#!/usr/bin/python3
# -*- coding: utf-8 -*-

# Transposition Cipher Encryption
# https://www.nostarch.com/crackingcodes (BSD Licensed)


def main() -> None:
    myMessage = "Common sense is not so common."
    myKey = 8
    ciphertext = encryptMessage(myKey, myMessage)
    # Print the encrypted string in ciphertext to the screen,
    # with a | ("pipe" character) after it,
    # in case there are spaces at # the end of the encrypted message.
    print(ciphertext + "|")


def encryptMessage(key: int, message: str) -> str:
    # Each string in ciphertext represents a column in the grid.
    ciphertext = [""] * key
    # Loop through each column in ciphertext.
    for column in range(key):
        currentIndex = column
        # Keep looping until currentIndex goes past the message length.
        while currentIndex < len(message):
            # Place the character at currentIndex in message at the
            # end of the current column in the ciphertext list.
            ciphertext[column] += message[currentIndex]
            # move currentIndex over
            currentIndex += key
    # Convert the ciphertext list into a single string value and return it.
    return "".join(ciphertext)


# If transpositionEncrypt.py is run (instead of imported as a module) call
# the main() function.
if __name__ == "__main__":
    main()