from __future__ import annotations

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.entities import Backend


class BackendRepository:
    def __init__(self, session: AsyncSession) -> None:
        self.session = session

    async def get_by_name(self, name: str) -> Backend | None:
        result = await self.session.execute(select(Backend).where(Backend.name == name))
        return result.scalar_one_or_none()

    async def get_by_id(self, backend_id: str) -> Backend | None:
        return await self.session.get(Backend, backend_id)

    async def create(self, backend: Backend) -> Backend:
        self.session.add(backend)
        await self.session.flush()
        await self.session.refresh(backend)
        return backend

    async def list_all(self) -> list[Backend]:
        result = await self.session.execute(select(Backend).order_by(Backend.write_priority.desc(), Backend.name.asc()))
        return list(result.scalars().all())

    async def list_enabled(self) -> list[Backend]:
        result = await self.session.execute(
            select(Backend)
            .where(Backend.is_enabled.is_(True))
            .order_by(Backend.write_priority.desc(), Backend.read_priority.desc(), Backend.name.asc())
        )
        return list(result.scalars().all())

    async def save(self, backend: Backend) -> Backend:
        await self.session.flush()
        await self.session.refresh(backend)
        return backend