#!/usr/bin/env python3
"""Generate corpus-manifest.json from case directories."""
from __future__ import annotations

import hashlib
import json
from datetime import datetime, timezone
from pathlib import Path

ROOT = Path(__file__).resolve().parents[2]
CORPUS = ROOT / "bench" / "golden-corpus" / "categories"
OUTPUT = ROOT / "bench" / "golden-corpus" / "corpus-manifest.json"


def sha256(path: Path) -> str:
    h = hashlib.sha256()
    with path.open("rb") as fh:
        while True:
            chunk = fh.read(8192)
            if not chunk:
                break
            h.update(chunk)
    return h.hexdigest()


def main() -> int:
    cases = []
    for case_dir in sorted([p for p in CORPUS.rglob("*") if p.is_dir() and (p / "case-manifest.json").exists()]):
        manifest_path = case_dir / "case-manifest.json"
        cases.append({
            "id": case_dir.name,
            "path": str(case_dir.relative_to(ROOT)).replace("\\", "/"),
            "manifestDigest": f"sha256:{sha256(manifest_path)}",
        })

    payload = {
        "generatedAt": datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ"),
        "caseCount": len(cases),
        "cases": cases,
    }

    OUTPUT.write_text(json.dumps(payload, indent=2) + "\n", encoding="utf-8")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())