import atexit
import os
import sys
import threading
import traceback

import cloudpickle
import gym
import numpy as np


class GymWrapper:

    def __init__(self, env, obs_key='image', act_key='action'):
        self._env = env
        self._obs_is_dict = hasattr(self._env.observation_space, 'spaces')
        self._act_is_dict = hasattr(self._env.action_space, 'spaces')
        self._obs_key = obs_key
        self._act_key = act_key

    def __getattr__(self, name):
        if name.startswith('__'):
            raise AttributeError(name)
        try:
            return getattr(self._env, name)
        except AttributeError:
            raise ValueError(name)

    @property
    def obs_space(self):
        if self._obs_is_dict:
            spaces = self._env.observation_space.spaces.copy()
        else:
            spaces = {self._obs_key: self._env.observation_space}
        return {
            **spaces,
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
        }

    @property
    def act_space(self):
        if self._act_is_dict:
            return self._env.action_space.spaces.copy()
        else:
            return {self._act_key: self._env.action_space}

    def step(self, action):
        if not self._act_is_dict:
            action = action[self._act_key]
        obs, reward, done, info = self._env.step(action)
        if not self._obs_is_dict:
            obs = {self._obs_key: obs}
        obs['reward'] = float(reward)
        obs['is_first'] = False
        obs['is_last'] = done
        obs['is_terminal'] = info.get('is_terminal', done)
        return obs

    def reset(self):
        obs = self._env.reset()
        if not self._obs_is_dict:
            obs = {self._obs_key: obs}
        obs['reward'] = 0.0
        obs['is_first'] = True
        obs['is_last'] = False
        obs['is_terminal'] = False
        return obs


class DMC:
    def __init__(self, name, action_repeat=1, size=(64, 64), camera=None, **kwargs):
        os.environ['MUJOCO_GL'] = 'egl'
        domain, task = name.split('_', 1)
        if domain == 'cup':  # Only domain with multiple words.
            domain = 'ball_in_cup'
        if domain == 'manip':
            from dm_control import manipulation
            self._env = manipulation.load(task + '_vision')
        elif domain == 'locom':
            from dm_control.locomotion.examples import basic_rodent_2020
            self._env = getattr(basic_rodent_2020, task)()
        else:
            from dm_control import suite
            self._env = suite.load(domain, task, **kwargs)
        self._action_repeat = action_repeat
        self._size = size
        if camera in (-1, None):
            camera = dict(
                quadruped_walk=2, quadruped_run=2, quadruped_escape=2,
                quadruped_fetch=2, locom_rodent_maze_forage=1,
                locom_rodent_two_touch=1,
            ).get(name, 0)
        self._camera = camera
        self._ignored_keys = ['orientations', 'height', 'velocity', 'pixels']
        for key, value in self._env.observation_spec().items():
            if value.shape == (0,):
                print(f"Ignoring empty observation key '{key}'.")
                self._ignored_keys.append(key)

    @property
    def obs_space(self):
        spaces = {
            'image': gym.spaces.Box(0, 255, self._size + (3,), dtype=np.uint8),
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
        }
        for key, value in self._env.observation_spec().items():
            if key in self._ignored_keys:
                continue
            if value.dtype == np.float64:
                spaces[key] = gym.spaces.Box(-np.inf, np.inf, value.shape, np.float32)
            elif value.dtype == np.uint8:
                spaces[key] = gym.spaces.Box(0, 255, value.shape, np.uint8)
            else:
                raise NotImplementedError(value.dtype)
        return spaces

    @property
    def act_space(self):
        spec = self._env.action_spec()
        action = gym.spaces.Box(spec.minimum, spec.maximum, dtype=np.float32)
        return {'action': action}

    def step(self, action):
        assert np.isfinite(action['action']).all(), action['action']
        reward = 0.0
        for _ in range(self._action_repeat):
            time_step = self._env.step(action['action'])
            reward += time_step.reward or 0.0
            if time_step.last():
                break
        assert time_step.discount in (0, 1)
        obs = {
            'reward': reward,
            'is_first': False,
            'is_last': time_step.last(),
            'is_terminal': time_step.discount == 0,
            'image': self._env.physics.render(*self._size, camera_id=self._camera),
        }
        obs.update({
            k: v for k, v in dict(time_step.observation).items()
            if k not in self._ignored_keys})
        return obs

    def reset(self):
        time_step = self._env.reset()
        obs = {
            'reward': 0.0,
            'is_first': True,
            'is_last': False,
            'is_terminal': False,
            'image': self._env.physics.render(*self._size, camera_id=self._camera),
        }
        obs.update({
            k: v for k, v in dict(time_step.observation).items()
            if k not in self._ignored_keys})
        return obs


