"""Periodic retention cleanup for history tables."""

from __future__ import annotations

import asyncio
import logging
import sqlite3
import time

import aiosqlite

from ..config import StorageCfg
from ..core.stats import Stats

log = logging.getLogger(__name__)


async def run_retention(conn: aiosqlite.Connection, cfg: StorageCfg, stats: Stats) -> None:
    """Background task: periodically delete rows older than retention limits."""
    interval = max(60, cfg.retention_interval_sec)
    while True:
        try:
            await asyncio.sleep(interval)
            await cleanup_once(conn, cfg, stats)
        except asyncio.CancelledError:
            raise
        except Exception:
            log.exception("retention sweep failed")
            stats.incr("retention_errors")


async def cleanup_once(conn: aiosqlite.Connection, cfg: StorageCfg, stats: Stats) -> None:
    """Run one retention sweep; caller ensures this is not re-entrant."""
    now = time.time()
    rows_total = 0

    targets = (
        ("ais_dynamic", cfg.retention.ais_dynamic_days),
        ("gps_fix", cfg.retention.gps_fix_days),
        ("raw_nmea", cfg.retention.raw_nmea_days),
        ("radio_telemetry", cfg.retention.radio_telemetry_days),
    )
    for table, days in targets:
        if days <= 0:
            continue
        cutoff = now - days * 86400.0
        try:
            cur = await conn.execute(f"DELETE FROM {table} WHERE ts < ?", (cutoff,))
            await conn.commit()
            rows_total += cur.rowcount or 0
            stats.incr(f"retention_deleted_{table}", cur.rowcount or 0)
        except sqlite3.OperationalError as exc:
            log.warning("retention: transient error on %s: %s", table, exc)
            stats.incr("retention_transient_errors")
        except Exception:
            log.exception("retention: error deleting from %s", table)
            stats.incr("retention_errors")

    if rows_total > 0:
        log.info("retention sweep removed %d rows", rows_total)
    stats.incr("retention_sweeps")


__all__ = ["run_retention", "cleanup_once"]