import json
import csv
import os
import datasets

logger = datasets.logging.get_logger(__name__)


_DESCRIPTION = "BEIR Benchmark"
_DATASETS = ["fiqa", "trec-covid"]

URL = ""
_URLs = {
    dataset: {
        "corpus": URL + f"{dataset}/corpus.jsonl", 
        } for dataset in _DATASETS}


class BEIR(datasets.GeneratorBasedBuilder):
    """BEIR BenchmarkDataset."""

    BUILDER_CONFIGS = [
        datasets.BuilderConfig(
            name=dataset,
            description=f"This is the {dataset} dataset in BEIR Benchmark.",
        ) for dataset in _DATASETS
    ]
    
    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
             features=datasets.Features({
                "_id": datasets.Value("string"), 
                "title": datasets.Value("string"),
                "text": datasets.Value("string")
             }),
            supervised_keys=None,
        )

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

        my_urls = _URLs[self.config.name]
        data_dir = dl_manager.download_and_extract(my_urls)
        return [
            datasets.SplitGenerator(
                name="corpus",
                # These kwargs will be passed to _generate_examples
                gen_kwargs={"corpus_path": data_dir["corpus"]}
            ),
        ]

    def _generate_examples(self, corpus_path):
        """Yields examples."""
        with open(corpus_path, encoding="utf-8") as f:
            texts = f.readlines()
        for i, text in enumerate(texts):
            yield i, json.loads(text)