from sqlalchemy import create_engine, event, text
from sqlalchemy.orm import sessionmaker, DeclarativeBase
from app.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 _enable_wal_mode(dbapi_connection, connection_record):
        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)


class Base(DeclarativeBase):
    pass


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def create_tables():
    from app.models import client, audit  # noqa: F401
    Base.metadata.create_all(bind=engine)


def check_db_connection() -> bool:
    try:
        with engine.connect() as conn:
            conn.execute(text("SELECT 1"))
        return True
    except Exception:
        return False