randgen-catchy

#!/usr/bin/env python3

# many thanks to vain for this awesome work
# https://github.com/vain/bin-pub/blob/master/randgen-catchy


from argparse import ArgumentParser
from random import choice, randint


chars_start = list('bcdfghjklmnprstvwxz')
chars_vowels = list('aeiou') + ['ai', 'ao', 'au', 'ea', 'ee', 'ei',
                                'eu', 'ia', 'ie', 'oo', 'ou']
chars_cons = chars_start + ['bb', 'bl', 'cc', 'ch', 'ck', 'dd', 'dr',
                            'ds', 'dt', 'ff', 'gg', 'gn', 'kl', 'll',
                            'mb', 'md', 'mm', 'mp', 'mt', 'nc', 'nd',
                            'nn', 'np', 'nt', 'pp', 'rr', 'rt', 'sh',
                            'ss', 'st', 'tl', 'ts', 'tt']


def generate(words, per_word, digits):
    pwd = ''
    is_start = True
    word_length = 0
    words_done = 0
    while words_done < words:
        if is_start:
            add = choice(chars_start).upper()
            is_start = False
            is_vowel = True
        else:
            if is_vowel:
                add = choice(chars_vowels)
            else:
                add = choice(chars_cons)
            is_vowel = not is_vowel
        pwd += add

        word_length += 1
        if word_length == per_word:
            pwd += '-'
            word_length = 0
            words_done += 1
            is_start = True

    pwd += str(randint(10**(digits - 1), 10**digits - 1))

    return pwd

def complexity(words, per_word, digits):
    if per_word % 2 == 1:
        combis = ((len(chars_start) *
                   len(chars_vowels)**(per_word // 2) *
                   len(chars_cons)**(per_word // 2)
                  )**words
                 ) * 10**digits
    else:
        combis = ((len(chars_start) *
                   len(chars_vowels)**(per_word // 2) *
                   len(chars_cons)**(per_word // 2 - 1)
                  )**words
                 ) * 10**digits

    ex = 1
    while (26 + 26 + 10)**ex < combis:
        ex += 1
    ex -= 1

    print('Words: {}, per word: {}, digits: {}'.format(words, per_word, digits))
    print('Lengths of character classes: {}, {}, {}'.format(len(chars_start),
                                                            len(chars_vowels),
                                                            len(chars_cons)))
    print()
    print('Combinations: {}'.format(combis))
    print()
    print('This is better than a random alphanumeric string of {} characters,'.format(ex))
    print('which would yield {} combinations.'.format((26 + 26 + 10)**ex))


if __name__ == '__main__':
    parser = ArgumentParser()
    parser.add_argument('-w', '--words', type=int, default=4)
    parser.add_argument('-p', '--per-word', type=int, default=3)
    parser.add_argument('-d', '--digits', type=int, default=2)
    parser.add_argument('-c', '--complexity', action='store_true')
    args = parser.parse_args()

    if args.complexity:
        complexity(args.words, args.per_word, args.digits)
    else:
        print(generate(args.words, args.per_word, args.digits))