"""!
@file main.py
@brief Command-line entry point for the PyPassword Generator.
"""

import os
import sys

from password_generator.constants import (
    ANSI_BOLD,
    ANSI_CYAN,
    ANSI_GREEN,
    ANSI_MAGENTA,
    ANSI_RESET,
    ANSI_YELLOW,
    TITLE_ART,
)
from password_generator.generator import generate_easy_password, generate_hard_password


def _colorize(text: str, *codes: str) -> str:
    """!
    @brief Wrap text in ANSI color codes when the output supports colors.
    @details Colors are skipped when stdout is not a terminal or NO_COLOR is set.
    @param text Text to colorize.
    @param codes ANSI escape codes to apply.
    @return The (possibly) colorized text.
    """
    if not sys.stdout.isatty() or "NO_COLOR" in os.environ:
        return text
    return "".join(codes) + text + ANSI_RESET


def print_title() -> None:
    """!
    @brief Print the colored ASCII-art title.
    """
    if sys.stdout.isatty():
        os.system("")  # Enables ANSI escape sequences in Windows terminals.
    print(_colorize(TITLE_ART, ANSI_BOLD, ANSI_CYAN))


def _ask_int(prompt: str) -> int:
    """!
    @brief Ask the user for a non-negative whole number until a valid one is given.
    @param prompt Text shown to the user.
    @return The number entered by the user (0 or more).
    """
    while True:
        try:
            value = int(input(prompt))
        except ValueError:
            print("Please enter a whole number.")
            continue
        if value < 0:
            print("Please enter a number of 0 or more.")
            continue
        return value


def main() -> None:
    """!
    @brief Run the interactive program.
    @details Asks for the number of letters, symbols and numbers, then prints
             one easy-level and one hard-level password.
    """
    print_title()
    print(_colorize("Welcome to the PyPassword Generator!", ANSI_BOLD, ANSI_MAGENTA))
    nr_letters = _ask_int("How many letters would you like in your password?\n")
    nr_symbols = _ask_int("How many symbols would you like?\n")
    nr_numbers = _ask_int("How many numbers would you like?\n")

    easy = generate_easy_password(nr_letters, nr_symbols, nr_numbers)
    hard = generate_hard_password(nr_letters, nr_symbols, nr_numbers)
    print(f"Easy level:  {_colorize(easy, ANSI_GREEN)}")
    print(f"Hard level:  {_colorize(hard, ANSI_YELLOW)}")


if __name__ == "__main__":
    main()