#!/usr/bin/env python

# Copyright 2024 Columbia Artificial Intelligence, Robotics Lab,
# and The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Any

import torch

from lerobot.processor import (
    PolicyAction,
    PolicyProcessorPipeline,
    make_default_pre_post_processors,
)

from .configuration_diffusion import DiffusionConfig


def make_diffusion_pre_post_processors(
    config: DiffusionConfig,
    dataset_stats: dict[str, dict[str, torch.Tensor]] | None = None,
) -> tuple[
    PolicyProcessorPipeline[dict[str, Any], dict[str, Any]],
    PolicyProcessorPipeline[PolicyAction, PolicyAction],
]:
    """
    Constructs pre-processor and post-processor pipelines for a diffusion policy.

    The pre-processing pipeline prepares the input data for the model by:
    1. Renaming features.
    2. Normalizing the input and output features based on dataset statistics.
    3. Adding a batch dimension.
    4. Moving the data to the specified device.

    The post-processing pipeline handles the model's output by:
    1. Moving the data to the CPU.
    2. Unnormalizing the output features to their original scale.

    Args:
        config: The configuration object for the diffusion policy,
            containing feature definitions, normalization mappings, and device information.
        dataset_stats: A dictionary of statistics used for normalization.
            Defaults to None.

    Returns:
        A tuple containing the configured pre-processor and post-processor pipelines.
    """
    return make_default_pre_post_processors(config, dataset_stats)
