_cli_parsing.py

"""Argument parser initialization logic.

This defines helpers for setting up both the root parser and the parsers
of all the sub-commands.
"""

from argparse import ArgumentParser

from ._cli_subcommands import SUBCOMMAND_MODULES


def attach_subcommand_parsers_to(root_cli_parser: ArgumentParser, /) -> None:
    """Connect all sub-command parsers to the given one.

    This functions iterates over a mapping of subcommands to their
    respective population functions, executing them to augment the
    main parser.
    """
    subcommand_parsers = root_cli_parser.add_subparsers(
        dest='check_name',
        help='A check to be performed.',
        required=True,
    )
    for subcommand_module in SUBCOMMAND_MODULES:
        subcommand_parser = subcommand_parsers.add_parser(
            subcommand_module.CLI_SUBCOMMAND_NAME,
        )
        subcommand_parser.set_defaults(
            invoke_cli_app=subcommand_module.invoke_cli_app,
        )
        subcommand_module.populate_argument_parser(subcommand_parser)


def initialize_argument_parser() -> ArgumentParser:
    """Return the root argument parser with sub-commands.

    Returns:
        ArgumentParser: The root parser with sub-commands attached.

    """
    root_cli_parser = ArgumentParser(prog=f'python -m {__package__ !s}')
    attach_subcommand_parsers_to(root_cli_parser)
    return root_cli_parser


__all__ = ('initialize_argument_parser',)