"""
from bluechips import model
-from bluechips.model.meta import Session
+from bluechips.model import meta
-import sqlalchemy
+from bluechips.model.types import Currency
-from decimal import Decimal
+import sqlalchemy
class DirtyBooks(Exception):
"""
# In this scheme, negative numbers represent money the house owes
# the user, and positive numbers represent money the user owes the
# house
- users = Session.query(model.User)
+ users = meta.Session.query(model.User)
- debts = {}
+ debts_dict = {}
# First, credit everyone for expenditures they've made
for user in users:
- debts[user] = -sum(map((lambda x: x.amount), user.expenditures))
+ debts_dict[user] = Currency(-sum(map((lambda x: x.amount), user.expenditures)))
# Next, debit everyone for expenditures that they have an
# investment in (i.e. splits)
- total_splits = Session.query(model.Split).\
- add_column(sqlalchemy.func.sum(model.Split.share), 'total_split').\
+ total_splits = meta.Session.query(model.Split).\
+ add_column(sqlalchemy.func.sum(model.Split.share).label('total_split')).\
group_by(model.Split.user_id)
for split, total_cents in total_splits:
- debts[split.user] += (total_cents / 100)
+ debts_dict[split.user] += total_cents
# Finally, move transfers around appropriately
#
# To keep this from getting to be expensive, have SQL sum up
# transfers for us
- transfer_q = Session.query(model.Transfer).\
- add_column(sqlalchemy.func.sum(model.Transfer.amount), 'total_amount')
+ transfer_q = meta.Session.query(model.Transfer).\
+ add_column(sqlalchemy.func.sum(model.Transfer.amount).label('total_amount'))
total_debits = transfer_q.group_by(model.Transfer.debtor_id)
total_credits = transfer_q.group_by(model.Transfer.creditor_id)
for transfer, total_amount in total_debits:
- debts[transfer.debtor] -= total_amount
+ debts_dict[transfer.debtor] -= total_amount
for transfer, total_amount in total_credits:
- debts[transfer.creditor] += total_amount
+ debts_dict[transfer.creditor] += total_amount
- return debts
+ return debts_dict
def settle(debts_dict):
# This algorithm has been shamelessly stolen from Nelson Elhage's
debts_list = [dict(who=user, amount=amount) for user, amount in \
debts_dict.iteritems()]
- debts_list.sort(reverse=True, key=(lambda x: abs(x['amount'])))
+ #debts_list.sort(reverse=True, key=(lambda x: abs(x['amount'])))
owes_list = [debt for debt in debts_list if debt['amount'] > 0]
owed_list = [debt for debt in debts_list if debt['amount'] < 0]
- settle = []
+ settle_list = []
while len(owes_list) > 0 and len(owed_list) > 0:
+ owes_list.sort(reverse=True, key=(lambda x: abs(x['amount'])))
+ owed_list.sort(reverse=True, key=(lambda x: abs(x['amount'])))
+
owes = owes_list[0]
owed = owed_list[0]
owes_list.pop(0)
val = owes['amount']
- settle.append((owes['who'], owed['who'], val))
+ settle_list.append((owes['who'], owed['who'], val))
if len(owes_list) > 0:
raise DirtyBooks, ("People still owe money", owes_list)
if len(owed_list) > 0:
raise DirtyBooks, ("People are still owed money", owed_list)
- return settle
+ return settle_list
__all__ = ['debts', 'settle']