"""LISTEN/NOTIFY 리스너 — 잡 적재 시 워커를 즉시 깨운다(폴링 낭비 제거)."""

import asyncio

import asyncpg

from config.server_configs import main_db_config
from crud.job_crud import JOB_NOTIFY_CHANNEL


def _dsn() -> str:
    c = main_db_config
    pw = f":{c.write_pw}" if c.write_pw else ""
    return f"postgresql://{c.write_id}{pw}@{c.write_host}:{c.write_port}/{c.name}"


class JobListener:
    """잡 적재 NOTIFY 를 받아 워커를 깨우는 전용 asyncpg LISTEN 연결(SQLAlchemy 풀과 분리)."""

    def __init__(self, channel: str = JOB_NOTIFY_CHANNEL):
        self._channel = channel
        self._conn: asyncpg.Connection | None = None
        self._event = asyncio.Event()

    async def start(self):
        self._conn = await asyncpg.connect(_dsn())
        await self._conn.add_listener(self._channel, self._on_notify)

    def _on_notify(self, *_args):
        self._event.set()

    async def wait(self, timeout: float) -> bool:
        """알림이 오거나 timeout 까지 대기."""
        try:
            await asyncio.wait_for(self._event.wait(), timeout)
            return True
        except asyncio.TimeoutError:
            return False
        finally:
            self._event.clear()

    async def close(self):
        if self._conn is not None:
            await self._conn.close()
            self._conn = None