package com.jscape.inet.terminal.commands;

import com.jscape.inet.terminal.Terminal;

/**
 * Move the cursor to the left one character position,
 * unless it is at the left margin, in which case no action occurs.
 */
public class BSCommand
        implements ControlCommand {

    public static final String CANONICAL_FORM = "\010";
    private static final BSCommand INSTANCE = new BSCommand();

    //----------------------------------------------------------------------------

    /**
     * Returns one and only one instance of this type.
     *
     * @return one and only one instance of this type.
     */
    public static BSCommand getInstance() {
        return INSTANCE;
    }

    //----------------------------------------------------------------------------

    /**
     * Private constructor to prevent uncontrolled creation.
     */
    private BSCommand() {
    }

    //----------------------------------------------------------------------------

    /**
     * Executes command giving parameters and <code>Terminal</code> object.
     *
     * @param params   array of <code>int</code> command parametrs.
     * @param terminal target <code>Terminal</code> object.
     */
    public void execute(int[] params, Terminal terminal) {
        terminal.getScreen().getCursor().moveLeft(1);
    }

    //----------------------------------------------------------------------------

    /**
     * Sends command to remote host.
     *
     * @param params   command parameters.
     * @param terminal target <code>Terminal</code> object to send command.
     */
    public void send(int[] params, Terminal terminal) {
        terminal.send(CANONICAL_FORM);
    }

}
