from __future__ import annotations

import hashlib
import json
from pathlib import Path


def sha256_file(path: Path, chunk_size: int = 1024 * 1024) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as f:
        while True:
            chunk = f.read(chunk_size)
            if not chunk:
                break
            digest.update(chunk)
    return digest.hexdigest()


def main() -> None:
    root = Path(__file__).resolve().parents[1]
    registry = json.loads((root / "benchmark" / "scene_registry.json").read_text(encoding="utf-8"))
    tasks = json.loads((root / "benchmark" / "tasks.json").read_text(encoding="utf-8"))
    split = json.loads((root / "benchmark" / "split_v1.json").read_text(encoding="utf-8"))
    manifest = json.loads((root / "metadata" / "resource_manifest.json").read_text(encoding="utf-8"))

    assert len(registry["scenes"]) == 47, len(registry["scenes"])
    assert len(tasks["tasks"]) == 141, len(tasks["tasks"])
    assert len(split["dev_scene_ids"]) + len(split["test_scene_ids"]) == 47

    for item in manifest["items"]:
        path = root / item["package_path"]
        if not path.exists():
            raise FileNotFoundError(path)
        if path.stat().st_size != item["bytes"]:
            raise RuntimeError(f"Size mismatch: {path}")
        digest = sha256_file(path)
        if digest != item["sha256"]:
            raise RuntimeError(f"SHA256 mismatch: {path}")

    print("OK: 47 scenes, 141 tasks, all checksums match.")


if __name__ == "__main__":
    main()