import pybullet
import gym, gym.spaces, gym.utils
import numpy as np
import os, inspect
currentdir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
parentdir = os.path.dirname(currentdir)
os.sys.path.insert(0,parentdir)


class XmlBasedRobot:
	"""
	Base class for mujoco .xml based agents.
	"""

	self_collision = True

	def __init__(self, robot_name, action_dim, obs_dim, self_collision, add_ignored_joints=False):
		self.parts = None
		self.objects = []
		self.jdict = None
		self.ordered_joints = None
		self.robot_body = None
		self.add_ignored_joints = add_ignored_joints

		high = np.ones([action_dim])
		self.action_space = gym.spaces.Box(-high, high)
		high = np.inf * np.ones([obs_dim])
		self.observation_space = gym.spaces.Box(-high, high)

		self.robot_name = robot_name
		self.self_collision = self_collision

	def addToScene(self, bullet_client, bodies):
		self._p = bullet_client

		if self.parts is not None:
			parts = self.parts
		else:
			parts = {}

		if self.jdict is not None:
			joints = self.jdict
		else:
			joints = {}

		if self.ordered_joints is not None:
			ordered_joints = self.ordered_joints
		else:
			ordered_joints = []

		if np.isscalar(bodies):	 # streamline the case where bodies is actually just one body
			bodies = [bodies]

		dump = 0
		for i in range(len(bodies)):
			if self._p.getNumJoints(bodies[i]) == 0:
				part_name, robot_name = self._p.getBodyInfo(bodies[i])
				self.robot_name = robot_name.decode("utf8")
				part_name = part_name.decode("utf8")
				parts[part_name] = BodyPart(self._p, part_name, bodies, i, -1)
			for j in range(self._p.getNumJoints(bodies[i])):
				self._p.setJointMotorControl2(bodies[i], j, pybullet.POSITION_CONTROL, positionGain=0.1, velocityGain=0.1, force=0)
				jointInfo = self._p.getJointInfo(bodies[i], j)
				joint_name=jointInfo[1]
				part_name=jointInfo[12]

				joint_name = joint_name.decode("utf8")
				part_name = part_name.decode("utf8")

				if dump: print("ROBOT PART '%s'" % part_name)
				if dump: print("ROBOT JOINT '%s'" % joint_name)  # limits = %+0.2f..%+0.2f effort=%0.3f speed=%0.3f" % ((joint_name,) + j.limits()) )

				parts[part_name] = BodyPart(self._p, part_name, bodies, i, j)

				if part_name == self.robot_name:
					self.robot_body = parts[part_name]

				if i == 0 and j == 0 and self.robot_body is None:  # if nothing else works, we take this as robot_body
					parts[self.robot_name] = BodyPart(self._p, self.robot_name, bodies, 0, -1)
					self.robot_body = parts[self.robot_name]

				if joint_name[:6] == "ignore":
					ignored_joint = Joint(self._p, joint_name, bodies, i, j)
					ignored_joint.disable_motor()
					if self.add_ignored_joints:  # some of the robots (Hopper, Walker2D and HalfCheetah in mujoco) require read-access to these joints
						joints[joint_name] = ignored_joint
						ordered_joints.append(ignored_joint)
						joints[joint_name].power_coef = 0.0
					continue

				if joint_name[:8] != "jointfix":
					joints[joint_name] = Joint(self._p, joint_name, bodies, i, j)
					ordered_joints.append(joints[joint_name])

					joints[joint_name].power_coef = 100.0

		return parts, joints, ordered_joints, self.robot_body

	def reset_pose(self, position, orientation):
		self.parts[self.robot_name].reset_pose(position, orientation)


class MJCFBasedRobot(XmlBasedRobot):
	"""
	Base class for mujoco .xml based agents.
	"""

	def __init__(self, model_xml, robot_name, action_dim, obs_dim, self_collision=True, add_ignored_joints=False):
		XmlBasedRobot.__init__(self, robot_name, action_dim, obs_dim, self_collision, add_ignored_joints)
		self.model_xml = model_xml
		self.doneLoading=0

	def reset(self, bullet_client):

		full_path = os.path.join(os.path.dirname(__file__), "..", "..", "assets", "mjcf", self.model_xml)

		self._p = bullet_client
		#print("Created bullet_client with id=", self._p._client)
		if self.doneLoading == 0:
			self.ordered_joints = []
			self.doneLoading=1
			if self.self_collision:
				self.objects = self._p.loadMJCF(full_path, flags=pybullet.URDF_USE_SELF_COLLISION|pybullet.URDF_USE_SELF_COLLISION_EXCLUDE_ALL_PARENTS)
				self.parts, self.jdict, self.ordered_joints, self.robot_body = self.addToScene(self._p, self.objects)
			else:
				self.objects = self._p.loadMJCF(full_path)
				self.parts, self.jdict, self.ordered_joints, self.robot_body = self.addToScene(self._p, self.objects)
		self.robot_specific_reset(self._p)

