import json
import logging
import os
from typing import Any

import redis.asyncio as redis

logger = logging.getLogger(__name__)

_redis: redis.Redis | None = None


async def init_cache() -> None:
    """Create Redis connection from environment variables."""
    global _redis
    host = os.environ.get("REDIS_HOST", "localhost")
    port = int(os.environ.get("REDIS_PORT", "6379"))
    db = int(os.environ.get("REDIS_DB", "0"))
    try:
        _redis = redis.Redis(host=host, port=port, db=db, decode_responses=True)
        await _redis.ping()
        logger.info("Redis connected at %s:%d/%d", host, port, db)
    except Exception as e:
        logger.warning("Redis connection failed: %s — running without cache", e)
        _redis = None


async def close_cache() -> None:
    """Close Redis connection."""
    global _redis
    if _redis is not None:
        await _redis.aclose()
        _redis = None


def redis_available() -> bool:
    """Return whether Redis connection is live."""
    return _redis is not None


async def cache_get(key: str) -> Any | None:
    """GET key from Redis, return deserialized value or None on miss/error."""
    if _redis is None:
        return None
    try:
        raw = await _redis.get(key)
        if raw is None:
            return None
        return json.loads(raw)
    except Exception as e:
        logger.warning("Redis GET %s failed: %s", key, e)
        return None


async def cache_set(key: str, value: Any, ttl: int = 120) -> None:
    """SET key in Redis with expiry, silently catches errors."""
    if _redis is None:
        return
    try:
        await _redis.set(key, json.dumps(value), ex=ttl)
    except Exception as e:
        logger.warning("Redis SET %s failed: %s", key, e)