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from collections import defaultdict
from datetime import datetime
from flaskext.sqlalchemy import SQLAlchemy
db = SQLAlchemy()
# define models
class Project(db.Model):
_to_serialize = ("id", "name", "password", "contact_email",
"members", "active_members")
id = db.Column(db.String, primary_key=True)
name = db.Column(db.UnicodeText)
password = db.Column(db.String)
contact_email = db.Column(db.String)
members = db.relationship("Person", backref="project")
@property
def active_members(self):
return [m for m in self.members if m.activated]
def get_balance(self):
balances, should_pay, should_receive = defaultdict(int), defaultdict(int), defaultdict(int)
# for each person
for person in self.members:
# get the list of bills he has to pay
bills = Bill.query.filter(Bill.owers.contains(person))
for bill in bills.all():
if person != bill.payer:
should_pay[person] += bill.pay_each()
should_receive[bill.payer] += bill.pay_each()
for person in self.members:
balances[person] = should_receive[person] - should_pay[person]
return balances
def get_bills(self):
"""Return the list of bills related to this project"""
return Bill.query.join(Person, Project)\
.filter(Bill.payer_id == Person.id)\
.filter(Person.project_id == Project.id)\
.filter(Project.id == self.id)\
.order_by(Bill.date.desc())
def remove_member(self, member_id):
"""Remove a member from the project.
If the member is not bound to a bill, then he is deleted, otherwise
he is only deactivated.
This method returns the status DELETED or DEACTIVATED regarding the
changes made.
"""
person = Person.query.get_or_404(member_id)
if person.project == self:
if not person.has_bills():
db.session.delete(person)
db.session.commit()
else:
person.activated = False
db.session.commit()
return person
def __repr__(self):
return "<Project %s>" % self.name
class Person(db.Model):
_to_serialize = ("id", "name", "activated")
id = db.Column(db.Integer, primary_key=True)
project_id = db.Column(db.Integer, db.ForeignKey("project.id"))
bills = db.relationship("Bill", backref="payer")
name = db.Column(db.UnicodeText)
activated = db.Column(db.Boolean, default=True)
def has_bills(self):
bills_as_ower_number = db.session.query(Bill).join(billowers, Person)\
.filter("Bill.id == billowers.bill_id")\
.filter("Person.id == billowers.person_id")\
.filter(Person.id == self.id)\
.count()
return bills_as_ower_number != 0 or len(self.bills) != 0
def __str__(self):
return self.name
def __repr__(self):
return "<Person %s for project %s>" % (self.name, self.project.name)
# We need to manually define a join table for m2m relations
billowers = db.Table('billowers',
db.Column('bill_id', db.Integer, db.ForeignKey('bill.id')),
db.Column('person_id', db.Integer, db.ForeignKey('person.id')),
)
class Bill(db.Model):
id = db.Column(db.Integer, primary_key=True)
payer_id = db.Column(db.Integer, db.ForeignKey("person.id"))
owers = db.relationship(Person, secondary=billowers)
amount = db.Column(db.Float)
date = db.Column(db.Date, default=datetime.now)
what = db.Column(db.UnicodeText)
archive = db.Column(db.Integer, db.ForeignKey("archive.id"))
def pay_each(self):
"""Compute what each person has to pay"""
return round(self.amount / len(self.owers), 2)
def __repr__(self):
return "<Bill of %s from %s for %s>" % (self.amount,
self.payer, ", ".join([o.name for o in self.owers]))
class Archive(db.Model):
id = db.Column(db.Integer, primary_key=True)
project_id = db.Column(db.Integer, db.ForeignKey("project.id"))
name = db.Column(db.UnicodeText)
@property
def start_date(self):
pass
@property
def end_date(self):
pass
def __repr__(self):
return "<Archive>"
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