from typing import Protocol


class AIClientError(RuntimeError):
    """Raised when the configured AI provider cannot complete a request."""


class AIClient(Protocol):
    provider: str
    display_name: str

    async def list_models(self) -> list[str]:
        ...

    def normalize_model(self, model: str) -> str:
        ...

    async def chat(
        self,
        model: str,
        messages: list[dict[str, str]],
        json_mode: bool = False,
    ) -> str:
        ...