passgen.py

#!/usr/bin/python3
from random import choice, shuffle, randint
from re import findall
from os.path import expanduser
from sys import argv

with open(expanduser("/usr/share/keepassxc/wordlists/eff_large.wordlist"), "r") as f:
    words = list(map(str.strip, f.readlines()))

password_mask = list(argv[1] if len(argv) > 1 else "WWWWWWWWWWWWWWWWDDDS")
#password_mask = list("WWWWWWWWDDS")

while True:
    shuffle(password_mask)
    password_mask_str = str.join("", password_mask)

    parts = findall(r"W+|D+|S+", password_mask_str)

    n_words = sum(1 if part[0] == "W" else 0 for part in parts)
    shortest_word = min(len(part) for part in parts if part[0] == "W")
    longest_number = max(len(part) for part in parts if part[0] == "D")
    if (n_words <= 3
            and shortest_word >= 6
            and longest_number <= 2
            and parts[0][0] not in ("SD")):
        break

password = []
for part in parts:
    if part[0] == "W":
        word = choice(list(filter(lambda w: len(w) == len(part), words)))
        if randint(0, 100) <= 30:
            word = word.upper()
        password.append(word)
    elif part[0] == "S":
        password.append(choice("!#%-._+="))
    elif part[0] == "D":
        password.append(("%%0%dd" % len(part)) % randint(0, 10 ** len(part[0])))

print(str.join("", password))