compute.py

#!/usr/bin/env python

import time
from optparse import OptionParser

import user

def table(tax_table, income):
    the_table = tax_table[user.status]
    tax = 0
    income_table = the_table[0]
    tax_rate_table = the_table[1]
    for i in range(1, len(income_table)):
        if (income <= income_table[i]):
            break
        tax += (income_table[i] - income_table[i-1]) * tax_rate_table[i-1]/100
        #print ">>", i, income_table[i], tax_rate_table[i-1], tax

    if (income > income_table[i]):
        tax += (income - income_table[i]) * tax_rate_table[i]/100
    else:
        tax += (income - income_table[i-1]) * tax_rate_table[i-1]/100
    #print ">>>", i, income, tax
    return tax

def compute_amt(income):
    """TBD"""
    return 0

def compute_normal(income):
    ca_tax = table(state.tax, income)
    std_deduction = fed.std_deduction[user.status]
    exemption = fed.exemption[user.status]
    social_sec_tax = min(fed.social_sec_max, income) * fed.social_sec_rate/100
    medicare_tax = income * fed.medicare_rate/100
    itemized_deduction = ca_tax # TODO: Add other deductions here
    deduction = max(std_deduction, itemized_deduction)
    income = income - deduction - exemption
    income = max(income, 0)
    fed_tax = table(fed.tax, income)
    #print fed_tax, ca_tax
    return fed_tax + ca_tax + social_sec_tax + medicare_tax

def compute(income):
    return max(compute_normal(income), compute_amt(income))
       
if __name__ == '__main__':
    parser = OptionParser()
    default_year = time.strftime("%Y")
    parser.add_option("-y", "--year", dest="year", type="int",
                      default=int(default_year))
    (options, args) = parser.parse_args()

    modules = ["%s%s" % (x, options.year) for x in ['ca', 'fed'] ]
    (state, fed) = map(__import__, modules)

    user = user.User()
    user.status = 'married filing jointly'
    #user.status = 'single'

    intervals = range(10000,100000, 10000) + \
                range(100000, 500000, 25000) + \
                range(500000, 2000000, 100000) + \
                range(2000000, 10000000, 1000000)

    print "%-7s\t%-7s\t%-16s%-16s" % ("Income", "Tax", "Effective Rate", "Marginal Rate")
    last_tax = 0
    last_income = 0
    for income in intervals:
        tax = compute(income)
        marginal = (tax - last_tax) * 100.0/(income - last_income) 
        print "%07d\t%07d\t%-13.2f\t%3.2f" % (income, tax, tax * 100.0/income, marginal)
        last_tax = tax
        last_income = income