# Copyright (c) OpenMMLab. All rights reserved.

import os.path as osp
from typing import Callable, List, Optional, Union

import numpy as np

from mmdet3d.registry import DATASETS
from mmdet3d.structures import DepthInstance3DBoxes
from .det3d_dataset import Det3DDataset


@DATASETS.register_module()
class SUNRGBDDataset(Det3DDataset):
    r"""SUNRGBD Dataset.

    This class serves as the API for experiments on the SUNRGBD Dataset.

    See the `download page <http://rgbd.cs.princeton.edu/challenge.html>`_
    for data downloading.

    Args:
        data_root (str): Path of dataset root.
        ann_file (str): Path of annotation file.
        metainfo (dict, optional): Meta information for dataset, such as class
            information. Defaults to None.
        data_prefix (dict): Prefix for data. Defaults to
            `dict(pts='points',img='sunrgbd_trainval')`.
        pipeline (list[dict], optional): Pipeline used for data processing.
            Defaults to None.
        modality (dict, optional): Modality to specify the sensor data used
            as input. Defaults to `dict(use_camera=True, use_lidar=True)`.
        default_cam_key (str): The default camera name adopted.
            Defaults to "CAM0".
        box_type_3d (str): Type of 3D box of this dataset.
            Based on the `box_type_3d`, the dataset will encapsulate the box
            to its original format then converted them to `box_type_3d`.
            Defaults to 'Depth' in this dataset. Available options includes

            - 'LiDAR': Box in LiDAR coordinates.
            - 'Depth': Box in depth coordinates, usually for indoor dataset.
            - 'Camera': Box in camera coordinates.
        filter_empty_gt (bool): Whether to filter empty GT.
            Defaults to True.
        test_mode (bool): Whether the dataset is in test mode.
            Defaults to False.
    """
    METAINFO = {
        'CLASSES': ('bed', 'table', 'sofa', 'chair', 'toilet', 'desk',
                    'dresser', 'night_stand', 'bookshelf', 'bathtub')
    }

    def __init__(self,
                 data_root: str,
                 ann_file: str,
                 metainfo: Optional[dict] = None,
                 data_prefix: dict = dict(
                     pts='points', img='sunrgbd_trainval/image'),
                 pipeline: List[Union[dict, Callable]] = [],
                 default_cam_key: str = 'CAM0',
                 modality=dict(use_camera=True, use_lidar=True),
                 box_type_3d: str = 'Depth',
                 filter_empty_gt: bool = True,
                 test_mode: bool = False,
                 **kwargs):
        super().__init__(
            data_root=data_root,
            ann_file=ann_file,
            metainfo=metainfo,
            data_prefix=data_prefix,
            pipeline=pipeline,
            default_cam_key=default_cam_key,
            modality=modality,
            box_type_3d=box_type_3d,
            filter_empty_gt=filter_empty_gt,
            test_mode=test_mode,
            **kwargs)
        assert 'use_camera' in self.modality and \
            'use_lidar' in self.modality
        assert self.modality['use_camera'] or self.modality['use_lidar']

    def parse_data_info(self, info: dict) -> dict:
        """Process the raw data info.

        Convert all relative path of needed modality data file to
        the absolute path. And process
        the `instances` field to `ann_info` in training stage.

        Args:
            info (dict): Raw info dict.

        Returns:
            dict: Has `ann_info` in training stage. And
            all path has been converted to absolute path.
        """

        if self.modality['use_lidar']:
            info['lidar_points']['lidar_path'] = \
                osp.join(
                    self.data_prefix.get('pts', ''),
                    info['lidar_points']['lidar_path'])

        if self.modality['use_camera']:
            for cam_id, img_info in info['images'].items():
                if 'img_path' in img_info:
                    img_info['img_path'] = osp.join(
                        self.data_prefix.get('img', ''), img_info['img_path'])
            if self.default_cam_key is not None:
                info['img_path'] = info['images'][
                    self.default_cam_key]['img_path']
                info['depth2img'] = np.array(
                    info['images'][self.default_cam_key]['depth2img'],
                    dtype=np.float32)

        if not self.test_mode:
            # used in traing
            info['ann_info'] = self.parse_ann_info(info)
        if self.test_mode and self.load_eval_anns:
            info['eval_ann_info'] = self.parse_ann_info(info)

        return info

    def parse_ann_info(self, info: dict) -> dict:
        """Process the `instances` in data info to `ann_info`

        Args:
            info (dict): Info dict.

        Returns:
            dict: Processed `ann_info`
        """
        ann_info = super().parse_ann_info(info)
        # process data without any annotations
        if ann_info is None:
            ann_info = dict()
            ann_info['gt_bboxes_3d'] = np.zeros((0, 6), dtype=np.float32)
            ann_info['gt_labels_3d'] = np.zeros((0, ), dtype=np.int64)
        # to target box structure
        ann_info['gt_bboxes_3d'] = DepthInstance3DBoxes(
            ann_info['gt_bboxes_3d'],
            origin=(0.5, 0.5, 0.5)).convert_to(self.box_mode_3d)

        return ann_info
