import mmcv
import numpy as np

from mmdet.datasets.builder import PIPELINES
from mmdet.datasets.pipelines import LoadAnnotations


@PIPELINES.register_module()
class LoadMultiViewImageFromFiles(object):
    """Load multi channel images from a list of separate channel files.

    Expects results['img_filename'] to be a list of filenames
    """

    def __init__(self, to_float32=False, color_type='unchanged'):
        self.to_float32 = to_float32
        self.color_type = color_type

    def __call__(self, results):
        filename = results['img_filename']
        img = np.stack(
            [mmcv.imread(name, self.color_type) for name in filename], axis=-1)
        if self.to_float32:
            img = img.astype(np.float32)
        results['filename'] = filename
        results['img'] = img
        results['img_shape'] = img.shape
        results['ori_shape'] = img.shape
        # Set initial values for default meta_keys
        results['pad_shape'] = img.shape
        results['scale_factor'] = 1.0
        num_channels = 1 if len(img.shape) < 3 else img.shape[2]
        results['img_norm_cfg'] = dict(
            mean=np.zeros(num_channels, dtype=np.float32),
            std=np.ones(num_channels, dtype=np.float32),
            to_rgb=False)
        return results

    def __repr__(self):
        return "{} (to_float32={}, color_type='{}')".format(
            self.__class__.__name__, self.to_float32, self.color_type)


@PIPELINES.register_module()
class LoadPointsFromMultiSweeps(object):
    """Load points from multiple sweeps.

    This is usually used for nuScenes dataset to utilize previous sweeps.

    Args:
        sweeps_num (int): number of sweeps
        load_dim (int): dimension number of the loaded points
        file_client_args (dict): Config dict of file clients, refer to
            https://github.com/open-mmlab/mmcv/blob/master/mmcv/fileio/file_client.py
            for more details.
    """

    def __init__(self,
                 sweeps_num=10,
                 load_dim=5,
                 file_client_args=dict(backend='disk')):
        self.load_dim = load_dim
        self.sweeps_num = sweeps_num
        self.file_client_args = file_client_args.copy()
        self.file_client = None

    def _load_points(self, pts_filename):
        if self.file_client is None:
            self.file_client = mmcv.FileClient(**self.file_client_args)
        try:
            pts_bytes = self.file_client.get(pts_filename)
            points = np.frombuffer(pts_bytes, dtype=np.float32)
        except ConnectionError:
            mmcv.check_file_exist(pts_filename)
            if pts_filename.endswith('.npy'):
                points = np.load(pts_filename)
            else:
                points = np.fromfile(pts_filename, dtype=np.float32)
        return points

    def __call__(self, results):
        points = results['points']
        points[:, 3] /= 255
        points[:, 4] = 0
        sweep_points_list = [points]
        ts = results['timestamp']

        for idx, sweep in enumerate(results['sweeps']):
            if idx >= self.sweeps_num:
                break
            points_sweep = self._load_points(sweep['data_path'])
            points_sweep = np.copy(points_sweep).reshape(-1, self.load_dim)
            sweep_ts = sweep['timestamp'] / 1e6
            points_sweep[:, 3] /= 255
            points_sweep[:, :3] = points_sweep[:, :3] @ sweep[
                'sensor2lidar_rotation'].T
            points_sweep[:, :3] += sweep['sensor2lidar_translation']
            points_sweep[:, 4] = ts - sweep_ts
            sweep_points_list.append(points_sweep)

        points = np.concatenate(sweep_points_list, axis=0)[:, [0, 1, 2, 4]]
        results['points'] = points
        return results

    def __repr__(self):
        return f'{self.__class__.__name__}(sweeps_num={self.sweeps_num})'


@PIPELINES.register_module()
class PointSegClassMapping(object):
    """Map original semantic class to valid category ids.

    Map valid classes as 0~len(valid_cat_ids)-1 and
    others as len(valid_cat_ids).

