#!/usr/bin/env python3
"""Download + extract OASIS-1 cross-sectional dataset (discs 1-12).

The WashU host throttles per-connection (~48 KB/s single) but not in aggregate:
16 segmented connections reach ~1.9 MB/s. We use aria2c for segmented download
+ built-in resume. Idempotent: skips discs already extracted.
"""
import subprocess
import sys
import tarfile
from pathlib import Path

RAW = Path(__file__).resolve().parents[3] / "data" / "raw"
BASE = "https://download.nrg.wustl.edu/data"
N_DISCS = 12
MIN_DISC_BYTES = 1_000_000_000


def download_all() -> None:
    """aria2c downloads all discs: -x16 conns/host, -s16 segments, -j3 files at once."""
    urls = [f"{BASE}/oasis_cross-sectional_disc{i}.tar.gz" for i in range(1, N_DISCS + 1)]
    (RAW / "urls.txt").write_text("\n".join(urls) + "\n")
    subprocess.run(
        ["aria2c", "-x16", "-s16", "-j3", "-c", "-k", "1M",
         "--retry-wait=5", "--max-tries=0",           # 0 = infinite retries
         "--timeout=30", "--connect-timeout=30",
         "--summary-interval=30", "--console-log-level=warn",
         "-d", str(RAW), "-i", str(RAW / "urls.txt")],
        check=True,
    )


def extract_all() -> None:
    for i in range(1, N_DISCS + 1):
        tar_path = RAW / f"oasis_cross-sectional_disc{i}.tar.gz"
        marker = tar_path.with_suffix(".extracted")
        if marker.exists():
            print(f"[skip] disc{i} already extracted", flush=True)
            continue
        if not (tar_path.exists() and tar_path.stat().st_size >= MIN_DISC_BYTES):
            sys.exit(f"disc{i} missing/incomplete: {tar_path}")
        print(f"[tar ] disc{i}", flush=True)
        with tarfile.open(tar_path, "r:gz") as t:
            t.extractall(RAW, filter="data")
        marker.touch()


def main() -> None:
    RAW.mkdir(parents=True, exist_ok=True)
    download_all()
    extract_all()
    print("[done] all discs downloaded + extracted", flush=True)


if __name__ == "__main__":
    main()