import os,  inspect
currentdir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
parentdir = os.path.dirname(os.path.dirname(currentdir))
os.sys.path.insert(0,parentdir)

import math
import gym
from gym import spaces
from gym.utils import seeding
import numpy as np
import time
import pybullet
from . import bullet_client
from . import racecar
import random
import pybullet_data
from pkg_resources import parse_version

RENDER_HEIGHT = 720
RENDER_WIDTH = 960

class RacecarZEDGymEnv(gym.Env):
  metadata = {
      'render.modes': ['human', 'rgb_array'],
      'video.frames_per_second' : 50
  }

  def __init__(self,
               urdfRoot=pybullet_data.getDataPath(),
               actionRepeat=10,
               isEnableSelfCollision=True,
               isDiscrete=False,
               renders=True):
    print("init")
    self._timeStep = 0.01
    self._urdfRoot = urdfRoot
    self._actionRepeat = actionRepeat
    self._isEnableSelfCollision = isEnableSelfCollision
    self._ballUniqueId = -1
    self._envStepCounter = 0
    self._renders = renders
    self._width = 100
    self._height = 10

    self._isDiscrete = isDiscrete
    if self._renders:
      self._p = bullet_client.BulletClient(
          connection_mode=pybullet.GUI)
    else:
      self._p = bullet_client.BulletClient()

    self._seed()
    self.reset()
    observationDim = len(self.getExtendedObservation())
    #print("observationDim")
    #print(observationDim)

    observation_high = np.array([np.finfo(np.float32).max] * observationDim)
    if (isDiscrete):
      self.action_space = spaces.Discrete(9)
    else:
       action_dim = 2
       self._action_bound = 1
       action_high = np.array([self._action_bound] * action_dim)
       self.action_space = spaces.Box(-action_high, action_high)
    self.observation_space = spaces.Box(low=0, high=255, shape=(self._height, self._width, 4))

    self.viewer = None

  def _reset(self):
    self._p.resetSimulation()
    #p.setPhysicsEngineParameter(numSolverIterations=300)
    self._p.setTimeStep(self._timeStep)
    #self._p.loadURDF(os.path.join(os.path.dirname(__file__),"../data","plane.urdf"))
    stadiumobjects = self._p.loadSDF(os.path.join(self._urdfRoot,"stadium.sdf"))
    #move the stadium objects slightly above 0
    for i in stadiumobjects:
      pos,orn = self._p.getBasePositionAndOrientation(i)
      newpos = [pos[0],pos[1],pos[2]+0.1]
      self._p.resetBasePositionAndOrientation(i,newpos,orn)

    dist = 5 +2.*random.random()
    ang = 2.*3.1415925438*random.random()

    ballx = dist * math.sin(ang)
    bally = dist * math.cos(ang)
    ballz = 1

    self._ballUniqueId = self._p.loadURDF(os.path.join(self._urdfRoot,"sphere2red.urdf"),[ballx,bally,ballz])
    self._p.setGravity(0,0,-10)
    self._racecar = racecar.Racecar(self._p,urdfRootPath=self._urdfRoot, timeStep=self._timeStep)
    self._envStepCounter = 0
    for i in range(100):
      self._p.stepSimulation()
    self._observation = self.getExtendedObservation()
    return np.array(self._observation)

  def __del__(self):
    self._p = 0

  def _seed(self, seed=None):
    self.np_random, seed = seeding.np_random(seed)
    return [seed]

  def getExtendedObservation(self):
     carpos,carorn = self._p.getBasePositionAndOrientation(self._racecar.racecarUniqueId)
     carmat = self._p.getMatrixFromQuaternion(carorn)
     ballpos,ballorn = self._p.getBasePositionAndOrientation(self._ballUniqueId)
     invCarPos,invCarOrn = self._p.invertTransform(carpos,carorn)
     ballPosInCar,ballOrnInCar = self._p.multiplyTransforms(invCarPos,invCarOrn,ballpos,ballorn)
     dist0 = 0.3
     dist1 = 1.
     eyePos = [carpos[0]+dist0*carmat[0],carpos[1]+dist0*carmat[3],carpos[2]+dist0*carmat[6]+0.3]
     targetPos = [carpos[0]+dist1*carmat[0],carpos[1]+dist1*carmat[3],carpos[2]+dist1*carmat[6]+0.3]
     up = [carmat[2],carmat[5],carmat[8]]
     viewMat = self._p.computeViewMatrix(eyePos,targetPos,up)
     #viewMat = self._p.computeViewMatrixFromYawPitchRoll(carpos,1,0,0,0,2)
     #print("projectionMatrix:")
     #print(self._p.getDebugVisualizerCamera()[3])
     projMatrix = [0.7499999403953552, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, -1.0000200271606445, -1.0, 0.0, 0.0, -0.02000020071864128, 0.0]
     img_arr = self._p.getCameraImage(width=self._width,height=self._height,viewMatrix=viewMat,projectionMatrix=projMatrix)
     rgb=img_arr[2]
     np_img_arr = np.reshape(rgb, (self._height, self._width, 4))
     self._observation = np_img_arr
     return self._observation

  def _step(self, action):
    if (self._renders):
      basePos,orn = self._p.getBasePositionAndOrientation(self._racecar.racecarUniqueId)
      #self._p.resetDebugVisualizerCamera(1, 30, -40, basePos)

    if (self._isDiscrete):
            fwd = [-1,-1,-1,0,0,0,1,1,1]
            steerings = [-0.6,0,0.6,-0.6,0,0.6,-0.6,0,0.6]
            forward = fwd[action]
            steer = steerings[action]
            realaction = [forward,steer]
    else:
      realaction = action

    self._racecar.applyAction(realaction)
    for i in range(self._actionRepeat):
      self._p.stepSimulation()
      if self._renders:
        time.sleep(self._timeStep)
      self._observation = self.getExtendedObservation()

      if self._termination():
        break
      self._envStepCounter += 1
    reward = self._reward()
    done = self._termination()
    #print("len=%r" % len(self._observation))

    return np.array(self._observation), reward, done, {}

  def _render(self, mode='human', close=False):
    if mode != "rgb_array":
      return np.array([])
    base_pos,orn = self._p.getBasePositionAndOrientation(self._racecar.racecarUniqueId)
    view_matrix = self._p.computeViewMatrixFromYawPitchRoll(
        cameraTargetPosition=base_pos,
        distance=self._cam_dist,
        yaw=self._cam_yaw,
        pitch=self._cam_pitch,
        roll=0,
        upAxisIndex=2)
    proj_matrix = self._p.computeProjectionMatrixFOV(
        fov=60, aspect=float(RENDER_WIDTH)/RENDER_HEIGHT,
        nearVal=0.1, farVal=100.0)
    (_, _, px, _, _) = self._p.getCameraImage(
        width=RENDER_WIDTH, height=RENDER_HEIGHT, viewMatrix=view_matrix,
        projectionMatrix=proj_matrix, renderer=pybullet.ER_BULLET_HARDWARE_OPENGL)
    rgb_array = np.array(px)
    rgb_array = rgb_array[:, :, :3]
    return rgb_array


  def _termination(self):
    return self._envStepCounter>1000

  def _reward(self):
    closestPoints = self._p.getClosestPoints(self._racecar.racecarUniqueId,self._ballUniqueId,10000)

    numPt = len(closestPoints)
    reward=-1000
    #print(numPt)
    if (numPt>0):
      #print("reward:")
      reward = -closestPoints[0][8]
      #print(reward)
    return reward

  if parse_version(gym.__version__)>=parse_version('0.9.6'):
    render = _render
    reset = _reset
    seed = _seed
    step = _step
