class CmdNotFound(Exception):
  pass

class NoApiKey(Exception):
  pass

class FeatureMissing(Exception):
  pass

class Command:
  FTR_PRFX = "vultron_"

  def __init__(self, cmd, api_key):
    self.cmd = cmd
    self.uses_api = True
    self.default = "help"

    self.init()

    if self.uses_api and api_key is None:
      raise NoApiKey()

  def init(self):
    pass

  def find(self, name):
    needle = "{prfx}{name}".format(prfx=self.FTR_PRFX, name=name.lower())
    haystack = dir(self)

    for legume in haystack:
      if legume.lower().startswith(needle):
        fn = getattr(self, legume)

        if callable(fn):
          return fn
        else:
          raise FeatureMissing(legume)

    raise CmdNotFound(name)

  def vultron_help(self, *args):
    pass

def find_cmd(needle):
  needle = needle.lower()
  haystack = Command.__subclasses__()

  for legume in haystack:
    if legume.__name__.lower().startswith(needle):
      return legume

  raise CmdNotFound(needle)