import inspect
import numpy as np

from manimlib.constants import DEGREES
from manimlib.constants import RIGHT
from manimlib.mobject.mobject import Mobject


def always(method, *args, **kwargs):
    assert(inspect.ismethod(method))
    mobject = method.__self__
    assert(isinstance(mobject, Mobject))
    func = method.__func__
    mobject.add_updater(lambda m: func(m, *args, **kwargs))


def always_redraw(func):
    mob = func()
    mob.add_updater(lambda m: mob.become(func()))
    return mob


def always_shift(mobject, direction=RIGHT, rate=0.1):
    mobject.add_updater(
        lambda m, dt: m.shift(dt * rate * direction)
    )
    return mobject


def always_rotate(mobject, rate=20 * DEGREES, **kwargs):
    mobject.add_updater(
        lambda m, dt: m.rotate(dt * rate, **kwargs)
    )
    return mobject


def turn_animation_into_updater(animation):
    """
    Note sure if this is actually useful.  This is really
    here just to replace past usage of
    turn_animation_into_updater
    """
    mobject = animation.mobject
    animation.suspend_mobject_updating = False
    animation.begin()
    animation.total_time = 0

    def update(m, dt):
        alpha = np.clip(
            animation.total_time / animation.get_run_time(),
            0, 1,
        )
        if alpha >= 1:
            animation.finish()
            m.remove_updater(update)
        else:
            animation.interpolate(alpha)
            animation.total_time += dt
            animation.update_mobjects(dt)

    mobject.add_updater(update)
    return mobject