import numpy as np
from gym.spaces import  Box

from metaworld.envs import reward_utils
from metaworld.envs.asset_path_utils import full_v2_path_for
from metaworld.envs.mujoco.sawyer_xyz.sawyer_xyz_env import SawyerXYZEnv, _assert_task_is_set


class SawyerWindowOpenEnvV2(SawyerXYZEnv):
    """
    Motivation for V2:
        When V1 scripted policy failed, it was often due to limited path length.
    Changelog from V1 to V2:
        - (8/11/20) Updated to Byron's XML
        - (7/7/20) Added 3 element handle position to the observation
            (for consistency with other environments)
        - (6/15/20) Increased max_path_length from 150 to 200
    """
    TARGET_RADIUS = 0.05

    def __init__(self):

        hand_low = (-0.5, 0.40, 0.05)
        hand_high = (0.5, 1, 0.5)
        obj_low = (-0.1, 0.7, 0.16)
        obj_high = (0.1, 0.9, 0.16)

        super().__init__(
            self.model_name,
            hand_low=hand_low,
            hand_high=hand_high,
        )

        self.init_config = {
            'obj_init_angle': np.array([0.3, ], dtype=np.float32),
            'obj_init_pos': np.array([-0.1, 0.785, 0.16], dtype=np.float32),
            'hand_init_pos': np.array([0, 0.4, 0.2], dtype=np.float32),
        }
        self.obj_init_pos = self.init_config['obj_init_pos']
        self.obj_init_angle = self.init_config['obj_init_angle']
        self.hand_init_pos = self.init_config['hand_init_pos']

        goal_low = self.hand_low
        goal_high = self.hand_high

        self._random_reset_space = Box(
            np.array(obj_low),
            np.array(obj_high),
        )
        self.goal_space = Box(np.array(goal_low), np.array(goal_high))

        self.maxPullDist = 0.2
        self.target_reward = 1000 * self.maxPullDist + 1000 * 2

    @property
    def model_name(self):
        return full_v2_path_for('sawyer_xyz/sawyer_window_horizontal.xml')

    @_assert_task_is_set
    def evaluate_state(self, obs, action):
        (reward,
        tcp_to_obj,
        _,
        target_to_obj,
        object_grasped,
        in_place) = self.compute_reward(action, obs)

        info = {
            'success': float(target_to_obj <= self.TARGET_RADIUS),
            'near_object': float(tcp_to_obj <= 0.05),
            'grasp_success': 1.,
            'grasp_reward': object_grasped,
            'in_place_reward': in_place,
            'obj_to_target': target_to_obj,
            'unscaled_reward': reward,
        }

        return reward, info

    def _get_pos_objects(self):
        return self._get_site_pos('handleOpenStart')

    def _get_quat_objects(self):
        return np.zeros(4)

    def reset_model(self):
        self._reset_hand()
        self.prev_obs = self._get_curr_obs_combined_no_goal()

        if self.random_init:
            self.obj_init_pos = self._get_state_rand_vec()

        self._target_pos = self.obj_init_pos + np.array([.2, .0, .0])

        self.sim.model.body_pos[self.model.body_name2id(
            'window'
        )] = self.obj_init_pos
        self.window_handle_pos_init = self._get_pos_objects()
        self.data.set_joint_qpos('window_slide', 0.0)

        return self._get_obs()

    def compute_reward(self, actions, obs):
        del actions
        obj = self._get_pos_objects()
        tcp = self.tcp_center
        target = self._target_pos.copy()
        
        target_to_obj = (obj[0] - target[0])
        target_to_obj = np.linalg.norm(target_to_obj)
        target_to_obj_init = (self.obj_init_pos[0] - target[0])
        target_to_obj_init = np.linalg.norm(target_to_obj_init)

        in_place = reward_utils.tolerance(
            target_to_obj,
            bounds=(0, self.TARGET_RADIUS),
            margin=abs(target_to_obj_init - self.TARGET_RADIUS),
            sigmoid='long_tail',
        )

        handle_radius = 0.02
        tcp_to_obj = np.linalg.norm(obj - tcp)
        tcp_to_obj_init = np.linalg.norm(self.window_handle_pos_init - self.init_tcp)
        reach = reward_utils.tolerance(
            tcp_to_obj,
            bounds=(0, handle_radius),
            margin=abs(tcp_to_obj_init - handle_radius),
            sigmoid='long_tail',
        )
        tcp_opened = 0
        object_grasped = reach

        reward = 10 * reward_utils.hamacher_product(reach, in_place)
        return (reward,
               tcp_to_obj,
               tcp_opened,
               target_to_obj,
               object_grasped,
               in_place)
