#! /usr/bin/python

from utility import lineno

class CashFlow:

  def __init__(self, name, value, rate, period_start, period_last):
    self.name         = name
    self.value        = value
    self.rate         = rate
    self.period_start = period_start
    self.period_last  = period_last

  def used_this_period(self, period):
    return period >= self.period_start and period <= self.period_last

  def current_value(self, period):
    return (self.used_this_period(period) and  self.value * (1 + self.rate)**period) or 0



def unit_test():
  cf = CashFlow("Test", 1000, 0.03, 5, 11)
  
  value = 0
  for i in range(0, 20):
    value = int(cf.current_value(i))

    if (i <= 4 and i >= 12): assert(value == 0) 
    if i == 5: assert(value == 1159)
    if i == 6: assert(value == 1194) 
    if i == 7: assert(value == 1229) 
    if i == 8: assert(value == 1266) 
    if i == 9: assert(value == 1304) 
    if i == 10: assert(value == 1343) 
    if i == 11: assert(value == 1384) 

  cf = CashFlow("Test", 1000, 0.03, 0, 5)
  
  for i in range(0, 20):
    value = int(cf.current_value(i))

    if i >= 6: assert(value == 0) 
    if i == 0: assert(value == 1000)  
    if i == 1: assert(value == 1030)  
    if i == 2: assert(value == 1060)  
    if i == 3: assert(value == 1092)  
    if i == 4: assert(value == 1125)  
    if i == 5: assert(value == 1159)  


if __name__ == '__main__':
  unit_test()