"""Base LLM provider - abstract interface for vision extraction."""

from abc import ABC, abstractmethod

from app.schemas.transaction import TransactionExtractItem


class BaseLLMProvider(ABC):
    """Abstract base for LLM vision providers. Each provider implements extract_from_image."""

    @abstractmethod
    async def extract_from_image(self, image_bytes: bytes) -> list[TransactionExtractItem]:
        """
        Analyze a billing screenshot and return structured transaction list.
        :param image_bytes: Raw image file content (PNG/JPEG)
        :return: List of extracted transactions (may be empty or partial on failure)
        """
        pass