from collections.abc import AsyncIterator
from functools import lru_cache

from sqlalchemy.ext.asyncio import (
    AsyncEngine,
    AsyncSession,
    async_sessionmaker,
    create_async_engine,
)
from sqlalchemy.orm import DeclarativeBase

from .config import get_settings


class Base(DeclarativeBase):
    pass


def make_engine(database_url: str) -> AsyncEngine:
    return create_async_engine(database_url, pool_pre_ping=True)


@lru_cache
def get_engine() -> AsyncEngine:
    return make_engine(get_settings().database_url)


@lru_cache
def get_sessionmaker() -> async_sessionmaker[AsyncSession]:
    return async_sessionmaker(get_engine(), expire_on_commit=False)


async def session_scope() -> AsyncIterator[AsyncSession]:
    async_session = get_sessionmaker()
    async with async_session() as session:
        yield session