# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.


import dataclasses
import os
from enum import Enum
from typing import Any, cast, Dict, List, Optional, Tuple

import lpips
import torch
from pytorch3d.implicitron.dataset.data_source import ImplicitronDataSource
from pytorch3d.implicitron.dataset.json_index_dataset import JsonIndexDataset
from pytorch3d.implicitron.dataset.json_index_dataset_map_provider import (
    CO3D_CATEGORIES,
)
from pytorch3d.implicitron.evaluation.evaluate_new_view_synthesis import (
    aggregate_nvs_results,
    eval_batch,
    pretty_print_nvs_metrics,
    summarize_nvs_eval_results,
)
from pytorch3d.implicitron.models.model_dbir import ModelDBIR
from pytorch3d.implicitron.tools.utils import dataclass_to_cuda_
from tqdm import tqdm


class Task(Enum):
    SINGLE_SEQUENCE = "singlesequence"
    MULTI_SEQUENCE = "multisequence"


def main() -> None:
    """
    Evaluates new view synthesis metrics of a simple depth-based image rendering
    (DBIR) model for multisequence/singlesequence tasks for several categories.

    The evaluation is conducted on the same data as in [1] and, hence, the results
    are directly comparable to the numbers reported in [1].

    References:
        [1] J. Reizenstein, R. Shapovalov, P. Henzler, L. Sbordone,
                P. Labatut, D. Novotny:
            Common Objects in 3D: Large-Scale Learning
                and Evaluation of Real-life 3D Category Reconstruction
    """

    task_results = {}
    for task in (Task.SINGLE_SEQUENCE, Task.MULTI_SEQUENCE):
        task_results[task] = []
        for category in CO3D_CATEGORIES[: (20 if task == Task.SINGLE_SEQUENCE else 10)]:
            for single_sequence_id in (
                (0, 1) if task == Task.SINGLE_SEQUENCE else (None,)
            ):
                category_result = evaluate_dbir_for_category(
                    category, task=task, single_sequence_id=single_sequence_id
                )
                print("")
                print(
                    f"Results for task={task}; category={category};"
                    + (
                        f" sequence={single_sequence_id}:"
                        if single_sequence_id is not None
                        else ":"
                    )
                )
                pretty_print_nvs_metrics(category_result)
                print("")

                task_results[task].append(category_result)
            _print_aggregate_results(task, task_results)

    for task in task_results:
        _print_aggregate_results(task, task_results)


def evaluate_dbir_for_category(
    category: str,
    task: Task,
    bg_color: Tuple[float, float, float] = (0.0, 0.0, 0.0),
    single_sequence_id: Optional[int] = None,
    num_workers: int = 16,
):
    """
    Evaluates new view synthesis metrics of a simple depth-based image rendering
    (DBIR) model for a given task, category, and sequence (in case task=='singlesequence').

    Args:
        category: Object category.
        bg_color: Background color of the renders.
        task: Evaluation task. Either singlesequence or multisequence.
        single_sequence_id: The ID of the evaluiation sequence for the singlesequence task.
        num_workers: The number of workers for the employed dataloaders.
        path_manager: (optional) Used for interpreting paths.

    Returns:
        category_result: A dictionary of quantitative metrics.
    """

    single_sequence_id = single_sequence_id if single_sequence_id is not None else -1

    torch.manual_seed(42)

    dataset_map_provider_args = {
        "category": category,
        "dataset_root": os.environ["CO3D_DATASET_ROOT"],
        "assert_single_seq": task == Task.SINGLE_SEQUENCE,
        "task_str": task.value,
        "test_on_train": False,
        "test_restrict_sequence_id": single_sequence_id,
        "dataset_JsonIndexDataset_args": {"load_point_clouds": True},
    }
    data_source = ImplicitronDataSource(
        dataset_map_provider_JsonIndexDatasetMapProvider_args=dataset_map_provider_args
    )

    datasets, dataloaders = data_source.get_datasets_and_dataloaders()

    test_dataset = datasets.test
    test_dataloader = dataloaders.test
    if test_dataset is None or test_dataloader is None:
        raise ValueError("must have a test dataset.")

    image_size = cast(JsonIndexDataset, test_dataset).image_width

    if image_size is None:
        raise ValueError("Image size should be set in the dataset")

    # init the simple DBIR model
    model = ModelDBIR(
        render_image_width=image_size,
        render_image_height=image_size,
        bg_color=bg_color,
        max_points=int(1e5),
    )
    model.cuda()

    # init the lpips model for eval
    lpips_model = lpips.LPIPS(net="vgg")
    lpips_model = lpips_model.cuda()

    per_batch_eval_results = []
    print("Evaluating DBIR model ...")
    for frame_data in tqdm(test_dataloader):
        frame_data = dataclass_to_cuda_(frame_data)
        preds = model(**dataclasses.asdict(frame_data))
        per_batch_eval_results.append(
            eval_batch(
                frame_data,
                preds["implicitron_render"],
                bg_color=bg_color,
                lpips_model=lpips_model,
            )
        )

    category_result_flat, category_result = summarize_nvs_eval_results(
        per_batch_eval_results,
        is_multisequence=task != Task.SINGLE_SEQUENCE,
    )

    return category_result["results"]


def _print_aggregate_results(
    task: Task, task_results: Dict[Task, List[List[Dict[str, Any]]]]
) -> None:
    """
    Prints the aggregate metrics for a given task.
    """
    aggregate_task_result = aggregate_nvs_results(task_results[task])
    print("")
    print(f"Aggregate results for task={task}:")
    pretty_print_nvs_metrics(aggregate_task_result)
    print("")


if __name__ == "__main__":
    main()
