#!/usr/bin/env python3
# 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.

"""Script to visualize a previously trained model. Example call:

    projects/implicitron_trainer/visualize_reconstruction.py
    exp_dir='./exps/checkpoint_dir' visdom_show_preds=True visdom_port=8097
    n_eval_cameras=40 render_size="[64,64]" video_size="[256,256]"
"""

import os
import sys
from typing import Optional, Tuple

import numpy as np
import torch
from omegaconf import OmegaConf
from pytorch3d.implicitron.models.visualization import render_flyaround
from pytorch3d.implicitron.tools.configurable import get_default_args

from .experiment import Experiment


def visualize_reconstruction(
    exp_dir: str = "",
    restrict_sequence_name: Optional[str] = None,
    output_directory: Optional[str] = None,
    render_size: Tuple[int, int] = (512, 512),
    video_size: Optional[Tuple[int, int]] = None,
    split: str = "train",
    n_source_views: int = 9,
    n_eval_cameras: int = 40,
    visdom_show_preds: bool = False,
    visdom_server: str = "http://127.0.0.1",
    visdom_port: int = 8097,
    visdom_env: Optional[str] = None,
):
    """
    Given an `exp_dir` containing a trained Implicitron model, generates videos consisting
    of renderes of sequences from the dataset used to train and evaluate the trained
    Implicitron model.

    Args:
        exp_dir: Implicitron experiment directory.
        restrict_sequence_name: If set, defines the list of sequences to visualize.
        output_directory: If set, defines a custom directory to output visualizations to.
        render_size: The size (HxW) of the generated renders.
        video_size: The size (HxW) of the output video.
        split: The dataset split to use for visualization.
            Can be "train" / "val" / "test".
        n_source_views: The number of source views added to each rendered batch. These
            views are required inputs for models such as NeRFormer / NeRF-WCE.
        n_eval_cameras: The number of cameras each fly-around trajectory.
        visdom_show_preds: If `True`, outputs visualizations to visdom.
        visdom_server: The address of the visdom server.
        visdom_port: The port of the visdom server.
        visdom_env: If set, defines a custom name for the visdom environment.
    """

    # In case an output directory is specified use it. If no output_directory
    # is specified create a vis folder inside the experiment directory
    if output_directory is None:
        output_directory = os.path.join(exp_dir, "vis")
    os.makedirs(output_directory, exist_ok=True)

    # Set the random seeds
    torch.manual_seed(0)
    np.random.seed(0)

    # Get the config from the experiment_directory,
    # and overwrite relevant fields
    config = _get_config_from_experiment_directory(exp_dir)
    config.exp_dir = exp_dir
    # important so that the CO3D dataset gets loaded in full
    dataset_args = (
        config.data_source_args.dataset_map_provider_JsonIndexDatasetMapProvider_args
    )
    dataset_args.test_on_train = False
    # Set the rendering image size
    model_factory_args = config.model_factory_ImplicitronModelFactory_args
    model_args = model_factory_args.model_GenericModel_args
    model_args.render_image_width = render_size[0]
    model_args.render_image_height = render_size[1]
    if restrict_sequence_name is not None:
        dataset_args.restrict_sequence_name = restrict_sequence_name

    # Load the previously trained model
    experiment = Experiment(config)
    model = experiment.model_factory(force_resume=True)
    model.cuda()
    model.eval()

    # Setup the dataset
    data_source = experiment.data_source
    dataset_map, _ = data_source.get_datasets_and_dataloaders()
    dataset = dataset_map[split]
    if dataset is None:
        raise ValueError(f"{split} dataset not provided")

    # iterate over the sequences in the dataset
    for sequence_name in dataset.sequence_names():
        with torch.no_grad():
            render_flyaround(
                dataset=dataset,
                sequence_name=sequence_name,
                model=model,
                output_video_path=os.path.join(output_directory, "video"),
                n_source_views=n_source_views,
                visdom_show_preds=visdom_show_preds,
                n_flyaround_poses=n_eval_cameras,
                visdom_server=visdom_server,
                visdom_port=visdom_port,
                visdom_environment=f"visualizer_{config.visdom_env}"
                if visdom_env is None
                else visdom_env,
                video_resize=video_size,
            )


def _get_config_from_experiment_directory(experiment_directory):
    cfg_file = os.path.join(experiment_directory, "expconfig.yaml")
    config = OmegaConf.load(cfg_file)
    return config


def main(argv):
    # automatically parses arguments of visualize_reconstruction
    cfg = OmegaConf.create(get_default_args(visualize_reconstruction))
    cfg.update(OmegaConf.from_cli())
    with torch.no_grad():
        visualize_reconstruction(**cfg)


if __name__ == "__main__":
    main(sys.argv)
