"""Async engine and session factory."""

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

SessionMaker = async_sessionmaker[AsyncSession]


def make_engine(url: str) -> AsyncEngine:
    if url.startswith("sqlite"):
        # In-memory SQLite lives per connection: share one connection so every session sees the same DB.
        kwargs = (
            {"poolclass": StaticPool, "connect_args": {"check_same_thread": False}}
            if ":memory:" in url or url.endswith("://")
            else {}
        )
        engine = create_async_engine(url, **kwargs)
        event.listen(engine.sync_engine, "connect", _sqlite_foreign_keys)
        return engine
    return create_async_engine(url, pool_pre_ping=True)


def _sqlite_foreign_keys(dbapi_conn: object, _record: object) -> None:
    # SQLite ignores FOREIGN KEY / ON DELETE CASCADE unless asked per connection
    cursor = dbapi_conn.cursor()  # type: ignore[attr-defined]
    cursor.execute("PRAGMA foreign_keys=ON")
    cursor.close()


def make_sessionmaker(engine: AsyncEngine) -> SessionMaker:
    return async_sessionmaker(engine, expire_on_commit=False)


__all__ = ["SessionMaker", "make_engine", "make_sessionmaker"]