import numpy as np
import pickle
from mmcv import track_iter_progress
from pathlib import Path

from mmdet3d.core.bbox import box_np_ops
from .kitti_data_utils import get_kitti_image_info


def convert_to_kitti_info_version2(info):
    """convert kitti info v1 to v2 if possible.

    Args:
        info (dict): Info of the input kitti data.
            - image (dict): image info
            - calib (dict): calibration info
            - point_cloud (dict): point cloud info
    """
    if 'image' not in info or 'calib' not in info or 'point_cloud' not in info:
        info['image'] = {
            'image_shape': info['img_shape'],
            'image_idx': info['image_idx'],
            'image_path': info['img_path'],
        }
        info['calib'] = {
            'R0_rect': info['calib/R0_rect'],
            'Tr_velo_to_cam': info['calib/Tr_velo_to_cam'],
            'P2': info['calib/P2'],
        }
        info['point_cloud'] = {
            'velodyne_path': info['velodyne_path'],
        }


def _read_imageset_file(path):
    with open(path, 'r') as f:
        lines = f.readlines()
    return [int(line) for line in lines]


def _calculate_num_points_in_gt(data_path,
                                infos,
                                relative_path,
                                remove_outside=True,
                                num_features=4):
    for info in track_iter_progress(infos):
        pc_info = info['point_cloud']
        image_info = info['image']
        calib = info['calib']
        if relative_path:
            v_path = str(Path(data_path) / pc_info['velodyne_path'])
        else:
            v_path = pc_info['velodyne_path']
        points_v = np.fromfile(
            v_path, dtype=np.float32, count=-1).reshape([-1, num_features])
        rect = calib['R0_rect']
        Trv2c = calib['Tr_velo_to_cam']
        P2 = calib['P2']
        if remove_outside:
            points_v = box_np_ops.remove_outside_points(
                points_v, rect, Trv2c, P2, image_info['image_shape'])

        # points_v = points_v[points_v[:, 0] > 0]
        annos = info['annos']
        num_obj = len([n for n in annos['name'] if n != 'DontCare'])
        # annos = kitti.filter_kitti_anno(annos, ['DontCare'])
        dims = annos['dimensions'][:num_obj]
        loc = annos['location'][:num_obj]
        rots = annos['rotation_y'][:num_obj]
        gt_boxes_camera = np.concatenate([loc, dims, rots[..., np.newaxis]],
                                         axis=1)
        gt_boxes_lidar = box_np_ops.box_camera_to_lidar(
            gt_boxes_camera, rect, Trv2c)
        indices = box_np_ops.points_in_rbbox(points_v[:, :3], gt_boxes_lidar)
        num_points_in_gt = indices.sum(0)
        num_ignored = len(annos['dimensions']) - num_obj
        num_points_in_gt = np.concatenate(
            [num_points_in_gt, -np.ones([num_ignored])])
        annos['num_points_in_gt'] = num_points_in_gt.astype(np.int32)


def create_kitti_info_file(data_path,
                           pkl_prefix='kitti_',
                           save_path=None,
                           relative_path=True):
    """Create info file of KITTI dataset.

    Given the raw data, generate its related info file in pkl format.

    Args:
        data_path (str): Path of the data root.
        pkl_prefix (str): Prefix of the info file to be generated.
        save_path (str): Path to save the info file.
        relative_path (bool): Whether to use relative path.
    """
    imageset_folder = Path(data_path) / 'ImageSets'
    train_img_ids = _read_imageset_file(str(imageset_folder / 'train.txt'))
    val_img_ids = _read_imageset_file(str(imageset_folder / 'val.txt'))
    test_img_ids = _read_imageset_file(str(imageset_folder / 'test.txt'))

