import os

import datasets
from typing import List
import json

logger = datasets.logging.get_logger(__name__)


_CITATION = """
"""

_DESCRIPTION = """
This is the dataset repository for HiNER Dataset accepted to be published at LREC 2022.
The dataset can help build sequence labelling models for the task Named Entity Recognitin for the Hindi language.
"""

class HiNERConfig(datasets.BuilderConfig):
    """BuilderConfig for HiNER Dataset."""

    def __init__(self, **kwargs):
        """BuilderConfig for HiNER.
        Args:
          **kwargs: keyword arguments forwarded to super.
        """
        super(HiNERConfig, self).__init__(**kwargs)


class HiNERConfig(datasets.GeneratorBasedBuilder):
    """HiNER dataset."""

    BUILDER_CONFIGS = [
        HiNERConfig(name="HiNER", version=datasets.Version("0.0.2"), description="Hindi Named Entity Recognition dataset"),
    ]

    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=datasets.Features(
                {
                    "id": datasets.Value("string"),
                    "tokens": datasets.Sequence(datasets.Value("string")),
                    "ner_tags": datasets.Sequence(
                        datasets.features.ClassLabel(
                            names=[
                                "O",
                                "B-PERSON",
                                "I-PERSON",
                                "B-LOCATION",
                                "I-LOCATION",
                                "B-ORGANIZATION",
                                "I-ORGANIZATION",
                                "B-FESTIVAL",
                                "I-FESTIVAL",
                                "B-GAME",
                                "I-GAME",
                                "B-LANGUAGE",
                                "I-LANGUAGE",
                                "B-LITERATURE",
                                "I-LITERATURE",
                                "B-MISC",
                                "I-MISC",
                                "B-NUMEX",
                                "I-NUMEX",
                                "B-RELIGION",
                                "I-RELIGION",
                                "B-TIMEX",
                                "I-TIMEX",
                            ]
                        )
                    ),
                }
            ),
            supervised_keys=None,
            homepage="https://github.com/cfiltnlp/HiNER",
            citation=_CITATION,
        )

    _URL = "https://huggingface.co/datasets/cfilt/HiNER-original/resolve/main/data/"
    _URLS = {
        "train": _URL + "train.json",
        "dev": _URL + "validation.json",
        "test": _URL + "test.json"
    }

    def _split_generators(self, dl_manager: datasets.DownloadManager) -> List[datasets.SplitGenerator]:
        urls_to_download = self._URLS
        downloaded_files = dl_manager.download_and_extract(urls_to_download)

        return [
            datasets.SplitGenerator(name=datasets.Split.TRAIN, gen_kwargs={"filepath": downloaded_files["train"]}),
            datasets.SplitGenerator(name=datasets.Split.VALIDATION, gen_kwargs={"filepath": downloaded_files["dev"]}),
            datasets.SplitGenerator(name=datasets.Split.TEST, gen_kwargs={"filepath": downloaded_files["test"]})
        ]

    def _generate_examples(self, filepath):
        """This function returns the examples in the raw (text) form."""
        logger.info("generating examples from = %s", filepath)
        with open(filepath) as f:
            hiner = json.load(f)
            for object in hiner:
                id_ = int(object['id'])
                yield id_, {
                    "id": str(id_),
                    "tokens": object['tokens'],
                    "ner_tags": object['ner_tags'],
                }