#!/usr/bin/env python3
"""Copy the dividend/capitalGain event files from the data root into
overrides/event-backup/ (the fallback data.py uses when a re-download
empties them — Yahoo dropped capitalGain events for some funds in 2026).

Re-runnable: it refreshes every file from the current data root, so run it
again whenever the dump is updated (or not — the backup is a floor, new
data still wins while it is non-empty). Symbols with a frozen copy are
skipped (overrides/frozen/ already preserves them).

Usage:  python3 scripts/backup_events.py [--data DIR]
"""
import argparse
import shutil
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
BACKUP = ROOT / "overrides" / "event-backup"
FROZEN = ROOT / "overrides" / "frozen"


def main() -> int:
    ap = argparse.ArgumentParser()
    ap.add_argument("--data", type=Path, default=Path("~/prog/fin/stocks").expanduser())
    args = ap.parse_args()
    BACKUP.mkdir(parents=True, exist_ok=True)
    n = skipped = 0
    for sfx in ("dividend", "capitalGain"):
        for f in sorted(args.data.glob(f"*-{sfx}.csv")):
            sym = f.name[: -len(f"-{sfx}.csv")]
            if (FROZEN / f"{sym}-history.csv").exists():
                skipped += 1
                continue
            # only files with real rows (a re-download may leave header-only)
            if sum(1 for _ in open(f, errors="replace")) <= 1:
                continue
            shutil.copyfile(f, BACKUP / f.name)
            n += 1
    print(f"backed up {n} event files to {BACKUP}, "
          f"skipped {skipped} frozen symbols")
    return 0


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