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

from models.library import Subject


async def get_subject_by_name(db: AsyncSession, subject: str) -> int:
    stmt = select(Subject).where(Subject.name == subject)
    subject = (await db.execute(stmt)).scalar_one_or_none()
    if not subject:
        raise ValueError("Subject not found")

    return subject.id