"""Redis connection management.

Redis is disposable acceleration/coordination — caching, rate limiting,
distributed locks, and the arq job queue. It is never the system of record.
If `REDIS_REQUIRED` is false, the application degrades gracefully (caching
becomes a no-op, readiness does not depend on Redis) instead of failing when
Redis is unavailable.
"""

from __future__ import annotations

from collections.abc import AsyncGenerator
from functools import lru_cache

import redis.asyncio as redis_asyncio
from redis.asyncio import Redis

from app.core.config import get_settings

settings = get_settings()


@lru_cache
def get_redis_pool() -> Redis:
    return redis_asyncio.from_url(
        settings.REDIS_URL,
        encoding="utf-8",
        decode_responses=True,
        socket_connect_timeout=2,
        socket_timeout=2,
    )


async def get_redis() -> AsyncGenerator[Redis, None]:
    """FastAPI dependency yielding the shared Redis client."""

    yield get_redis_pool()


async def redis_is_ready() -> bool:
    try:
        client = get_redis_pool()
        return bool(await client.ping())
    except Exception:
        return False


async def close_redis() -> None:
    client = get_redis_pool()
    await client.aclose()  # type: ignore[attr-defined]  # present at runtime; stubs lag redis-py 5.x