# app/services/slot_snapshot_service.py

from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from redis.asyncio import Redis
from app.models.slot_snapshot import VasSlotSnapshot
from app.schemas.slot_snapshot import SlotSnapshotCreate, SlotSnapshotOut
from app.services.notification_service import NotificationService


class SlotSnapshotService:

    @staticmethod
    async def report(
        db: AsyncSession,
        redis_client: Redis,
        data: SlotSnapshotCreate
    ) -> VasSlotSnapshot:
        rec = VasSlotSnapshot(**data.dict())
        db.add(rec)
        await db.commit()
        await db.refresh(rec) 
        # 修复点在这里：手动将 datetime 对象转为 string
        earliest_date_str = rec.earliest_date.isoformat() if rec.earliest_date else None
        snapshot_at_str = rec.snapshot_at.isoformat() if rec.snapshot_at else None

        await NotificationService.post_wechat(
            redis_client=redis_client,
            template_id="slot_snapshot",
            payload={
                "country": rec.country,
                "city": rec.city,
                "visa_type": rec.visa_type,
                "routing_key": rec.routing_key,
                "availability_status": rec.availability_status,
                # 使用转换后的字符串
                "earliest_date": earliest_date_str,
                "availability": rec.availability,
                "snapshot_source": rec.snapshot_source,
                "snapshot_at": snapshot_at_str
            }
        )
        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)