"""Export the liquidations of the last N hours to CSV with the Blockmetric Python SDK.

    BLOCKMETRIC_API_KEY=bm_live_... BLOCKMETRIC_BASE_URL=https://<domain>/api/v1 \
        python export_liquidations.py --hours 24 --out liquidations.csv

Columns: ts, venue, coin, side, price, qty, usd (newest first; times ISO 8601 UTC, usd = notional in USD).
The look-back is capped by your plan's history (free key: 30 days). Venues whose single liquidations the API may not
redistribute are not in the feed (meta.sources names what is); asking for one answers source_restricted.
"""

import argparse
import csv
import sys
from typing import IO, Optional, Sequence

from blockmetric import Blockmetric, BlockmetricError

COLUMNS = ["ts", "venue", "coin", "side", "price", "qty", "usd"]


def export(client: Blockmetric, out: IO[str], hours: int = 24, coin: Optional[str] = None, venue: Optional[str] = None) -> int:
    """Writes every liquidation of the window (follows the cursor pages) and returns the number of rows."""
    writer = csv.DictWriter(out, fieldnames=COLUMNS, extrasaction="ignore", lineterminator="\n")
    writer.writeheader()
    rows = 0
    for liq in client.paginate("liquidations", since_minutes=hours * 60, coin=coin, venue=venue, limit=1000):
        writer.writerow(liq)
        rows += 1
    return rows


def main(argv: Optional[Sequence[str]] = None) -> int:
    p = argparse.ArgumentParser(description=__doc__.split("\n")[0])
    p.add_argument("--hours", type=int, default=24, help="look-back window in hours (default 24)")
    p.add_argument("--coin", help="only this coin, e.g. BTC")
    p.add_argument("--venue", help="only this venue, e.g. hyperliquid")
    p.add_argument("--out", default="-", help="output file (default: stdout)")
    args = p.parse_args(argv)
    try:
        client = Blockmetric()  # BLOCKMETRIC_API_KEY, BLOCKMETRIC_BASE_URL
        if args.out == "-":
            n = export(client, sys.stdout, args.hours, args.coin, args.venue)
        else:
            with open(args.out, "w", newline="", encoding="utf-8") as f:
                n = export(client, f, args.hours, args.coin, args.venue)
    except BlockmetricError as e:
        print(f"error: {e}", file=sys.stderr)
        if e.doc_url:
            print(f"  see {e.doc_url}", file=sys.stderr)
        return 1
    print(f"{n} liquidations exported" + ("" if args.out == "-" else f" to {args.out}"), file=sys.stderr)
    return 0


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