"""
경보 발송 — CRITICAL/HIGH 이벤트에 대해 prediction_alerts INSERT.

현재는 DASHBOARD 채널만 기록 (실제 SMS/EMAIL은 향후 연동).
"""
import logging
from datetime import datetime, timezone

from psycopg2.extras import execute_values

from config import qualified_table
from db.kcgdb import get_conn

logger = logging.getLogger(__name__)

ALERTS_TABLE = qualified_table('prediction_alerts')
EVENTS_TABLE = qualified_table('prediction_events')

# CRITICAL/HIGH 이벤트만 알림 대상
ALERT_LEVELS = ('CRITICAL', 'HIGH')


def run_alert_dispatcher() -> dict:
    """
    아직 알림이 없는 CRITICAL/HIGH 이벤트에 대해 알림 생성.

    Returns:
        { 'dispatched': int }
    """
    now = datetime.now(timezone.utc)
    dispatched = 0

    with get_conn() as conn:
        cur = conn.cursor()

        # 알림이 아직 없는 CRITICAL/HIGH 이벤트 조회
        cur.execute(
            f"""SELECT e.id, e.ai_confidence
                FROM {EVENTS_TABLE} e
                LEFT JOIN {ALERTS_TABLE} a ON a.event_id = e.id
                WHERE e.level IN %s AND a.id IS NULL
                ORDER BY e.occurred_at DESC
                LIMIT 100""",
            (ALERT_LEVELS,)
        )
        rows = cur.fetchall()

        if rows:
            alerts = [
                (event_id, 'DASHBOARD', None, now, 'SENT', confidence)
                for event_id, confidence in rows
            ]
            execute_values(
                cur,
                f"""INSERT INTO {ALERTS_TABLE}
                    (event_id, channel, recipient, sent_at, delivery_status, ai_confidence)
                    VALUES %s""",
                alerts,
            )
            conn.commit()
            dispatched = len(alerts)

    logger.info(f'alert_dispatcher: dispatched={dispatched}')
    return {'dispatched': dispatched}