#!/usr/bin/env python3
"""
Shadow Database TTL Purge — deletes messages/extractions older than 24 hours.
Called by the shadow-ttl-purge cron job every 6 hours.
"""

import sqlite3
import logging
import sys
from datetime import datetime, timezone, timedelta
from pathlib import Path

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s %(levelname)s:%(name)s:%(message)s",
    handlers=[
        logging.StreamHandler(sys.stdout),
    ],
)

logger = logging.getLogger("shadow.purge")

SHADOW_DB = Path.home() / ".icarus" / "shadow" / "shadow.db"
TTL_HOURS = 24

def purge_old_messages(db_path: Path, ttl_hours: int = 24):
    """Delete shadow_messages and shadow_extractions older than ttl_hours."""
    if not db_path.exists():
        logger.info("Shadow DB not found at %s — nothing to purge.", db_path)
        return 0

    cutoff = datetime.now(timezone.utc) - timedelta(hours=ttl_hours)
    cutoff_iso = cutoff.isoformat()

    conn = sqlite3.connect(str(db_path))
    conn.execute("PRAGMA foreign_keys = ON")
    try:
        # Delete extractions linked to old messages
        cur = conn.execute("""
            DELETE FROM shadow_extractions
            WHERE shadow_message_id IN (
                SELECT id FROM shadow_messages WHERE timestamp < ?
            )
        """, (cutoff_iso,))
        ext_deleted = cur.rowcount

        # Delete old messages
        cur = conn.execute(
            "DELETE FROM shadow_messages WHERE timestamp < ?",
            (cutoff_iso,)
        )
        msg_deleted = cur.rowcount

        conn.commit()

        # VACUUM to reclaim space
        conn.execute("VACUUM")

        logger.info(
            "Purge complete: %d messages, %d extractions redacted (TTL: %dh). "
            "Cutoff: %s",
            msg_deleted, ext_deleted, ttl_hours, cutoff_iso
        )

        # Append to purge log
        log_path = db_path.parent / "purge.log"
        with open(log_path, "a") as f:
            f.write(
                f"INFO:{datetime.now(timezone.utc).isoformat()}:"
                f"Purge: {msg_deleted} msgs, {ext_deleted} extractions (TTL: {ttl_hours}h)\n"
            )

        return msg_deleted
    finally:
        conn.close()


if __name__ == "__main__":
    purge_old_messages(SHADOW_DB, TTL_HOURS)