"""草稿服务（Redis 存储，零迁移）"""

import redis.asyncio as aioredis
from app.config import settings


class DraftService:
    def __init__(self):
        self._redis = None

    async def _get_redis(self):
        if self._redis is None:
            self._redis = aioredis.from_url(settings.REDIS_URL, decode_responses=True)
        return self._redis

    async def get(self, user_id: str, conv_id: str) -> str:
        r = await self._get_redis()
        return await r.get(f"draft:{user_id}:{conv_id}") or ""

    async def set(self, user_id: str, conv_id: str, text: str):
        r = await self._get_redis()
        key = f"draft:{user_id}:{conv_id}"
        if text:
            await r.set(key, text, ex=30 * 86400)  # 30 天 TTL
        else:
            await r.delete(key)