"""
app/services/status_service.py
Tracks server startup time and agent activity.
"""

from __future__ import annotations

import logging
import sqlite3
from datetime import datetime, timezone
from typing import Optional

from app.config import AGENT_STALE_AFTER_SECONDS
from app.database import get_conn, get_write_conn

logger = logging.getLogger(__name__)

_server_started_at: datetime = datetime.now(timezone.utc)


def server_started_at() -> datetime:
    return _server_started_at


def _now_iso() -> str:
    return datetime.now(timezone.utc).isoformat()


# ---------------------------------------------------------------------------
# Agent activity
# ---------------------------------------------------------------------------

def record_agent_activity(agent_id: str, result_type: str) -> None:
    """Upsert agent activity record on every tool call."""
    now = _now_iso()
    with get_write_conn() as conn:
        conn.execute(
            """
            INSERT INTO agent_activity (agent_id, last_seen_at, last_fetch_at, last_result_type)
            VALUES (?, ?, ?, ?)
            ON CONFLICT(agent_id) DO UPDATE SET
                last_seen_at = excluded.last_seen_at,
                last_fetch_at = excluded.last_fetch_at,
                last_result_type = excluded.last_result_type
            """,
            (agent_id, now, now, result_type),
        )
    logger.debug("Agent activity recorded agent=%s result=%s", agent_id, result_type)


def get_latest_agent_activity() -> Optional[sqlite3.Row]:
    """Return the most recently active agent row, or None."""
    with get_conn() as conn:
        return conn.execute(
            "SELECT * FROM agent_activity ORDER BY last_seen_at DESC LIMIT 1"
        ).fetchone()


def is_agent_connected() -> bool:
    """True if the most recent agent activity is within the stale threshold."""
    row = get_latest_agent_activity()
    if row is None:
        return False
    last_seen = datetime.fromisoformat(row["last_seen_at"])
    now = datetime.now(timezone.utc)
    if last_seen.tzinfo is None:
        last_seen = last_seen.replace(tzinfo=timezone.utc)
    delta = (now - last_seen).total_seconds()
    return delta <= AGENT_STALE_AFTER_SECONDS