import random
def gen_key():
    al = 'a ą b c ć d e ę f g h i j k l ł m n ń o ó p r s ś t u w y z ź ż'.split()
    alshuffled = al[:]
    random.shuffle(alshuffled)
    keymap = dict(zip(al, alshuffled))
    return keymap

def coded(char, key):
    upper = char.isupper()
    try:
        outchar=key[char.lower()]
    except KeyError:
        outchar = char
    if upper:
        outchar = outchar.upper()
    return outchar
if __name__ == '__main__':
    key = gen_key()
    with open('key.txt', 'w', encoding="utf-8") as keyf:
        keyf.write(str(key))
    with open('dokodowania.TXT', encoding="utf-8") as f:
        with open('coded.txt', 'w', encoding="utf-8") as fout:
            for line in f:
                newline = []
                for char in line:
                    newline.append(coded(char, key=key))
                fout.write(''.join(newline))