import datasets
import json


RAW_METADATA_URL = r'https://huggingface.co/datasets/OleehyO/latex-formulas/resolve/main/raw_formulas.jsonl'

FILTERED_METADATA_URL = r'https://huggingface.co/datasets/OleehyO/latex-formulas/resolve/main/formulas_finally.jsonl'
FILTERED_IMG_URL = r'https://huggingface.co/datasets/OleehyO/latex-formulas/resolve/main/formulas_pic.tar.gz'


class LatexFormulasConfig(datasets.BuilderConfig):
    def __init__(self, img_archive_url, metadata_url, **kwargs):
        super().__init__(**kwargs)
        self.img_archive_url = img_archive_url
        self.metadata_url = metadata_url


class LatexFormulas(datasets.GeneratorBasedBuilder):
    BUILDER_CONFIGS = [
        LatexFormulasConfig(
            name="raw_formulas",
            img_archive_url=None,
            metadata_url=RAW_METADATA_URL
        ),
        LatexFormulasConfig(
            name="filtered_formulas",
            img_archive_url=FILTERED_IMG_URL,
            metadata_url=FILTERED_METADATA_URL
        )
    ]

    def _info(self):
        if self.config.name == "raw_formulas":
            return datasets.DatasetInfo(
                features=datasets.Features({
                    "latex_formula": datasets.Value("string")
                })
            )
        if self.config.name == "filtered_formulas":
            return datasets.DatasetInfo(
                features=datasets.Features({
                    "image": datasets.Image(),
                    "latex_formula": datasets.Value("string")
                })
            )

    def _split_generators(self, dl_manager: datasets.DownloadManager):
        metadata_path = dl_manager.download(self.config.metadata_url)

        if self.config.name == "filtered_formulas":
            image_archive_path = self.config.img_archive_url
            images = dl_manager.iter_archive(image_archive_path)
        elif self.config.name == "raw_formulas":
            images = None

        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN,
                gen_kwargs={
                    "images": images,
                    "metadata_path": metadata_path
                }
            )
        ]

    def _generate_examples(self, images, metadata_path):
        if images is not None:
            img_formula_pair = {}
            with open(metadata_path, 'r', encoding="utf-8") as f:
                for line in f:
                    single_json = json.loads(line)
                    img_formula_pair[single_json["id"]] = single_json["formula"]

            for img_path, img_obj in images:
                img_name = img_path.split('/')[-1]
                if img_name in img_formula_pair:
                    yield img_path, {
                        "image": {"path": img_path, "bytes": img_obj.read()},
                        "latex_formula": img_formula_pair[img_name]
                    }
        else:
            with open(metadata_path, 'r', encoding="utf-8") as f:
                for idx, line in enumerate(f):
                    yield idx, {
                        "latex_formula": json.loads(line)["formula"]
                    }