# Copyright 2020 The HuggingFace Datasets Authors and the current dataset script contributor.
#
# 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.
"""Wikipedia-Utils: Preprocessed Wikipedia Texts for NLP"""


import json
from typing import Dict, Iterator, List, Tuple, Union

import datasets


_DESCRIPTION = "Preprocessed Wikipedia texts generated with scripts in singletongue/wikipedia-utils repo."

_HOMEPAGE = "https://github.com/singletongue/wikipedia-utils"

_LICENSE = "The content of Wikipedia is licensed under the CC-BY-SA 3.0 and GFDL licenses."

_URL_BASE = "https://github.com/singletongue/wikipedia-utils/releases/download"
_URLS = {
    "corpus-jawiki-20230403": f"{_URL_BASE}/2023-04-03/corpus-jawiki-20230403.txt.gz",
    "corpus-jawiki-20230403-cirrus": f"{_URL_BASE}/2023-04-03/corpus-jawiki-20230403-cirrus.txt.gz",
    "corpus-jawiki-20230403-filtered-large": f"{_URL_BASE}/2023-04-03/corpus-jawiki-20230403-filtered-large.txt.gz",
    "paragraphs-jawiki-20230403": f"{_URL_BASE}/2023-04-03/paragraphs-jawiki-20230403.json.gz",
    "passages-c300-jawiki-20230403": f"{_URL_BASE}/2023-04-03/passages-c300-jawiki-20230403.json.gz",
    "passages-c400-jawiki-20230403": f"{_URL_BASE}/2023-04-03/passages-c400-jawiki-20230403.json.gz",
    "passages-para-jawiki-20230403": f"{_URL_BASE}/2023-04-03/passages-para-jawiki-20230403.json.gz",
}

_VERSION = datasets.Version("1.0.0")


class WikipediaUtils(datasets.GeneratorBasedBuilder):
    """Wikipedia-Utils dataset."""

    BUILDER_CONFIGS = [datasets.BuilderConfig(name=name, version=_VERSION) for name in _URLS.keys()]

    def _info(self) -> datasets.DatasetInfo:
        if self.config.name.startswith("corpus"):
            features = datasets.Features({"text": datasets.Value("string")})
        elif self.config.name.startswith("paragraphs"):
            features = datasets.Features(
                {
                    "id": datasets.Value("string"),
                    "pageid": datasets.Value("int64"),
                    "revid": datasets.Value("int64"),
                    "paragraph_index": datasets.Value("int64"),
                    "title": datasets.Value("string"),
                    "section": datasets.Value("string"),
                    "text": datasets.Value("string"),
                    "html_tag": datasets.Value("string"),
                }
            )
        elif self.config.name.startswith("passages"):
            features = datasets.Features(
                {
                    "id": datasets.Value("int64"),
                    "pageid": datasets.Value("int64"),
                    "revid": datasets.Value("int64"),
                    "title": datasets.Value("string"),
                    "section": datasets.Value("string"),
                    "text": datasets.Value("string"),
                }
            )
        else:
            raise ValueError("Invalid dataset config name is specified.")

        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=features,
            homepage=_HOMEPAGE,
            license=_LICENSE,
        )

    def _split_generators(self, dl_manager: datasets.DownloadManager) -> List[datasets.SplitGenerator]:
        url = _URLS[self.config.name]
        filepath = dl_manager.download_and_extract(url)
        return [datasets.SplitGenerator(name=datasets.Split.TRAIN, gen_kwargs={"filepath": filepath})]

    def _generate_examples(self, filepath: str) -> Iterator[Tuple[int, Dict[str, Union[int, str]]]]:
        if self.config.name.startswith("corpus"):
            with open(filepath) as f:
                for id_, line in enumerate(f):
                    line = line.rstrip("\n")
                    yield id_, {"text": line}

        elif self.config.name.startswith(("paragraphs", "passages")):
            with open(filepath) as f:
                for line in f:
                    item = json.loads(line)
                    yield item["id"], item

        else:
            raise ValueError("Invalid dataset config name is specified.")