"""Download the pinned accession index from bucket storage once per runtime."""
from contextlib import closing
import fcntl
import json
from pathlib import Path
import sqlite3

from huggingface_hub import HfApi, get_token

ROOT = Path(__file__).resolve().parent


def catalog_path():
    pointer = ROOT / "data/catalog_snapshot.json"
    if not pointer.exists():
        return ROOT / "data/catalog.sqlite"
    spec = json.loads(pointer.read_text())
    cache = ROOT / ".cache/catalog"
    cache.mkdir(parents=True, exist_ok=True)
    target = cache / (spec["xet_hash"] + ".sqlite")
    with (cache / "download.lock").open("a") as lock:
        fcntl.flock(lock, fcntl.LOCK_EX)
        if target.exists() and target.stat().st_size == spec["size"]:
            return target
        api = HfApi(token=get_token())
        entries = list(api.get_bucket_paths_info(spec["bucket_id"], [spec["path"]]))
        if len(entries) != 1 or entries[0].xet_hash != spec["xet_hash"] or entries[0].size != spec["size"]:
            raise RuntimeError("The pinned accession snapshot is missing or has changed.")
        temporary = target.with_suffix(".downloading")
        print("Downloading accession index snapshot from bucket storage", flush=True)
        api.download_bucket_files(spec["bucket_id"], [(entries[0], temporary)], raise_on_missing_files=True)
        if temporary.stat().st_size != spec["size"]:
            raise RuntimeError("Incomplete accession index download.")
        with closing(sqlite3.connect(temporary.resolve().as_uri() + "?mode=ro", uri=True)) as connection:
            manifest = json.loads(connection.execute("SELECT value FROM metadata WHERE key='manifest'").fetchone()[0])
        if manifest.get("inventory_sha256") != spec["inventory_sha256"] or not manifest.get("full_snapshot"):
            raise RuntimeError("Accession index does not match the published inventory.")
        temporary.replace(target)
        return target