jw-python/tools/python/jwutils/Cmd.py

from __future__ import annotations
from typing import List, Type, Union, TypeVar
import abc
import argparse
from abc import ABC
from argparse import ArgumentParser, _SubParsersAction
import inspect, sys, re

from jwutils import log

# full blown example of one level of nested subcommands
# git -C project remote -v show -n myremote

class Cmd(ABC): # export

    @abc.abstractmethod
    async def run(self, args):
        pass

    def __init__(self, name: str, help: str) -> None:
        self.name = name
        self.help = help
        self.parent = None
        self.children: List[Cmd] = []
        self.child_classes: List[Type[Cmd]] = []

    async def _run(self, args):
        pass

    def add_parser(self, parsers) -> ArgumentParser:
        r = parsers.add_parser(self.name, help=self.help,
            formatter_class=argparse.ArgumentDefaultsHelpFormatter)
        r.set_defaults(func=self.run)
        return r

    def add_subcommands(self, cmd: Union[str, Type[Cmd], List[Type[Cmd]]]) -> None:
        if isinstance(cmd, str):
            sc = []
            for name, obj in inspect.getmembers(sys.modules[self.__class__.__module__]):
                if inspect.isclass(obj):
                    if re.search(cmd, str(obj)):
                        sc.append(obj)
                        log.slog(log.DEBUG, f"Found subcommand {obj}")
            self.add_subcommands(sc)
            return
        if isinstance(cmd, list):
            for c in cmd:
                self.add_subcommands(c)
            return
        self.child_classes.append(cmd)

    # To be overriden by derived class in case the command does take arguments.
    # Will be called from App base class constructor and set up the parser hierarchy
    def add_arguments(self, parser: ArgumentParser) -> None:
        pass