'''
Plugin which (de)cyphers a string
Doesn't cypher non-alphanumeric strings yet.
by instanceoftom
'''

from util import hook
chars = "abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ "
len_chars = len(chars)


@hook.command
def cypher(inp):
    ".cypher <pass> <string> -- Cyphers <string> with <password>."

    passwd = inp.split(" ")[0]
    len_passwd = len(passwd)
    inp = " ".join(inp.split(" ")[1:])

    out = ""
    passwd_index = 0
    for character in inp:
        try:
            chr_index = chars.index(character)
            passwd_chr_index = chars.index(passwd[passwd_index])

            out_chr_index = (chr_index + passwd_chr_index) % len_chars
            out_chr = chars[out_chr_index]

            out += out_chr

            passwd_index = (passwd_index + 1) % len_passwd
        except ValueError:
            out += character
            continue
    return out


@hook.command
def decypher(inp):
    ".decypher <pass> <string> -- Decyphers <string> with <password>."

    passwd = inp.split(" ")[0]
    len_passwd = len(passwd)
    inp = " ".join(inp.split(" ")[1:])

    passwd_index = 0
    for character in inp:
        try:
            chr_index = chars.index(character)
            passwd_index = (passwd_index + 1) % len_passwd
        except ValueError:
            continue

    passwd_index = passwd_index - 1
    reversed_message = inp[::-1]

    out = ""
    for character in reversed_message:
        try:
            chr_index = chars.index(character)
            passwd_chr_index = chars.index(passwd[passwd_index])

            out_chr_index = (chr_index - passwd_chr_index) % len_chars
            out_chr = chars[out_chr_index]

            out += out_chr

            passwd_index = (passwd_index - 1) % len_passwd
        except ValueError:
            out += character
            continue

    return out[::-1]