"""Abstract interface for visa data providers."""

from abc import ABC, abstractmethod
from typing import List, Optional

from app.models.visa_data import VisaEligibility, VisaGuideline


class VisaDataProvider(ABC):
    """Base class all visa data providers must implement."""

    @abstractmethod
    async def check_eligibility(
        self, nationality: str, destination: str
    ) -> Optional[VisaEligibility]:
        """
        Check visa eligibility for a nationality/destination pair.

        Args:
            nationality: ISO-2 country code of the passport holder.
            destination: ISO-2 country code of the destination.

        Returns:
            VisaEligibility or None if the provider cannot determine it.
        """

    @abstractmethod
    async def get_visa_details(
        self, nationality: str, destination: str
    ) -> List[VisaGuideline]:
        """
        Fetch detailed visa guidelines for a nationality/destination pair.

        Args:
            nationality: ISO-2 country code of the passport holder.
            destination: ISO-2 country code of the destination.

        Returns:
            List of VisaGuideline objects (may be empty if no data found).
        """