from typing import Sequence
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, delete, update
from ..schemas import UserRead, UserCreate,UserUpdate
from ..models import UserModel



async def get_all_users(
        session: AsyncSession
) -> Sequence[UserModel]:
    stmt = select(UserModel).order_by(UserModel.id)
    result = await session.scalars(stmt)
    return result.all()

async def get_user(
        session: AsyncSession,
        user_id: int
) -> UserModel:
    db_user = await session.get(UserModel, user_id)
    if db_user is None:
        return None
    return db_user

async def create_user(
        session:AsyncSession,
        user_create: UserCreate
) -> UserModel:
    user = UserModel(**user_create.model_dump())
    session.add(user)
    await session.commit()
    return user

async def delete_user(
        session: AsyncSession,
        user_id: int
) -> UserModel:
    db_user = await session.get(UserModel, user_id)
    if db_user is None:
        return None
    stmt = delete(UserModel).filter(UserModel.id == user_id)
    await session.execute(stmt)
    await session.commit()
    return db_user.one_or_none()

async def update_user(
        session:AsyncSession,
        user_id: int,
        user_update: UserUpdate
) -> UserModel:
    db_user = await session.get(UserModel, user_id)
    if db_user is None:
        return None
    for var, value in vars(user_update).items():
        setattr(db_user, var, value) if value else None
    await session.commit()
    await session.refresh(db_user)
    return db_user