import numpy as np

from metaworld.policies.action import Action
from metaworld.policies.policy import Policy, assert_fully_parsed, move


class SawyerSoccerV2Policy(Policy):

    @staticmethod
    @assert_fully_parsed
    def _parse_obs(obs):
        return {
            'hand_pos': obs[:3],
            'ball_pos': obs[3:6],
            'goal_pos': obs[9:],
            'unused_info': obs[6:9],
        }

    def get_action(self, obs):
        o_d = self._parse_obs(obs)

        action = Action({
            'delta_pos': np.arange(3),
            'grab_effort': 3
        })

        action['delta_pos'] = move(o_d['hand_pos'], to_xyz=self._desired_pos(o_d), p=25.)
        action['grab_effort'] = 1.

        return action.array

    @staticmethod
    def _desired_pos(o_d):
        pos_curr = o_d['hand_pos']
        pos_ball = o_d['ball_pos'] + np.array([.0, .0, .03])
        pos_goal = o_d['goal_pos']

        desired_z = 0.1 if np.linalg.norm(pos_curr[:2] - pos_ball[:2]) < 0.02 \
            else 0.03

        to_left_of_goal = pos_ball[0] - pos_goal[0] < -0.05
        to_right_of_goal = pos_ball[0] - pos_goal[0] > 0.05

        offset = 0.03
        push_location = pos_ball + np.array([.0, -offset, .0])
        if to_left_of_goal:
            push_location = pos_ball + np.array([-offset, .0, .0])
        elif to_right_of_goal:
            push_location = pos_ball + np.array([+offset, .0, .0])

        push_location[2] = desired_z

        if np.linalg.norm(pos_curr - push_location) > 0.01:
            return push_location
        return pos_ball
