# Invoice.py

# Instance Methods for a Class Object
class Invoice:

    # define base attr
    def __init__(self, subtotal, tax_rate):
        self.subtotal = subtotal
        self.tax_rate = tax_rate  # decimal 7% as .07

    # Instance Methods
    ## Instance method to calculate tax bases on the subtotal
    def calculate_tax(self):
        # subtotal * tax_rate
        return self.subtotal * self.tax_rate
        # 100 * .07 
        # return 7

    ## Instance method to calculate invoice total
    def calculate_total(self):
        return self.subtotal + self.calculate_tax()
        # 100 + return(7) ASSERTING 107

    ## Instance method to display the invoice total
    def display_invoice(self):
        return f"Subtotal: ${self.subtotal:.2f} Tax: ${self.calculate_tax():.2f} Total: ${self.calculate_total():.2f}"

    ## Instance method to covert tax_rate to percentage
    def tax_asPerc(self):
        asPerc = self.tax_rate * 100  # .07 * 100 Assert 7
        return f"Tax Rate: {asPerc:.2f}%"  # 7.00%


# Output
invoice = Invoice(100, .07)
# print the tax_rate as a percentage
print(invoice.tax_asPerc())   # Tax: 7%
print(invoice.display_invoice())