# Copyright (c) OpenMMLab. All rights reserved.
from concurrent import futures as futures
from os import path as osp

import mmcv
import numpy as np
from scipy import io as sio


def random_sampling(points, num_points, replace=None):
    """Random sampling.

    Sampling point cloud to a certain number of points.

    Args:
        points (ndarray): Point cloud.
        num_points (int): The number of samples.
        replace (bool): Whether the sample is with or without replacement.

    Returns:
        points (ndarray): Point cloud after sampling.
    """
    if num_points < 0:
        return points
    if replace is None:
        replace = (points.shape[0] < num_points)
    choices = np.random.choice(points.shape[0], num_points, replace=replace)
    return points[choices]


class SUNRGBDInstance(object):

    def __init__(self, line):
        data = line.split(' ')
        data[1:] = [float(x) for x in data[1:]]
        self.classname = data[0]
        self.xmin = data[1]
        self.ymin = data[2]
        self.xmax = data[1] + data[3]
        self.ymax = data[2] + data[4]
        self.box2d = np.array([self.xmin, self.ymin, self.xmax, self.ymax])
        self.centroid = np.array([data[5], data[6], data[7]])
        self.width = data[8]
        self.length = data[9]
        self.height = data[10]
        # data[9] is x_size (length), data[8] is y_size (width), data[10] is
        # z_size (height) in our depth coordinate system,
        # l corresponds to the size along the x axis
        self.size = np.array([data[9], data[8], data[10]]) * 2
        self.orientation = np.zeros((3,))
        self.orientation[0] = data[11]
        self.orientation[1] = data[12]
        self.heading_angle = np.arctan2(self.orientation[1],
                                        self.orientation[0])
        self.box3d = np.concatenate(
            [self.centroid, self.size, self.heading_angle[None]])


class SUNRGBDData(object):
    """SUNRGBD data.

    Generate scannet infos for sunrgbd_converter.

    Args:
        root_path (str): Root path of the raw data.
        split (str, optional): Set split type of the data. Default: 'train'.
        use_v1 (bool, optional): Whether to use v1. Default: False.
        num_points (int, optional): Number of points to sample. Set to -1
            to utilize all points. Defaults to -1.
    """

    def __init__(self, root_path, split='train', use_v1=False, num_points=-1):
        self.root_dir = root_path
        self.split = split
        self.split_dir = osp.join(root_path, 'sunrgbd_trainval')
        self.num_points = num_points
        self.classes = [
            'bed', 'table', 'sofa', 'chair', 'toilet', 'desk', 'dresser',
            'night_stand', 'bookshelf', 'bathtub'
        ]
        self.cat2label = {cat: self.classes.index(cat) for cat in self.classes}
        self.label2cat = {
            label: self.classes[label]
            for label in range(len(self.classes))
        }
        assert split in ['train', 'val', 'test']
        split_file = osp.join(self.split_dir, f'{split}_data_idx.txt')
        mmcv.check_file_exist(split_file)
        self.sample_id_list = map(int, mmcv.list_from_file(split_file))
        self.image_dir = osp.join(self.split_dir, 'image')
        self.calib_dir = osp.join(self.split_dir, 'calib')
        self.depth_dir = osp.join(self.split_dir, 'depth')
        if use_v1:
            self.label_dir = osp.join(self.split_dir, 'label_v1')
        else:
            self.label_dir = osp.join(self.split_dir, 'label')

    def __len__(self):
        return len(self.sample_id_list)

    def get_image(self, idx):
        img_filename = osp.join(self.image_dir, f'{idx:06d}.jpg')
        return mmcv.imread(img_filename)

    def get_image_shape(self, idx):
        image = self.get_image(idx)
        return np.array(image.shape[:2], dtype=np.int32)

    def get_depth(self, idx):
        depth_filename = osp.join(self.depth_dir, f'{idx:06d}.mat')
        depth = sio.loadmat(depth_filename)['instance']
        return depth

