caesar_cipher.py

# Import the logo from art.py when the program starts
from art import logo

# Define the alphabet list, repeating to handle shifts easily
alphabet = list("abcdefghijklmnopqrstuvwxyz" * 2)

def caesar(start_text, shift_amount, cipher_direction):
    """Encode or decode a message using Caesar cipher."""
    end_text = ""
    if cipher_direction == "decode":
        shift_amount *= -1
    for char in start_text:
        if char in alphabet:
            position = alphabet.index(char)
            new_position = position + shift_amount
            end_text += alphabet[new_position]
        else:
            end_text += char
    print(f"Here's the {cipher_direction}d result: {end_text}")

def main():
    """Main function to run the Caesar Cipher program."""
    print(logo)
    should_end = False
    while not should_end:
        direction = input("Type 'encode' to encrypt, type 'decode' to decrypt:\n")
        text = input("Type your message:\n").lower()
        shift = int(input("Type the shift number:\n"))
        shift = shift % 26
        caesar(start_text=text, shift_amount=shift, cipher_direction=direction)
        restart = input("Type 'yes' if you want to go again. Otherwise type 'no'.\n")
        if restart == "no":
            should_end = True
            print("Goodbye")

if __name__ == "__main__":
    main()