# coding: utf-8

from argparse import ArgumentParser
import matplotlib.pyplot as plt
from lorem import text as loremtext


def checkArguments():
	args = ArgumentParser(description='Cryptanalyst')
	args.add_argument('-f', '--filename', help='Text to analyze')
	args.add_argument('-s', '--stats', help='Statistics', action='store_true')
	args.add_argument('-d', '--decrypt', help='Decrypt Caesar text', action='store_true')
	return args.parse_args()

def readCipherText(filename):
	file = []
	with open(filename, 'r') as f:
		data = f.readlines()

		for entry in data:
			file.append(entry.strip())

	return file

def main():
	args = checkArguments()
	cipherFile = None

	if args.filename:
		cipherFile = readCipherText(args.filename)

	if args.stats:
		stats(cipherFile)
	if args.decrypt:
		decryptCaesarText(cipherFile)	
	

def stats(file=None):
	if file is None:
		text = loremtext()
	else:
		text = file

	lettersOccurence = {}
	letterUpperToAscii = ord('A') # Get the ASCII code
	for i in range (0, 26):
		lettersOccurence[chr(i + letterUpperToAscii)] = 0

	for line in text:
		for letter in line:
			letter = letter.upper()
			if letter in lettersOccurence:
				lettersOccurence[letter] = lettersOccurence[letter] + 1

	x = [chr(letter + 65) for letter in range(0, 26)]
	y = [lettersOccurence[tmp] for tmp in lettersOccurence]

	largeur = 0.5
	plt.bar(x, y, largeur)
	plt.show()

def decryptCaesarText(cipherFile):
	if cipherFile is None:
		return

	letterAToAscii = ord('A') # Get the ASCII code
	letterZToAscii = ord('Z') # Get the ASCII code
	letteraToAscii = ord('a') # Get the ASCII code
	letterzToAscii = ord('z') # Get the ASCII code
	for key in range (0, 26):
		foo = []
		for line in cipherFile:
			newLine = str()
			for letter in line:
				letter = letter.upper()
				l = ord(letter)
				if l >= letterAToAscii and l <= letterZToAscii:
					l = l - letterAToAscii
					res = ((l - key) % 26) + letterAToAscii
					newLine = newLine + chr(res)
				elif l >= letteraToAscii and l <= letterzToAscii:
					l = l - letteraToAscii
					res = ((l - key) % 26) + letteraToAscii
					newLine = newLine + chr(res)
				else:
					newLine = newLine + letter
			foo.append(newLine)
		print(f"key: {key}")
		print(foo)

if __name__ == "__main__":
	main()