#!/usr/bin/env python
############################
# Author: Don C. Weber
# Date: 08242008
# File: otp2.py
# Description: One Time Pad Program
# Usage: opt.py: [-h] -e|-d <work file> <key file> <output file>
############################
import getopt, sys

# Set up
alpha = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']
work = ""
key = ""
encrypted = ""
plain2 = ""

# Check what needs to be done
if (len(sys.argv) > 1):
	if (sys.argv[1] == "-h"):
		print "opt.py: [-h] -e|-d <work file> <key file> <output file>"
		sys.exit()
	elif (len(sys.argv) != 5):
		print "opt.py: [-h] -e|-d <work file> <key file> <output file>"
		print "Num: " + str(sys.argv)
		sys.exit()
	else:
		workfile=open(sys.argv[2],'r')
		keyfile=open(sys.argv[3],'r')
		outfile=open(sys.argv[4],'w')
	for line in workfile.readlines():
		work = work + line
	for line in keyfile.readlines():
		key = key + line
	#print work
	#print key
		
else:
	print "opt.py: [-h] -e|-d <work file> <key file> <output file>"
	sys.exit()


# Clean input
	# Convert to upper case
work = work.upper()
key = key.upper()
	# Remove all except alpha characters
	# From In Text
txtlen = (len(work) - 1)
for i in range(0,txtlen):
	if work.isalpha():
		break
	if not work[(txtlen - i)].isalpha():
		work = work.replace(work[(txtlen - i)],'',1)
print "Input: " + work
	# From Key Text
txtlen = (len(key) - 1)
for i in range(0,txtlen):
	if key.isalpha():
		break
	if not key[(txtlen - i)].isalpha():
		key = key.replace(key[(txtlen - i)],'',1)
if (len(key) > len(work)):
	key =  key[0:len(work)]
elif (len(work) > len(key)):
	print "opt.py: Key must be longer or equal to that of the text to be worked."
	sys.exit()
print "Key:   " + key

# Encrypt
if (sys.argv[1] == "-e"):
	print "Encryting"
	for i in range(0,len(work)):
		encrypted = encrypted + alpha[(alpha.index(work[i]) + alpha.index(key[i]))% 26]
	print "Encrypted: " + encrypted
	if (len(sys.argv) > 1):
		outfile.write(encrypted)
		workfile.close
		keyfile.close
		outfile.close
# Decrypt
elif (sys.argv[1] == "-d"):
	print "Decrypting"
	for i in range(0,len(work)):
		#plain2 = plain2 + alpha[(alpha.index(work[i]) - alpha.index(key[i]))% 26]
		# Modified for LostboY's Logic
		plain2 = plain2 + alpha[((alpha.index(work[i]) - alpha.index(key[i]))% 26)-1]
	print "Decrypted: " + plain2
	if (len(sys.argv) > 1):
		outfile.write(plain2)
		workfile.close
		keyfile.close
		outfile.close
# Oh Hell
else:
	print "Oh Hell"
	workfile.close
	keyfile.close
	outfile.close
	print "opt.py: [-h] -e|-d <work file> <key file> <output file>"
	sys.exit()