class Atari:
    LOCK = threading.Lock()

    def __init__(
            self, name, action_repeat=4, size=(84, 84), grayscale=True, noops=30,
            life_done=False, sticky=True, all_actions=False):
        assert size[0] == size[1]
        import gym.wrappers
        import gym.envs.atari
        if name == 'james_bond':
            name = 'jamesbond'
        with self.LOCK:
            env = gym.envs.atari.AtariEnv(
                game=name, obs_type='image', frameskip=1,
                repeat_action_probability=0.25 if sticky else 0.0,
                full_action_space=all_actions)
        # Avoid unnecessary rendering in inner env.
        env._get_obs = lambda: None
        # Tell wrapper that the inner env has no action repeat.
        env.spec = gym.envs.registration.EnvSpec('NoFrameskip-v0')
        self._env = gym.wrappers.AtariPreprocessing(
            env, noops, action_repeat, size[0], life_done, grayscale)
        self._size = size
        self._grayscale = grayscale

    @property
    def obs_space(self):
        shape = self._size + (1 if self._grayscale else 3,)
        return {
            'image': gym.spaces.Box(0, 255, shape, np.uint8),
            'ram': gym.spaces.Box(0, 255, (128,), np.uint8),
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
        }

    @property
    def act_space(self):
        return {'action': self._env.action_space}

    def step(self, action):
        image, reward, done, info = self._env.step(action['action'])
        if self._grayscale:
            image = image[..., None]
        return {
            'image': image,
            'ram': self._env.env._get_ram(),
            'reward': reward,
            'is_first': False,
            'is_last': done,
            'is_terminal': done,
        }

    def reset(self):
        with self.LOCK:
            image = self._env.reset()
        if self._grayscale:
            image = image[..., None]
        return {
            'image': image,
            'ram': self._env.env._get_ram(),
            'reward': 0.0,
            'is_first': True,
            'is_last': False,
            'is_terminal': False,
        }

    def close(self):
        return self._env.close()


class Crafter:

    def __init__(self, outdir=None, reward=True, seed=None):
        import crafter
        self._env = crafter.Env(reward=reward, seed=seed)
        self._env = crafter.Recorder(
            self._env, outdir,
            save_stats=True,
            save_video=False,
            save_episode=False,
        )
        self._achievements = crafter.constants.achievements.copy()

    @property
    def obs_space(self):
        spaces = {
            'image': self._env.observation_space,
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'log_reward': gym.spaces.Box(-np.inf, np.inf, (), np.float32),
        }
        spaces.update({
            f'log_achievement_{k}': gym.spaces.Box(0, 2 ** 31 - 1, (), np.int32)
            for k in self._achievements})
        return spaces

    @property
    def act_space(self):
        return {'action': self._env.action_space}

    def step(self, action):
        image, reward, done, info = self._env.step(action['action'])
        obs = {
            'image': image,
            'reward': reward,
            'is_first': False,
            'is_last': done,
            'is_terminal': info['discount'] == 0,
            'log_reward': info['reward'],
        }
        obs.update({
            f'log_achievement_{k}': v
            for k, v in info['achievements'].items()})
        return obs

    def reset(self):
        obs = {
            'image': self._env.reset(),
            'reward': 0.0,
            'is_first': True,
            'is_last': False,
            'is_terminal': False,
            'log_reward': 0.0,
        }
        obs.update({
            f'log_achievement_{k}': 0
            for k in self._achievements})
        return obs


class Dummy:

    def __init__(self):
        pass

    @property
    def obs_space(self):
        return {
            'image': gym.spaces.Box(0, 255, (64, 64, 3), dtype=np.uint8),
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
        }

    @property
    def act_space(self):
        return {'action': gym.spaces.Box(-1, 1, (6,), dtype=np.float32)}

    def step(self, action):
        return {
            'image': np.zeros((64, 64, 3)),
            'reward': 0.0,
            'is_first': False,
            'is_last': False,
            'is_terminal': False,
        }

    def reset(self):
        return {
            'image': np.zeros((64, 64, 3)),
            'reward': 0.0,
            'is_first': True,
            'is_last': False,
            'is_terminal': False,
        }


class TimeLimit:

    def __init__(self, env, duration):
        self._env = env
        self._duration = duration
        self._step = None

    def __getattr__(self, name):
        if name.startswith('__'):
            raise AttributeError(name)
        try:
            return getattr(self._env, name)
        except AttributeError:
            raise ValueError(name)

