Write a program that can both encrypt and decrypt text using the Vigen$$re cipher

Requirements

Your program will be required to both encrypt and decrypt ciphertext. The mode is specified by a program argument flag, $-$e for encrypt mode, and $-$d for decrypt mode.

Your program should work for both upper and lowercase plaintext$/$ciphertext$/$keys$,$ even if the key and plaintext$/$ciphertext do not have the same case as eachother.

Your program should also have another option for grouping output characters together. This can be specified by the $-$g flag. What this will do is strip the ciphertext or plaintext of any non$-$alphabetic characters and group the output into space$-$separated groups consisting of uppercase characters.