"""
Calculate EMI for given Principal, Interest, Tenure

Author: T K Sourab<sourabhtk37@gmail.com>
"""


# todo: implement extra payments
class EmiCalc:

    """ Implements Equated Monthly Instalment (EMI)
    """

    def __init__(self, principal_amt, interest_rt, tenure_period):
        self.principal_amt = principal_amt
        self.interest_rt = interest_rt / (12 * 100)  # monthly interest
        self.tenure_period = tenure_period

    @property
    def monthly_emi(self):
        """Returns monthly EMI amount to be paid
        EMI = (p * r * pow(1 + r, t)) / (pow(1 + r, t) - 1)
        """
        return (
            self.principal_amt * self.interest_rt * pow(1 + self.interest_rt,
                                                        self.tenure_period)) / (pow(1 + self.interest_rt,
                                                                                    self.tenure_period) - 1)

    def print_monthly_breakdown(self):
        """Provides breakdown of monthly interest, principal,EMI,
        opening and closing balance.
        """
        begin_bal = self.principal_amt
        end_bal = 0
        monthly_interest = 0
        monthly_principal = 0

        print("Month \t Beginning Balance \t EMI \t\t Interest Amount"
              " \t Principal Amount \t Ending Balance")

        for month in range(1, self.tenure_period + 1):

            monthly_interest = self.interest_rt * begin_bal
            monthly_principal = self.monthly_emi - monthly_interest
            end_bal = begin_bal - monthly_principal

            # todo: seperate function/class for formatter
            format_tuple = (month, begin_bal,
                            self.monthly_emi,
                            monthly_interest,
                            monthly_principal,
                            abs(end_bal))
            formatted_out = """{0} \t {1:.3f} \t\t {2:.3f} \t {3:.3f} \t\t {4:.3f} \t\t {5:.3f}
                            """.format(*format_tuple)

            print(formatted_out)

            begin_bal = end_bal  # next month opening balance updation


if __name__ == '__main__':
    loan_user = EmiCalc(25000, 10, 4)
    print("The monthly EMI to be paid is %s" % loan_user.monthly_emi)
    loan_user.print_monthly_breakdown()