import abc
import argparse

from jwutils import log

# compatible with Python 2 *and* 3
ABC = abc.ABCMeta('ABC', (object,), {'__slots__': ()})

# 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, help):
        self.name = name
        self.help = help
        self.parent = None
        self.children = []
        self.child_classes = []

    async def _run(self, args):
        pass

    def add_parser(self, parsers):
        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):
        if isinstance(cmd, list):
            for c in cmd:
                self.add_subcommands(c)
                return
        self.child_classes.append(cmd)

    def add_arguments(self, parser):
        pass