale_args,
scale_prefix=scale_prefix,
**url_params
)
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"""
Convertit une spécification de scales en arguments GET utilisables par ScaleMixin.
La spécification est de la forme suivante :
- scales_def : liste de champs de la forme (label, scale)
- scale_args : arguments à passer à Scale.__init__
- other_url_params : paramètres GET supplémentaires
"""
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# Étant donné un queryset d'operations
# rend la somme des article_nb
def tot_ventes(queryset):
res = queryset.aggregate(Sum("article_nb"))["article_nb__sum"]
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return res and res or 0
class ScaleMixin(object):
scale_args_prefix = "scale_"
def get_scale_args(self, params=None, prefix=None):
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"""
Récupère les paramètres de subdivision encodés dans une requête GET.
"""
if params is None:
params = self.request.GET
if prefix is None:
prefix = self.scale_args_prefix
scale_args = {}
name = params.get(prefix + "name", None)
if name is not None:
scale_args["name"] = name
n_steps = params.get(prefix + "n_steps", None)
if n_steps is not None:
scale_args["n_steps"] = int(n_steps)
begin = params.get(prefix + "begin", None)
if begin is not None:
scale_args["begin"] = dateutil_parse(begin)
end = params.get(prefix + "send", None)
if end is not None:
scale_args["end"] = dateutil_parse(end)
last = params.get(prefix + "last", None)
if last is not None:
scale_args["last"] = last in ["true", "True", "1"] and True or False
return scale_args
def get_context_data(self, *args, **kwargs):
context = super().get_context_data(*args, **kwargs)
scale_args = self.get_scale_args()
scale_name = scale_args.pop("name", None)
scale_cls = Scale.by_name(scale_name)
if scale_cls is None:
scale = self.get_default_scale()
else:
scale = scale_cls(**scale_args)
self.scale = scale
context["labels"] = scale.get_labels()
return context
def get_default_scale(self):
return DayScale(n_steps=7, last=True)