from collections.abc import AsyncIterator
from functools import lru_cache

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

from app.core.config import get_settings


@lru_cache
def get_engine() -> AsyncEngine:
    settings = get_settings()
    return create_async_engine(
        settings.database_url,
        echo=settings.debug,
        pool_pre_ping=True,
        pool_size=settings.database_pool_size,
        max_overflow=settings.database_max_overflow,
    )


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


async def get_session() -> AsyncIterator[AsyncSession]:
    async with get_session_factory()() as session:
        yield session