# 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.
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#
#     http://www.apache.org/licenses/LICENSE-2.0
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# 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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"""A Benchmark Dataset for Understanding Disfluencies in Question Answering"""


import json

import datasets
from datasets.tasks import QuestionAnsweringExtractive


_CITATION = """\
@inproceedings{gupta-etal-2021-disflqa,
    title = "{Disfl-QA: A Benchmark Dataset for Understanding Disfluencies in Question Answering}",
    author = "Gupta, Aditya and Xu, Jiacheng and Upadhyay, Shyam and Yang, Diyi and Faruqui, Manaal",
    booktitle = "Findings of ACL",
    year = "2021"
}

"""

_DESCRIPTION = """\
Disfl-QA is a targeted dataset for contextual disfluencies in an information seeking setting,
namely question answering over Wikipedia passages. Disfl-QA builds upon the SQuAD-v2 (Rajpurkar et al., 2018)
dataset, where each question in the dev set is annotated to add a contextual disfluency using the paragraph as
a source of distractors.

The final dataset consists of ~12k (disfluent question, answer) pairs. Over 90% of the disfluencies are
corrections or restarts, making it a much harder test set for disfluency correction. Disfl-QA aims to fill a
major gap between speech and NLP research community. We hope the dataset can serve as a benchmark dataset for
testing robustness of models against disfluent inputs.

Our expriments reveal that the state-of-the-art models are brittle when subjected to disfluent inputs from
Disfl-QA. Detailed experiments and analyses can be found in our paper.
"""

_HOMEPAGE = "https://github.com/google-research-datasets/disfl-qa"

_LICENSE = "Disfl-QA dataset is licensed under CC BY 4.0"

_URL = "https://raw.githubusercontent.com/google-research-datasets/Disfl-QA/main/"

_URLS_squad_v2 = {
    "train": "https://rajpurkar.github.io/SQuAD-explorer/dataset/" + "train-v2.0.json",
    "dev": "https://rajpurkar.github.io/SQuAD-explorer/dataset/" + "dev-v2.0.json",
}


class DisflQA(datasets.GeneratorBasedBuilder):
    """A Benchmark Dataset for Understanding Disfluencies in Question Answering"""

    VERSION = datasets.Version("1.1.0")

    def _info(self):
        features = datasets.Features(
            {
                "squad_v2_id": datasets.Value("string"),
                "original question": datasets.Value("string"),
                "disfluent question": datasets.Value("string"),
                "title": datasets.Value("string"),
                "context": datasets.Value("string"),
                "answers": datasets.features.Sequence(
                    {
                        "text": datasets.Value("string"),
                        "answer_start": datasets.Value("int32"),
                    }
                ),
            }
        )
        return datasets.DatasetInfo(
            # This is the description that will appear on the datasets page.
            description=_DESCRIPTION,
            # This defines the different columns of the dataset and their types
            features=features,  # Here we define them above because they are different between the two configurations
            # If there's a common (input, target) tuple from the features,
            # specify them here. They'll be used if as_supervised=True in
            # builder.as_dataset.
            supervised_keys=None,
            # Homepage of the dataset for documentation
            homepage=_HOMEPAGE,
            # License for the dataset if available
            license=_LICENSE,
            # Citation for the dataset
            citation=_CITATION,
            task_templates=[
                QuestionAnsweringExtractive(
                    question_column="disfluent question", context_column="context", answers_column="answers"
                )
            ],
        )

    def _split_generators(self, dl_manager):
        """Returns SplitGenerators."""

        squad_v2_downloaded_files = dl_manager.download_and_extract(_URLS_squad_v2)

        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN,
                # These kwargs will be passed to _generate_examples
                gen_kwargs={
                    "filepath": dl_manager.download_and_extract(_URL + "train.json"),
                    "split": "train",
                    "squad_v2_data": squad_v2_downloaded_files,
                },
            ),
            datasets.SplitGenerator(
                name=datasets.Split.TEST,
                # These kwargs will be passed to _generate_examples
                gen_kwargs={
                    "filepath": dl_manager.download_and_extract(_URL + "test.json"),
                    "split": "test",
                    "squad_v2_data": squad_v2_downloaded_files,
                },
            ),
            datasets.SplitGenerator(
                name=datasets.Split.VALIDATION,
                # These kwargs will be passed to _generate_examples
                gen_kwargs={
                    "filepath": dl_manager.download_and_extract(_URL + "dev.json"),
                    "split": "dev",
                    "squad_v2_data": squad_v2_downloaded_files,
                },
            ),
        ]

    def _generate_examples(
        self,
        filepath,
        split,
        squad_v2_data,  # method parameters are unpacked from `gen_kwargs` as given in `_split_generators`
    ):
        """Yields examples as (key, example) tuples."""

        merge_squad_v2_json = {}

        for file in squad_v2_data:
            with open(squad_v2_data[file], encoding="utf-8") as f:
                merge_squad_v2_json.update(json.load(f))

        squad_v2_dict = _helper_dict(merge_squad_v2_json)  # contains all squad_v2 data in a dict with id as key

        with open(filepath, encoding="utf-8") as f:
            glob_id = 0
            for id_, row in enumerate(f):
                data = json.loads(row)
                for i in data:
                    yield glob_id, {
                        "squad_v2_id": i,
                        "disfluent question": data[i]["disfluent"],
                        "title": squad_v2_dict[i]["title"],
                        "context": squad_v2_dict[i]["context"],
                        "original question": squad_v2_dict[i]["question"],
                        "answers": {
                            "answer_start": squad_v2_dict[i]["answers"]["answer_start"],
                            "text": squad_v2_dict[i]["answers"]["text"],
                        },
                    }
                    glob_id += 1


def _helper_dict(row_squad_v2: dict):  # creates dict with id as key for combined squad_v2

    squad_v2_dict = {}

    for example in row_squad_v2["data"]:
        title = example.get("title", "").strip()
        for paragraph in example["paragraphs"]:
            context = paragraph["context"].strip()
            for qa in paragraph["qas"]:
                question = qa["question"].strip()
                id_ = qa["id"]

                answer_starts = [answer["answer_start"] for answer in qa["answers"]]
                answers = [answer["text"].strip() for answer in qa["answers"]]

                squad_v2_dict[id_] = {
                    "title": title,
                    "context": context,
                    "question": question,
                    "id": id_,
                    "answers": {
                        "answer_start": answer_starts,
                        "text": answers,
                    },
                }
    return squad_v2_dict