from collections.abc import AsyncIterator
from functools import lru_cache

from sqlalchemy import event
from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession, async_sessionmaker, create_async_engine

from app.core.config import get_settings


@lru_cache(maxsize=1)
def create_engine() -> AsyncEngine:
    settings = get_settings()
    engine = create_async_engine(settings.database_url, future=True)

    @event.listens_for(engine.sync_engine, "connect")
    def _set_sqlite_pragma(dbapi_connection, _connection_record) -> None:
        cursor = dbapi_connection.cursor()
        cursor.execute("PRAGMA foreign_keys=ON")
        cursor.close()

    return engine


def create_session_factory() -> async_sessionmaker[AsyncSession]:
    return async_sessionmaker(create_engine(), class_=AsyncSession, expire_on_commit=False)


async def get_db_session() -> AsyncIterator[AsyncSession]:
    session_factory = create_session_factory()
    async with session_factory() as session:
        yield session


async def dispose_engine() -> None:
    engine = create_engine()
    await engine.dispose()
    create_engine.cache_clear()