    def step(self, action):
        assert self._step is not None, 'Must reset environment.'
        obs = self._env.step(action)
        self._step += 1
        if self._duration and self._step >= self._duration:
            obs['is_last'] = True
            self._step = None
        return obs

    def reset(self):
        self._step = 0
        return self._env.reset()


class NormalizeAction:

    def __init__(self, env, key='action'):
        self._env = env
        self._key = key
        space = env.act_space[key]
        self._mask = np.isfinite(space.low) & np.isfinite(space.high)
        self._low = np.where(self._mask, space.low, -1)
        self._high = np.where(self._mask, space.high, 1)

    def __getattr__(self, name):
        if name.startswith('__'):
            raise AttributeError(name)
        try:
            return getattr(self._env, name)
        except AttributeError:
            raise ValueError(name)

    @property
    def act_space(self):
        low = np.where(self._mask, -np.ones_like(self._low), self._low)
        high = np.where(self._mask, np.ones_like(self._low), self._high)
        space = gym.spaces.Box(low, high, dtype=np.float32)
        return {**self._env.act_space, self._key: space}

    def step(self, action):
        orig = (action[self._key] + 1) / 2 * (self._high - self._low) + self._low
        orig = np.where(self._mask, orig, action[self._key])
        return self._env.step({**action, self._key: orig})


class OneHotAction:

    def __init__(self, env, key='action'):
        assert hasattr(env.act_space[key], 'n')
        self._env = env
        self._key = key
        self._random = np.random.RandomState()

    def __getattr__(self, name):
        if name.startswith('__'):
            raise AttributeError(name)
        try:
            return getattr(self._env, name)
        except AttributeError:
            raise ValueError(name)

    @property
    def act_space(self):
        shape = (self._env.act_space[self._key].n,)
        space = gym.spaces.Box(low=0, high=1, shape=shape, dtype=np.float32)
        space.sample = self._sample_action
        space.n = shape[0]
        return {**self._env.act_space, self._key: space}

    def step(self, action):
        index = np.argmax(action[self._key]).astype(int)
        reference = np.zeros_like(action[self._key])
        reference[index] = 1
        if not np.allclose(reference, action[self._key]):
            raise ValueError(f'Invalid one-hot action:\n{action}')
        return self._env.step({**action, self._key: index})

    def reset(self):
        return self._env.reset()

    def _sample_action(self):
        actions = self._env.act_space.n
        index = self._random.randint(0, actions)
        reference = np.zeros(actions, dtype=np.float32)
        reference[index] = 1.0
        return reference


class ResizeImage:

    def __init__(self, env, size=(64, 64)):
        self._env = env
        self._size = size
        self._keys = [
            k for k, v in env.obs_space.items()
            if len(v.shape) > 1 and v.shape[:2] != size]
        print(f'Resizing keys {",".join(self._keys)} to {self._size}.')
        if self._keys:
            from PIL import Image
            self._Image = Image

    def __getattr__(self, name):
        if name.startswith('__'):
            raise AttributeError(name)
        try:
            return getattr(self._env, name)
        except AttributeError:
            raise ValueError(name)

    @property
    def obs_space(self):
        spaces = self._env.obs_space
        for key in self._keys:
            shape = self._size + spaces[key].shape[2:]
            spaces[key] = gym.spaces.Box(0, 255, shape, np.uint8)
        return spaces

    def step(self, action):
        obs = self._env.step(action)
        for key in self._keys:
            obs[key] = self._resize(obs[key])
        return obs

    def reset(self):
        obs = self._env.reset()
        for key in self._keys:
            obs[key] = self._resize(obs[key])
        return obs

    def _resize(self, image):
        image = self._Image.fromarray(image)
        image = image.resize(self._size, self._Image.NEAREST)
        image = np.array(image)
        return image


class RenderImage:

    def __init__(self, env, key='image'):
        self._env = env
        self._key = key
        self._shape = self._env.render().shape

    def __getattr__(self, name):
        if name.startswith('__'):
            raise AttributeError(name)
        try:
            return getattr(self._env, name)
        except AttributeError:
            raise ValueError(name)

