from __future__ import annotations

import time
from dataclasses import dataclass
from typing import Any


@dataclass
class CacheItem:
    value: Any
    expires_at: float | None


class CacheManager:
    def __init__(self, *, default_timeout: int = 300) -> None:
        self.default_timeout = default_timeout
        self._items: dict[str, CacheItem] = {}

    def get(self, key: str) -> Any:
        item = self._items.get(key)
        if item is None:
            return None
        if item.expires_at is not None and item.expires_at < time.time():
            self._items.pop(key, None)
            return None
        return item.value

    def set(self, key: str, value: Any, timeout: int | None = None) -> None:
        timeout = self.default_timeout if timeout is None else timeout
        expires_at = None if timeout <= 0 else time.time() + timeout
        self._items[key] = CacheItem(value=value, expires_at=expires_at)

    def delete(self, key: str) -> None:
        self._items.pop(key, None)

    def clear(self) -> None:
        self._items.clear()