from itertools import chain, tee

from bcrypter.lib.result import Result
from bcrypter.cli.opt import Overlap

class Command:
    NAME = '' # intentionally left empty (invalid name)
    ARGS = []
    FLAGS = []
    OPTIONS = []
    def __init__(self, args: list[string]) -> None:
        pass

    @classmethod
    def parse(cls: Command, cmd: list[str]) -> Result[Command]:
        for arg in cmd[1:]:
            # flag or option
            if arg.startswith('--'):
                match = cls._match_arg(arg[2:])
                if match

    '''
    Check whether FLAGS and OPTIONS are defined consistently
    (ie no duplicate names or parsing ambiguity)  
    '''
    @classmethod
    def _is_well_defined(cls: Command) -> Result[list[Overlap]]:
        overlaps: list[Overlap] = []
        opts = chain(cls.FLAGS, cls.OPTIONS)
        # Detect duplicate names and duplicate short/longforms
        for optX in opts:
            overlap = Overlap.empty(optX)
            other_opts = tee(opts) # duplicate the opts iterator
            for optY in other_opts:
                overlap += Overlap.of(optX, optY)
            # check if overlap occurred, add to list of all overlaps
            if not overlap.is_empty():
                overlaps.append(overlap)
        if overlaps:
            return Result.fail(overlaps)
        return Result.succeed([])
                
    '''
    Attempt to match an arg to its flag or option
    NOTE: _match_arg() assumes _is_well_defined() == True 
    '''
    @classmethod
    def _match_arg(cls: Command, arg: str) -> Result[None]:
        for opt in chain(cls.FLAGS, cls.OPTIONS):
            if opt.matches(arg):
                return Result.succeed(None)
        return Result.fail()


class Builtin(Command):
    NAME = '' # intentionally left empty (invalid name)
    ARGS = []
    FLAGS = []
    OPTIONS = []
    def __init__(self, 
                 repl_builtins: list[Builtin], 
                 repl_cmds: list[Command]) -> None:
        super().__init__()
        self._repl_builtins = repl_builtins
        self._repl_cmds = repl_cmds