    @property
    def obs_space(self):
        spaces = self._env.obs_space
        spaces[self._key] = gym.spaces.Box(0, 255, self._shape, np.uint8)
        return spaces

    def step(self, action):
        obs = self._env.step(action)
        obs[self._key] = self._env.render('rgb_array')
        return obs

    def reset(self):
        obs = self._env.reset()
        obs[self._key] = self._env.render('rgb_array')
        return obs


class Async:
    # Message types for communication via the pipe.
    _ACCESS = 1
    _CALL = 2
    _RESULT = 3
    _CLOSE = 4
    _EXCEPTION = 5

    def __init__(self, constructor, strategy='thread'):
        self._pickled_ctor = cloudpickle.dumps(constructor)
        if strategy == 'process':
            import multiprocessing as mp
            context = mp.get_context('spawn')
        elif strategy == 'thread':
            import multiprocessing.dummy as context
        else:
            raise NotImplementedError(strategy)
        self._strategy = strategy
        self._conn, conn = context.Pipe()
        self._process = context.Process(target=self._worker, args=(conn,))
        atexit.register(self.close)
        self._process.start()
        self._receive()  # Ready.
        self._obs_space = None
        self._act_space = None

    def access(self, name):
        self._conn.send((self._ACCESS, name))
        return self._receive

    def call(self, name, *args, **kwargs):
        payload = name, args, kwargs
        self._conn.send((self._CALL, payload))
        return self._receive

    def close(self):
        try:
            self._conn.send((self._CLOSE, None))
            self._conn.close()
        except IOError:
            pass  # The connection was already closed.
        self._process.join(5)

    @property
    def obs_space(self):
        if not self._obs_space:
            self._obs_space = self.access('obs_space')()
        return self._obs_space

    @property
    def act_space(self):
        if not self._act_space:
            self._act_space = self.access('act_space')()
        return self._act_space

    def step(self, action, blocking=False):
        promise = self.call('step', action)
        if blocking:
            return promise()
        else:
            return promise

    def reset(self, blocking=False):
        promise = self.call('reset')
        if blocking:
            return promise()
        else:
            return promise

    def _receive(self):
        try:
            message, payload = self._conn.recv()
        except (OSError, EOFError):
            raise RuntimeError('Lost connection to environment worker.')
        # Re-raise exceptions in the main process.
        if message == self._EXCEPTION:
            stacktrace = payload
            raise Exception(stacktrace)
        if message == self._RESULT:
            return payload
        raise KeyError('Received message of unexpected type {}'.format(message))

    def _worker(self, conn):
        try:
            ctor = cloudpickle.loads(self._pickled_ctor)
            env = ctor()
            conn.send((self._RESULT, None))  # Ready.
            while True:
                try:
                    # Only block for short times to have keyboard exceptions be raised.
                    if not conn.poll(0.1):
                        continue
                    message, payload = conn.recv()
                except (EOFError, KeyboardInterrupt):
                    break
                if message == self._ACCESS:
                    name = payload
                    result = getattr(env, name)
                    conn.send((self._RESULT, result))
                    continue
                if message == self._CALL:
                    name, args, kwargs = payload
                    result = getattr(env, name)(*args, **kwargs)
                    conn.send((self._RESULT, result))
                    continue
                if message == self._CLOSE:
                    break
                raise KeyError('Received message of unknown type {}'.format(message))
        except Exception:
            stacktrace = ''.join(traceback.format_exception(*sys.exc_info()))
            print('Error in environment process: {}'.format(stacktrace))
            conn.send((self._EXCEPTION, stacktrace))
        finally:
            try:
                conn.close()
            except IOError:
                pass  # The connection was already closed.


class DMCMultitask:
    def __init__(self, name, action_repeat=1, size=(64, 64), camera=None):
        os.environ['MUJOCO_GL'] = 'egl'
        domain, task, xml = name.split('_', 2)

        import envs.fb_mtenv_dmc as fb_mtenv_dmc
        self._env = fb_mtenv_dmc.load(
            domain_name=domain,
            task_name=task,
            task_kwargs={'xml_file_id': xml},
        )

        self._action_repeat = action_repeat
        self._size = size
        if camera in (-1, None):
            camera = dict(
                quadruped_walk=2, quadruped_run=2, quadruped_escape=2,
                quadruped_fetch=2, locom_rodent_maze_forage=1,
                locom_rodent_two_touch=1,
            ).get(name, 0)
        self._camera = camera
        self._ignored_keys = ['orientations', 'height', 'velocity', 'pixels']
        for key, value in self._env.observation_spec().items():
            if value.shape == (0,):
                print(f"Ignoring empty observation key '{key}'.")
                self._ignored_keys.append(key)