    Args:
        valid_cat_ids (tuple[int]): A tuple of valid category.
    """

    def __init__(self, valid_cat_ids):
        self.valid_cat_ids = valid_cat_ids

    def __call__(self, results):
        assert 'pts_semantic_mask' in results
        pts_semantic_mask = results['pts_semantic_mask']
        neg_cls = len(self.valid_cat_ids)

        for i in range(pts_semantic_mask.shape[0]):
            if pts_semantic_mask[i] in self.valid_cat_ids:
                converted_id = self.valid_cat_ids.index(pts_semantic_mask[i])
                pts_semantic_mask[i] = converted_id
            else:
                pts_semantic_mask[i] = neg_cls

        results['pts_semantic_mask'] = pts_semantic_mask
        return results

    def __repr__(self):
        repr_str = self.__class__.__name__
        repr_str += '(valid_cat_ids={})'.format(self.valid_cat_ids)
        return repr_str


@PIPELINES.register_module()
class NormalizePointsColor(object):
    """Normalize color of points.

    Args:
        color_mean (list[float]): Mean color of the point cloud.
    """

    def __init__(self, color_mean):
        self.color_mean = color_mean

    def __call__(self, results):
        points = results['points']
        assert points.shape[1] >= 6,\
            f'Expect points have channel >=6, got {points.shape[1]}'
        points[:, 3:6] = points[:, 3:6] - np.array(self.color_mean) / 256.0
        results['points'] = points
        return results

    def __repr__(self):
        repr_str = self.__class__.__name__
        repr_str += '(color_mean={})'.format(self.color_mean)
        return repr_str


@PIPELINES.register_module()
class LoadPointsFromFile(object):
    """Load Points From File.

    Load sunrgbd and scannet points from file.

    Args:
        shift_height (bool): Whether to use shifted height.
        load_dim (int): The dimension of the loaded points.
            Default: 6.
        use_dim (list[int]): Which dimensions of the points to be used.
            Default: [0, 1, 2]. For KITTI dataset, set use_dim=4
            or use_dim=[0, 1, 2, 3] to use the intensity dimension
        file_client_args (dict): Config dict of file clients, refer to
            https://github.com/open-mmlab/mmcv/blob/master/mmcv/fileio/file_client.py
            for more details.
    """

    def __init__(self,
                 load_dim=6,
                 use_dim=[0, 1, 2],
                 shift_height=False,
                 file_client_args=dict(backend='disk')):
        self.shift_height = shift_height
        if isinstance(use_dim, int):
            use_dim = list(range(use_dim))
        assert max(use_dim) < load_dim, \
            f'Expect all used dimensions < {load_dim}, got {use_dim}'

        self.load_dim = load_dim
        self.use_dim = use_dim
        self.file_client_args = file_client_args.copy()
        self.file_client = None

    def _load_points(self, pts_filename):
        if self.file_client is None:
            self.file_client = mmcv.FileClient(**self.file_client_args)
        try:
            pts_bytes = self.file_client.get(pts_filename)
            points = np.frombuffer(pts_bytes, dtype=np.float32)
        except ConnectionError:
            mmcv.check_file_exist(pts_filename)
            if pts_filename.endswith('.npy'):
                points = np.load(pts_filename)
            else:
                points = np.fromfile(pts_filename, dtype=np.float32)
        return points

    def __call__(self, results):
        pts_filename = results['pts_filename']
        points = self._load_points(pts_filename)
        points = points.reshape(-1, self.load_dim)
        points = points[:, self.use_dim]

        if self.shift_height:
            floor_height = np.percentile(points[:, 2], 0.99)
            height = points[:, 2] - floor_height
            points = np.concatenate([points, np.expand_dims(height, 1)], 1)
        results['points'] = points
        return results

    def __repr__(self):
        repr_str = self.__class__.__name__ + '('
        repr_str += 'shift_height={}, '.format(self.shift_height)
        repr_str += 'file_client_args={}), '.format(self.file_client_args)
        repr_str += 'load_dim={}, '.format(self.load_dim)
        repr_str += 'use_dim={})'.format(self.use_dim)
        return repr_str


@PIPELINES.register_module()
class LoadAnnotations3D(LoadAnnotations):
    """Load Annotations3D.

    Load instance mask and semantic mask of points and
    encapsulate the items into related fields.

