Python: Password Generator

#!/usr/bin/env python3

# Version 10

# POSTED ONLINE: https://pastebin.com/g10jVftx

# Windows: $ pip install pyperclip asciimatics
#
# Linux:   $ sudo pacman -S python-pyperclip
#          $ sudo pacman -S wl-clipboard    <-- Pyperclip has issues with KDE + Wayland. Installing this seems to get it to work.
#          $ yay -S python-asciimatics
#
#          NOTE: For Linux you also need to install a copy/paste mechanism if you don't have one.
#                KDE has /bin/klipper installed by default. For other window managers try [$ sudo pacman -S xclip] or [$ sudo pacman -S xsel].
#
#          NOTE: If you get error "Cannot find '.setClipboardContents' in object /klipper at org.kde.klipper",
#                its because klipper isn't running on startup. Try Start > klipper to see if the problem goes away.
#
#          NOTE: To display klipper in the taskbar, right click the ^ > Configure System Tray... > Entries > Clipboard: [Show when relevant].

import pyperclip
from asciimatics.screen import Screen
from asciimatics.event import KeyboardEvent

# -----

def draw_menu(screen, menuItems, selectedIndex, title, highlight):
    # Clear screen.
    clear(screen)

    # Draw title.
    if title:
        writeline(screen, title)

    # Draw menu items.
    for i in range(len(menuItems)):
        menuItem = menuItems[i]
        if highlight in menuItem:
            left,right = menuItem.split(highlight)
            write(screen, f' {"●" if i == selectedIndex else "○"} {left}', Screen.COLOUR_GREEN if i == selectedIndex else Screen.COLOUR_CYAN)
            write(screen, f'{highlight}', Screen.COLOUR_RED)
            writeline(screen, f'{right}', Screen.COLOUR_GREEN if i == selectedIndex else Screen.COLOUR_CYAN)
        else:
            writeline(screen, f' {"●" if i == selectedIndex else "○"} {menuItem}', Screen.COLOUR_RED)

    # Draw usage information.
    writeline(screen)
    writeline(screen, ' Make → Space', Screen.COLOUR_YELLOW)
    writeline(screen, ' Copy → Enter', Screen.COLOUR_YELLOW)
    writeline(screen, ' Rise → Up', Screen.COLOUR_YELLOW)
    writeline(screen, ' Fall → Down', Screen.COLOUR_YELLOW)
    writeline(screen, ' Smol → Left', Screen.COLOUR_YELLOW)
    writeline(screen, ' Swol → Right', Screen.COLOUR_YELLOW)
    writeline(screen, ' Quit → Escape', Screen.COLOUR_YELLOW)

    # Draw screen.
    screen.refresh()

# -----

row = 0
col = 0
def writeline(screen, text='', color=Screen.COLOUR_WHITE):
    global row
    global col
    lines = text.split('\n')
    for i, line in enumerate(lines):
        screen.print_at(line, col, row, color)
        row += 1
        col = 0

def write(screen, text='', color=Screen.COLOUR_WHITE):
    global row
    global col
    lines = text.split('\n')
    for i, line in enumerate(lines):
        screen.print_at(line, col, row, color)
        if i < len(lines) - 1:
            row += 1
            col = 0
        else:
            col += len(line)

def clear(screen):
    global row
    global col
    row = 0
    col = 0
    screen.clear()

# -----

import string

# Character groups to be used in the password.
CHARACTER_GROUPS = [
    string.ascii_lowercase,
    string.ascii_uppercase,
    string.digits,
    string.punctuation,
]

TIMESTAMP_DIVIDER = '_'

from datetime import datetime
import secrets
def generate_timestamped_passwords(password_length, count=5):
    dt = datetime.now()
    short_time_stamp = dt.strftime('%y%m%d')
    password_characters = ''.join(CHARACTER_GROUPS)
    password_characters = password_characters.replace(TIMESTAMP_DIVIDER, '')

    passwords = []
    retries = 100
    for _ in range(count):
        for attempt in range(retries):
            # SOURCE: https://docs.python.org/3/library/secrets.html
            password = ''.join(secrets.choice(password_characters) for _ in range(password_length))
            password = shuffle(short_time_stamp, password, TIMESTAMP_DIVIDER)
            if validate_password(password):
                passwords.append(password)
                break
        else:
            passwords.append(f'ERROR: Failed to generate a valid password after {retries} attempts.')

