def update_stats(self, from_log=None):
if from_log is None:
from_log = PriceLog.query.filter_by(product=self).order_by(db.desc(PriceLog.fetched_date)).first()
self.one_month_change = self._get_change(to_date=date.today() - timedelta(days=30), from_log=from_log)
self.three_month_change = self._get_change(to_date=date.today() - timedelta(days=90), from_log=from_log)
self.six_month_change = self._get_change(to_date=date.today() - timedelta(days=180), from_log=from_log)
self.one_year_change = self._get_change(to_date=date.today() - timedelta(days=365), from_log=from_log)
self.updated_date = datetime.utcnow()
def __init__(self, price=None, currency=None, product=None, fetched_date=None):
previous_log = PriceLog.query.filter_by(product=product).order_by(db.desc(PriceLog.fetched_date)).limit(1).all()
if previous_log:
previous_log = previous_log[0]
self.change = ((price - previous_log.price) / previous_log.price) * 100
else:
self.change = 0
self.price = price
self.currency = currency
self.product = product
if fetched_date:
self.fetched_date = fetched_date
else:
self.fetched_date = datetime.utcnow()
# Actualizo los valores.
product.update_stats(from_log=self)
def _get_change(self, to_date=None, from_date=None, from_log=None):
if from_log is None:
if from_date is None:
from_log = PriceLog.query.filter_by(product=self).order_by(db.desc(PriceLog.fetched_date)).first()
else:
from_log = (
PriceLog.query.filter_by(product=self)
.filter(PriceLog.fetched_date.between(from_date, from_date + timedelta(days=1)))
.first()
)
to_log = (
PriceLog.query.filter_by(product=self)
.filter(PriceLog.fetched_date.between(to_date, to_date + timedelta(days=1)))
.first()
)
if to_log is None:
to_log = PriceLog.query.filter_by(product=self).order_by(db.asc(PriceLog.fetched_date)).first()
if from_log is None or to_log is None:
return 0
return (from_log.price - to_log.price) / to_log.price * 100