import { ServerlessMysql } from "serverless-mysql";

type QueryObject = {
    query: string;
    values?: (string | number | undefined)[];
};

type Return<ReturnType = any> = ReturnType | null;

/**
 * # Run Query From MySQL Connection
 * @description Run a query from a pre-existing MySQL/Mariadb Connection
 * setup with `serverless-mysql` npm module
 */
export default async function connDbHandler<ReturnType = any>(
    /**
     * ServerlessMySQL Connection Object
     */
    conn: ServerlessMysql,
    /**
     * String Or `QueryObject` Array
     */
    query: QueryObject["query"] | QueryObject[],
    /**
     * Array of Values to Sanitize and Inject
     */
    values?: QueryObject["values"]
): Promise<Return<ReturnType>> {
    try {
        if (typeof query == "string") {
            const res = await conn.query(query, values);
            return JSON.parse(JSON.stringify(res));
        } else if (typeof query == "object") {
            const resArray = [];
            for (let i = 0; i < query.length; i++) {
                const queryObj = query[i];
                const queryObjRes = await conn.query(
                    queryObj.query,
                    queryObj.values
                );
                resArray.push(JSON.parse(JSON.stringify(queryObjRes)));
            }
            return resArray as any;
        } else {
            return null;
        }
    } catch (error) {
        return null;
    } finally {
        conn.end();
    }
}