django-orchestra/orchestra/contrib/plans/ratings.py

213 lines
7.3 KiB
Python

import sys
from django.utils.translation import ugettext_lazy as _
from orchestra.utils.python import AttrDict
def _compute_steps(rates, metric):
value = 0
num = len(rates)
accumulated = 0
barrier = 1
next_barrier = None
end = False
ix = 0
steps = []
while ix < num and not end:
fold = 1
# Multiple contractions
while ix < num-1 and rates[ix] == rates[ix+1]:
ix += 1
fold += 1
if ix+1 == num:
quantity = metric - accumulated
next_barrier = quantity
else:
quantity = rates[ix+1].quantity - rates[ix].quantity
next_barrier = quantity
if rates[ix+1].price > rates[ix].price:
quantity *= fold
if accumulated+quantity > metric:
quantity = metric - accumulated
end = True
price = rates[ix].price
steps.append(AttrDict(**{
'quantity': quantity,
'price': price,
'barrier': barrier,
}))
accumulated += quantity
barrier += next_barrier
value += quantity*price
ix += 1
return value, steps
def _standardize(rates):
"""
Support for incomplete rates
When first rate (quantity=5, price=10) defaults to nominal_price
"""
std_rates = []
minimal = rates[0].quantity
for rate in rates:
if rate.quantity == 0:
rate.quantity = 1
elif rate.quantity == minimal and rate.quantity > 1:
service = rate.service
rate_class = type(rate)
std_rates.append(
rate_class(service=service, plan=rate.plan, quantity=1, price=service.nominal_price)
)
std_rates.append(rate)
return std_rates
def step_price(rates, metric):
if rates.query.order_by != ['plan', 'quantity']:
raise ValueError("rates queryset should be ordered by 'plan' and 'quantity'")
# Step price
group = []
minimal = (sys.maxsize, [])
for plan, rates in rates.group_by('plan').items():
rates = _standardize(rates)
value, steps = _compute_steps(rates, metric)
if plan.is_combinable:
group.append(steps)
else:
minimal = min(minimal, (value, steps), key=lambda v: v[0])
if len(group) == 1:
value, steps = _compute_steps(rates, metric)
minimal = min(minimal, (value, steps), key=lambda v: v[0])
elif len(group) > 1:
# Merge
steps = []
for rates in group:
steps += rates
steps.sort(key=lambda s: s.price)
result = []
counter = 0
value = 0
ix = 0
targets = []
while counter < metric:
barrier = steps[ix].barrier
if barrier <= counter+1:
price = steps[ix].price
quantity = steps[ix].quantity
if quantity + counter > metric:
quantity = metric - counter
else:
for target in targets:
if counter + quantity >= target:
quantity = (counter+quantity+1) - target
steps[ix].quantity -= quantity
if not steps[ix].quantity:
steps.pop(ix)
break
else:
steps.pop(ix)
counter += quantity
value += quantity*price
if result and result[-1].price == price:
result[-1].quantity += quantity
else:
result.append(AttrDict(quantity=quantity, price=price))
ix = 0
targets = []
else:
targets.append(barrier)
ix += 1
minimal = min(minimal, (value, result), key=lambda v: v[0])
return minimal[1]
step_price.verbose_name = _("Step price")
step_price.help_text = _("All rates with a quantity lower or equal than the metric are applied. "
"Nominal price will be used when initial block is missing.")
def match_price(rates, metric):
if rates.query.order_by != ['plan', 'quantity']:
raise ValueError("rates queryset should be ordered by 'plan' and 'quantity'")
candidates = []
selected = False
prev = None
rates = _standardize(rates.distinct())
for rate in rates:
if prev:
if prev.plan != rate.plan:
if not selected and prev.quantity <= metric:
candidates.append(prev)
selected = False
if not selected and rate.quantity > metric:
if prev.quantity <= metric:
candidates.append(prev)
selected = True
prev = rate
if not selected and prev.quantity <= metric:
candidates.append(prev)
candidates.sort(key=lambda r: r.price)
if candidates:
return [AttrDict(**{
'quantity': metric,
'price': candidates[0].price,
})]
return None
match_price.verbose_name = _("Match price")
match_price.help_text = _("Only <b>the rate</b> with a) inmediate inferior metric and b) lower price is applied. "
"Nominal price will be used when initial block is missing.")
def best_price(rates, metric):
if rates.query.order_by != ['plan', 'quantity']:
raise ValueError("rates queryset should be ordered by 'plan' and 'quantity'")
candidates = []
for plan, rates in rates.group_by('plan').items():
rates = _standardize(rates)
plan_candidates = []
for rate in rates:
if rate.quantity > metric:
break
if plan_candidates:
ant = plan_candidates[-1]
if ant.price == rate.price:
# Multiple plans support
ant.fold += 1
else:
ant.quantity = rate.quantity-1
plan_candidates.append(AttrDict(
price=rate.price,
quantity=metric,
fold=1,
))
else:
plan_candidates.append(AttrDict(
price=rate.price,
quantity=metric,
fold=1,
))
candidates.extend(plan_candidates)
results = []
accumulated = 0
for candidate in sorted(candidates, key=lambda c: c.price):
if candidate.quantity < accumulated:
# Out of barrier
continue
candidate.quantity *= candidate.fold
if accumulated+candidate.quantity > metric:
quantity = metric - accumulated
else:
quantity = candidate.quantity
accumulated += quantity
if quantity:
if results and results[-1].price == candidate.price:
results[-1].quantity += quantity
else:
results.append(AttrDict(**{
'quantity': quantity,
'price': candidate.price
}))
return results
best_price.verbose_name = _("Best price")
best_price.help_text = _("Produces the best possible price given all active rating lines (those with quantity lower or equal to the metric).")