# Modifications Copyright 2021 - present, OpenDR European Project
#
# Copyright 2021 RangiLyu.
#
# 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 copy
from opendr.engine.datasets import ExternalDataset
from opendr.perception.object_detection_2d.datasets import XMLBasedDataset
from opendr.perception.object_detection_2d.nanodet.algorithm.nanodet.data.dataset.coco import CocoDataset
from opendr.perception.object_detection_2d.nanodet.algorithm.nanodet.data.dataset.xml_dataset import XMLDataset


def build_dataset(cfg, dataset, class_names, mode, verbose=True):
    dataset_cfg = copy.deepcopy(cfg)
    supported_datasets = ['coco', 'voc']
    if isinstance(dataset, ExternalDataset):
        if dataset.dataset_type.lower() not in supported_datasets:
            raise UserWarning("ExternalDataset dataset_type must be one of: ", supported_datasets)

        if verbose:
            print("Loading {} type dataset...".format(dataset.dataset_type))
            print("From {}".format(dataset.path))

        if dataset.dataset_type.lower() == 'voc':
            if mode == "train":
                img_path = "{}/train/JPEGImages".format(dataset.path)
                ann_path = "{}/train/Annotations".format(dataset.path)
            else:
                img_path = "{}/val/JPEGImages".format(dataset.path)
                ann_path = "{}/val/Annotations".format(dataset.path)
            dataset = XMLDataset(img_path=img_path, ann_path=ann_path, mode=mode,
                                 class_names=class_names, **dataset_cfg)

        elif dataset.dataset_type.lower() == 'coco':
            if mode == "train":
                img_path = "{}/train2017".format(dataset.path)
                ann_path = "{}/annotations/instances_train2017.json".format(dataset.path)
            else:
                img_path = "{}/val2017".format(dataset.path)
                ann_path = "{}/annotations/instances_val2017.json".format(dataset.path)
            dataset = CocoDataset(img_path=img_path, ann_path=ann_path, mode=mode, **dataset_cfg)
        if verbose:
            print("ExternalDataset loaded.")
        return dataset
    elif isinstance(dataset, XMLBasedDataset):
        dataset = XMLDataset(img_path=dataset.abs_images_dir, ann_path=dataset.abs_annot_dir, mode=mode,
                             class_names=dataset.classes, **dataset_cfg)
        return dataset
    elif isinstance(dataset, XMLDataset) or isinstance(dataset, CocoDataset):
        return dataset
    else:
        raise ValueError("Dataset type {} not supported".format(type(dataset)))
