from sqlalchemy import inspect, text
from sqlalchemy.engine import Engine


def migrate_schema(engine: Engine) -> None:
    """Apply lightweight schema updates for existing deployments."""
    inspector = inspect(engine)
    if "parse_jobs" not in inspector.get_table_names():
        return

    columns = {col["name"] for col in inspector.get_columns("parse_jobs")}
    statements: list[str] = []

    if "interval_seconds" not in columns:
        statements.append(
            "ALTER TABLE parse_jobs ADD COLUMN interval_seconds INTEGER NOT NULL DEFAULT 3600"
        )
    if "is_active" not in columns:
        statements.append(
            "ALTER TABLE parse_jobs ADD COLUMN is_active BOOLEAN NOT NULL DEFAULT TRUE"
        )

    if not statements:
        return

    with engine.begin() as conn:
        for stmt in statements:
            conn.execute(text(stmt))