from __future__ import annotations

import json
from typing import Any, Optional

from core.settings import REDIS_DEFAULT_TTL, REDIS_ENABLED, REDIS_PREFIX, REDIS_URL

try:
    from redis import Redis
except Exception:  # pragma: no cover
    Redis = None  # type: ignore


class RedisCache:
    def __init__(self, *, prefix_override: Optional[str] = None, default_ttl_override: Optional[int] = None):
        self.prefix = str(prefix_override or REDIS_PREFIX).strip() or REDIS_PREFIX
        self.default_ttl = int(default_ttl_override if default_ttl_override is not None else REDIS_DEFAULT_TTL)
        self.enabled = False
        self.status = "disabled"
        self.status_detail = ""
        self._client: Optional["Redis"] = None
        if not REDIS_ENABLED:
            return
        if not REDIS_URL:
            self.status = "missing_url"
            return
        if Redis is None:
            self.status = "client_unavailable"
            self.status_detail = "redis python package is not installed"
            return
        try:
            self._client = Redis.from_url(REDIS_URL, decode_responses=True)
            self._client.ping()
            self.enabled = True
            self.status = "connected"
        except Exception as exc:
            self.enabled = False
            self._client = None
            self.status = "connection_failed"
            self.status_detail = str(exc or "").strip()[:200]

    def _full_key(self, key: str) -> str:
        return f"{self.prefix}:{key}"

    def ping(self) -> bool:
        if not self.enabled or self._client is None:
            return False
        try:
            return bool(self._client.ping())
        except Exception:
            return False

    def get(self, key: str) -> Optional[str]:
        if not self.enabled or self._client is None:
            return None
        try:
            return self._client.get(self._full_key(key))
        except Exception:
            return None

    def set(self, key: str, value: str, ttl: Optional[int] = None) -> None:
        if not self.enabled or self._client is None:
            return
        try:
            ttl_seconds = int(ttl if ttl is not None else self.default_ttl)
            self._client.setex(self._full_key(key), ttl_seconds, str(value))
        except Exception:
            return

    def get_json(self, key: str) -> Any:
        if not self.enabled or self._client is None:
            return None
        try:
            raw = self.get(key)
            if not raw:
                return None
            return json.loads(raw)
        except Exception:
            return None

    def set_json(self, key: str, value: Any, ttl: Optional[int] = None) -> None:
        if not self.enabled or self._client is None:
            return
        try:
            self.set(key, json.dumps(value, ensure_ascii=False, default=str), ttl=ttl)
        except Exception:
            return

    def sadd(self, key: str, *members: str) -> None:
        if not self.enabled or self._client is None:
            return
        normalized = [str(member or "").strip() for member in members if str(member or "").strip()]
        if not normalized:
            return
        try:
            self._client.sadd(self._full_key(key), *normalized)
        except Exception:
            return

    def srem(self, key: str, *members: str) -> None:
        if not self.enabled or self._client is None:
            return
        normalized = [str(member or "").strip() for member in members if str(member or "").strip()]
        if not normalized:
            return
        try:
            self._client.srem(self._full_key(key), *normalized)
        except Exception:
            return

    def smembers(self, key: str) -> set[str]:
        if not self.enabled or self._client is None:
            return set()
        try:
            rows = self._client.smembers(self._full_key(key))
            return {str(row or "").strip() for row in rows if str(row or "").strip()}
        except Exception:
            return set()

    def expire(self, key: str, ttl: int) -> None:
        if not self.enabled or self._client is None:
            return
        try:
            self._client.expire(self._full_key(key), max(1, int(ttl)))
        except Exception:
            return

    def delete(self, *keys: str) -> None:
        if not self.enabled or self._client is None:
            return
        full_keys = [self._full_key(key) for key in keys if str(key or "").strip()]
        if not full_keys:
            return
        try:
            self._client.delete(*full_keys)
        except Exception:
            return

    def delete_prefix(self, prefix: str) -> None:
        if not self.enabled or self._client is None:
            return
        pattern = self._full_key(f"{prefix}*")
        try:
            cursor = 0
            while True:
                cursor, rows = self._client.scan(cursor=cursor, match=pattern, count=200)
                if rows:
                    self._client.delete(*rows)
                if cursor == 0:
                    break
        except Exception:
            return


cache = RedisCache()
auth_cache = RedisCache(prefix_override=f"{REDIS_PREFIX}_auth")