    large_time_stamp = f' Created: {dt.strftime("%Y-%m-%d %H:%M:%S")}\n'
    large_time_stamp += f' Length: {password_length}\n'
    return passwords, large_time_stamp, short_time_stamp

# -----

MIN_CHARACTERS_PER_GROUP = 2
def validate_password(password):
    for group in CHARACTER_GROUPS:
        if sum(char in group for char in password) < MIN_CHARACTERS_PER_GROUP:
            return False
    return True

# -----

# Insert a word into a sentence randomly.
def shuffle(word, sentence, divider = ' '):
    max_word_index = len(sentence) - len(word)

    # Generate a random integer in the range [0, n).
    random_index = secrets.randbelow(max_word_index + 1)

    # Prevent sentences from starting/ending with a word divider.
    if random_index == 1:
        random_index = 0 # Push word left one position.
    elif random_index == max_word_index - 1:
        random_index = max_word_index # Push word right one position.

    # Insert the word into the sentence.
    sentence = sentence[:random_index] + word + sentence[random_index + len(word):]

    # Insert word dividers.
    sentence = list(sentence)
    left_index = random_index - 1
    right_index = random_index + len(word)
    if left_index >= 0:
        sentence[left_index] = divider
    if right_index < len(sentence):
        sentence[right_index] = divider
    return ''.join(sentence)

# -----

def wait_for_any_keypress(screen):
    writeline(screen, ' Press any key to continue . . . ')
    screen.refresh()

    # Wait for user keyboard input indefinitely.
    while True:
        screen.wait_for_input(5) # Sleep for this many seconds while waiting for input. This prevents 100% CPU usage from the loop.
        ev = screen.get_event()
        if isinstance(ev, KeyboardEvent):
            break

# -----

MIN_PASSWORD_LENGTH = 13

def main(screen):
    password_length = 32
    menuItems, large_time_stamp, short_time_stamp = generate_timestamped_passwords(password_length)
    selectedIndex = 0

    draw_menu(screen, menuItems, selectedIndex, large_time_stamp, short_time_stamp) # Initial drawing.

    while True:
        # Get keyboard input.
        screen.wait_for_input(5) # Sleep for this many seconds while waiting for input. This prevents 100% CPU usage from the loop.
        ev = screen.get_event()
        if not isinstance(ev, KeyboardEvent):
            continue

        # If Escape key is pressed.
        elif ev.key_code == -1:
            break

        # If Space key is pressed.
        elif ev.key_code == ord(' '):
            menuItems, large_time_stamp, short_time_stamp = generate_timestamped_passwords(password_length)

        # If Up key is pressed.
        elif ev.key_code == Screen.KEY_UP:
            # Loop around backwards.
            selectedIndex = (selectedIndex - 1 + len(menuItems)) % len(menuItems)

        # If Down key is pressed.
        elif ev.key_code == Screen.KEY_DOWN:
            # Loop around forwards.
            selectedIndex = (selectedIndex + 1) % len(menuItems)

        # If Left key is pressed.
        elif ev.key_code == Screen.KEY_LEFT:
            # Reduce length of passwords.
            password_length = max(MIN_PASSWORD_LENGTH, password_length - 1)
            menuItems, large_time_stamp, short_time_stamp = generate_timestamped_passwords(password_length)

        # If Right key is pressed.
        elif ev.key_code == Screen.KEY_RIGHT:
            # Increase length of passwords.
            password_length = password_length + 1
            menuItems, large_time_stamp, short_time_stamp = generate_timestamped_passwords(password_length)

        # If Enter key is pressed.
        # NOTE: On Windows the enter key appears to be \r, and on Linux its \n.
        elif ev.key_code == ord('\r') or ev.key_code == ord('\n'):
            pyperclip.copy(menuItems[selectedIndex])
            writeline(screen, f"\n Copied {menuItems[selectedIndex]} to clipboard.\n")
            wait_for_any_keypress(screen)

        # Else an unexpected key is pressed.
        #  else:
        #      try:
        #          writeline(screen, "\n The pressed key '{}' {} is not associated with a menu function.\n".format(chr(ev.key_code), ev.key_code))
        #      except ValueError:
        #          writeline(screen, "\n The pressed key {} is not associated with a menu function.\n".format(ev.key_code))
        #      wait_for_any_keypress(screen)

        draw_menu(screen, menuItems, selectedIndex, large_time_stamp, short_time_stamp)

if __name__ == '__main__':
    Screen.wrapper(main)