    print('Generate info. this may take several minutes.')
    if save_path is None:
        save_path = Path(data_path)
    else:
        save_path = Path(save_path)
    kitti_infos_train = get_kitti_image_info(
        data_path,
        training=True,
        velodyne=True,
        calib=True,
        image_ids=train_img_ids,
        relative_path=relative_path)
    _calculate_num_points_in_gt(data_path, kitti_infos_train, relative_path)
    filename = save_path / f'{pkl_prefix}_infos_train.pkl'
    print(f'Kitti info train file is saved to {filename}')
    with open(filename, 'wb') as f:
        pickle.dump(kitti_infos_train, f)
    kitti_infos_val = get_kitti_image_info(
        data_path,
        training=True,
        velodyne=True,
        calib=True,
        image_ids=val_img_ids,
        relative_path=relative_path)
    _calculate_num_points_in_gt(data_path, kitti_infos_val, relative_path)
    filename = save_path / f'{pkl_prefix}_infos_val.pkl'
    print(f'Kitti info val file is saved to {filename}')
    with open(filename, 'wb') as f:
        pickle.dump(kitti_infos_val, f)
    filename = save_path / f'{pkl_prefix}_infos_trainval.pkl'
    print(f'Kitti info trainval file is saved to {filename}')
    with open(filename, 'wb') as f:
        pickle.dump(kitti_infos_train + kitti_infos_val, f)

    kitti_infos_test = get_kitti_image_info(
        data_path,
        training=False,
        label_info=False,
        velodyne=True,
        calib=True,
        image_ids=test_img_ids,
        relative_path=relative_path)
    filename = save_path / f'{pkl_prefix}_infos_test.pkl'
    print(f'Kitti info test file is saved to {filename}')
    with open(filename, 'wb') as f:
        pickle.dump(kitti_infos_test, f)


def _create_reduced_point_cloud(data_path,
                                info_path,
                                save_path=None,
                                back=False):
    with open(info_path, 'rb') as f:
        kitti_infos = pickle.load(f)

    for info in track_iter_progress(kitti_infos):
        pc_info = info['point_cloud']
        image_info = info['image']
        calib = info['calib']

        v_path = pc_info['velodyne_path']
        v_path = Path(data_path) / v_path
        points_v = np.fromfile(
            str(v_path), dtype=np.float32, count=-1).reshape([-1, 4])
        rect = calib['R0_rect']
        P2 = calib['P2']
        Trv2c = calib['Tr_velo_to_cam']
        # first remove z < 0 points
        # keep = points_v[:, -1] > 0
        # points_v = points_v[keep]
        # then remove outside.
        if back:
            points_v[:, 0] = -points_v[:, 0]
        points_v = box_np_ops.remove_outside_points(points_v, rect, Trv2c, P2,
                                                    image_info['image_shape'])
        if save_path is None:
            save_dir = v_path.parent.parent / (v_path.parent.stem + '_reduced')
            if not save_dir.exists():
                save_dir.mkdir()
            save_filename = save_dir / v_path.name
            # save_filename = str(v_path) + '_reduced'
            if back:
                save_filename += '_back'
        else:
            save_filename = str(Path(save_path) / v_path.name)
            if back:
                save_filename += '_back'
        with open(save_filename, 'w') as f:
            points_v.tofile(f)


def create_reduced_point_cloud(data_path,
                               pkl_prefix,
                               train_info_path=None,
                               val_info_path=None,
                               test_info_path=None,
                               save_path=None,
                               with_back=False):
    """Create reduced point cloud info file.

    Args:
        data_path (str): Path of original infos.
        pkl_prefix (str): Prefix of info files.
        train_info_path (str | None): Path of training set info.
            Default: None.
        val_info_path (str | None): Path of validation set info.
            Default: None.
        test_info_path (str | None): Path of test set info.
            Default: None.
        save_path (str | None): Path to save reduced info.
        with_back (bool | None): Whether to create backup info.
    """
    if train_info_path is None:
        train_info_path = Path(data_path) / f'{pkl_prefix}_infos_train.pkl'
    if val_info_path is None:
        val_info_path = Path(data_path) / f'{pkl_prefix}_infos_val.pkl'
    if test_info_path is None:
        test_info_path = Path(data_path) / f'{pkl_prefix}_infos_test.pkl'

    print('create reduced point cloud for training set')
    _create_reduced_point_cloud(data_path, train_info_path, save_path)
    print('create reduced point cloud for validatin set')
    _create_reduced_point_cloud(data_path, val_info_path, save_path)
    print('create reduced point cloud for testing set')
    _create_reduced_point_cloud(data_path, test_info_path, save_path)
    if with_back:
        _create_reduced_point_cloud(
            data_path, train_info_path, save_path, back=True)
        _create_reduced_point_cloud(
            data_path, val_info_path, save_path, back=True)
        _create_reduced_point_cloud(
            data_path, test_info_path, save_path, back=True)
