import numpy as np
from gym.spaces import Box

from metaworld.envs.asset_path_utils import full_v1_path_for
from metaworld.envs.mujoco.sawyer_xyz.sawyer_xyz_env import SawyerXYZEnv, _assert_task_is_set


class SawyerDoorEnv(SawyerXYZEnv):
    def __init__(self):

        hand_low = (-0.5, 0.40, 0.05)
        hand_high = (0.5, 1, 0.5)
        obj_low = (0., 0.85, 0.1)
        obj_high = (0.1, 0.95, 0.1)

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

        self.init_config = {
            'obj_init_angle': np.array([0.3, ]),
            'obj_init_pos': np.array([0.1, 0.95, 0.1]),
            'hand_init_pos': np.array([0, 0.6, 0.2]),
        }

        self.goal = np.array([-0.2, 0.7, 0.15])
        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.door_angle_idx = self.model.get_joint_qpos_addr('doorjoint')

    @property
    def model_name(self):
        return full_v1_path_for('sawyer_xyz/sawyer_door_pull.xml')

    @_assert_task_is_set
    def step(self, action):
        ob = super().step(action)
        reward, reachDist, pullDist = self.compute_reward(action, ob)
        info = {
            'reachDist': reachDist,
            'goalDist': pullDist,
            'epRew': reward,
            'pickRew': None,
            'success': float(pullDist <= 0.08)
        }

        return ob, reward, False, info

    def _get_pos_objects(self):
        return self.data.get_geom_xpos('handle').copy()

    def _set_obj_xyz(self, pos):
        qpos = self.data.qpos.copy()
        qvel = self.data.qvel.copy()
        qpos[self.door_angle_idx] = pos
        qvel[self.door_angle_idx] = 0
        self.set_state(qpos.flatten(), qvel.flatten())

    def reset_model(self):
        self._reset_hand()

        self.objHeight = self.data.get_geom_xpos('handle')[2]

        self.obj_init_pos = self._get_state_rand_vec() if self.random_init \
            else self.init_config['obj_init_pos']
        self._target_pos = self.obj_init_pos + np.array([-0.3, -0.25, 0.05])

        self.sim.model.body_pos[self.model.body_name2id('door')] = self.obj_init_pos
        self.sim.model.site_pos[self.model.site_name2id('goal')] = self._target_pos
        self._set_obj_xyz(0)
        self.maxPullDist = np.linalg.norm(self.data.get_geom_xpos('handle')[:-1] - self._target_pos[:-1])
        self.target_reward = 1000*self.maxPullDist + 1000*2

        return self._get_obs()

    def _reset_hand(self):
        super()._reset_hand(10)

        rightFinger, leftFinger = self._get_site_pos('rightEndEffector'), self._get_site_pos('leftEndEffector')
        self.init_fingerCOM  =  (rightFinger + leftFinger)/2
        self.reachCompleted = False

    def compute_reward(self, actions, obs):
        del actions
        objPos = obs[3:6]

        rightFinger, leftFinger = self._get_site_pos('rightEndEffector'), self._get_site_pos('leftEndEffector')
        fingerCOM  =  (rightFinger + leftFinger)/2

        pullGoal = self._target_pos

        pullDist = np.linalg.norm(objPos[:-1] - pullGoal[:-1])
        reachDist = np.linalg.norm(objPos - fingerCOM)
        reachRew = -reachDist

        self.reachCompleted = reachDist < 0.05

        def pullReward():
            c1 = 1000
            c2 = 0.01
            c3 = 0.001

            if self.reachCompleted:
                pullRew = 1000*(self.maxPullDist - pullDist) + c1*(np.exp(-(pullDist**2)/c2) + np.exp(-(pullDist**2)/c3))
                pullRew = max(pullRew,0)
                return pullRew
            else:
                return 0

        pullRew = pullReward()
        reward = reachRew + pullRew

        return [reward, reachDist, pullDist]