    def get_calibration(self, idx):
        calib_filepath = osp.join(self.calib_dir, f'{idx:06d}.txt')
        lines = [line.rstrip() for line in open(calib_filepath)]
        Rt = np.array([float(x) for x in lines[0].split(' ')])
        Rt = np.reshape(Rt, (3, 3), order='F').astype(np.float32)
        K = np.array([float(x) for x in lines[1].split(' ')])
        K = np.reshape(K, (3, 3), order='F').astype(np.float32)
        return K, Rt

    def get_label_objects(self, idx):
        label_filename = osp.join(self.label_dir, f'{idx:06d}.txt')
        lines = [line.rstrip() for line in open(label_filename)]
        objects = [SUNRGBDInstance(line) for line in lines]
        return objects

    def get_infos(self, num_workers=4, has_label=True, sample_id_list=None):
        """Get data infos.

        This method gets information from the raw data.

        Args:
            num_workers (int, optional): Number of threads to be used.
                Default: 4.
            has_label (bool, optional): Whether the data has label.
                Default: True.
            sample_id_list (list[int], optional): Index list of the sample.
                Default: None.

        Returns:
            infos (list[dict]): Information of the raw data.
        """

        def process_single_scene(sample_idx):
            print(f'{self.split} sample_idx: {sample_idx}')
            # convert depth to points
            pc_upright_depth = self.get_depth(sample_idx)
            pc_upright_depth_subsampled = random_sampling(
                pc_upright_depth, self.num_points)

            info = dict()
            pc_info = {'num_features': 6, 'lidar_idx': sample_idx}
            info['point_cloud'] = pc_info

            mmcv.mkdir_or_exist(osp.join(self.root_dir, 'points'))
            pc_upright_depth_subsampled.tofile(
                osp.join(self.root_dir, 'points', f'{sample_idx:06d}.bin'))

            info['pts_path'] = osp.join('points', f'{sample_idx:06d}.bin')
            img_path = osp.join('image', f'{sample_idx:06d}.jpg')
            image_info = {
                'image_idx': sample_idx,
                'image_shape': self.get_image_shape(sample_idx),
                'image_path': img_path
            }
            info['image'] = image_info

            K, Rt = self.get_calibration(sample_idx)
            calib_info = {'K': K, 'Rt': Rt}
            info['calib'] = calib_info

            if has_label:
                obj_list = self.get_label_objects(sample_idx)
                annotations = {}
                annotations['gt_num'] = len([
                    obj.classname for obj in obj_list
                    if obj.classname in self.cat2label.keys()
                ])
                if annotations['gt_num'] != 0:
                    annotations['name'] = np.array([
                        obj.classname for obj in obj_list
                        if obj.classname in self.cat2label.keys()
                    ])
                    annotations['bbox'] = np.concatenate([
                        obj.box2d.reshape(1, 4) for obj in obj_list
                        if obj.classname in self.cat2label.keys()
                    ],
                        axis=0)
                    annotations['location'] = np.concatenate([
                        obj.centroid.reshape(1, 3) for obj in obj_list
                        if obj.classname in self.cat2label.keys()
                    ],
                        axis=0)
                    annotations['dimensions'] = 2 * np.array([
                        [obj.length, obj.width, obj.height] for obj in obj_list
                        if obj.classname in self.cat2label.keys()
                    ])  # lwh (depth) format
                    annotations['rotation_y'] = np.array([
                        obj.heading_angle for obj in obj_list
                        if obj.classname in self.cat2label.keys()
                    ])
                    annotations['index'] = np.arange(
                        len(obj_list), dtype=np.int32)
                    annotations['class'] = np.array([
                        self.cat2label[obj.classname] for obj in obj_list
                        if obj.classname in self.cat2label.keys()
                    ])
                    annotations['gt_boxes_upright_depth'] = np.stack(
                        [
                            obj.box3d for obj in obj_list
                            if obj.classname in self.cat2label.keys()
                        ],
                        axis=0)  # (K,8)
                info['annos'] = annotations
            return info

        sample_id_list = sample_id_list if \
            sample_id_list is not None else self.sample_id_list
        with futures.ThreadPoolExecutor(num_workers) as executor:
            infos = executor.map(process_single_scene, sample_id_list)
        return list(infos)