		s = self.calc_state()  # optimization: calc_state() can calculate something in self.* for calc_potential() to use

		return s

	def calc_potential(self):
		return 0


class URDFBasedRobot(XmlBasedRobot):
	"""
	Base class for URDF .xml based robots.
	"""

	def __init__(self, model_urdf, robot_name, action_dim, obs_dim, basePosition=None, baseOrientation=None, fixed_base=False, self_collision=False):
		XmlBasedRobot.__init__(self, robot_name, action_dim, obs_dim, self_collision)

		self.model_urdf = model_urdf
		self.basePosition = basePosition if basePosition is not None else [0, 0, 0]
		self.baseOrientation = baseOrientation if baseOrientation is not None else [0, 0, 0, 1]
		self.fixed_base = fixed_base

	def reset(self, bullet_client):
		self._p = bullet_client
		self.ordered_joints = []

		full_path = os.path.join(os.path.dirname(__file__), "assets", "robots", self.model_urdf)
		print(full_path)

		if self.self_collision:
			self.parts, self.jdict, self.ordered_joints, self.robot_body = self.addToScene(self._p,
				self._p.loadURDF(full_path,
				basePosition=self.basePosition,
				baseOrientation=self.baseOrientation,
				useFixedBase=self.fixed_base,
				flags=pybullet.URDF_USE_SELF_COLLISION))
		else:
			self.parts, self.jdict, self.ordered_joints, self.robot_body = self.addToScene(self._p,
				self._p.loadURDF(full_path,
				basePosition=self.basePosition,
				baseOrientation=self.baseOrientation,
				useFixedBase=self.fixed_base))

		self.robot_specific_reset(self._p)

		s = self.calc_state()  # optimization: calc_state() can calculate something in self.* for calc_potential() to use
		self.potential = self.calc_potential()

		return s

	def calc_potential(self):
		return 0


class SDFBasedRobot(XmlBasedRobot):
	"""
	Base class for SDF robots in a Scene.
	"""

	def __init__(self, model_sdf, robot_name, action_dim, obs_dim, basePosition=None, baseOrientation=None, fixed_base=False, self_collision=False):
		XmlBasedRobot.__init__(self, robot_name, action_dim, obs_dim, self_collision)

		if basePosition is None:
			basePosition = [0, 0, 0]
		if baseOrientation is None:
			baseOrientation = [0, 0, 0, 1]

		self.model_sdf = model_sdf
		self.fixed_base = fixed_base

	def reset(self, bullet_client):
		self._p = bullet_client

		self.ordered_joints = []

		self.parts, self.jdict, self.ordered_joints, self.robot_body = self.addToScene(self._p,  # TODO: Not sure if this works, try it with kuka
			self._p.loadSDF(os.path.join("models_robot", self.model_sdf)))

		self.robot_specific_reset(self._p)

		s = self.calc_state()  # optimization: calc_state() can calculate something in self.* for calc_potential() to use
		self.potential = self.calc_potential()

		return s

	def calc_potential(self):
		return 0


class PoseHelper: # dummy class to comply to original interface
	def __init__(self, body_part):
		self.body_part = body_part

	def xyz(self):
		return self.body_part.current_position()

	def rpy(self):
		return pybullet.getEulerFromQuaternion(self.body_part.current_orientation())

	def orientation(self):
		return self.body_part.current_orientation()

	def speed(self):
		return self.body_part.speed()


class BodyPart:
	def __init__(self, bullet_client, body_name, bodies, bodyIndex, bodyPartIndex):
		self.bodies = bodies
		self._p = bullet_client
		self.bodyIndex = bodyIndex
		self.bodyPartIndex = bodyPartIndex
		self.initialPosition = self.current_position()
		self.initialOrientation = self.current_orientation()
		self.bp_pose = PoseHelper(self)

	def state_fields_of_pose_of(self, body_id, link_id=-1):  # a method you will most probably need a lot to get pose and orientation
		if link_id == -1:
			(x, y, z), (a, b, c, d) = self._p.getBasePositionAndOrientation(body_id)
		else:
			(x, y, z), (a, b, c, d), _, _, _, _ = self._p.getLinkState(body_id, link_id)
		return np.array([x, y, z, a, b, c, d])

	def get_pose(self):
		return self.state_fields_of_pose_of(self.bodies[self.bodyIndex], self.bodyPartIndex)

