from sqlalchemy import inspect, text

from app.core.database import engine


def run_migrations() -> None:
    """Apply lightweight schema updates for existing databases."""
    inspector = inspect(engine)
    if "students" not in inspector.get_table_names():
        return

    columns = {col["name"] for col in inspector.get_columns("students")}
    if "school_level" not in columns:
        with engine.begin() as conn:
            conn.execute(
                text(
                    "ALTER TABLE students ADD COLUMN school_level VARCHAR(32) "
                    "NOT NULL DEFAULT 'junior_high'"
                )
            )