'''
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 a string with the 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 a string with the password"

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


	passwd_index=0
	#I am lazy and I could do the math to get the passwd_index
	#for this inp, but meh thats for a later day so lets loop.
	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]