app.py

from tkinter import Tk, messagebox, simpledialog
import pyperclip


def is_even(number):
    return number % 2 == 0


def get_even_letters(message):
    even_letters = []
    for counter in range(0, len(message)):
        if is_even(counter):
            even_letters.append(message[counter])
    return even_letters


def get_odd_letters(message):
    odd_letters = []
    for counter in range(0, len(message)):
        if not is_even(counter):
            odd_letters.append(message[counter])
    return odd_letters


def swap_letters(message):
    letter_list = []
    if not is_even(len(message)):
        message = message + "#"
    even_letters = get_even_letters(message)
    odd_letters = get_odd_letters(message)

    for counter in range(0, int(len(message) / 2)):
        letter_list.append(odd_letters[counter])
        letter_list.append(even_letters[counter])
    new_message = "".join(letter_list)
    return new_message


def remove_extra_character(message):
    # Remove the '#' if it exists at the end of the message
    if message.endswith("#"):
        message = message[:-1]
    return message


def get_task():
    task = simpledialog.askstring("Task", "Do you want to encrypt or decrypt")
    return task


def get_message():
    message = simpledialog.askstring("Message", "Enter the secret message: ")
    return message


root = Tk()
root.withdraw()  # Hide the root window

while True:
    task = get_task()

    if task in ("encrypt", "Encrypt"):
        message = get_message()
        encrypted = swap_letters(message)
        pyperclip.copy(encrypted)  # Copy to clipboard
        messagebox.showinfo(
            "Encrypted Message",
            f"Message in encrypted version is: {encrypted}\n\nThe message has been copied to the clipboard!",
        )

    elif task in ("decrypt", "Decrypt"):
        message = get_message()
        decrypted = swap_letters(message)
        decrypted = remove_extra_character(
            decrypted
        )  # Remove the extra character if present
        messagebox.showinfo(
            "Decrypted Message", f"Message in decrypted version: {decrypted}"
        )

    else:
        break

root.mainloop()