tools/sp-rand/src/sp_rand/init.py

"""Set up the random volume name prefix."""

from __future__ import annotations

import argparse
import datetime
import pathlib
import random

from typing import NamedTuple, Tuple  # noqa: H301

from . import defs

DEFAULT_TAG = "osci-1-date"


class Config(NamedTuple):
    """Runtime configuration for the sp_rand_init tool."""

    confdir: pathlib.Path
    noop: bool
    prefix_var: str
    tag: str

    @staticmethod
    def default() -> Config:
        """Build a configuration object with the default values."""
        return Config(
            confdir=defs.DEFAULT_CONFDIR,
            noop=False,
            prefix_var=defs.PREFIX_VAR,
            tag=DEFAULT_TAG,
        )


def generate_prefix(cfg: Config) -> str:
    """Generate a random name prefix."""
    now = datetime.datetime.now()
    rval = random.randint(1000, 9999)
    tdate = f"{now.year:04}{now.month:02}{now.day:02}"
    ttime = f"{now.hour:02}{now.minute:02}"
    return f"{cfg.tag}-{tdate}-{ttime}-{rval}-"


def store_prefix(cfg: Config) -> Tuple[pathlib.Path, str]:
    """Generate and store the random name prefix into a file."""
    prefix = generate_prefix(cfg)
    conffile = cfg.confdir / defs.FILENAME
    if not cfg.noop:
        conffile.write_text(f"{cfg.prefix_var}={prefix}\n", encoding="UTF-8")
    return conffile, prefix


def parse_args() -> Config:
    """Parse the command-line arguments."""
    parser = argparse.ArgumentParser(prog="sp_rand_init")
    parser.add_argument(
        "-d",
        "--confdir",
        type=pathlib.Path,
        default=defs.DEFAULT_CONFDIR,
        help="The directory to create the configuration file in",
    )
    parser.add_argument(
        "-N",
        "--noop",
        action="store_true",
        help="No-operation mode; display what would have been done",
    )
    parser.add_argument(
        "-p",
        "--prefix-var",
        type=str,
        default=defs.PREFIX_VAR,
        help="The name of the variable to store into the configuration file",
    )
    parser.add_argument(
        "-t",
        "--tag",
        type=str,
        default=DEFAULT_TAG,
        help="The tag that the prefix should start with",
    )

    args = parser.parse_args()

    return Config(
        confdir=args.confdir, noop=args.noop, prefix_var=args.prefix_var, tag=args.tag
    )


def main() -> None:
    """Main program: parse options, generate a prefix, store it."""
    cfg = parse_args()
    conffile, prefix = store_prefix(cfg)
    print(f"{prefix}\n{conffile}")


if __name__ == "__main__":
    main()