import datasets
from datasets.download.download_manager import DownloadManager
import pyarrow.parquet as pq

_DESCRIPTION = """\
The MSRA NER dataset is a Chinese Named Entity Recognition dataset 
"""

_CITATION = """\
@inproceedings{levow-2006-third,
    title = "The Third International {C}hinese Language Processing Bakeoff: Word Segmentation and Named Entity Recognition",
    author = "Levow, Gina-Anne",
    booktitle = "Proceedings of the Fifth {SIGHAN} Workshop on {C}hinese Language Processing",
    month = jul,
    year = "2006",
    address = "Sydney, Australia",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/W06-0115",
    pages = "108--117",
}
"""

_URL = "https://huggingface.co/datasets/minskiter/msra_dev/resolve/main/"
_URLS = {
    "train": _URL + "data/train.parquet",
    'validation': _URL + "data/validation.parquet",
    "test": _URL + "data/test.parquet",
}

class MSRANamedEntities(datasets.GeneratorBasedBuilder):
    VERSION = datasets.Version("1.0.0")

    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=datasets.Features(
                {
                    "text": datasets.Sequence(datasets.Value("string")),
                    "labels": datasets.Sequence(
                        datasets.features.ClassLabel(
                            names=[
                                'O',    
                                'B-NS',
                                'M-NS',
                                'E-NS',
                                'S-NS',
                                'B-NT',
                                'M-NT',
                                'E-NT',
                                'S-NT',
                                'B-NR',
                                'M-NR',
                                'E-NR',
                                'S-NR'                               
                            ]
                        )
                    ),
                }
            ),
            supervised_keys=None,
            homepage="https://aclanthology.org/W06-0115/",
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager: DownloadManager):
        urls_to_download = _URLS
        download_files = dl_manager.download_and_extract(urls_to_download)
        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN,
                gen_kwargs={"filepath": download_files["train"]},
            ),
            datasets.SplitGenerator(
                name=datasets.Split.VALIDATION,
                gen_kwargs={"filepath": download_files["validation"]},
            ),
            datasets.SplitGenerator(
                name=datasets.Split.TEST,
                gen_kwargs={"filepath": download_files["test"]},
            ),
        ]

    def _generate_examples(self, filepath):
        with open(filepath,"rb") as f:
            with pq.ParquetFile(f) as file:
                _id = -1
                for i in file.iter_batches(batch_size=64):
                    rows = i.to_pylist()
                    for row in rows:
                        _id+=1
                        yield _id, row