pmbootstrap/pmb/helpers/cli.py

# Copyright 2023 Oliver Smith
# SPDX-License-Identifier: GPL-3.0-or-later
import datetime
from pmb.helpers import logging
import os
import re
import readline
import sys
from collections.abc import KeysView
from typing import Any

import pmb.config
from pmb.core.context import get_context


class ReadlineTabCompleter:
    """Store intermediate state for completer function."""

    def __init__(self, options: KeysView[str] | dict[str, Any] | list[str]) -> None:
        """:param options: list of possible completions."""
        self.options = sorted(options)
        self.matches: list[str] = []

    def completer_func(self, input_text: str, iteration: int) -> str | None:
        """
        :param input_text: text that shall be autocompleted
        :param iteration: how many times "tab" was hit
        """
        # First time: build match list
        if iteration == 0:
            if input_text:
                self.matches = [s for s in self.options if s and s.startswith(input_text)]
            else:
                self.matches = self.options[:]

        # Return the N'th item from the match list, if we have that many.
        if iteration < len(self.matches):
            return self.matches[iteration]
        return None


def ask(
    question: str = "Continue?",
    choices: list[str] | None = ["y", "n"],
    default: int | str | None = "n",
    lowercase_answer: bool | None = True,
    validation_regex: str | None = None,
    complete: KeysView[str] | dict[str, Any] | list[str] | None = None,
) -> str:
    """Ask a question on the terminal.

    :param question: display prompt
    :param choices: short list of possible answers, displayed after prompt if set
    :param default: default value to return if user doesn't input anything
    :param lowercase_answer: if True, convert return value to lower case
    :param validation_regex: if set, keep asking until regex matches
    :param complete: set to a list to enable tab completion
    """
    styles = pmb.config.styles

    while True:
        date = datetime.datetime.now().strftime("%H:%M:%S")
        line = question
        if choices:
            line += f" ({str.join('/', choices)})"
        if default:
            line += f" [{default}]"
        line_color = f"[{date}] {styles['BOLD']}{line}{styles['END']}"
        line = f"[{date}] {line}"

        if complete:
            readline.parse_and_bind("tab: complete")
            delims = readline.get_completer_delims()
            if "-" in delims:
                delims = delims.replace("-", "")
                readline.set_completer_delims(delims)
            readline.set_completer(ReadlineTabCompleter(complete).completer_func)

        ret = input(f"{line_color}: ")

        # Stop completing (question is answered)
        if complete:
            # set_completer(None) would use the default file system completer
            readline.set_completer(lambda text, state: None)

        if lowercase_answer:
            ret = ret.lower()
        if ret == "":
            ret = str(default)

        pmb.helpers.logging.logfd.write(f"{line}: {ret}\n")
        pmb.helpers.logging.logfd.flush()

        # Validate with regex
        if not validation_regex:
            return ret

        if re.fullmatch(validation_regex, ret):
            return ret

        logging.fatal(
            "ERROR: Input did not pass validation (regex: "
            + validation_regex
            + "). Please try again."
        )


def confirm(
    question: str = "Continue?", default: bool = False, no_assumptions: bool = False
) -> bool:
    """Convenience wrapper around ask for simple yes-no questions with validation.

    :param no_assumptions: ask for confirmation, even if "pmbootstrap -y' is set
    :returns: True for "y", False for "n"
    """
    default_str = "y" if default else "n"
    if get_context().assume_yes and not no_assumptions:
        logging.info(question + " (y/n) [" + default_str + "]: y")
        return True
    answer = ask(question, ["y", "n"], default_str, True, "(y|n)")
    return answer == "y"


def progress_print(progress: float) -> None:
    """Print a snapshot of a progress bar to STDOUT.

    Call progress_flush to end  printing progress and clear the line. No output is printed in
    non-interactive mode.

    :param progress: completion percentage as a number between 0 and 1
    """
    width = 79
    try:
        width = os.get_terminal_size().columns - 6
    except OSError:
        pass
    chars = int(width * progress)
    filled = "\u2588" * chars
    empty = " " * (width - chars)
    percent = int(progress * 100)
    if pmb.config.is_interactive and not get_context().details_to_stdout:
        sys.stdout.write(f"\u001b7{percent:>3}% {filled}{empty}")
        sys.stdout.flush()
        sys.stdout.write("\u001b8\u001b[0K")


def progress_flush() -> None:
    """Finish printing a progress bar.

    This will erase the line. Does nothing in non-interactive mode.
    """
    if pmb.config.is_interactive and not get_context().details_to_stdout:
        sys.stdout.flush()