AA Pay Calculator

AA Pay Calculator Input

X 38 #July 1st Taxi
$ (0, []),

T 6.74 #July 7th Super Fresh Asian Market
$ (0, []),

T 37.922 #July 7th Superstore
$ (10.85, [M, C, W]), (0, []),

M 20 #July 9th 711
$ (0, []),

C 52.48 #July 9th Superstore
$ (0, []),

Z 30 #July 13th Parking Ticket
$ (0, [M, C, W, X, Z]),

X 61.52 #July 15th Super Store
$ (0, []),

$

AA Pay Calculator Output

Please paste the raw record here, end with single $ in seperate line, 
[RAW RECORD HERE]
%%%%%%%%%%%%%%%%%%%%
%% HERE WE GO!!!
%%%%%%%%%%%%%%%%%%%%
%% W 	spent 43.919	paid 0.000	should pay 43.90
%% M 	spent 43.919	paid 20.000	should pay 23.90
%% T 	spent 34.302	paid 44.662	should receive 10.35
%% X 	spent 40.302	paid 99.520	should receive 59.20
%% Z 	spent 40.302	paid 30.000	should pay 10.30
%% C 	spent 43.919	paid 52.480	should receive 8.55
%% error = -0.000
%%%%%%%%%%%%%%%%%%%%
%% HERE WE DONE!!!
%%%%%%%%%%%%%%%%%%%%

AA Pay Calculator.py

#! /usr/bin/env python3

from enum import Enum


class Calculator(object):
    """docstring for Calculator"""
    @staticmethod
    def round_005(x):
        b = 0.05
        dr = x // 0.05
        frac = x - dr * b
        if frac >= b / 2:
            return x - frac + b
        else:
            return x - frac

    class Status(Enum):
        Ground = 0
        Intermediate = 1

    # initial status and str
    status = Status.Ground
    str = ''
    last_paid = 0

    # datas
    # Please do change these to the people's symbol
    all = ['W', 'M', 'T', 'X', 'Z', 'C']
    paids = {}
    spents = {}

    def __init__(self):
        for who in self.all:
            self.paids[who] = 0.0
            self.spents[who] = 0.0

    def add_quote(self, spent_str):
        for who in self.all:
            spent_str = spent_str.replace(who, '\'%s\'' % (who,))
        return spent_str

    def add_paid(self, who, amount):
        if who not in self.all:
            print('invalid person: %s' % (who,))
            exit()
        self.paids[who] = self.paids[who] + amount

    def add_spent(self, who, amount):
        if who not in self.all:
            print('invalid person: %s' % (who,))
            exit()
        self.spents[who] = self.spents[who] + amount

    def process_spent(self, spent_str):
        spent_str = self.add_quote(spent_str)
        spent_list = eval(spent_str)
        bill_whos = set()
        bill_special_spent = 0.0
        for spent_item in spent_list:
            amount = spent_item[0]
            whos = spent_item[1]
            if len(whos) == 0:
                whos = self.all
            number_who = len(whos)
            for who in whos:
                self.add_spent(who, amount / number_who)
                bill_whos.add(who)
            bill_special_spent = bill_special_spent + amount
        common_spent = self.last_paid - bill_special_spent
        for bill_who in bill_whos:
            self.add_spent(bill_who, common_spent / len(bill_whos))

    def process(self):
        if self.str == '':
            return
        tokens = self.str.split()
        if len(tokens) < 2:
            print('invalid line: %s' % (str,))
            exit()
        if self.status == self.Status.Ground:
            # read overall money
            # and add to paids
            who = tokens[0]
            amount = float(tokens[1])
            self.add_paid(who, amount)
            self.last_paid = amount
            # switch status
            self.status = self.Status.Intermediate
        else:
            # read detail money
            if tokens[0] != '$':
                print('invalid line: %s' % (str,))
                exit()
            # deal with each spent
            spent_str = self.str[1:].strip()
            self.process_spent(spent_str)
            # switch status
            self.status = self.Status.Ground

    def print_result(self):
        print('%' * 20)
        print('%% HERE WE GO!!!')
        print('%' * 20)
        error = 0
        for who in self.all:
            balance = Calculator.round_005(self.paids[who] - self.spents[who])
            error = error + balance
            behaviour = 'receive'
            if balance < 0:
                behaviour = 'pay'
                balance = 0 - balance
            print('%%%% %s \tspent %.3f\tpaid %.3f\tshould %s %.2f'
                  % (who,
                     self.spents[who],
                     self.paids[who],
                     behaviour,
                     balance))
        print('%%%% error = %.3f' % (error,))
        print('%' * 20)
        print('%% HERE WE DONE!!!')
        print('%' * 20)

    def calculate(self):
        print('Please paste the raw record here, '
              'end with single $ in seperate line, \n[RAW RECORD HERE]')
        while True:
            self.str = input('').strip()
            if self.str == '$':
                break
            self.process()
        self.print_result()

calculator = Calculator()
calculator.calculate()