# coding: utf-8

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


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 stats(file=None):
    """
        This function get a stats of all letter occurrence in a text
    """
    if file is None:
        dataFile = loremtext()
    else:
        dataFile = file

    #dataFile = str()
    #for d in text:
    #    u = unidecode(d.lower(), 'utf-8')
    #    dataFile += sub(r'[^a-z]', '', u)

    lettersOccurence = []

    # Init our tab
    for i in range (0, 26):
        lettersOccurence.append(0)

    letterToAscii = ord('a') # Get the ASCII code
    for letter in dataFile:
        l = ord(letter) - letterToAscii
        if l >= 0 and l <= 26:
           lettersOccurence[l] += 1

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

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

def decryptCaesarText(cipherFile):
    """
        This function breach the caesar ciphertext with all key
    """
    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()
                letterAscii = ord(letter)
                if letterAscii >= letterAToAscii and letterAscii <= letterZToAscii:
                    newLetter = getNewLetter(letterAscii, letterAToAscii, key)
                elif letterAscii >= letteraToAscii and letterAscii <= letterzToAscii:
                    newLetter = getNewLetter(letteraToAscii, key)
                else:
                    newLetter = letter

                newLine = newLine + newLetter

            foo.append(newLine)

        print(f"key: {key}")
        print(foo)

def getNewLetter(letterAscii, letterToAscii, key):
    """
        This function return the new letter and we substract with the key.
        The function return the new letter into a char
    """
    letterAscii = letterAscii - letterToAscii
    res = ((letterAscii - key) % 26) + letterToAscii
    return chr(res)

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

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

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

if __name__ == "__main__":
    main()