import io

import zstandard
import jsonlines
import datasets

import json


def parse_json(x):
    return json.loads(x)


_DESCRIPTION = "DaruLM for LLM"
_URLS = [
    "libru_accounting_0.jsonl.zst",
    "libru_antique_0.jsonl.zst",
    "libru_antique_1.jsonl.zst",
    "libru_aphorisms_0.jsonl.zst",
    "libru_art_0.jsonl.zst",
    "libru_biography_0.jsonl.zst",
    "libru_biography_1.jsonl.zst",
    "libru_biography_2.jsonl.zst",
    "libru_biography_3.jsonl.zst",
    "libru_biography_4.jsonl.zst",
    "libru_biology_0.jsonl.zst",
    "libru_business_0.jsonl.zst",
    "libru_cinema_0.jsonl.zst",
    "libru_computers_0.jsonl.zst",
    "libru_design_0.jsonl.zst",
    "libru_dramaturgy_0.jsonl.zst",
    "libru_economics_0.jsonl.zst",
    "libru_essay_0.jsonl.zst",
    "libru_essay_1.jsonl.zst",
    "libru_essay_2.jsonl.zst",
    "libru_fantasy_0.jsonl.zst",
    "libru_geography_0.jsonl.zst",
    "libru_guidebooks_0.jsonl.zst",
    "libru_guidebooks_1.jsonl.zst",
    "libru_history_0.jsonl.zst",
    "libru_history_1.jsonl.zst",
    "libru_history_2.jsonl.zst",
    "libru_history_3.jsonl.zst",
    "libru_history_4.jsonl.zst",
    "libru_history_5.jsonl.zst",
    "libru_humor_0.jsonl.zst",
    "libru_language_0.jsonl.zst",
    "libru_law_0.jsonl.zst",
    "libru_literature_0.jsonl.zst",
    "libru_medicine_0.jsonl.zst",
    "libru_military_0.jsonl.zst",
    "libru_music_0.jsonl.zst",
    "libru_philosophy_0.jsonl.zst",
    "libru_politic_0.jsonl.zst",
    "libru_prose_0.jsonl.zst",
    "libru_prose_1.jsonl.zst",
    "libru_prose_2.jsonl.zst",
    "libru_psychology_0.jsonl.zst",
    "libru_psychology_1.jsonl.zst",
    "libru_reference_0.jsonl.zst",
    "libru_religion_0.jsonl.zst",
    "libru_religion_1.jsonl.zst",
    "libru_religion_2.jsonl.zst",
    "libru_religion_3.jsonl.zst",
    "libru_science_0.jsonl.zst",
    "libru_science_1.jsonl.zst",
    "libru_science_2.jsonl.zst",
    "libru_sociology_0.jsonl.zst",
    "libru_textbook_0.jsonl.zst",
    "libru_UNDEFINED_0.jsonl.zst",
    "rulm_buriy_0.jsonl.zst",
    "rulm_buriy_1.jsonl.zst",
    "rulm_buriy_2.jsonl.zst",
    "rulm_gazeta_0.jsonl.zst",
    "rulm_habr_0.jsonl.zst",
    "rulm_habr_1.jsonl.zst",
    "rulm_lenta_0.jsonl.zst",
    "rulm_ods-tass_0.jsonl.zst",
    "rulm_ods-tass_1.jsonl.zst",
    "rulm_pikabu_0.jsonl.zst",
    "rulm_pikabu_1.jsonl.zst",
    "rulm_pikabu_2.jsonl.zst",
    "rulm_taiga-fontanka_0.jsonl.zst",
    "rulm_wiki_0.jsonl.zst",
    "rulm_wiki_1.jsonl.zst",
    "rulm_wiki_2.jsonl.zst",
    "wiki40_enwiki_0.jsonl.zst",
]


DOMAINS = sorted(set(url.split('_')[1] for url in _URLS))

_VERSION = datasets.Version("1.1.0")


class DarulmConfig(datasets.BuilderConfig):
    """BuilderConfig for DaruLM."""

    def __init__(self, domains="all", version=_VERSION, **kwargs):
        """BuilderConfig for DaruLM.
        Args:
            domains (str or list, default 'all'): domain names.
            **kwargs: keyword arguments forwarded to super.
        """
        if isinstance(domains, str):
            domains = [domains]
        name = "+".join(domains)
        if name == "all":
            domains = DOMAINS

        missing_domains = set(domains)-set(DOMAINS)
        assert len(
            missing_domains) == 0, f"{missing_domains} not found in domain list"

        if version != _VERSION:
            name = f"{name}-{version}"
        super().__init__(name=name, version=version, **kwargs)
        self.domains = domains


class DarulmDataset(datasets.GeneratorBasedBuilder):
    VERSION = _VERSION

    BUILDER_CONFIG_CLASS = DarulmConfig
    BUILDER_CONFIGS = [
        DarulmConfig(
            domains="all",
            description="Full DaruLM collection.",
        ),
    ] + [
        DarulmConfig(
            domains=dn,
            description=f"DaruLM part with {dn} texts",
        )
        for dn in sorted(DOMAINS)
    ]
    DEFAULT_CONFIG_NAME = "all"

    def _info(self):
        features = datasets.Features(
            {
                "text": datasets.Value("string"),
                "domain": datasets.Value("string"),
            }
        )
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=features
        )

    def _split_generators(self, dl_manager):
        required_urls = [
            path for dn in self.config.domains for path in _URLS if f"_{dn}_" in path
        ]
        downloaded_files = dl_manager.download(required_urls)
        return [
            datasets.SplitGenerator(name=datasets.Split.TRAIN, gen_kwargs={
                                    "paths": downloaded_files}),
        ]

    def _generate_examples(self, paths):
        true_id = 0
        for path in paths:
            with open(path, "rb") as f:
                cctx = zstandard.ZstdDecompressor()
                reader_stream = io.BufferedReader(cctx.stream_reader(f))
                reader = jsonlines.Reader(reader_stream, loads=parse_json)
                for id_, item in enumerate(reader):
                    yield true_id, item
                    true_id += 1