# Copyright (c) 2024 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import os
import pickle
import tarfile
from pathlib import Path
from typing import Any, Dict, List, Union

from ....utils import logging
from ....utils.cache import CACHE_DIR
from ....utils.download import download
from .base_batch_sampler import BaseBatchSampler


class Det3DBatchSampler(BaseBatchSampler):

    def __init__(self, temp_dir) -> None:
        super().__init__()
        self.temp_dir = temp_dir

    # XXX: auto download for url
    def _download_from_url(self, in_path: str) -> str:
        file_name = Path(in_path).name
        save_path = Path(CACHE_DIR) / "predict_input" / file_name
        download(in_path, save_path, overwrite=True)
        return save_path.as_posix()

    @property
    def batch_size(self) -> int:
        """Gets the batch size."""
        return self._batch_size

    @batch_size.setter
    def batch_size(self, batch_size: int) -> None:
        """Sets the batch size.

        Args:
            batch_size (int): The batch size to set.
        """
        if batch_size != 1:
            logging.warning(
                "inference for 3D models only support batch_size equal to 1"
            )
        self._batch_size = batch_size

    def load_annotations(self, ann_file: str, data_root_dir: str) -> List[Dict]:
        """Load annotations from ann_file.

        Args:
            ann_file (str): Path of the annotation file.
            data_root_dir: (str): Path of the data root directory.

        Returns:
            list[dict]: List of annotations sorted by timestamps.
        """
        data = pickle.load(open(ann_file, "rb"))
        data_infos = list(sorted(data["infos"], key=lambda e: e["timestamp"]))
        # append root_dir to image and lidar filepaths
        for item in data_infos:
            # lidar data
            lidar_path = item["lidar_path"]
            new_lidar_path = os.path.join(data_root_dir, lidar_path)
            item["lidar_path"] = new_lidar_path
            # camera data
            cam_data = item["cams"]
            for cam_data_item_key in cam_data:
                cam_data_item = cam_data[cam_data_item_key]
                cam_data_item_path = cam_data_item["data_path"]
                new_cam_data_item_path = os.path.join(data_root_dir, cam_data_item_path)
                cam_data_item["data_path"] = new_cam_data_item_path
            # sweep data
            sweeps = item["sweeps"]
            for sweep_item in sweeps:
                sweep_item_path = sweep_item["data_path"]
                new_sweep_item_path = os.path.join(data_root_dir, sweep_item_path)
                sweep_item["data_path"] = new_sweep_item_path
        return data_infos

    def sample(self, inputs: Union[List[str], str]):
        if not isinstance(inputs, list):
            inputs = [inputs]

        sample_set = []
        for input in inputs:
            if isinstance(input, str):
                ann_path = (
                    self._download_from_url(input)
                    if input.startswith("http")
                    else input
                )
            else:
                logging.warning(
                    f"Not supported input data type! Only `str` is supported! So has been ignored: {input}."
                )
            # extract tar file to tempdir
            dataset_name = self.extract_tar(ann_path, self.temp_dir)
            data_root_dir = os.path.join(self.temp_dir, dataset_name)
            ann_pkl_path = os.path.join(data_root_dir, "nuscenes_infos_val.pkl")
            self.data_infos = self.load_annotations(ann_pkl_path, data_root_dir)
            sample_set.extend(self.data_infos)

        batch = []
        for sample in sample_set:
            batch.append(sample)
            if len(batch) == self.batch_size:
                yield batch
                batch = []

        if len(batch) > 0:
            yield batch

    def _rand_batch(self, data_size: int) -> List[Any]:
        raise NotImplementedError(
            "rand batch is not supported for 3D detection annotation data"
        )

    def extract_tar(self, tar_path, extract_path="."):
        try:
            memdirs = set()
            with tarfile.open(tar_path, "r") as tar:
                for member in tar.getmembers():
                    memdir = member.name.split("/")[0]
                    memdirs.add(memdir)
                    tar.extract(member, path=extract_path)
                logging.info(f"file extract to {extract_path}")
            assert (
                len(memdirs) == 1
            ), "Only one base directory is allowed for 3d bev dataset!"
            return list(memdirs)[0]
        except Exception as e:
            logging.error(f"error occurred while extracting tar file")
            raise e