import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class SysRun {
    public static void main(String[] args) {
        if (args.length != 6) {
            System.err.println("Usage: java SysRun server port user password database timeout");
            return;
        }
        Connection connection = null;
        int timeout = Integer.parseInt(args[5]);
        try {
            // Load the JDBC driver
            String driverName = "oracle.jdbc.driver.OracleDriver";
            Class.forName(driverName);

            // Create a connection to the database
            String serverName = args[0]; //"127.0.0.1";
            String portNumber = args[1]; //"1521";
            String sid = args[4]; //"mydatabase";
            String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
            String username = args[2]; //"username";
            String password = args[3]; //"password";
            connection = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException e) {
            // Could not find the database driver
            System.err.println("Couldn't find a driver for Oracle. Forgot to add the jar to the classpath?");
            return;
        } catch (SQLException e) {
            // Could not connect to the database
            System.err.println("Couldn't connect to the database. Wrong credentials?");
            return;
        }
        while (true) {
            try {
                Statement stmt = connection.createStatement();
                ResultSet rs = stmt.executeQuery("SELECT * FROM (SELECT sh_command, done, id FROM md_shell WHERE done IS NULL ORDER BY id) WHERE ROWNUM=1");
                String id = null;
                if (rs.next()) {
                    String command = rs.getString(1);
                    Process p;
                    try {
                        p = Runtime.getRuntime().exec(command);
                        p.waitFor();
                    } catch (IOException e) {
                        e.printStackTrace();
                        System.err.println("Error while executing \"" + command + "\"");
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                        System.err.println("The command \"" + command + "\" has been interrupted.");
                    }
                    id = rs.getString(3);
                }
                if (null != id) {
                    stmt.execute("UPDATE md_shell SET done=1 WHERE id=" + id);
                    connection.commit();
                }
                else {
                    try {
                        Thread.sleep(timeout * 1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                        // but not of interest here
                    }
                }
            } catch (SQLException e) {
                e.printStackTrace();
                System.err.println("Error creating a connection statement or executing an SQL update/query.");
            }
        }
    }
}