"""Async SQLAlchemy engine/session setup."""

from collections.abc import AsyncIterator

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

from gogo.config import get_settings


class Base(DeclarativeBase):
    pass


_engine = None
_sessionmaker: async_sessionmaker[AsyncSession] | None = None


def get_engine():
    global _engine, _sessionmaker
    if _engine is None:
        _engine = create_async_engine(get_settings().database_url, pool_pre_ping=True)
        _sessionmaker = async_sessionmaker(_engine, expire_on_commit=False)
    return _engine


def get_sessionmaker() -> async_sessionmaker[AsyncSession]:
    get_engine()
    assert _sessionmaker is not None
    return _sessionmaker


async def get_session() -> AsyncIterator[AsyncSession]:
    """FastAPI dependency."""
    async with get_sessionmaker()() as session:
        yield session


def reset_engine() -> None:
    """Test helper: force re-creation of the engine (e.g. after settings change)."""
    global _engine, _sessionmaker
    _engine = None
    _sessionmaker = None