	def speed(self):
		if self.bodyPartIndex == -1:
			(vx, vy, vz), _ = self._p.getBaseVelocity(self.bodies[self.bodyIndex])
		else:
			(x,y,z), (a,b,c,d), _,_,_,_, (vx, vy, vz), (vr,vp,vy) = self._p.getLinkState(self.bodies[self.bodyIndex], self.bodyPartIndex, computeLinkVelocity=1)
		return np.array([vx, vy, vz])

	def current_position(self):
		return self.get_pose()[:3]

	def current_orientation(self):
		return self.get_pose()[3:]

	def get_position(self):
		return self.current_position()

	def get_orientation(self):
		return self.current_orientation()

	def get_velocity(self):
		return self._p.getBaseVelocity(self.bodies[self.bodyIndex])

	def reset_position(self, position):
		self._p.resetBasePositionAndOrientation(self.bodies[self.bodyIndex], position, self.get_orientation())

	def reset_orientation(self, orientation):
		self._p.resetBasePositionAndOrientation(self.bodies[self.bodyIndex], self.get_position(), orientation)

	def reset_velocity(self, linearVelocity=None, angularVelocity=None):
		if linearVelocity is None:
			linearVelocity = [0, 0, 0]
		if angularVelocity is None:
			angularVelocity = [0, 0, 0]
		self._p.resetBaseVelocity(self.bodies[self.bodyIndex], linearVelocity, angularVelocity)

	def reset_pose(self, position, orientation):
		self._p.resetBasePositionAndOrientation(self.bodies[self.bodyIndex], position, orientation)

	def pose(self):
		return self.bp_pose

	def contact_list(self):
		return self._p.getContactPoints(self.bodies[self.bodyIndex], -1, self.bodyPartIndex, -1)


class Joint:
	def __init__(self, bullet_client, joint_name, bodies, bodyIndex, jointIndex):
		self.bodies = bodies
		self._p = bullet_client
		self.bodyIndex = bodyIndex
		self.jointIndex = jointIndex
		self.joint_name = joint_name

		joint_info = self._p.getJointInfo(self.bodies[self.bodyIndex], self.jointIndex)
		self.jointType = joint_info[2]
		self.lowerLimit = joint_info[8]
		self.upperLimit = joint_info[9]
		self.jointHasLimits = self.lowerLimit < self.upperLimit
		self.jointMaxVelocity = joint_info[11]
		self.power_coeff = 0

	def set_state(self, x, vx):
		self._p.resetJointState(self.bodies[self.bodyIndex], self.jointIndex, x, vx)

	def current_position(self):  # just some synonym method
		return self.get_state()

	def current_relative_position(self):
		pos, vel = self.get_state()
		if self.jointHasLimits:
			pos_mid = 0.5 * (self.lowerLimit + self.upperLimit)
			pos = 2 * (pos - pos_mid) / (self.upperLimit - self.lowerLimit)

		if self.jointMaxVelocity > 0:
			vel /= self.jointMaxVelocity
		elif self.jointType == 0:  # JOINT_REVOLUTE_TYPE
			vel *= 0.1
		else:
			vel *= 0.5
		return (
			pos,
			vel
		)

	def get_state(self):
		x, vx,_,_ = self._p.getJointState(self.bodies[self.bodyIndex],self.jointIndex)
		return x, vx

	def get_position(self):
		x, _ = self.get_state()
		return x

	def get_orientation(self):
		_,r = self.get_state()
		return r

	def get_velocity(self):
		_, vx = self.get_state()
		return vx

	def set_position(self, position):
		self._p.setJointMotorControl2(self.bodies[self.bodyIndex],self.jointIndex,pybullet.POSITION_CONTROL, targetPosition=position)

	def set_velocity(self, velocity):
		self._p.setJointMotorControl2(self.bodies[self.bodyIndex],self.jointIndex,pybullet.VELOCITY_CONTROL, targetVelocity=velocity)

	def set_motor_torque(self, torque): # just some synonym method
		self.set_torque(torque)

	def set_torque(self, torque):
		self._p.setJointMotorControl2(bodyIndex=self.bodies[self.bodyIndex], jointIndex=self.jointIndex, controlMode=pybullet.TORQUE_CONTROL, force=torque) #, positionGain=0.1, velocityGain=0.1)

	def reset_current_position(self, position, velocity): # just some synonym method
		self.reset_position(position, velocity)

	def reset_position(self, position, velocity):
		self._p.resetJointState(self.bodies[self.bodyIndex],self.jointIndex,targetValue=position, targetVelocity=velocity)
		self.disable_motor()

	def disable_motor(self):
		self._p.setJointMotorControl2(self.bodies[self.bodyIndex],self.jointIndex,controlMode=pybullet.POSITION_CONTROL, targetPosition=0, targetVelocity=0, positionGain=0.1, velocityGain=0.1, force=0)
