"""Abstract base class for rate limit storage backends."""

from __future__ import annotations

from abc import ABC, abstractmethod
from typing import Any


class Backend(ABC):
    """Abstract base class for rate limit storage backends."""

    @abstractmethod
    async def get(self, key: str) -> dict[str, Any] | None:
        """Get the current state for a key.

        Args:
            key: The rate limit key.

        Returns:
            The stored state dictionary or None if not found.
        """
        ...

    @abstractmethod
    async def set(self, key: str, value: dict[str, Any], *, ttl: float) -> None:
        """Set the state for a key with TTL.

        Args:
            key: The rate limit key.
            value: The state dictionary to store.
            ttl: Time-to-live in seconds.
        """
        ...

    @abstractmethod
    async def delete(self, key: str) -> None:
        """Delete the state for a key.

        Args:
            key: The rate limit key.
        """
        ...

    @abstractmethod
    async def exists(self, key: str) -> bool:
        """Check if a key exists.

        Args:
            key: The rate limit key.

        Returns:
            True if the key exists, False otherwise.
        """
        ...

    @abstractmethod
    async def increment(self, key: str, amount: int = 1) -> int:
        """Atomically increment a counter.

        Args:
            key: The rate limit key.
            amount: The amount to increment by.

        Returns:
            The new value after incrementing.
        """
        ...

    @abstractmethod
    async def clear(self) -> None:
        """Clear all rate limit data."""
        ...

    @abstractmethod
    async def close(self) -> None:
        """Close the backend connection."""
        pass

    async def __aenter__(self) -> Backend:
        """Async context manager entry."""
        return self

    async def __aexit__(
        self,
        exc_type: type[BaseException] | None,
        exc_val: BaseException | None,
        exc_tb: Any,
    ) -> None:
        """Async context manager exit."""
        await self.close()