webapp/app/services/slot_snapshot_service.py

# app/services/slot_snapshot_service.py

from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.models.slot_snapshot import VasSlotSnapshot
from app.schemas.slot_snapshot import SlotSnapshotCreate


class SlotSnapshotService:

    @staticmethod
    async def create(
        db: AsyncSession,
        data: SlotSnapshotCreate
    ) -> VasSlotSnapshot:
        rec = VasSlotSnapshot(**data.dict())
        db.add(rec)
        await db.commit()
        await db.refresh(rec)
        return rec

    @staticmethod
    async def latest_for(
        db: AsyncSession,
        country: str,
        city: str,
        visa_type: str
    ) -> VasSlotSnapshot:
        stmt = (
            select(VasSlotSnapshot)
            .where(
                VasSlotSnapshot.country == country,
                VasSlotSnapshot.city == city,
                VasSlotSnapshot.visa_type == visa_type,
            )
            .order_by(VasSlotSnapshot.snapshot_at.desc())
            .limit(1)
        )

        return await db.scalar(stmt)