#!/usr/bin/env python3
"""Create a consistent SQLite backup from the running Docker service."""

import argparse
import subprocess
import sys
from datetime import datetime, timedelta, timezone
from pathlib import Path
from uuid import uuid4

CONTAINER_BACKUP = """import sqlite3
source = sqlite3.connect('/data/eternity.db')
destination = sqlite3.connect('/tmp/eternity-backup.db')
with destination:
    source.backup(destination)
destination.close()
source.close()
"""


def run(command, **kwargs):
    return subprocess.run(command, check=True, text=True, **kwargs)


def main():
    parser = argparse.ArgumentParser(description="Back up the live Eternity Project SQLite database.")
    parser.add_argument("--output-dir", default="backups", help="Directory for timestamped backup files")
    parser.add_argument("--keep-days", type=int, default=30, help="Delete backups older than this many days; use 0 to keep all")
    args = parser.parse_args()

    output_dir = Path(args.output_dir).resolve()
    output_dir.mkdir(parents=True, exist_ok=True)
    timestamp = datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
    destination = output_dir / f"eternity-{timestamp}.db"
    temporary_path = f"/tmp/eternity-backup-{uuid4().hex}.db"

    try:
        container_id = run(["docker", "compose", "ps", "-q", "eternityproject"], capture_output=True).stdout.strip()
        if not container_id:
            raise RuntimeError("The eternityproject Docker service must be running.")
        run(["docker", "exec", container_id, "python", "-c", CONTAINER_BACKUP.replace("/tmp/eternity-backup.db", temporary_path)])
        run(["docker", "cp", f"{container_id}:{temporary_path}", str(destination)])
    except (OSError, subprocess.CalledProcessError, RuntimeError) as error:
        print(f"DATABASE_BACKUP_FAILED: {error}", file=sys.stderr)
        return 1
    finally:
        if "container_id" in locals() and container_id:
            subprocess.run(["docker", "exec", container_id, "rm", "-f", temporary_path], check=False)

    print(f"DATABASE_BACKUP_CREATED={destination}")
    if args.keep_days > 0:
        cutoff = datetime.now(timezone.utc) - timedelta(days=args.keep_days)
        removed = 0
        for backup in output_dir.glob("eternity-*.db"):
            if backup != destination and datetime.fromtimestamp(backup.stat().st_mtime, timezone.utc) < cutoff:
                backup.unlink()
                removed += 1
        print(f"DATABASE_BACKUP_RETENTION: removed={removed} keep_days={args.keep_days}")
    return 0


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