from sqlalchemy import create_engine, event
from sqlalchemy.orm import sessionmaker, DeclarativeBase

from app.config import settings

connect_args = {}
if settings.DATABASE_URL.startswith("sqlite"):
    connect_args["check_same_thread"] = False

engine = create_engine(
    settings.DATABASE_URL,
    connect_args=connect_args,
    pool_pre_ping=True,
)

# Enable WAL mode for SQLite for better concurrent read performance
if settings.DATABASE_URL.startswith("sqlite"):
    @event.listens_for(engine, "connect")
    def set_sqlite_pragma(dbapi_conn, connection_record):
        cursor = dbapi_conn.cursor()
        cursor.execute("PRAGMA journal_mode=WAL")
        cursor.execute("PRAGMA foreign_keys=ON")
        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()