password validation

password.py

import re

PASSWORD_MIN_LENGTH = 8
PASSWORD_MAX_LENGTH = 128
PASSWORD_MIN_UNIQUE_CHARS = 5
PASSWORD_MAX_REPEATED_CHARS = 3
MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES = 3


class PasswordValidationError(Exception):
    pass


def validate_password(raw_password: str) -> bool:
    # sourcery skip: low-code-quality
    if len(raw_password) < PASSWORD_MIN_LENGTH:
        raise PasswordValidationError(f'Password must be at least {PASSWORD_MIN_LENGTH} characters long.')

    if len(raw_password) > PASSWORD_MAX_LENGTH:
        raise PasswordValidationError(f'Password must be at most {PASSWORD_MAX_LENGTH} characters long.')

    uniq_chars = set(raw_password)

    if len(uniq_chars) < PASSWORD_MIN_UNIQUE_CHARS:
        raise PasswordValidationError(f'Password must contain at least {PASSWORD_MIN_UNIQUE_CHARS} different characters.')

    # If there are too many repeated chars
    for c in uniq_chars:
        repetition = c * PASSWORD_MAX_REPEATED_CHARS
        if repetition in raw_password:
            raise PasswordValidationError(
                f'Password cannot contain more than {PASSWORD_MAX_REPEATED_CHARS} consecutive repeated characters.'
                f' (notice [red]{repetition}[/red])'
            )

    # If there are continuous increasing or decreasing sequences
    incr_decr_seqs = set()
    for c in uniq_chars:
        n = ord(c)
        if (
            c.isdigit() and n + MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES - 1 <= ord('9')
            or c.isupper() and n + MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES - 1 <= ord('Z')
            or c.islower() and n + MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES - 1 <= ord('z')
        ):
            if (seq := ''.join(chr(n + i) for i in range(MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES))) in raw_password:
                incr_decr_seqs.add(seq)

        if (
            c.isdigit() and n - MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES + 1 >= ord('0')
            or c.isupper() and n - MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES + 1 >= ord('A')
            or c.islower() and n - MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES + 1 >= ord('a')
        ):
            if (seq := ''.join(chr(n - i) for i in range(MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES))) in raw_password:
                incr_decr_seqs.add(seq)

    if incr_decr_seqs:
        raise PasswordValidationError(
            f'Password cannot contain more than {MAX_CONTINUOUS_INCREASING_OR_DECREASING_SEQUENCES} '
            f'consecutive increasing or decreasing characters. (notice [red]{", ".join(incr_decr_seqs)}[/red])'
        )

    contains_lower_letters = re.search(r'[a-z]', raw_password)
    contains_upper_letters = re.search(r'[A-Z]', raw_password)
    contains_digits = re.search(r'[0-9]', raw_password)
    contains_special_chars = re.search(r'[^a-zA-Z0-9]', raw_password)

    if len([fct for fct in [
        contains_lower_letters,
        contains_upper_letters,
        contains_digits,
        contains_special_chars
    ] if fct]) < 3:
        raise PasswordValidationError(
            'Password must contain at least 3 of the following: '
            '1. lowercase letters, 2. uppercase letters, 3. digits, '
            '4. special characters.'
        )

    return True