# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause

"""
This script tests the functionality of texture randomization applied to the cartpole scene.
"""

"""Launch Isaac Sim Simulator first."""

from isaaclab.app import AppLauncher

# launch omniverse app
app_launcher = AppLauncher(headless=True, enable_cameras=True)
simulation_app = app_launcher.app

"""Rest everything follows."""

import math

import pytest
import torch

import omni.usd

import isaaclab.envs.mdp as mdp
from isaaclab.envs import ManagerBasedEnv, ManagerBasedEnvCfg
from isaaclab.managers import EventTermCfg as EventTerm
from isaaclab.managers import ObservationGroupCfg as ObsGroup
from isaaclab.managers import ObservationTermCfg as ObsTerm
from isaaclab.managers import SceneEntityCfg
from isaaclab.utils import configclass
from isaaclab.utils.version import get_isaac_sim_version

from isaaclab_tasks.manager_based.classic.cartpole.cartpole_env_cfg import CartpoleSceneCfg


@configclass
class ActionsCfg:
    """Action specifications for the environment."""

    joint_efforts = mdp.JointEffortActionCfg(asset_name="robot", joint_names=["slider_to_cart"], scale=5.0)


@configclass
class ObservationsCfg:
    """Observation specifications for the environment."""

    @configclass
    class PolicyCfg(ObsGroup):
        """Observations for policy group."""

        # observation terms (order preserved)
        joint_pos_rel = ObsTerm(func=mdp.joint_pos_rel)
        joint_vel_rel = ObsTerm(func=mdp.joint_vel_rel)

        def __post_init__(self) -> None:
            self.enable_corruption = False
            self.concatenate_terms = True

    # observation groups
    policy: PolicyCfg = PolicyCfg()


@configclass
class EventCfg:
    """Configuration for events."""

    # on prestartup apply a new set of textures
    # note from @mayank: Changed from 'reset' to 'prestartup' to make test pass.
    #   The error happens otherwise on Kit thread which is not the main thread.
    cart_texture_randomizer = EventTerm(
        func=mdp.randomize_visual_color,
        mode="prestartup",
        params={
            "asset_cfg": SceneEntityCfg("robot", body_names=["cart"]),
            "colors": {"r": (0.0, 1.0), "g": (0.0, 1.0), "b": (0.0, 1.0)},
            "event_name": "cart_color_randomizer",
        },
    )

    # on reset apply a new set of textures
    pole_texture_randomizer = EventTerm(
        func=mdp.randomize_visual_color,
        mode="reset",
        params={
            "asset_cfg": SceneEntityCfg("robot", body_names=["pole"]),
            "colors": {"r": (0.0, 1.0), "g": (0.0, 1.0), "b": (0.0, 1.0)},
            "event_name": "pole_color_randomizer",
        },
    )

    reset_cart_position = EventTerm(
        func=mdp.reset_joints_by_offset,
        mode="reset",
        params={
            "asset_cfg": SceneEntityCfg("robot", joint_names=["slider_to_cart"]),
            "position_range": (-1.0, 1.0),
            "velocity_range": (-0.1, 0.1),
        },
    )

    reset_pole_position = EventTerm(
        func=mdp.reset_joints_by_offset,
        mode="reset",
        params={
            "asset_cfg": SceneEntityCfg("robot", joint_names=["cart_to_pole"]),
            "position_range": (-0.125 * math.pi, 0.125 * math.pi),
            "velocity_range": (-0.01 * math.pi, 0.01 * math.pi),
        },
    )


@configclass
class CartpoleEnvCfg(ManagerBasedEnvCfg):
    """Configuration for the cartpole environment."""

    # Scene settings
    scene = CartpoleSceneCfg(env_spacing=2.5)

    # Basic settings
    actions = ActionsCfg()
    observations = ObservationsCfg()
    events = EventCfg()

    def __post_init__(self):
        """Post initialization."""
        # viewer settings
        self.viewer.eye = [4.5, 0.0, 6.0]
        self.viewer.lookat = [0.0, 0.0, 2.0]
        # step settings
        self.decimation = 4  # env step every 4 sim steps: 200Hz / 4 = 50Hz
        # simulation settings
        self.sim.dt = 0.005  # sim step every 5ms: 200Hz


@pytest.mark.parametrize("device", ["cpu", "cuda"])
def test_color_randomization(device):
    """Test color randomization for cartpole environment."""
    # skip test if stage in memory is not supported
    if get_isaac_sim_version().major < 5:
        pytest.skip("Color randomization test hangs in this version of Isaac Sim")

    # Create a new stage
    omni.usd.get_context().new_stage()

    try:
        # Set the arguments
        env_cfg = CartpoleEnvCfg()
        env_cfg.scene.num_envs = 16
        env_cfg.scene.replicate_physics = False
        env_cfg.sim.device = device

        # Setup base environment
        env = ManagerBasedEnv(cfg=env_cfg)

        try:
            # Simulate physics
            with torch.inference_mode():
                for count in range(50):
                    # Reset every few steps to check nothing breaks
                    if count % 10 == 0:
                        env.reset()
                    # Sample random actions
                    joint_efforts = torch.randn_like(env.action_manager.action)
                    # Step the environment
                    env.step(joint_efforts)
        finally:
            env.close()
    finally:
        # Clean up stage
        omni.usd.get_context().close_stage()
