# SPDX-License-Identifier: GPL-3.0-only
"""Generate a passphrase from a list of predefined words."""
from __future__ import annotations

import logging
from secrets import randbelow

from gi.repository import Gio, GLib, GObject


class Passphrase(GObject.Object):
    """Generate a passphrase from a list of predefined words."""

    def generate(self, num_words: int, separator: str = "-") -> None:
        """Generate a passphrase.

        :param int num_words: number of words requested
        :param str separator: separator
        """
        word_file: Gio.File = Gio.File.new_for_uri(
            "resource:///org/gnome/World/Secrets/crypto/eff_large_wordlist.txt"
        )

        def callback(gfile, result):
            try:
                gbytes, _ = gfile.load_bytes_finish(result)
            except GLib.Error as err:
                logging.debug("Could not read word file: %s", err)
            else:
                word_str: str = gbytes.get_data().decode("utf-8")
                word_list: list[str] = word_str.split("\n")
                len_words: int = len(word_list)

                words = [word_list[randbelow(len_words)] for _ in range(0, num_words)]
                passphrase: str = separator.join(words) or ""
                self.emit("generated", passphrase)

        word_file.load_bytes_async(None, callback)

    @GObject.Signal(arg_types=(str,))
    def generated(self, _passphrase):
        return
