calculate rent share | Python Fiddle

'''
Created on Feb 18, 2012

@author: aman
'''
from copy import copy, deepcopy
class Share:
    def __init__(self, id, paid=0.0, percent=None, share=None):
        self.id = id
        self.paid = paid
        self.share = share
        self.percent = percent
    
    def to_pay(self):
        return self.share - self.paid

def pay_back(self):
        return self.paid - self.share
    
class Txn:

def __init__(self):
        self.parties = []
        self.total = 0.0
        #self.avg = 0.0

def calc(self):
        self.calc_percent()
        
        self.total = 0.0
        #self.avg = 0.0
        #avg = 0.0
        if len(self.parties) == 0:
            return
        
        for party in self.parties:
            self.total = self.total + party.paid
        
        #self.avg = self.total / len(self.parties)
        #avg = self.total / len(self.parties)
        
        for party in self.parties:
            if party.share == None:
                #party.share = self.avg
                #party.share = avg
                party.share = (self.total * party.percent) / 100.0

def calc_percent(self):
        assigned_percent = 0
        assigned_count = 0
        
        for party in self.parties:
            if party.percent != None:
                assigned_percent = party.percent 
                assigned_count = assigned_count + 1
                
        unassigned_percent = 100.0 - assigned_percent
        unassigned_count = len(self.parties) - assigned_count
        none_percent = unassigned_percent / unassigned_count
        
        if abs(unassigned_percent) > 0.0001 and unassigned_count == 0:
            print "Total percentage does not add up to 100% - auto adjusting percentage "
            for party in self.parties:
                party.percent = (party.percent * 100.0) / assigned_percent 
        elif unassigned_count > 0:
            for party in self.parties:
                if party.percent == None:
                    party.percent = none_percent
                
                
def addShare(map, share):
    if share.id in map:
        total = map[share.id]
        total.share = total.share + share.share
        total.paid = total.paid + share.paid
    else:
        total = deepcopy(share)
        map[total.id] = total

def split(txns):

total_share = dict()
    for txn in txns:
        txn.calc()
        for party in txn.parties:
            addShare(total_share, party)

share_list = []
    for id in total_share:
        share = total_share[id]
        share_list.append(share)
    
    share_list = sorted(share_list, key=lambda share: (share.paid - share.share)) 
    for share in share_list:
        print ' %s : Total : %f, Paid : %f, To Pay : %f ' % (share.id, share.share, share.paid, share.share - share.paid)
    
    
    
    # decide shares order in ascending
    summary_txns = []
    pay_back = []
    #ti = 0
    bi = len(share_list)
    for i in range(len(share_list)):
        top = share_list[i]

for j in reversed(range(bi)):
           bi = j+1
           bot = share_list[j]  
           # i pays to j 
           if top.to_pay() <= 0.0:
               # paid his share
               break
           
           if bot.pay_back() <= 0.0:
               # got his share
               continue
               
           if top.to_pay() < bot.pay_back():
               summary_txn = Txn()
               summary_txn.parties.append(Share(top.id))
               summary_txn.parties.append(Share(bot.id, top.to_pay(), 0.0))
               summary_txn.calc()
               summary_txns.append(summary_txn)
               
               pay_back.append('%s pays %f to %s' % (top.id, top.to_pay(), bot.id))
               
               bot.paid = bot.paid - top.to_pay() 
               top.paid = top.share
               break
           elif top.to_pay() > bot.pay_back():
               summary_txn = Txn()
               summary_txn.parties.append(Share(top.id))
               summary_txn.parties.append(Share(bot.id, bot.pay_back(), 0.0))
               summary_txn.calc()
               summary_txns.append(summary_txn)

pay_back.append('%s pays %f to %s' % (top.id, bot.pay_back(), bot.id))
               top.paid = top.paid + bot.pay_back()
               bot.paid = bot.share 
               continue
           else:
               summary_txn = Txn()
               summary_txn.parties.append(Share(top.id))
               summary_txn.parties.append(Share(bot.id, top.to_pay(), 0.0))
               summary_txn.calc()
               summary_txns.append(summary_txn)

pay_back.append('%s pays %f to %s' % (top.id, top.to_pay(), bot.id))
               top.paid = top.share
               bot.paid = bot.share 
               #bi = j - 1
               break
           
    for s in pay_back:
        print s
        
    return summary_txns

if __name__ == "__main__":
    txns = []
    txn = Txn()
    txn.parties.append(Share('A', 100.0))
    txn.parties.append(Share('B'))
    txn.parties.append(Share('C'))
    txns.append(txn)

txn = Txn()
    txn.parties.append(Share('A'))
    txn.parties.append(Share('B', 50.0))
    txns.append(txn)

txn = Txn()
    txn.parties.append(Share('A'))
    txn.parties.append(Share('D', 150.0))
    txns.append(txn)

txn = Txn()
    txn.parties.append(Share('A', 100.0))
    txn.parties.append(Share('E'))
    txns.append(txn)

txn = Txn()
    txn.parties.append(Share('Q', 1000.0))
    txn.parties.append(Share('D'))
    txn.parties.append(Share('A'))
    txn.parties.append(Share('B'))
    txn.parties.append(Share('C'))
    txns.append(txn)

txn = Txn()
    txn.parties.append(Share('A', 1500))
    txn.parties.append(Share('C'))
    txns.append(txn)
    
    # split
    summary_txns = split(txns)

for txn1 in summary_txns:
        print '**********TXN**********'
        for share in txn1.parties:
            print "%s : to pay : %.2f" % (share.id, share.to_pay())

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