"""Database session management."""
from collections.abc import Generator

from sqlalchemy import create_engine, event
from sqlalchemy.orm import Session, declarative_base, sessionmaker

from app.core.config import settings

_is_sqlite = "sqlite" in settings.database_url

engine = create_engine(
    settings.database_url,
    connect_args={"check_same_thread": False} if _is_sqlite else {},
)

if _is_sqlite:
    @event.listens_for(engine, "connect")
    def _set_sqlite_pragma(dbapi_connection, connection_record) -> None:
        """Enable WAL mode + a busy timeout so concurrent readers/writers
        don't immediately hit 'database is locked' errors."""
        cursor = dbapi_connection.cursor()
        cursor.execute("PRAGMA journal_mode=WAL")
        cursor.execute("PRAGMA busy_timeout=5000")
        cursor.close()

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()


def get_db() -> Generator[Session, None, None]:
    """Get database session."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()