# Invoice.py
# Chapter 5

class Invoice:
    def __init__(self, subtotal, tax_rate):
        # pass the tax_rate 0.07 for 7%
        self.subtotal = subtotal
        self.tax_rate = tax_rate

    # instance methods page 55
    ''' Level 1 defining and calling a function
    def total(st,tr):
        formula

    total(100,.07)
    '''
    # level 2 use an instance method on the class
    def calculate_tax(self):
        return self.subtotal * self.tax_rate  # (100,.07) assert 7.0
    
    # instance method AND call another instance method
    def calculate_total(self):
        return self.subtotal + self.calculate_tax() # 100 + return 7.0
    
    # instance method to display the invoice details
    # Subtotal: $100.00, Tax: $7.00, Total: $107.00
    def display_invoice(self):
        return f"Subtotal: ${self.subtotal:.2f}, Tax: ${self.calculate_tax():.2f}, Total: ${self.calculate_total():.2f}"

# program class
invoice = Invoice(100, .07)
print(invoice.display_invoice())

# Chapter 6 datetime class standard modules
'''
datetime module
several common classes to use from datetime module
datetime class -> date and time values yyyy-mm-dd hh:mm:ss.mmmmmm
date class -> date with time as empty yyyy-mm-dd 12:00:00... or 00:00:00
time class -> time hh:mm:ss.mmmmmm
timedelta -> calculate time differences, add/sub date/time

standard module that needs to be imported
import datetime as dt import modulename as namespace  dt.class
from datetime import timedelta, datetime   from modulename import objects
import datetime import modulename  ex. datetime.datetime.objName
'''

import datetime as dt

currentDateTime = dt.datetime.now()  # module.class.function()
print(currentDateTime) # 2024-12-12 15:44:11.723126

# date formatter
date_format = '%m/%d/%Y'

# create an invoice date from datetime stamp
invoice_date = currentDateTime.strftime(date_format)
print(invoice_date) # 12/12/2024

# calculate a due date
# timedelta class to do date/time calculations
due_date = currentDateTime + dt.timedelta(days=30)
format_due_date = due_date.strftime(date_format)
print(format_due_date) # 01/11/2025

# strftime vs strptime
# strftime -> formats a datetime to a string data type
# strptime -> parses a string data type and converts to datetime

# Enter a ship date for the order
# ALL inputs are data type as strings
input_shipDate = input("Enter the ship date (YYYY-MM-DD): ")

# convert the input to a datetime using data validation
try:
    ship_date = dt.datetime.strptime(input_shipDate, '%Y-%m-%d')
except ValueError:
    print("Invalid date format")

print(ship_date) # 2024-12-12 00:00:00

# EOF Invoice.py