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# examples/python/t_reconstruction_system/ray_casting.py

# P.S. This example is used in documentation, so, please ensure the changes are
# synchronized.

import os
import numpy as np
import open3d as o3d
import open3d.core as o3c
import time
import matplotlib.pyplot as plt

from tqdm import tqdm
from config import ConfigParser
from common import load_depth_file_names, load_intrinsic, load_extrinsics, get_default_dataset, extract_rgbd_frames
import matplotlib.pyplot as plt
import numpy as np

if __name__ == '__main__':
    parser = ConfigParser()
    parser.add(
        '--config',
        is_config_file=True,
        help='YAML config file path. Please refer to default_config.yml as a '
        'reference. It overrides the default config file, but will be '
        'overridden by other command line inputs.')
    parser.add('--default_dataset',
               help='Default dataset is used when config file is not provided. '
               'Default dataset may be selected from the following options: '
               '[lounge, jack_jack]',
               default='lounge')
    parser.add('--path_trajectory',
               help='path to the trajectory .log or .json file.')
    parser.add('--path_npz',
               required=True,
               help='path to the npz file that stores voxel block grid.')
    config = parser.get_config()

    if config.path_dataset == '':
        config = get_default_dataset(config)

    # Extract RGB-D frames and intrinsic from bag file.
    if config.path_dataset.endswith(".bag"):
        assert os.path.isfile(
            config.path_dataset), (f"File {config.path_dataset} not found.")
        print("Extracting frames from RGBD video file")
        config.path_dataset, config.path_intrinsic, config.depth_scale = extract_rgbd_frames(
            config.path_dataset)

    vbg = o3d.t.geometry.VoxelBlockGrid.load(config.path_npz)
    depth_file_names = load_depth_file_names(config)
    intrinsic = load_intrinsic(config)
    extrinsics = load_extrinsics(config.path_trajectory, config)
    device = o3d.core.Device(config.device)

    for i, extrinsic in tqdm(enumerate(extrinsics)):
        depth = o3d.t.io.read_image(depth_file_names[i]).to(device)
        frustum_block_coords = vbg.compute_unique_block_coordinates(
            depth, intrinsic, extrinsic, config.depth_scale, config.depth_max)

        result = vbg.ray_cast(block_coords=frustum_block_coords,
                              intrinsic=intrinsic,
                              extrinsic=extrinsic,
                              width=depth.columns,
                              height=depth.rows,
                              render_attributes=[
                                  'depth', 'normal', 'color', 'index',
                                  'interp_ratio'
                              ],
                              depth_scale=config.depth_scale,
                              depth_min=config.depth_min,
                              depth_max=config.depth_max,
                              weight_threshold=1,
                              range_map_down_factor=8)

        fig, axs = plt.subplots(2, 2)

        # Colorized depth
        colorized_depth = o3d.t.geometry.Image(result['depth']).colorize_depth(
            config.depth_scale, config.depth_min, config.depth_max)

        # Render color via indexing
        vbg_color = vbg.attribute('color').reshape((-1, 3))
        nb_indices = result['index'].reshape((-1))
        nb_interp_ratio = result['interp_ratio'].reshape((-1, 1))
        nb_colors = vbg_color[nb_indices] * nb_interp_ratio
        sum_colors = nb_colors.reshape((depth.rows, depth.columns, 8, 3)).sum(
            (2)) / 255.0

        axs[0, 0].imshow(colorized_depth.as_tensor().cpu().numpy())
        axs[0, 0].set_title('depth')

        axs[0, 1].imshow(result['normal'].cpu().numpy())
        axs[0, 1].set_title('normal')

        axs[1, 0].imshow(result['color'].cpu().numpy())
        axs[1, 0].set_title('color via kernel')

        axs[1, 1].imshow(sum_colors.cpu().numpy())
        axs[1, 1].set_title('color via indexing')

        plt.tight_layout()
        plt.show()