    Args:
        with_bbox_3d (bool, optional): Whether to load 3D boxes.
            Defaults to True.
        with_label_3d (bool, optional): Whether to load 3D labels.
            Defaults to True.
        with_mask_3d (bool, optional): Whether to load 3D instance masks.
            for points. Defaults to False.
        with_seg_3d (bool, optional): Whether to load 3D semantic masks.
            for points. Defaults to False.
        with_bbox (bool, optional): Whether to load 2D boxes.
            Defaults to False.
        with_label (bool, optional): Whether to load 2D labels.
            Defaults to False.
        with_mask (bool, optional): Whether to load 2D instance masks.
            Defaults to False.
        with_seg (bool, optional): Whether to load 2D semantic masks.
            Defaults to False.
        poly2mask (bool, optional): Whether to convert polygon annotations
            to bitmasks. Defaults to True.
        file_client_args (dict): Config dict of file clients, refer to
            https://github.com/open-mmlab/mmcv/blob/master/mmcv/fileio/file_client.py
            for more details.
    """

    def __init__(self,
                 with_bbox_3d=True,
                 with_label_3d=True,
                 with_mask_3d=False,
                 with_seg_3d=False,
                 with_bbox=False,
                 with_label=False,
                 with_mask=False,
                 with_seg=False,
                 poly2mask=True,
                 file_client_args=dict(backend='disk')):
        super().__init__(
            with_bbox,
            with_label,
            with_mask,
            with_seg,
            poly2mask,
            file_client_args=file_client_args)
        self.with_bbox_3d = with_bbox_3d
        self.with_label_3d = with_label_3d
        self.with_mask_3d = with_mask_3d
        self.with_seg_3d = with_seg_3d

    def _load_bboxes_3d(self, results):
        results['gt_bboxes_3d'] = results['ann_info']['gt_bboxes_3d']
        results['bbox3d_fields'].append('gt_bboxes_3d')
        return results

    def _load_labels_3d(self, results):
        results['gt_labels_3d'] = results['ann_info']['gt_labels_3d']
        return results

    def _load_masks_3d(self, results):
        pts_instance_mask_path = results['ann_info']['pts_instance_mask_path']

        if self.file_client is None:
            self.file_client = mmcv.FileClient(**self.file_client_args)
        try:
            mask_bytes = self.file_client.get(pts_instance_mask_path)
            pts_instance_mask = np.frombuffer(mask_bytes, dtype=np.int)
        except ConnectionError:
            mmcv.check_file_exist(pts_instance_mask_path)
            pts_instance_mask = np.fromfile(
                pts_instance_mask_path, dtype=np.long)

        results['pts_instance_mask'] = pts_instance_mask
        results['pts_mask_fields'].append('pts_instance_mask')
        return results

    def _load_semantic_seg_3d(self, results):
        pts_semantic_mask_path = results['ann_info']['pts_semantic_mask_path']

        if self.file_client is None:
            self.file_client = mmcv.FileClient(**self.file_client_args)
        try:
            mask_bytes = self.file_client.get(pts_semantic_mask_path)
            # add .copy() to fix read-only bug
            pts_semantic_mask = np.frombuffer(mask_bytes, dtype=np.int).copy()
        except ConnectionError:
            mmcv.check_file_exist(pts_semantic_mask_path)
            pts_semantic_mask = np.fromfile(
                pts_semantic_mask_path, dtype=np.long)

        results['pts_semantic_mask'] = pts_semantic_mask
        results['pts_seg_fields'].append('pts_semantic_mask')
        return results

    def __call__(self, results):
        results = super().__call__(results)
        if self.with_bbox_3d:
            results = self._load_bboxes_3d(results)
            if results is None:
                return None
        if self.with_label_3d:
            results = self._load_labels_3d(results)
        if self.with_mask_3d:
            results = self._load_masks_3d(results)
        if self.with_seg_3d:
            results = self._load_semantic_seg_3d(results)

        return results

    def __repr__(self):
        indent_str = '    '
        repr_str = self.__class__.__name__ + '(\n'
        repr_str += f'{indent_str}with_bbox_3d={self.with_bbox_3d}, '
        repr_str += f'{indent_str}with_label_3d={self.with_label_3d}, '
        repr_str += f'{indent_str}with_mask_3d={self.with_mask_3d}, '
        repr_str += f'{indent_str}with_seg_3d={self.with_seg_3d}, '
        repr_str += f'{indent_str}with_bbox={self.with_bbox}, '
        repr_str += f'{indent_str}with_label={self.with_label}, '
        repr_str += f'{indent_str}with_mask={self.with_mask}, '
        repr_str += f'{indent_str}with_seg={self.with_seg}, '
        repr_str += f'{indent_str}poly2mask={self.poly2mask})'
        return repr_str
