#!/usr/bin/python

goodCharacters = [ chr(z) for (f,t) in [('a', 'z'), ('0', '9'), (' ', ' ')] for z in range(ord(f),ord(t)+1) ]
#goodCharacters = [ chr(z) for (f,t) in [('a', 'z')] for z in range(ord(f),ord(t)+1) ]

def encrypt(plaintext, key):
	ciphertext = ""
	last = 0
	for j in range(len(plaintext)):
		c = plaintext[j]
		i = goodCharacters.index(c)
		i = (i + key[j%len(key)] + j + last) % len(goodCharacters)
		#i = (i + key[j%len(key)]) % len(goodCharacters)
		cp = goodCharacters[i]
		ciphertext = ciphertext + cp
		last = i
	return ciphertext

def to_original(encrypted):
	ciphertext = ""
	last = 0
	aux_last = 0
	for j in range(len(encrypted)):
		c = encrypted[j]
		i = goodCharacters.index(c)
		aux_last = i
		i = (i - j - last) % len(goodCharacters)
		last = aux_last

		cp = goodCharacters[i]
		ciphertext = ciphertext + cp
	return ciphertext

def decrypt(plaintext, key):
	ciphertext = ""
	last = 0
	for j in range(len(plaintext)):
		c = plaintext[j]
		i = goodCharacters.index(c)
		i = (i - key[j%len(key)]) % len(goodCharacters)
		cp = goodCharacters[i]
		ciphertext = ciphertext + cp
		last = i
	return ciphertext


def get_max(dict):
	maximum = 0;
	key = 0;
	for k,v in dict.items():
		#print (k)
		if maximum < v:
			maximum = v
			key = k

	print(key)

def print_distances(encrypted):
	print("%20s%20s%20s%20s" % ("Repeated Bigram","Location","Distance","Factors") )

	values_list = dict()

	for i in range(1, len(plaintext)):
		pair = encrypted[i-1] + encrypted[i]
		for j in range(i, len(plaintext)-1):
			nextpair = encrypted[j] + encrypted[j+1]
			if pair == nextpair:
				dist = j-i+1
				#print("%20s%20d%20d" % (pair, j, j-i+1) )
				if dist in values_list:
					values_list[dist] = values_list[dist] + 1
					if dist == 3:
						print ("dist: " + str(dist) + " value: " + str(values_list[dist]))
				else:
					values_list[dist] = 1;

				break

	get_max(values_list)

def bruteforce(original):
	key = ""

	the_occurrences = 0
	count = 0

	for i in range(len(goodCharacters)):
		for j in range(len(goodCharacters)):
			for k in range(len(goodCharacters)):
				count = count + 1
				if count % 100 == 0:
					print(str(count) + " out of " + str(len(goodCharacters)**3))
				key = [i, j, k]
				plaintext = decrypt(original, key)
				the_occurrences = plaintext.count(" the ")
				if the_occurrences > 10:
					print ("FOR KEY: " + str(key))
					print (plaintext)

plaintext = ""
f = open("cipher.txt", "r")
for line in f:
	line = line.lower()
	line = line.strip()
	line = line + " "
	plaintext = plaintext + "".join([c for c in line if c in goodCharacters])

f.close()

# you need to figure out the real key
#print encrypt(plaintext, [1,2,3,4,5,6,7,8,9,10])
#key = [17,4,11,0,19,8,14,13,18] #RELATIONS
#encrypted = encrypt(plaintext, key)
# print (encrypted)

original = to_original(plaintext)
# print(original)

bruteforce(original)

#print_distances(original)

# decrypted = decrypt(original, key)
# print (decrypted)