    @property
    def obs_space(self):
        spaces = {
            'image': gym.spaces.Box(0, 255, self._size + (3,), dtype=np.uint8),
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
        }
        for key, value in self._env.observation_spec().items():
            if key in self._ignored_keys:
                continue
            if value.dtype == np.float64:
                spaces[key] = gym.spaces.Box(-np.inf, np.inf, value.shape, np.float32)
            elif value.dtype == np.uint8:
                spaces[key] = gym.spaces.Box(0, 255, value.shape, np.uint8)
            else:
                raise NotImplementedError(value.dtype)
        return spaces

    @property
    def act_space(self):
        spec = self._env.action_spec()
        action = gym.spaces.Box(spec.minimum, spec.maximum, dtype=np.float32)
        return {'action': action}

    def step(self, action):
        assert np.isfinite(action['action']).all(), action['action']
        reward = 0.0
        for _ in range(self._action_repeat):
            time_step = self._env.step(action['action'])
            reward += time_step.reward or 0.0
            if time_step.last():
                break
        assert time_step.discount in (0, 1)
        obs = {
            'reward': reward,
            'is_first': False,
            'is_last': time_step.last(),
            'is_terminal': time_step.discount == 0,
            'image': self._env.physics.render(*self._size, camera_id=self._camera),
        }
        obs.update({
            k: v for k, v in dict(time_step.observation).items()
            if k not in self._ignored_keys})
        return obs

    def reset(self):
        time_step = self._env.reset()
        obs = {
            'reward': 0.0,
            'is_first': True,
            'is_last': False,
            'is_terminal': False,
            'image': self._env.physics.render(*self._size, camera_id=self._camera),
        }
        obs.update({
            k: v for k, v in dict(time_step.observation).items()
            if k not in self._ignored_keys})
        return obs


class DistractingDMC:
    def __init__(self, name, action_repeat=1, size=(64, 64), camera=None, **kwargs):
        os.environ['MUJOCO_GL'] = 'egl'
        domain, task, difficulty = name.split('_', 2)

        from envs.distracting_control import suite as dsuite
        self._env = dsuite.load(
            domain_name=domain,
            task_name=task,
            difficulty=difficulty,
            **kwargs
        )

        self._action_repeat = action_repeat
        self._size = size
        if camera in (-1, None):
            camera = dict(
                quadruped_walk=2, quadruped_run=2, quadruped_escape=2,
                quadruped_fetch=2, locom_rodent_maze_forage=1,
                locom_rodent_two_touch=1,
            ).get(name, 0)
        self._camera = camera
        self._ignored_keys = []
        for key, value in self._env.observation_spec().items():
            if value.shape == (0,):
                print(f"Ignoring empty observation key '{key}'.")
                self._ignored_keys.append(key)

    @property
    def obs_space(self):
        spaces = {
            'image': gym.spaces.Box(0, 255, self._size + (3,), dtype=np.uint8),
            'reward': gym.spaces.Box(-np.inf, np.inf, (), dtype=np.float32),
            'is_first': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_last': gym.spaces.Box(0, 1, (), dtype=np.bool),
            'is_terminal': gym.spaces.Box(0, 1, (), dtype=np.bool),
        }
        for key, value in self._env.observation_spec().items():
            if key in self._ignored_keys:
                continue
            if value.dtype == np.float64:
                spaces[key] = gym.spaces.Box(-np.inf, np.inf, value.shape, np.float32)
            elif value.dtype == np.uint8:
                spaces[key] = gym.spaces.Box(0, 255, value.shape, np.uint8)
            else:
                raise NotImplementedError(value.dtype)
        return spaces

    @property
    def act_space(self):
        spec = self._env.action_spec()
        action = gym.spaces.Box(spec.minimum, spec.maximum, dtype=np.float32)
        return {'action': action}

    def step(self, action):
        assert np.isfinite(action['action']).all(), action['action']
        reward = 0.0
        for _ in range(self._action_repeat):
            time_step = self._env.step(action['action'])
            reward += time_step.reward or 0.0
            if time_step.last():
                break
        assert time_step.discount in (0, 1)
        obs = {
            'reward': reward,
            'is_first': False,
            'is_last': time_step.last(),
            'is_terminal': time_step.discount == 0,
            'image': self._env.physics.render(*self._size, camera_id=self._camera),
        }
        obs.update({
            k: v for k, v in dict(time_step.observation).items()
            if k not in self._ignored_keys})
        return obs

    def reset(self):
        time_step = self._env.reset()
        obs = {
            'reward': 0.0,
            'is_first': True,
            'is_last': False,
            'is_terminal': False,
            'image': self._env.physics.render(*self._size, camera_id=self._camera),
        }
        obs.update({
            k: v for k, v in dict(time_step.observation).items()
            if k not in self._ignored_keys})
        return obs