"""ObjectStorage port — 对象存储能力契约。"""

from typing import Protocol, runtime_checkable


@runtime_checkable
class ObjectStorage(Protocol):
    def upload(self, key: str, data: bytes, content_type: str) -> str:
        """Upload object, return its public or base URL."""
        ...

    def get_url(self, key: str, expires: int = 3600) -> str:
        """Generate a presigned download URL."""
        ...

    def delete(self, key: str) -> None:
        """Delete an object by key."""
        ...