import datetime
from datetime import date
from typing import Optional

from sqlalchemy import extract, select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from database.crud import users
from database.schemas import Birthday, User

__all__ = ["add_birthday", "get_birthday_for_user", "get_birthdays_on_day"]


async def add_birthday(session: AsyncSession, user_id: int, birthday: date):
    """Add a user's birthday into the database

    If already present, overwrites the existing one
    """
    user = await users.get_or_add(session, user_id, options=[selectinload(User.birthday)])

    if user.birthday is not None:
        bd = user.birthday
        await session.refresh(bd)
        bd.birthday = birthday
    else:
        bd = Birthday(user_id=user_id, birthday=birthday)

    session.add(bd)
    await session.commit()


async def get_birthday_for_user(session: AsyncSession, user_id: int) -> Optional[Birthday]:
    """Find a user's birthday"""
    statement = select(Birthday).where(Birthday.user_id == user_id)
    return (await session.execute(statement)).scalar_one_or_none()


async def get_birthdays_on_day(session: AsyncSession, day: datetime.date) -> list[Birthday]:
    """Get all birthdays that happen on a given day"""
    days = extract("day", Birthday.birthday)
    months = extract("month", Birthday.birthday)

    statement = select(Birthday).where((days == day.day) & (months == day.month))
    return list((await session.execute(statement)).scalars().all())