def _isfunc(x):
    if type(x) == type(_isfunc):
        return True
    return False

def _hook_add(func, add):
    if not hasattr(func, '_skybot_hook'):
        func._skybot_hook = []
    func._skybot_hook.append(add)

def _make_sig(f):
    return f.func_code.co_filename, f.func_name, f.func_code.co_firstlineno

def sieve(func):
    if func.func_code.co_argcount != 4:
        raise ValueError, \
                'sieves must take 4 arguments: (bot, input, func, args)'
    _hook_add(func, ['sieve', (_make_sig(func), func)])
    return func

def command(func, hook=None, **kwargs):
    args = {}
    def command_wrapper(func):
        if func.func_code.co_argcount not in (1, 2):
            raise ValueError, \
                'commands must take 1 or 2 arguments: (inp) or (bot, input)'
        args.setdefault('name', func.func_name)
        args.setdefault('hook', args['name'] + r'\s*(.*)')
        _hook_add(func, ['command', (_make_sig(func), func, args)])
        return func
    
    if hook is not None or kwargs or not _isfunc(func):
        if func is not None:
            args['name'] = func
        if hook is not None:
            args['hook'] = hook
        args.update(kwargs)
        return command_wrapper
    else:
        return command_wrapper(func)

def event(arg):
    args = {}
    def event_wrapper(func):
        if func.func_code.co_argcount != 2:
            raise ValueError, \
                'events must take 2 arguments: (bot, input)'
        args['name'] = func.func_name
        args['prefix'] = False
        args.setdefault('events', '*')
        _hook_add(func, ['event', (_make_sig(func), func, args)])
        return func
    
    if _isfunc(arg):
        return event_wrapper(arg)
    else:
        args['events'] = arg.split()
        return event_wrapper