from abc import ABC, abstractmethod
from collections.abc import AsyncGenerator


class AIProvider(ABC):
    @abstractmethod
    async def chat(self, messages: list[dict], system_prompt: str) -> str:
        """Send messages and return assistant reply text."""

    @abstractmethod
    async def stream_chat(
        self, messages: list[dict], system_prompt: str
    ) -> AsyncGenerator[str, None]:
        """Stream assistant reply token by token."""

    @abstractmethod
    async def chat_with_extraction(
        self, messages: list[dict], system_prompt: str
    ) -> tuple[str, dict]:
        """Send messages and return (reply_text, extracted_json).

        The provider should request JSON output and parse it.
        Falls back to empty dict if parsing fails.
        """