"""生成偏好数据访问（模型网关 §4.3）。

本地单用户单行，按 owner_scope 固定；无则由 service 层返回默认值。
"""

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

from app.models.governance import GenerationPreferences


async def get_preferences(session: AsyncSession, owner_scope: str) -> GenerationPreferences | None:
    result = await session.execute(
        select(GenerationPreferences).where(GenerationPreferences.owner_scope == owner_scope)
    )
    return result.scalars().first()


async def add_preferences(
    session: AsyncSession, prefs: GenerationPreferences
) -> GenerationPreferences:
    session.add(prefs)
    await session.flush()
    return prefs