#!/usr/bin/env python3
"""Validate CARLA-MWRS tar.zst member names and counts without extraction."""

from __future__ import annotations

import argparse
import hashlib
import json
import subprocess
import sys
from pathlib import Path

MODALITIES = {
    "image_2": (".png", 2400, 1200),
    "gt_image_2": (".png", 2400, 1200),
    "depth_u16": (".png", 2400, 1200),
    "depth_meters": (".npy", 2400, 1200),
    "normal": (".npy", 2400, 1200),
    "calib": (".txt", 2400, 1200),
}


def members(path: Path) -> list[str]:
    # GNU tar + zstd is also the extraction command documented in README.
    proc = subprocess.run(["tar", "--zstd", "-tf", str(path)], text=True, capture_output=True)
    if proc.returncode:
        raise RuntimeError(f"{path}: tar listing failed: {proc.stderr[-1000:]}")
    return [line.rstrip("/") for line in proc.stdout.splitlines() if line and not line.endswith("/")]


def sha256(path: Path) -> str:
    h = hashlib.sha256()
    with path.open("rb") as f:
        for block in iter(lambda: f.read(8 * 1024 * 1024), b""):
            h.update(block)
    return h.hexdigest()


def main() -> int:
    ap = argparse.ArgumentParser()
    ap.add_argument("--release-root", type=Path, required=True)
    ap.add_argument("--report", type=Path)
    args = ap.parse_args()
    errors: list[str] = []
    result: dict = {"status": "PASS", "archives": {}}
    for split_idx, split in enumerate(("training", "validation")):
        expected_count_idx = 0 if split == "training" else 1
        for modality, (suffix, train_count, val_count) in MODALITIES.items():
            path = args.release_root / split / f"{modality}.tar.zst"
            key = f"{split}/{modality}.tar.zst"
            if not path.is_file():
                errors.append(f"missing archive {key}")
                continue
            try:
                all_members = members(path)
            except Exception as exc:
                errors.append(str(exc))
                continue
            data_members = [m for m in all_members if m.startswith(modality + "/") and not m.endswith("/")]
            bad = [m for m in data_members if not m.lower().endswith(suffix)]
            if bad:
                errors.append(f"{key}: wrong suffix in {bad[:3]}")
            expected = train_count if expected_count_idx == 0 else val_count
            if len(data_members) != expected:
                errors.append(f"{key}: expected {expected} data members, got {len(data_members)}")
            outside = [m for m in all_members if not (m == modality or m.startswith(modality + "/"))]
            if outside:
                errors.append(f"{key}: members outside {modality}/: {outside[:3]}")
            result["archives"][key] = {"bytes": path.stat().st_size, "members": len(data_members), "sha256": sha256(path)}
    result["errors"] = errors
    result["status"] = "PASS" if not errors else "FAIL"
    text = json.dumps(result, indent=2) + "\n"
    if args.report:
        args.report.write_text(text, encoding="utf-8")
    print(text, end="")
    return 0 if not errors else 1


if __name__ == "__main__":
    sys.exit(main())