from collections.abc import AsyncIterator

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

from app.config import Settings


def create_database(
    settings: Settings,
) -> tuple[AsyncEngine, async_sessionmaker[AsyncSession]]:
    engine = create_async_engine(
        settings.database_url,
        pool_pre_ping=True,
        pool_recycle=1800,
        pool_size=settings.db_pool_size,
        max_overflow=settings.db_max_overflow,
    )
    return engine, async_sessionmaker(engine, expire_on_commit=False)


async def get_session(request: Request) -> AsyncIterator[AsyncSession]:
    session_factory: async_sessionmaker[AsyncSession] = (
        request.app.state.db_session_factory
    )
    async with session_factory() as session:
        yield session