from dataclasses import dataclass
from typing import Protocol, runtime_checkable


@dataclass(frozen=True)
class SimilarArtist:
    mbid: str
    name: str
    score: float


@runtime_checkable
class SimilaritySource(Protocol):
    name: str

    def health(self) -> bool:
        """Is this source reachable right now?"""
        ...

    def similar_artists(self, mbid: str) -> list[SimilarArtist]:
        """Artists similar to the given artist MBID (MBID-native)."""
        ...