package library.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 * The one place that knows how to connect to MySQL).
 *
 * Credentials come from environment variables, never from source code:
 *   DB_URL      
 *   DB_USER
 *   DB_PASSWORD
 */
public final class DB {

    private static final String URL = System.getenv("DB_URL");
    private static final String USER = System.getenv("DB_USER");
    private static final String PASSWORD = System.getenv("DB_PASSWORD");

    private DB() {
    }

    public static Connection getConnection() throws SQLException {
        if (URL == null || USER == null || PASSWORD == null) {
            throw new SQLException("Set DB_URL, DB_USER, and DB_PASSWORD in the environment");
        }
        return DriverManager.getConnection(URL, USER, PASSWORD);
    }
}