# coding=utf-8
# 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.
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# limitations under the License.
"""BiSECT is a Split and Rephrase corpus created via bilingual pivoting."""

import os
import datasets


_CITATION = """\
@inproceedings{kim-etal-2021-bisect,
    title = "{B}i{SECT}: Learning to Split and Rephrase Sentences with Bitexts",
    author = "Kim, Joongwon  and
      Maddela, Mounica  and
      Kriz, Reno  and
      Xu, Wei  and
      Callison-Burch, Chris",
    booktitle = "Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing",
    month = nov,
    year = "2021",
    address = "Online and Punta Cana, Dominican Republic",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2021.emnlp-main.500",
    pages = "6193--6209"
}
"""

_DESCRIPTION = """\
BiSECT is a Split and Rephrase corpus created via bilingual pivoting.
"""

_HOMEPAGE = "https://github.com/mounicam/BiSECT"

_URL = "https://raw.githubusercontent.com/mounicam/BiSECT/main/"
_URL_MAIN = _URL + "bisect/"
_URL_CHALLENGE = _URL + "bisect_challenge/"

_URLs = {
    datasets.Split.TRAIN: {
        "src": _URL_MAIN + "train.src.gz",
        "dst": _URL_MAIN + "train.dst.gz",
    },
    datasets.Split.VALIDATION: {
        "src": _URL_MAIN + "valid.src.gz",
        "dst": _URL_MAIN + "valid.dst.gz",
    },
    datasets.Split.TEST: {
        "src": _URL_MAIN + "test.src.gz",
        "dst": _URL_MAIN + "test.dst.gz",
    },
    "challenge_hsplit": {
        "src": "https://raw.githubusercontent.com/cocoxu/simplification/master/data/turkcorpus/test.8turkers.tok.norm",
        "dst": "https://raw.githubusercontent.com/eliorsulem/HSplit-corpus/master/HSplit/HSplit2_full",
    },
    "challenge_bisect": {
        "src": _URL_CHALLENGE + "challenge_test.src",
        "dst": _URL_CHALLENGE + "challenge_test.dst",
    },
}


class BiSECT(datasets.GeneratorBasedBuilder):
    """The BiSECT Split and Rephrase corpus."""

    VERSION = datasets.Version("1.1.0")

    BUILDER_CONFIGS = [
        datasets.BuilderConfig(
            name="en",
            version=VERSION,
            description="English data described in the BiSECT paper",
        ),
        datasets.BuilderConfig(
            name="de",
            version=VERSION,
            description="German data described in the BiSECT paper",
        ),
        datasets.BuilderConfig(
            name="es",
            version=VERSION,
            description="Spanish data described in the BiSECT paper",
        ),
        datasets.BuilderConfig(
            name="fr",
            version=VERSION,
            description="French data described in the BiSECT paper",
        ),
    ]

    DEFAULT_CONFIG_NAME = "en"

    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=datasets.Features(
                {
                    "gem_id": datasets.Value("string"),
                    "source": datasets.Value("string"),
                    "target": datasets.Value("string"),
                    "references": [datasets.Value("string")],
                }
            ),
            supervised_keys=None,
            homepage=_HOMEPAGE,
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        """Returns SplitGenerators."""
        if self.config.name == "en":
            data_dir = dl_manager.download_and_extract(_URLs)
            return [
                datasets.SplitGenerator(
                    name=split_name,
                    gen_kwargs={"filepath": data_dir[split_name], "split": split_name},
                )
                for split_name in data_dir
            ]
        else:
            lang = self.config.name
            url = _URL + "bisect_multilingual/" + f"bisect_{lang}.gz"
            data_dir = dl_manager.download_and_extract(url)

            return [
                datasets.SplitGenerator(
                    name=f"{split}",
                    gen_kwargs={
                        "filepath": os.path.join(data_dir, lang),
                        "split": split,
                    },
                )
                for split in (
                    datasets.Split.TRAIN,
                    datasets.Split.VALIDATION,
                    datasets.Split.TEST,
                )
            ]

    def _generate_examples(self, filepath, split):
        """Yields examples as (key, example) tuples."""

        if self.config.name == "en":
            source_filepath = filepath["src"]
            target_filepath = filepath["dst"]
        else:
            source_filepath = os.path.join(filepath, f"{split}.complex")
            target_filepath = os.path.join(filepath, f"{split}.simple")

        with open(source_filepath, encoding="utf-8") as f:
            source_lines = [line.strip() for line in f if line.strip()]
        with open(target_filepath, encoding="utf-8") as f:
            target_lines = [
                line.strip().replace(" <SEP>", "") for line in f if line.strip()
            ]

        for id_ in range(len(source_lines)):
            yield id_, {
                "gem_id": f"BiSECT_{self.config.name}-{split}-{id_}",
                "source": source_lines[id_],
                "target": target_lines[id_],
                "references": [target_lines[id_]],
            }