from sqlalchemy import create_engine, event
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from config import get_settings

settings = get_settings()

engine = create_engine(
    settings.DATABASE_URL,
    connect_args={"check_same_thread": False},
)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()


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


def create_tables():
    Base.metadata.create_all(bind=engine)


def run_migrations():
    """Apply lightweight schema migrations for SQLite."""
    from sqlalchemy import inspect, text
    insp = inspect(engine)

    # AuditLog: add username column if missing
    if "audit_log" in insp.get_table_names():
        audit_cols = {c["name"] for c in insp.get_columns("audit_log")}
        if "username" not in audit_cols:
            with engine.connect() as conn:
                conn.execute(text("ALTER TABLE audit_log ADD COLUMN username TEXT"))
                conn.commit()