# Copyright (c) OpenMMLab. All rights reserved.
import numpy as np
from mmcv import BaseTransform
from mmcv.transforms import to_tensor
from mmengine import InstanceData

from mmdet3d.core import Det3DDataSample
from mmdet3d.core.bbox import BaseInstance3DBoxes
from mmdet3d.core.points import BasePoints
from mmdet3d.registry import TRANSFORMS


@TRANSFORMS.register_module()
class Pack3DDetInputs(BaseTransform):
    INPUTS_KEYS = ['points', 'img']
    INSTANCEDATA_3D_KEYS = [
        'gt_bboxes_3d', 'gt_labels_3d', 'attr_labels', 'depths', 'centers_2d'
    ]
    INSTANCEDATA_2D_KEYS = [
        'gt_bboxes',
        'gt_labels',
    ]

    SEG_KEYS = [
        'gt_seg_map', 'pts_instance_mask', 'pts_semantic_mask',
        'gt_semantic_seg'
    ]

    def __init__(
        self,
        keys: dict,
        meta_keys: dict = ('filename', 'ori_shape', 'img_shape', 'lidar2img',
                           'depth2img', 'cam2img', 'pad_shape', 'scale_factor',
                           'flip', 'pcd_horizontal_flip', 'pcd_vertical_flip',
                           'box_mode_3d', 'box_type_3d', 'img_norm_cfg',
                           'pcd_trans', 'sample_idx', 'pcd_scale_factor',
                           'pcd_rotation', 'pcd_rotation_angle',
                           'pts_filename', 'transformation_3d_flow',
                           'trans_mat', 'affine_aug')):
        self.keys = keys
        self.meta_keys = meta_keys

    def _remove_prefix(self, key: str) -> str:
        if key.startswith('gt_'):
            key = key[3:]
        return key

    def transform(self, results: dict) -> dict:
        """Method to pack the input data.

        Args:
            results (dict): Result dict from the data pipeline.

        Returns:
            dict:

            - 'inputs' (dict): The forward data of models. It usually contains
              following keys:

                - points
                - img

            - 'data_sample' (obj:`Det3DDataSample`): The annotation info of the
              sample.
        """
        packed_results = dict()

        # Format 3D data
        if 'points' in results:
            assert isinstance(results['points'], BasePoints)
            results['points'] = results['points'].tensor

        if 'img' in results:
            if isinstance(results['img'], list):
                # process multiple imgs in single frame
                imgs = [img.transpose(2, 0, 1) for img in results['img']]
                imgs = np.ascontiguousarray(np.stack(imgs, axis=0))
                results['img'] = to_tensor(imgs)
            else:
                img = results['img']
                if len(img.shape) < 3:
                    img = np.expand_dims(img, -1)
                results['img'] = np.ascontiguousarray(img.transpose(2, 0, 1))

        for key in [
                'proposals', 'gt_bboxes', 'gt_bboxes_ignore', 'gt_labels',
                'gt_labels_3d', 'attr_labels', 'pts_instance_mask',
                'pts_semantic_mask', 'centers2d', 'depths'
        ]:
            if key not in results:
                continue
            if isinstance(results[key], list):
                results[key] = [to_tensor(res) for res in results[key]]
            else:
                results[key] = to_tensor(results[key])
        if 'gt_bboxes_3d' in results:
            if not isinstance(results['gt_bboxes_3d'], BaseInstance3DBoxes):
                results['gt_bboxes_3d'] = to_tensor(results['gt_bboxes_3d'])

        if 'gt_semantic_seg' in results:
            results['gt_semantic_seg'] = to_tensor(
                results['gt_semantic_seg'][None])
        if 'gt_seg_map' in results:
            results['gt_seg_map'] = results['gt_seg_map'][None, ...]

        data_sample = Det3DDataSample()
        gt_instances_3d = InstanceData()
        gt_instances = InstanceData()
        seg_data = dict()

        img_metas = {}
        for key in self.meta_keys:
            if key in results:
                img_metas[key] = results[key]
        data_sample.set_metainfo(img_metas)

        inputs = {}
        for key in self.keys:
            if key in results:
                if key in self.INPUTS_KEYS:
                    inputs[key] = results[key]
                elif key in self.INSTANCEDATA_3D_KEYS:
                    gt_instances_3d[self._remove_prefix(key)] = results[key]
                elif key in self.INSTANCEDATA_2D_KEYS:
                    gt_instances[self._remove_prefix(key)] = results[key]
                elif key in self.SEG_KEYS:
                    seg_data[self._remove_prefix(key)] = results[key]
                else:
                    raise NotImplementedError(f'Please modified '
                                              f'`Pack3DDetInputs` '
                                              f'to put {key} to '
                                              f'corresponding field')

        data_sample.gt_instances_3d = gt_instances_3d
        data_sample.gt_instances = gt_instances
        data_sample.seg_data = seg_data
        packed_results['data_sample'] = data_sample
        packed_results['inputs'] = inputs

        return packed_results

    def __repr__(self) -> str:
        repr_str = self.__class__.__name__
        repr_str += f'(keys={self.keys})'
        repr_str += f'(meta_keys={self.meta_keys})'
        return repr_str
